I HAVE ALWAYS admired racing aircraft of the so-called “Golden Age
of Aviation”: an era that extended from the end of World War I to the
onset of World War II. It was the time of rakish designs, open cockpits,
and “flying by the seat of one’s pants.”
Aircraft designs of the time were largely grand
experiments, and from those experiments
emerged the Granville Brothers’ Gee Bee series,
the Hughes H-1 racer, the Travel Air Mystery Ship,
the Hall Bulldog, and the rest of the list, which is too
numerous to include here.
I was weary of going to our flying field and finding almost
nothing between ARF training models, sticks, and the usual bunch of 3-D
ARFs. I realized that if I wanted something with a style I liked, I’d
have to build my own.
Accordingly, I made a couple pencil sketches, loaded
ModelCAD 3000 into my PC, and sat down at my electronic
drawing board to play. The Golden Era 60 is the result.
Although this airplane is conventional in its construction, it is
unsuitable for a first scratch-building project. This article assumes
that the builder has some experience beyond ARF assembly and is
familiar with common building techniques.
Unless you get the laser-cut “short kit” I’ll tell you about, you shouldn’t attempt this build without a scroll saw
or band saw, a Dremel or other rotary tool, and the usual collection of hand tools. The judicious use of a square and
straightedge is necessary throughout construction if you expect to manufacture a straight, easy-to-trim aircraft.
If the previous paragraphs haven’t discouraged you, we can proceed.
18 MODEL AVIATION
BY FRED RANDALL
A Williams Brothers Sportsman pilot bust complements the
open cockpit. Enamel brush paint can be spray-fixed with a
fuelproof clear coat.
Grooving through the open sky, the Golden Era 60 handles as
the popular Stick models do but has the looks of a 1930s
racer.
The grunt of a .60-size engine adds thrills
to this pioneer-reminiscent building project
05sig1.QXD 3/25/08 10:33 AM Page 18
Materials: Creative Hobbies of Mendon, Massachusetts, sells a short
kit of laser-cut 1/8 light plywood, 1/4 plywood, and 3/8 balsa parts at a
reasonable cost. These accurate precut components and a full-size
rolled plans set from MA will greatly simplify construction. It
eliminates tedium, and what remains is the equivalent of building a
good kit.
Regardless of whether or not you purchase the short kit, I suggest
that you have all fabricated parts (wing ribs, fuselage formers, etc.) on
hand before starting the build.
The landing gear and wheel pants on the original are Four-Star 120
parts ordered from Sig Manufacturing. I suggest that builders use the
same parts since they are a good match appearancewise, they fit the
gear mounting plates designed into the fuselage, and using other units
may significantly change the balance point. But if you prefer to
fabricate your own landing gear, have at it!
I did not design this airplane to be superlight since it is not
intended for “3-D.” It has an allup
weight of approximately
9 pounds and a wing
loading of roughly 26
ounces per square foot.
However, it is extremely
strong. This model is
extensively planked,
including wing
May 2008 19
After a full-power run of roughly 50 feet, the model lifts off smoothly.
The wide-track gear absorbs many of the bumps in the grass.
The former positions have been marked on the fuselage sides,
and the firewall assembly has been epoxied in place.
capstrips, and composite tubing is used for the LE and the main spar.
CONSTRUCTION
Fuselage: Although I usually begin with the wings, the fuselage was
my starting point for this project.
The first task was selecting the 1/8 balsa for the fuselage sides. The
importance of matching the side sheets’ hardness and grain cannot be
stressed enough. If the balsa is poorly matched, it will be next to
impossible to make a straight fuselage.
The fuselage sides’ maximum height is approximately 7 inches. I
used matched 4-inch-wide, 1/8 balsa sheets. Cement them together with
cyanoacrylate before cutting them to shape. (In the remainder of this
document, cyanoacrylate means medium cyanoacrylate unless
otherwise specified.)
After you have cut the balsa sides to shape, use cyanoacrylate to
glue the 1/8 plywood fuselage doublers in place. Be careful; it is easier
than you can imagine to end up with two right or two left sides.
Adhere, with cyanoacrylate, the doubler to the bottom of former F1.
After the fuselage doublers have set, epoxy and clamp the two
landing-gear (LG) and hatch-support rails to the fuselage doublers.
Refer to the plans for position. Make sure to wipe off any excess epoxy
from around the perimeter with alcohol.
Epoxy the 1/8 plywood firewall doubler to the 1/4 plywood firewall.
(Epoxy means 30-minute epoxy unless otherwise specified.)
Lay the fuselage plans on your building board, protecting them with
waxed paper or the like. With the plans as a guide, use a square
referenced to the top of the fuselage sides to mark the position of all
formers on the inside of both fuselage sides.
05sig1.QXD 3/25/08 10:44 AM Page 19
20 MODEL AVIATION
Formers F1 and F2 have been put in place, and the servo plate has
been mounted between them.
With the fuselage wide open, it’s a good time to fit the fuel tank.
Silicone sealant will be used to mount the tank permanently.
The left side has been epoxied in place after a careful alignment
check. Notice how the rear wing mount is locked into cutouts in
the doubler.
Bevel the tail post and then glue it in place. Dry-fit the fin and the
remaining formers to assure good alignment.
The tail-wheel mount area is supported by a 1/8 plywood plate.
It’s recessed to allow room for balsa, which will be sanded flush
with the fuselage sides.
Scrap 3/8 balsa sheet is substituted for the stabilizer during
preliminary alignment. The forward stringers are added at
this point.
05sig1.QXD 3/25/08 11:26 AM Page 20
May 2008 21
Once the sheeting is complete, it’s a good time to test-fit the
landing gear and engine mount. The cockpit area can be detailed
at this time.
Notice the smart use of carbon-fiber tubing to form the LE and
support the wing spar. The wing will be sheeted next.
Above: The completed one-piece wing is mounted with dowel pins
and nylon bolts. The light tail structure is designed to keep the
weight mass balanced on the recommended CG.
Left: Build the cowl from wood or purchase the fiberglass
version from Fiberglass Specialties. The mounting screws are
hidden inside.
Type: RC sport
Pilot skill level:
Intermediate to expert
Wingspan: 65.25 inches
Flying weight: 10 pounds
Wing area: 792 square inches
Wing loading: 26-27 ounces/square foot
Length: 51 inches
Engine: GMS .61 glow
Tank: Modeltech 360cc
Flight battery: Four cells, 4.8 volts
Radio: Spektrum DX7 system, AR7000 receiver, three DS821
and two Hitec HS-625MG servos
Spinner: Du-Bro (LXE 149) 3 inch
Construction: Balsa and light plywood
Covering/finish: Builder’s choice (Sig AeroKote is recommended.)
Photos by the author
05sig1.QXD 3/25/08 10:58 AM Page 21
22 MODEL AVIATION
The GMS .61 two-stroke engine hides inside the spacious cowl. A
four-stroke .82-1.00 would also fit this model neatly.
Stock Sig Four-Star 120 wheel pants complete this sport model’s 1930s racing look. The long and tall fuselage offers good knifeedge
performance.
Put the right fuselage side in place on the plans and secure it. Using
a square to position it, epoxy the firewall/doubler assembly flush with
the front of the fuselage side. When it has set, Formers F1 and F2 can
be cemented in place using cyanoacrylate. Position the servo tray in the
slots provided in formers F1 and F2, and secure it with cyanoacrylate.
Fashion the 11/2 x 47/16-inch rear wing anchor plate from 1/4
plywood. Do not drill it. Temporarily insert it into the slot provided in
the fuselage doubler. Test-fit the left side for perfect alignment. The
firewall assembly, the formers, the wing anchor plate, and both
fuselage sides must align properly.
When you are satisfied, remove the left side and apply epoxy to the
edge of the firewall assembly and the wing anchor plate edges that
mate with F2 and the fuselage sides. Apply cyanoacrylate to the mating
edges of F1 and F2. Put the left side back in position.
Place a book or similar weight on top to ensure a good bond, and
then take a break.
Shape the tail post from 1/2 x 3/4 x 13-inch balsa. It should taper
from 1/2 inch at the LE to 3/16 inch at the TE. It is important that this
piece be symmetrical. It will be further shaped and cut for the stabilizer
later, during fuselage assembly.
Notch the front roughly 1/8 inch deep to accept the light-plywood
fin. Refer to the plans for notch location.
With the fuselage secured to the top view of the plans, use T-pins to
temporarily hold the rear of the fuselage sides together, sandwiching
the tail post into position. The tail post should be centered over the
plans and flush with the bottom and back of the fuselage sides. Ensure
that the tail post is vertical in both axes when referenced to the fuselage
sides.
Reposition the pins until these conditions are met. Temporarily tack
the assembly together using a few drops of thin cyanoacrylate.
Remove the T-pins and recheck alignment. When you are satisfied,
flow in more thin cyanoacrylate for a permanent bond.
Install the remaining formers using cyanoacrylate. If necessary, use
rubber bands around the fuselage to ensure a full-contact fit.
Employing the plywood fin as a pattern, make doublers
approximately 3/8 inch wide from 3/16 balsa sheet. The doublers enable
a smooth transition between the planking and the fin. There is a
detailed drawing on the fuselage plans.
Cement the balsa doublers to both sides of the fin with
cyanoacrylate. Cut 1/8-inch gaps in the doubler where the fin fits into
05sig1.QXD 3/25/08 10:06 AM Page 22
the F5 and F6 notches and another at the rear
of the fin where it will be inserted into the
tail-post notch. Install the fin and secure it
with cyanoacrylate, and then sand the top of
the tail post to blend with the fin and doublers.
Cut the cockpit floor from 1/8 balsa sheet.
See the fuselage top view for the pattern.
Using cyanoacrylate, install the floor as
indicated and test-fit the dash panel. The dashpanel
pattern is somewhat oversize; you must
sand it to mount flush with the cockpit floor
and F3. Use a long sanding block to blend the
panel with the fuselage.
Install former F8. Fit it between F6 and the
tail post. See the plans for location. Trim it as
necessary for a proper fit. Ensure that F8 is at
right angles to, and level with, the top of the
notch in the fuselage sides. Take your time;
this establishes proper alignment and angle of
incidence.
I found it helpful to cut a piece of 3/8 balsa
sheet 3 inches wide and 12-15 inches long to
use as a spacer and alignment aid. Lay it on
top of F8 to use as a temporary substitute for
the stabilizer.
Position F7 as indicated on the plans, and
snug it against the temporary spacer. Adhere
F7 in place with cyanoacrylate and remove
the spacer. Trim F7 as necessary for a proper
fit.
Install the stringers using cyanoacrylate.
The front stringers extend aft to the panel.
There are no notches in the panel, so shape
the ends of the stringers for a nice butt fit
26 MODEL AVIATION
INTRODUCING
• Safe chemistry will not explode or catch fire
• Fast charge capable – 100% in 15 minutes
• 30c continuous, 60c bursts
• Exclusive Duralite Stay Balance Circuitry built-in
to every pack – no external balancing needed
• Charge through the charge lead with a Duralite Plus
Charger or through the power lead with an A123 capable
charger like the Orbit Pocketlader
• No regulator needed for most Rx applications
• Longer life cycle than lithium polymer chemistry
LITHIUM POWER SOLUTIONS FOR EVERYTHING YOU FLY
Order toll free 877-744-3685
Shop online www.duraliteflightsystems.com
PLUS
WITH STAY BALANCE
CIRCUITRY BUILT-IN
TO EVERY PACK
against it. The rear stringers should terminate
flush with the front of the tail post.
Epoxy four 1/4-20 captive nuts to the inner
LG mounting plate. Remove your fuselage
assembly from the building board, flip it over,
and use epoxy to bond the inner LG mounting
plate to the support rails. Don’t spare the
epoxy here; the LG takes considerable abuse
(at least when I’m flying).
The battery hatch came about because the
finished model needed a bit of nose weight. I
don’t like to add lead for balance when I can
reposition something to compensate. I
relocated the flight battery forward, in a foam
nest made for perfect balance with no
additional ballast. As a bonus, you have access
to the LG support assembly, engine-mount
captive nuts, and fuel tank should something
go awry.
Fashion the battery hatch from a piece of
1/8 light plywood. It should fit nicely between
the firewall, the fuselage sides, and the LG
mounting plate. It should rest on the support
rails. Drill holes at four corners for your
selected screw hardware.
I band-sawed a small amount of
downthrust and right thrust into my engine
mounts before installation. Offset the mounts
so that the spinner will be centered at the
proper location. When positioned, drill the
firewall and install the captive nuts.
Empennage: Building this area is
straightforward, and little explanation is
necessary beyond what is on the plans. The
only item that may need clarification is the
elevator joiner.
I originally intended to use a double
pushrod for elevator control. However, I had a
nice piece of .317 composite tubing left from
the wing construction, and it seemed
reasonable to use as a torque tube to join the
elevator halves. If you prefer double pushrods,
eliminate the torque tube and the clearance
notch in the rudder.
Wings: Select the right-wing full plans and
secure them to your building board. Using
cyanoacrylate, bond an RR1 rib to an RR2.
RR1 should be inboard. This assembly forms
the root rib.
Bond an R3 to an R1. The rib with no LE
notch is an R3; it should be inboard. Refer to
the plans for confirmation.
The wing will be built using the centermost
bottom spar as a reference. Cut a piece of 1/8 x
1/4 basswood to length and secure it in place
on the plans. Use a square to position the root
rib assembly on the plans with the spar snug in
its notch. Use cyanoacrylate to adhere the root
rib assembly to the spar.
Follow suit with an R1, R2 pair. Install the
remaining ribs, and adhere them to the spar
with cyanoacrylate. All ribs’ break-off stubs
should lay flat on the plans.
R2 is slightly different; it establishes a
small amount of washout in the wingtips to
improve low-speed stability. When all ribs are
in place, cut and install the three top spars. Cut
the .317-inch composite LE to length and glue
it in place with cyanoacrylate.
You should be able to insert the composite
spar as far as shown on the plans. Test-fit it. It
05sig1.QXD 3/25/08 10:09 AM Page 26
should be snug but not distort the ribs as it
passes through. Make any adjustments needed
until this condition is met, and then remove
the spar.
Remove the wing from the plans. Install
the remaining bottom spars, and then check
the assembly for straightness. It should lay
flat, resting on the centermost bottom spar and
rib break-off stubs. Correct any twist in the
wing before proceeding.
Following the diagram below the right
wing assembly drawing, shape the TE from 1/2
x 3/8 balsa. When you are finished, glue it into
position with cyanoacrylate.
Temporarily position the 1/8 light-plywood
servo plate to the bottom of the wing. Make
sure to place it at a point that is deep enough
on the chord to ensure that a standard servo’s
body does not protrude through the top. (Ask
me why I added this instruction.)
When you are satisfied with its position,
adhere the servo plate in place with
cyanoacrylate, flush with the bottom of the
ribs. Use scrap 1/8 x 1/4 spar material to make
rails to support and stiffen it.
Use cyanoacrylate to glue the 1/8 lightplywood
wingtip in place. It should be
centered between the LE and TE and at right
angles to R2. Make spar extensions and
cement them between the rib and the tip. See
the plans for positioning. Snap off the rib
stubs and sand the areas smooth.
Remove the right wing plans from the
building board and replace them with the left.
28 MODEL AVIATION
(We don’t want two right wings, do we?)
Take a deep breath and repeat the wing
instructions.
Having completed the framing of both
wings, fabricate and add the 1/4-inch plywood
dowel support webbing and the wing
mounting dowels. Ensure that the pegs will
align with the holes in F1. The detail diagram
will aid in drilling the peg holes and installing
the pegs.
Cut the .505 composite-tubing spar to
length and test-fit the joined wings. Be sure to
allow for the 1/16-inch planking. This work is
critical; it affects the final wing leveling and
wing/stabilizer angle of incidence. If the wing
is too wide, it does no harm to remove some
material from the TE where it fits within the
fuselage.
Wing Planking: The LE planking is a 1/16 x
12 x 36 balsa “wing skin.” The plans indicate
the areas that are covered with planking. Do
not trim the width until it is installed.
Thoroughly soak the balsa with Windex and
wait several minutes before attempting to
make the sharp LE bend.
When the balsa is pliable enough to make
the bend, start at the top, rear 1/8 x 1/4 spar.
Use cyanoacrylate to bond the balsa to the
spar. Clamp it along its length until the
adhesive sets.
Work slowly. Starting at the middle of the
wing and moving outward, glue, with
cyanoacrylate, the ribs, front spar, LE, etc.,
until you have the entire wing skin bonded,
top and bottom. If you do the job properly,
the planking should be tight, with no bulges.
Trim whatever planking extends beyond the
center, bottom spar.
Install the remaining planking and the rib
capstrips. It’s better to plank the entire
wingtip on both sides; it makes the covering
job easier and neater. When you have
finished both wings, prepare them to accept
covering.
Fuselage Planking: Starting with the front
deck, plank the fuselage with 3/32 sheet balsa.
I made a cardboard pattern and used it as a
guide to cut the planking for the forward
“hood,” from the firewall to F3. Soak the
planking for installation. After test-fitting, use
cyanoacrylate to install it.
Make the 3/32 balsa planking for the area
aft of the cockpit. Use a single piece to cover
from F5 to the tail post and up to the 1/8-inch
top stringer on each side. This piece should
cover the tail post and terminate at the back
of the fuselage. The bend is fairly gentle and
should pose little problem. When you are
satisfied with the fit, glue the planking in
place with cyanoacrylate. Shape and add the
pieces that go between the top stringer and
the fin doublers.
When the cyanoacrylate has set, use a
sanding block to shape the back of the tail
post so it is flat. Blend the planking into the
fin doubler and the fuselage sides.
Cut two pieces of 3/8 balsa stock 11/4
inches wide and 83/8 inches long. These fit
between F5 and the instrument panel. Shape
the fronts to fit flush with the panel. Position
them so they are 3/32 inch inboard of the
05sig1.QXD 3/25/08 10:09 AM Page 28
fuselage sides, and adhere them in place with
cyanoacrylate.
Sand both sides so they follow the contour
of the panel and F5. These provide support for
the planking around the cockpit. See photos
for clarification.
Shape and fit the planking around the
cockpit. When you are satisfied, sand
everything flush. Use balsa filler to fill any
gaps, and finish-sand the entire fuselage
smooth and even. Cut—but do not install—
the 3/32-inch bottom piece. With the fuselage
planking complete, cut the tail post for the
stabilizer. This marks the end of the planking
phase.
Ailerons: These are cut from 3/8 x 3 tapered
balsa. See the wing plans for patterns.
Before shaping the aileron LE, use
cyanoacrylate to laminate a matching piece of
1/16 hard balsa to the top to strengthen the
structure. Temporarily attach the ailerons to
the wing with a few small spots of
cyanoacrylate, and then block-sand the bottom
of the ailerons to blend with the wing TE.
Remove the ailerons using debonder, and
sand the LEs for hinging.
Pushrods, Etc.: Install the pushrod tubes.
Holes are provided in F4 to support the front
of the pushrod tubes. I crossed mine in the
middle and they exited the fuselage on the
opposite side. I used a small cable tie at the
crossover point to support and stiffen the
tubes. Once the pushrod tubes are installed,
use cyanoacrylate to glue the bottom piece in
place. Sand the joint smooth.
A 360cc tank (Global Hobby part 120074)
I had on hand was employed in the original. I
used silicone adhesive to bond the front of the
fuel tank to the inside of the firewall, with the
neck protruding through the provided hole. I
Dremeled the bottom of the hole in F1 to
match the contour of the rear of the tank (see
dotted line on F1 pattern) and used silicon
adhesive there too.
Drill a hole in the firewall and F1 for the
throttle pushrod, positioned to make a straight
run from the carburetor to the throttle servo.
The fuselage servo linkages are typical. Use
your favorite clevises, etc. The wing servos
and linkages are installed after covering.
There are large openings in the ribs that
provide passage for the wires from the servos.
Make small openings in the planking inboard,
on the top of the wing, for the servo wires to
exit.
Insert the .505 composite wing spar in one
(either) wing up to the rib just past the servo
and glue it in place inside the root rib (only)
with cyanoacrylate.
It is unnecessary to cement the wing halves
together. It is much easier to store and
transport them separately. The mounting pegs
and nylon bolts will align and secure the wings
to the fuselage, and the spar is more than
strong enough to prevent them from folding.
Cowl: For the original model I made my cowl
from laminations of 3/8 balsa. Several good
articles have been written about the subject.
I also made a balsa cowl for a second
airplane, and I sent it out for Fiberglass
Specialties to duplicate in fiberglass. These
cowls are available for purchase if you don’t
want to expend the effort to fabricate your
own. Either way, the weight difference is
slight so the balance remains unchanged.
Covering: It seems like everyone has a
favorite covering material; I am no different. I
prefer Sig AeroKote, which I used on the
entire aircraft.
I don’t care for the elaborate, multicolor
schemes festooned with sponsor logos that are
rampant on ARFs. Thus Brodak’s CL Oriental
was the inspiration for the color scheme I used
on the original Golden Era 60. The Oriental is
black and red; I opted for Black and Naval
Orange.
If you use black on the fuselage, throw a
white cloth over it if the model is going to sit
in the sun for a long period. The black
covering absorbs heat and loosens, and you
will be faced with a session with the iron and
heat gun when you get home.
Nuts and Bolts: I used Du-Bro heavy-duty
.40-.91 control horns (item 867) throughout.
They require a single hole for mounting and are
rugged and easy to install. A bonus is that they
adjust for angle as well as throw. I installed a
steerable tail-wheel assembly from Global
Hobby. It mounts easily and works well.
My Spektrum DX7 came with four JR
RC System is distributed by:
SIG Manufacturing Company, Inc.
P.O. Box 520 • Montezuma, Iowa 50171-0520
Web Site: www.sigmfg.com • Phone: (641)623-5154
* actual Flightsimulator screens shown
There are different ways to learn model flying. If an
experienced model flyer is not on site then the first steps can
be disappointing. At worst case you could crash your first
model. Especially for learning R/C helicopter flying the so
called "Dry Run" on a simulator is an inexpensive and
suggested method. The SimTransmitter
"Joystick" in combination with the FMS
Flightsimulator provides the ideal virtual
beginner airplane or helicopter "model".
Simply plug the SimTransmitter into a free USB
port and configure it as a joystick.
SimTransmitter
Order No. RCSSIM062 - $39.99
* Prices at Participating Dealers
*
05sig1.QXD 3/25/08 10:09 AM Page 31
servos. Three are used in the fuselage, and
Hitec HD servos are used for the ailerons.
The Spektrum dual receivers are mounted
on opposite fuselage sides using Velcro. They
are oriented to provide opposite antenna
polarity, as the installation instructions
mandate. Not having to provide routing and
an exit for a long 72 MHz antenna is a
pleasant change!
The double 1/4-inch plate used to mount
the LG is a work-around because of a
clearance issue. The wing extends forward
from the mounting recess and engages the LG
if additional clearance isn’t provided. I didn’t
realize this until too late, and the second plate
proved to be a quick, effective remedy.
I cut the windshield from a plastic cake
container my supermarket provided free of
charge. Ask for one. If they refuse, you can
buy a cake and eat it!
The seat and headrest are carved from
balsa block and brushed with one coat of
Insignia Orange Aero Gloss. It imparts an
almost suedelike appearance. “Leo,” the pilot,
had to have his shoulders trimmed to fit in the
narrow cockpit. I repainted him with my
wife’s acrylics to match the model.
(References to “Leo” stem from the pilot
figure’s uncanny resemblance to a friend and
fellow RCer, Leo Desmarais.)
Hinging: I used cyanoacrylate hinges
throughout, but regardless of the type you
should have at least two on each elevator half,
three on the rudder, and four—equidistant—
along each aileron. Mounting procedures vary,
depending on the type chosen, and hingeinstallation
instruction is beyond the scope of
this article.
No matter what type of hinge you use,
make sure the movable surfaces fit closely to
the fixed surfaces. Gaps give birth to control
flutter, which can end an otherwise perfect
flying day.
Assembly: Since this is probably not your
first scratch build, I’ll be brief. There is
nothing unusual about the model and
assembly is straightforward
Assuming that the covering job is finished
and the elevator is hinged, insert the stabilizer
into its slot. Make sure it’s straight using a
string from the nose to the elevator tips. Mark
the stabilizer where it joins the fuselage, top
and bottom.
Remove the stabilizer and then remove the
covering that will be within the slot.
Permanently adhere the stabilizer, with
cyanoacrylate or epoxy, and hook up the
control hardware.
Drill the LG to accept the 1/4-20 nylon
mounting bolts. If the wheel pants haven’t
been assembled and painted and the wheels
haven’t been mounted, you haven’t been
reading far enough ahead!
Assemble the wings and fit them to the
fuselage. With the wings seated, carefully drill
9/32-inch holes through the centers of the wing
reinforcement pads into the rear wing
mounting plate.
Remove the wing and then further drill the
mounting plate to accept the captive 1/4-20
nuts. Epoxy them in place on the backside.
When they are set, reinstall the wing and
insert the 1/4-20 nylon bolts. Screw them into
the mounting plate slightly more than finger
tight.
Check the wing-to-stabilizer angle of
incidence using your favorite method; I use a
Great Planes laser setup. If your build is
accurate, it should be 0°-.5°. If it isn’t, make it
so. You can correct it several degrees either
way by removing or adding material to the
rear part of the wing saddle.
Balancing and Flying: I suggest a slightly
nose-heavy configuration for the first flights.
The balance point should fall one-third back
from the LE, or approximately where the LE
planking ends. Being an RC novice, I have
left the balance point there. If you’re more
experienced, you may find that a slightly more
aft point allows for better aerobatics.
This airplane has a thin symmetrical wing,
a somewhat short tail-moment arm, and high
wing loading; therefore, it flies like a
warbird—fast and without self-righting
properties. I programmed flaperons to help
during landings. Keep power on during
approach. As does a warbird, the Golden Era
likes to come in under power.
The large control surfaces beg dual rate
and exponential programming. This will allow
the experienced pilot to burn holes in the sky
while the less confident can fly it around
without working up a sweat.
The deep fuselage makes for easy knife
edge, and the slight wingtip washout and
aileron configuration help to keep it from
falling out of the sky at relatively low speeds.
This is not a good design for a first lowwing
sport airplane. It is satisfying for the
intermediate pilot and will draw attention at
the club field.
Electric Dreams: I gave little consideration to
making this aircraft light beyond what was
necessary for good 60-power performance. It
came in at slightly more than 9 pounds dry.
An electric conversion could include fewer
doublers, thinner and less planking, more
lightening holes, and a lighter LG assembly.
Several pounds could probably be shaved off
easily, making the wing loading nearer to a
more acceptable 20 ounces per square foot.
Being an old FF Gas aficionado, I revel in
the smell of nitro fuel in the morning, and the
postflight cleanup is akin to a labor of love.
I’ll leave it to you wattage mavens to do the
converting, but I’d love to see the results! MA
Fred Randall
[email protected]
Sources:
Short kit (1/8 light-plywood parts, 1/4 plywood
parts, 3/8 balsa rudder and elevator parts):
Creative Hobbies
(508) 473-8259
www.creativehobbies.net
Balsa, plywood stock:
National Balsa Co.
(413) 277-9500
www.nationalbalsa.com/
Composite tubing;
Kite Studio
(610) 395-3560
www.kitebuilder.com/
Fiberglass cowl:
Fiberglass Specialties
(479) 359-2429
www.fiberglassspecialtiesinc.com
Hardware, accessories:
Du-Bro
(800) 848-9411
http://dubro.com
Landing gear, wheel pants, AeroKote:
Sig Manufacturing
(641) 623-5154
www.sigmfg.com
32 MODEL AVIATION
05sig1.QXD 3/25/08 10:09 AM Page 32
Edition: Model Aviation - 2008/05
Page Numbers: 18,19,20,21,22,23,24,28,31,32
Edition: Model Aviation - 2008/05
Page Numbers: 18,19,20,21,22,23,24,28,31,32
I HAVE ALWAYS admired racing aircraft of the so-called “Golden Age
of Aviation”: an era that extended from the end of World War I to the
onset of World War II. It was the time of rakish designs, open cockpits,
and “flying by the seat of one’s pants.”
Aircraft designs of the time were largely grand
experiments, and from those experiments
emerged the Granville Brothers’ Gee Bee series,
the Hughes H-1 racer, the Travel Air Mystery Ship,
the Hall Bulldog, and the rest of the list, which is too
numerous to include here.
I was weary of going to our flying field and finding almost
nothing between ARF training models, sticks, and the usual bunch of 3-D
ARFs. I realized that if I wanted something with a style I liked, I’d
have to build my own.
Accordingly, I made a couple pencil sketches, loaded
ModelCAD 3000 into my PC, and sat down at my electronic
drawing board to play. The Golden Era 60 is the result.
Although this airplane is conventional in its construction, it is
unsuitable for a first scratch-building project. This article assumes
that the builder has some experience beyond ARF assembly and is
familiar with common building techniques.
Unless you get the laser-cut “short kit” I’ll tell you about, you shouldn’t attempt this build without a scroll saw
or band saw, a Dremel or other rotary tool, and the usual collection of hand tools. The judicious use of a square and
straightedge is necessary throughout construction if you expect to manufacture a straight, easy-to-trim aircraft.
If the previous paragraphs haven’t discouraged you, we can proceed.
18 MODEL AVIATION
BY FRED RANDALL
A Williams Brothers Sportsman pilot bust complements the
open cockpit. Enamel brush paint can be spray-fixed with a
fuelproof clear coat.
Grooving through the open sky, the Golden Era 60 handles as
the popular Stick models do but has the looks of a 1930s
racer.
The grunt of a .60-size engine adds thrills
to this pioneer-reminiscent building project
05sig1.QXD 3/25/08 10:33 AM Page 18
Materials: Creative Hobbies of Mendon, Massachusetts, sells a short
kit of laser-cut 1/8 light plywood, 1/4 plywood, and 3/8 balsa parts at a
reasonable cost. These accurate precut components and a full-size
rolled plans set from MA will greatly simplify construction. It
eliminates tedium, and what remains is the equivalent of building a
good kit.
Regardless of whether or not you purchase the short kit, I suggest
that you have all fabricated parts (wing ribs, fuselage formers, etc.) on
hand before starting the build.
The landing gear and wheel pants on the original are Four-Star 120
parts ordered from Sig Manufacturing. I suggest that builders use the
same parts since they are a good match appearancewise, they fit the
gear mounting plates designed into the fuselage, and using other units
may significantly change the balance point. But if you prefer to
fabricate your own landing gear, have at it!
I did not design this airplane to be superlight since it is not
intended for “3-D.” It has an allup
weight of approximately
9 pounds and a wing
loading of roughly 26
ounces per square foot.
However, it is extremely
strong. This model is
extensively planked,
including wing
May 2008 19
After a full-power run of roughly 50 feet, the model lifts off smoothly.
The wide-track gear absorbs many of the bumps in the grass.
The former positions have been marked on the fuselage sides,
and the firewall assembly has been epoxied in place.
capstrips, and composite tubing is used for the LE and the main spar.
CONSTRUCTION
Fuselage: Although I usually begin with the wings, the fuselage was
my starting point for this project.
The first task was selecting the 1/8 balsa for the fuselage sides. The
importance of matching the side sheets’ hardness and grain cannot be
stressed enough. If the balsa is poorly matched, it will be next to
impossible to make a straight fuselage.
The fuselage sides’ maximum height is approximately 7 inches. I
used matched 4-inch-wide, 1/8 balsa sheets. Cement them together with
cyanoacrylate before cutting them to shape. (In the remainder of this
document, cyanoacrylate means medium cyanoacrylate unless
otherwise specified.)
After you have cut the balsa sides to shape, use cyanoacrylate to
glue the 1/8 plywood fuselage doublers in place. Be careful; it is easier
than you can imagine to end up with two right or two left sides.
Adhere, with cyanoacrylate, the doubler to the bottom of former F1.
After the fuselage doublers have set, epoxy and clamp the two
landing-gear (LG) and hatch-support rails to the fuselage doublers.
Refer to the plans for position. Make sure to wipe off any excess epoxy
from around the perimeter with alcohol.
Epoxy the 1/8 plywood firewall doubler to the 1/4 plywood firewall.
(Epoxy means 30-minute epoxy unless otherwise specified.)
Lay the fuselage plans on your building board, protecting them with
waxed paper or the like. With the plans as a guide, use a square
referenced to the top of the fuselage sides to mark the position of all
formers on the inside of both fuselage sides.
05sig1.QXD 3/25/08 10:44 AM Page 19
20 MODEL AVIATION
Formers F1 and F2 have been put in place, and the servo plate has
been mounted between them.
With the fuselage wide open, it’s a good time to fit the fuel tank.
Silicone sealant will be used to mount the tank permanently.
The left side has been epoxied in place after a careful alignment
check. Notice how the rear wing mount is locked into cutouts in
the doubler.
Bevel the tail post and then glue it in place. Dry-fit the fin and the
remaining formers to assure good alignment.
The tail-wheel mount area is supported by a 1/8 plywood plate.
It’s recessed to allow room for balsa, which will be sanded flush
with the fuselage sides.
Scrap 3/8 balsa sheet is substituted for the stabilizer during
preliminary alignment. The forward stringers are added at
this point.
05sig1.QXD 3/25/08 11:26 AM Page 20
May 2008 21
Once the sheeting is complete, it’s a good time to test-fit the
landing gear and engine mount. The cockpit area can be detailed
at this time.
Notice the smart use of carbon-fiber tubing to form the LE and
support the wing spar. The wing will be sheeted next.
Above: The completed one-piece wing is mounted with dowel pins
and nylon bolts. The light tail structure is designed to keep the
weight mass balanced on the recommended CG.
Left: Build the cowl from wood or purchase the fiberglass
version from Fiberglass Specialties. The mounting screws are
hidden inside.
Type: RC sport
Pilot skill level:
Intermediate to expert
Wingspan: 65.25 inches
Flying weight: 10 pounds
Wing area: 792 square inches
Wing loading: 26-27 ounces/square foot
Length: 51 inches
Engine: GMS .61 glow
Tank: Modeltech 360cc
Flight battery: Four cells, 4.8 volts
Radio: Spektrum DX7 system, AR7000 receiver, three DS821
and two Hitec HS-625MG servos
Spinner: Du-Bro (LXE 149) 3 inch
Construction: Balsa and light plywood
Covering/finish: Builder’s choice (Sig AeroKote is recommended.)
Photos by the author
05sig1.QXD 3/25/08 10:58 AM Page 21
22 MODEL AVIATION
The GMS .61 two-stroke engine hides inside the spacious cowl. A
four-stroke .82-1.00 would also fit this model neatly.
Stock Sig Four-Star 120 wheel pants complete this sport model’s 1930s racing look. The long and tall fuselage offers good knifeedge
performance.
Put the right fuselage side in place on the plans and secure it. Using
a square to position it, epoxy the firewall/doubler assembly flush with
the front of the fuselage side. When it has set, Formers F1 and F2 can
be cemented in place using cyanoacrylate. Position the servo tray in the
slots provided in formers F1 and F2, and secure it with cyanoacrylate.
Fashion the 11/2 x 47/16-inch rear wing anchor plate from 1/4
plywood. Do not drill it. Temporarily insert it into the slot provided in
the fuselage doubler. Test-fit the left side for perfect alignment. The
firewall assembly, the formers, the wing anchor plate, and both
fuselage sides must align properly.
When you are satisfied, remove the left side and apply epoxy to the
edge of the firewall assembly and the wing anchor plate edges that
mate with F2 and the fuselage sides. Apply cyanoacrylate to the mating
edges of F1 and F2. Put the left side back in position.
Place a book or similar weight on top to ensure a good bond, and
then take a break.
Shape the tail post from 1/2 x 3/4 x 13-inch balsa. It should taper
from 1/2 inch at the LE to 3/16 inch at the TE. It is important that this
piece be symmetrical. It will be further shaped and cut for the stabilizer
later, during fuselage assembly.
Notch the front roughly 1/8 inch deep to accept the light-plywood
fin. Refer to the plans for notch location.
With the fuselage secured to the top view of the plans, use T-pins to
temporarily hold the rear of the fuselage sides together, sandwiching
the tail post into position. The tail post should be centered over the
plans and flush with the bottom and back of the fuselage sides. Ensure
that the tail post is vertical in both axes when referenced to the fuselage
sides.
Reposition the pins until these conditions are met. Temporarily tack
the assembly together using a few drops of thin cyanoacrylate.
Remove the T-pins and recheck alignment. When you are satisfied,
flow in more thin cyanoacrylate for a permanent bond.
Install the remaining formers using cyanoacrylate. If necessary, use
rubber bands around the fuselage to ensure a full-contact fit.
Employing the plywood fin as a pattern, make doublers
approximately 3/8 inch wide from 3/16 balsa sheet. The doublers enable
a smooth transition between the planking and the fin. There is a
detailed drawing on the fuselage plans.
Cement the balsa doublers to both sides of the fin with
cyanoacrylate. Cut 1/8-inch gaps in the doubler where the fin fits into
05sig1.QXD 3/25/08 10:06 AM Page 22
the F5 and F6 notches and another at the rear
of the fin where it will be inserted into the
tail-post notch. Install the fin and secure it
with cyanoacrylate, and then sand the top of
the tail post to blend with the fin and doublers.
Cut the cockpit floor from 1/8 balsa sheet.
See the fuselage top view for the pattern.
Using cyanoacrylate, install the floor as
indicated and test-fit the dash panel. The dashpanel
pattern is somewhat oversize; you must
sand it to mount flush with the cockpit floor
and F3. Use a long sanding block to blend the
panel with the fuselage.
Install former F8. Fit it between F6 and the
tail post. See the plans for location. Trim it as
necessary for a proper fit. Ensure that F8 is at
right angles to, and level with, the top of the
notch in the fuselage sides. Take your time;
this establishes proper alignment and angle of
incidence.
I found it helpful to cut a piece of 3/8 balsa
sheet 3 inches wide and 12-15 inches long to
use as a spacer and alignment aid. Lay it on
top of F8 to use as a temporary substitute for
the stabilizer.
Position F7 as indicated on the plans, and
snug it against the temporary spacer. Adhere
F7 in place with cyanoacrylate and remove
the spacer. Trim F7 as necessary for a proper
fit.
Install the stringers using cyanoacrylate.
The front stringers extend aft to the panel.
There are no notches in the panel, so shape
the ends of the stringers for a nice butt fit
26 MODEL AVIATION
INTRODUCING
• Safe chemistry will not explode or catch fire
• Fast charge capable – 100% in 15 minutes
• 30c continuous, 60c bursts
• Exclusive Duralite Stay Balance Circuitry built-in
to every pack – no external balancing needed
• Charge through the charge lead with a Duralite Plus
Charger or through the power lead with an A123 capable
charger like the Orbit Pocketlader
• No regulator needed for most Rx applications
• Longer life cycle than lithium polymer chemistry
LITHIUM POWER SOLUTIONS FOR EVERYTHING YOU FLY
Order toll free 877-744-3685
Shop online www.duraliteflightsystems.com
PLUS
WITH STAY BALANCE
CIRCUITRY BUILT-IN
TO EVERY PACK
against it. The rear stringers should terminate
flush with the front of the tail post.
Epoxy four 1/4-20 captive nuts to the inner
LG mounting plate. Remove your fuselage
assembly from the building board, flip it over,
and use epoxy to bond the inner LG mounting
plate to the support rails. Don’t spare the
epoxy here; the LG takes considerable abuse
(at least when I’m flying).
The battery hatch came about because the
finished model needed a bit of nose weight. I
don’t like to add lead for balance when I can
reposition something to compensate. I
relocated the flight battery forward, in a foam
nest made for perfect balance with no
additional ballast. As a bonus, you have access
to the LG support assembly, engine-mount
captive nuts, and fuel tank should something
go awry.
Fashion the battery hatch from a piece of
1/8 light plywood. It should fit nicely between
the firewall, the fuselage sides, and the LG
mounting plate. It should rest on the support
rails. Drill holes at four corners for your
selected screw hardware.
I band-sawed a small amount of
downthrust and right thrust into my engine
mounts before installation. Offset the mounts
so that the spinner will be centered at the
proper location. When positioned, drill the
firewall and install the captive nuts.
Empennage: Building this area is
straightforward, and little explanation is
necessary beyond what is on the plans. The
only item that may need clarification is the
elevator joiner.
I originally intended to use a double
pushrod for elevator control. However, I had a
nice piece of .317 composite tubing left from
the wing construction, and it seemed
reasonable to use as a torque tube to join the
elevator halves. If you prefer double pushrods,
eliminate the torque tube and the clearance
notch in the rudder.
Wings: Select the right-wing full plans and
secure them to your building board. Using
cyanoacrylate, bond an RR1 rib to an RR2.
RR1 should be inboard. This assembly forms
the root rib.
Bond an R3 to an R1. The rib with no LE
notch is an R3; it should be inboard. Refer to
the plans for confirmation.
The wing will be built using the centermost
bottom spar as a reference. Cut a piece of 1/8 x
1/4 basswood to length and secure it in place
on the plans. Use a square to position the root
rib assembly on the plans with the spar snug in
its notch. Use cyanoacrylate to adhere the root
rib assembly to the spar.
Follow suit with an R1, R2 pair. Install the
remaining ribs, and adhere them to the spar
with cyanoacrylate. All ribs’ break-off stubs
should lay flat on the plans.
R2 is slightly different; it establishes a
small amount of washout in the wingtips to
improve low-speed stability. When all ribs are
in place, cut and install the three top spars. Cut
the .317-inch composite LE to length and glue
it in place with cyanoacrylate.
You should be able to insert the composite
spar as far as shown on the plans. Test-fit it. It
05sig1.QXD 3/25/08 10:09 AM Page 26
should be snug but not distort the ribs as it
passes through. Make any adjustments needed
until this condition is met, and then remove
the spar.
Remove the wing from the plans. Install
the remaining bottom spars, and then check
the assembly for straightness. It should lay
flat, resting on the centermost bottom spar and
rib break-off stubs. Correct any twist in the
wing before proceeding.
Following the diagram below the right
wing assembly drawing, shape the TE from 1/2
x 3/8 balsa. When you are finished, glue it into
position with cyanoacrylate.
Temporarily position the 1/8 light-plywood
servo plate to the bottom of the wing. Make
sure to place it at a point that is deep enough
on the chord to ensure that a standard servo’s
body does not protrude through the top. (Ask
me why I added this instruction.)
When you are satisfied with its position,
adhere the servo plate in place with
cyanoacrylate, flush with the bottom of the
ribs. Use scrap 1/8 x 1/4 spar material to make
rails to support and stiffen it.
Use cyanoacrylate to glue the 1/8 lightplywood
wingtip in place. It should be
centered between the LE and TE and at right
angles to R2. Make spar extensions and
cement them between the rib and the tip. See
the plans for positioning. Snap off the rib
stubs and sand the areas smooth.
Remove the right wing plans from the
building board and replace them with the left.
28 MODEL AVIATION
(We don’t want two right wings, do we?)
Take a deep breath and repeat the wing
instructions.
Having completed the framing of both
wings, fabricate and add the 1/4-inch plywood
dowel support webbing and the wing
mounting dowels. Ensure that the pegs will
align with the holes in F1. The detail diagram
will aid in drilling the peg holes and installing
the pegs.
Cut the .505 composite-tubing spar to
length and test-fit the joined wings. Be sure to
allow for the 1/16-inch planking. This work is
critical; it affects the final wing leveling and
wing/stabilizer angle of incidence. If the wing
is too wide, it does no harm to remove some
material from the TE where it fits within the
fuselage.
Wing Planking: The LE planking is a 1/16 x
12 x 36 balsa “wing skin.” The plans indicate
the areas that are covered with planking. Do
not trim the width until it is installed.
Thoroughly soak the balsa with Windex and
wait several minutes before attempting to
make the sharp LE bend.
When the balsa is pliable enough to make
the bend, start at the top, rear 1/8 x 1/4 spar.
Use cyanoacrylate to bond the balsa to the
spar. Clamp it along its length until the
adhesive sets.
Work slowly. Starting at the middle of the
wing and moving outward, glue, with
cyanoacrylate, the ribs, front spar, LE, etc.,
until you have the entire wing skin bonded,
top and bottom. If you do the job properly,
the planking should be tight, with no bulges.
Trim whatever planking extends beyond the
center, bottom spar.
Install the remaining planking and the rib
capstrips. It’s better to plank the entire
wingtip on both sides; it makes the covering
job easier and neater. When you have
finished both wings, prepare them to accept
covering.
Fuselage Planking: Starting with the front
deck, plank the fuselage with 3/32 sheet balsa.
I made a cardboard pattern and used it as a
guide to cut the planking for the forward
“hood,” from the firewall to F3. Soak the
planking for installation. After test-fitting, use
cyanoacrylate to install it.
Make the 3/32 balsa planking for the area
aft of the cockpit. Use a single piece to cover
from F5 to the tail post and up to the 1/8-inch
top stringer on each side. This piece should
cover the tail post and terminate at the back
of the fuselage. The bend is fairly gentle and
should pose little problem. When you are
satisfied with the fit, glue the planking in
place with cyanoacrylate. Shape and add the
pieces that go between the top stringer and
the fin doublers.
When the cyanoacrylate has set, use a
sanding block to shape the back of the tail
post so it is flat. Blend the planking into the
fin doubler and the fuselage sides.
Cut two pieces of 3/8 balsa stock 11/4
inches wide and 83/8 inches long. These fit
between F5 and the instrument panel. Shape
the fronts to fit flush with the panel. Position
them so they are 3/32 inch inboard of the
05sig1.QXD 3/25/08 10:09 AM Page 28
fuselage sides, and adhere them in place with
cyanoacrylate.
Sand both sides so they follow the contour
of the panel and F5. These provide support for
the planking around the cockpit. See photos
for clarification.
Shape and fit the planking around the
cockpit. When you are satisfied, sand
everything flush. Use balsa filler to fill any
gaps, and finish-sand the entire fuselage
smooth and even. Cut—but do not install—
the 3/32-inch bottom piece. With the fuselage
planking complete, cut the tail post for the
stabilizer. This marks the end of the planking
phase.
Ailerons: These are cut from 3/8 x 3 tapered
balsa. See the wing plans for patterns.
Before shaping the aileron LE, use
cyanoacrylate to laminate a matching piece of
1/16 hard balsa to the top to strengthen the
structure. Temporarily attach the ailerons to
the wing with a few small spots of
cyanoacrylate, and then block-sand the bottom
of the ailerons to blend with the wing TE.
Remove the ailerons using debonder, and
sand the LEs for hinging.
Pushrods, Etc.: Install the pushrod tubes.
Holes are provided in F4 to support the front
of the pushrod tubes. I crossed mine in the
middle and they exited the fuselage on the
opposite side. I used a small cable tie at the
crossover point to support and stiffen the
tubes. Once the pushrod tubes are installed,
use cyanoacrylate to glue the bottom piece in
place. Sand the joint smooth.
A 360cc tank (Global Hobby part 120074)
I had on hand was employed in the original. I
used silicone adhesive to bond the front of the
fuel tank to the inside of the firewall, with the
neck protruding through the provided hole. I
Dremeled the bottom of the hole in F1 to
match the contour of the rear of the tank (see
dotted line on F1 pattern) and used silicon
adhesive there too.
Drill a hole in the firewall and F1 for the
throttle pushrod, positioned to make a straight
run from the carburetor to the throttle servo.
The fuselage servo linkages are typical. Use
your favorite clevises, etc. The wing servos
and linkages are installed after covering.
There are large openings in the ribs that
provide passage for the wires from the servos.
Make small openings in the planking inboard,
on the top of the wing, for the servo wires to
exit.
Insert the .505 composite wing spar in one
(either) wing up to the rib just past the servo
and glue it in place inside the root rib (only)
with cyanoacrylate.
It is unnecessary to cement the wing halves
together. It is much easier to store and
transport them separately. The mounting pegs
and nylon bolts will align and secure the wings
to the fuselage, and the spar is more than
strong enough to prevent them from folding.
Cowl: For the original model I made my cowl
from laminations of 3/8 balsa. Several good
articles have been written about the subject.
I also made a balsa cowl for a second
airplane, and I sent it out for Fiberglass
Specialties to duplicate in fiberglass. These
cowls are available for purchase if you don’t
want to expend the effort to fabricate your
own. Either way, the weight difference is
slight so the balance remains unchanged.
Covering: It seems like everyone has a
favorite covering material; I am no different. I
prefer Sig AeroKote, which I used on the
entire aircraft.
I don’t care for the elaborate, multicolor
schemes festooned with sponsor logos that are
rampant on ARFs. Thus Brodak’s CL Oriental
was the inspiration for the color scheme I used
on the original Golden Era 60. The Oriental is
black and red; I opted for Black and Naval
Orange.
If you use black on the fuselage, throw a
white cloth over it if the model is going to sit
in the sun for a long period. The black
covering absorbs heat and loosens, and you
will be faced with a session with the iron and
heat gun when you get home.
Nuts and Bolts: I used Du-Bro heavy-duty
.40-.91 control horns (item 867) throughout.
They require a single hole for mounting and are
rugged and easy to install. A bonus is that they
adjust for angle as well as throw. I installed a
steerable tail-wheel assembly from Global
Hobby. It mounts easily and works well.
My Spektrum DX7 came with four JR
RC System is distributed by:
SIG Manufacturing Company, Inc.
P.O. Box 520 • Montezuma, Iowa 50171-0520
Web Site: www.sigmfg.com • Phone: (641)623-5154
* actual Flightsimulator screens shown
There are different ways to learn model flying. If an
experienced model flyer is not on site then the first steps can
be disappointing. At worst case you could crash your first
model. Especially for learning R/C helicopter flying the so
called "Dry Run" on a simulator is an inexpensive and
suggested method. The SimTransmitter
"Joystick" in combination with the FMS
Flightsimulator provides the ideal virtual
beginner airplane or helicopter "model".
Simply plug the SimTransmitter into a free USB
port and configure it as a joystick.
SimTransmitter
Order No. RCSSIM062 - $39.99
* Prices at Participating Dealers
*
05sig1.QXD 3/25/08 10:09 AM Page 31
servos. Three are used in the fuselage, and
Hitec HD servos are used for the ailerons.
The Spektrum dual receivers are mounted
on opposite fuselage sides using Velcro. They
are oriented to provide opposite antenna
polarity, as the installation instructions
mandate. Not having to provide routing and
an exit for a long 72 MHz antenna is a
pleasant change!
The double 1/4-inch plate used to mount
the LG is a work-around because of a
clearance issue. The wing extends forward
from the mounting recess and engages the LG
if additional clearance isn’t provided. I didn’t
realize this until too late, and the second plate
proved to be a quick, effective remedy.
I cut the windshield from a plastic cake
container my supermarket provided free of
charge. Ask for one. If they refuse, you can
buy a cake and eat it!
The seat and headrest are carved from
balsa block and brushed with one coat of
Insignia Orange Aero Gloss. It imparts an
almost suedelike appearance. “Leo,” the pilot,
had to have his shoulders trimmed to fit in the
narrow cockpit. I repainted him with my
wife’s acrylics to match the model.
(References to “Leo” stem from the pilot
figure’s uncanny resemblance to a friend and
fellow RCer, Leo Desmarais.)
Hinging: I used cyanoacrylate hinges
throughout, but regardless of the type you
should have at least two on each elevator half,
three on the rudder, and four—equidistant—
along each aileron. Mounting procedures vary,
depending on the type chosen, and hingeinstallation
instruction is beyond the scope of
this article.
No matter what type of hinge you use,
make sure the movable surfaces fit closely to
the fixed surfaces. Gaps give birth to control
flutter, which can end an otherwise perfect
flying day.
Assembly: Since this is probably not your
first scratch build, I’ll be brief. There is
nothing unusual about the model and
assembly is straightforward
Assuming that the covering job is finished
and the elevator is hinged, insert the stabilizer
into its slot. Make sure it’s straight using a
string from the nose to the elevator tips. Mark
the stabilizer where it joins the fuselage, top
and bottom.
Remove the stabilizer and then remove the
covering that will be within the slot.
Permanently adhere the stabilizer, with
cyanoacrylate or epoxy, and hook up the
control hardware.
Drill the LG to accept the 1/4-20 nylon
mounting bolts. If the wheel pants haven’t
been assembled and painted and the wheels
haven’t been mounted, you haven’t been
reading far enough ahead!
Assemble the wings and fit them to the
fuselage. With the wings seated, carefully drill
9/32-inch holes through the centers of the wing
reinforcement pads into the rear wing
mounting plate.
Remove the wing and then further drill the
mounting plate to accept the captive 1/4-20
nuts. Epoxy them in place on the backside.
When they are set, reinstall the wing and
insert the 1/4-20 nylon bolts. Screw them into
the mounting plate slightly more than finger
tight.
Check the wing-to-stabilizer angle of
incidence using your favorite method; I use a
Great Planes laser setup. If your build is
accurate, it should be 0°-.5°. If it isn’t, make it
so. You can correct it several degrees either
way by removing or adding material to the
rear part of the wing saddle.
Balancing and Flying: I suggest a slightly
nose-heavy configuration for the first flights.
The balance point should fall one-third back
from the LE, or approximately where the LE
planking ends. Being an RC novice, I have
left the balance point there. If you’re more
experienced, you may find that a slightly more
aft point allows for better aerobatics.
This airplane has a thin symmetrical wing,
a somewhat short tail-moment arm, and high
wing loading; therefore, it flies like a
warbird—fast and without self-righting
properties. I programmed flaperons to help
during landings. Keep power on during
approach. As does a warbird, the Golden Era
likes to come in under power.
The large control surfaces beg dual rate
and exponential programming. This will allow
the experienced pilot to burn holes in the sky
while the less confident can fly it around
without working up a sweat.
The deep fuselage makes for easy knife
edge, and the slight wingtip washout and
aileron configuration help to keep it from
falling out of the sky at relatively low speeds.
This is not a good design for a first lowwing
sport airplane. It is satisfying for the
intermediate pilot and will draw attention at
the club field.
Electric Dreams: I gave little consideration to
making this aircraft light beyond what was
necessary for good 60-power performance. It
came in at slightly more than 9 pounds dry.
An electric conversion could include fewer
doublers, thinner and less planking, more
lightening holes, and a lighter LG assembly.
Several pounds could probably be shaved off
easily, making the wing loading nearer to a
more acceptable 20 ounces per square foot.
Being an old FF Gas aficionado, I revel in
the smell of nitro fuel in the morning, and the
postflight cleanup is akin to a labor of love.
I’ll leave it to you wattage mavens to do the
converting, but I’d love to see the results! MA
Fred Randall
[email protected]
Sources:
Short kit (1/8 light-plywood parts, 1/4 plywood
parts, 3/8 balsa rudder and elevator parts):
Creative Hobbies
(508) 473-8259
www.creativehobbies.net
Balsa, plywood stock:
National Balsa Co.
(413) 277-9500
www.nationalbalsa.com/
Composite tubing;
Kite Studio
(610) 395-3560
www.kitebuilder.com/
Fiberglass cowl:
Fiberglass Specialties
(479) 359-2429
www.fiberglassspecialtiesinc.com
Hardware, accessories:
Du-Bro
(800) 848-9411
http://dubro.com
Landing gear, wheel pants, AeroKote:
Sig Manufacturing
(641) 623-5154
www.sigmfg.com
32 MODEL AVIATION
05sig1.QXD 3/25/08 10:09 AM Page 32
Edition: Model Aviation - 2008/05
Page Numbers: 18,19,20,21,22,23,24,28,31,32
I HAVE ALWAYS admired racing aircraft of the so-called “Golden Age
of Aviation”: an era that extended from the end of World War I to the
onset of World War II. It was the time of rakish designs, open cockpits,
and “flying by the seat of one’s pants.”
Aircraft designs of the time were largely grand
experiments, and from those experiments
emerged the Granville Brothers’ Gee Bee series,
the Hughes H-1 racer, the Travel Air Mystery Ship,
the Hall Bulldog, and the rest of the list, which is too
numerous to include here.
I was weary of going to our flying field and finding almost
nothing between ARF training models, sticks, and the usual bunch of 3-D
ARFs. I realized that if I wanted something with a style I liked, I’d
have to build my own.
Accordingly, I made a couple pencil sketches, loaded
ModelCAD 3000 into my PC, and sat down at my electronic
drawing board to play. The Golden Era 60 is the result.
Although this airplane is conventional in its construction, it is
unsuitable for a first scratch-building project. This article assumes
that the builder has some experience beyond ARF assembly and is
familiar with common building techniques.
Unless you get the laser-cut “short kit” I’ll tell you about, you shouldn’t attempt this build without a scroll saw
or band saw, a Dremel or other rotary tool, and the usual collection of hand tools. The judicious use of a square and
straightedge is necessary throughout construction if you expect to manufacture a straight, easy-to-trim aircraft.
If the previous paragraphs haven’t discouraged you, we can proceed.
18 MODEL AVIATION
BY FRED RANDALL
A Williams Brothers Sportsman pilot bust complements the
open cockpit. Enamel brush paint can be spray-fixed with a
fuelproof clear coat.
Grooving through the open sky, the Golden Era 60 handles as
the popular Stick models do but has the looks of a 1930s
racer.
The grunt of a .60-size engine adds thrills
to this pioneer-reminiscent building project
05sig1.QXD 3/25/08 10:33 AM Page 18
Materials: Creative Hobbies of Mendon, Massachusetts, sells a short
kit of laser-cut 1/8 light plywood, 1/4 plywood, and 3/8 balsa parts at a
reasonable cost. These accurate precut components and a full-size
rolled plans set from MA will greatly simplify construction. It
eliminates tedium, and what remains is the equivalent of building a
good kit.
Regardless of whether or not you purchase the short kit, I suggest
that you have all fabricated parts (wing ribs, fuselage formers, etc.) on
hand before starting the build.
The landing gear and wheel pants on the original are Four-Star 120
parts ordered from Sig Manufacturing. I suggest that builders use the
same parts since they are a good match appearancewise, they fit the
gear mounting plates designed into the fuselage, and using other units
may significantly change the balance point. But if you prefer to
fabricate your own landing gear, have at it!
I did not design this airplane to be superlight since it is not
intended for “3-D.” It has an allup
weight of approximately
9 pounds and a wing
loading of roughly 26
ounces per square foot.
However, it is extremely
strong. This model is
extensively planked,
including wing
May 2008 19
After a full-power run of roughly 50 feet, the model lifts off smoothly.
The wide-track gear absorbs many of the bumps in the grass.
The former positions have been marked on the fuselage sides,
and the firewall assembly has been epoxied in place.
capstrips, and composite tubing is used for the LE and the main spar.
CONSTRUCTION
Fuselage: Although I usually begin with the wings, the fuselage was
my starting point for this project.
The first task was selecting the 1/8 balsa for the fuselage sides. The
importance of matching the side sheets’ hardness and grain cannot be
stressed enough. If the balsa is poorly matched, it will be next to
impossible to make a straight fuselage.
The fuselage sides’ maximum height is approximately 7 inches. I
used matched 4-inch-wide, 1/8 balsa sheets. Cement them together with
cyanoacrylate before cutting them to shape. (In the remainder of this
document, cyanoacrylate means medium cyanoacrylate unless
otherwise specified.)
After you have cut the balsa sides to shape, use cyanoacrylate to
glue the 1/8 plywood fuselage doublers in place. Be careful; it is easier
than you can imagine to end up with two right or two left sides.
Adhere, with cyanoacrylate, the doubler to the bottom of former F1.
After the fuselage doublers have set, epoxy and clamp the two
landing-gear (LG) and hatch-support rails to the fuselage doublers.
Refer to the plans for position. Make sure to wipe off any excess epoxy
from around the perimeter with alcohol.
Epoxy the 1/8 plywood firewall doubler to the 1/4 plywood firewall.
(Epoxy means 30-minute epoxy unless otherwise specified.)
Lay the fuselage plans on your building board, protecting them with
waxed paper or the like. With the plans as a guide, use a square
referenced to the top of the fuselage sides to mark the position of all
formers on the inside of both fuselage sides.
05sig1.QXD 3/25/08 10:44 AM Page 19
20 MODEL AVIATION
Formers F1 and F2 have been put in place, and the servo plate has
been mounted between them.
With the fuselage wide open, it’s a good time to fit the fuel tank.
Silicone sealant will be used to mount the tank permanently.
The left side has been epoxied in place after a careful alignment
check. Notice how the rear wing mount is locked into cutouts in
the doubler.
Bevel the tail post and then glue it in place. Dry-fit the fin and the
remaining formers to assure good alignment.
The tail-wheel mount area is supported by a 1/8 plywood plate.
It’s recessed to allow room for balsa, which will be sanded flush
with the fuselage sides.
Scrap 3/8 balsa sheet is substituted for the stabilizer during
preliminary alignment. The forward stringers are added at
this point.
05sig1.QXD 3/25/08 11:26 AM Page 20
May 2008 21
Once the sheeting is complete, it’s a good time to test-fit the
landing gear and engine mount. The cockpit area can be detailed
at this time.
Notice the smart use of carbon-fiber tubing to form the LE and
support the wing spar. The wing will be sheeted next.
Above: The completed one-piece wing is mounted with dowel pins
and nylon bolts. The light tail structure is designed to keep the
weight mass balanced on the recommended CG.
Left: Build the cowl from wood or purchase the fiberglass
version from Fiberglass Specialties. The mounting screws are
hidden inside.
Type: RC sport
Pilot skill level:
Intermediate to expert
Wingspan: 65.25 inches
Flying weight: 10 pounds
Wing area: 792 square inches
Wing loading: 26-27 ounces/square foot
Length: 51 inches
Engine: GMS .61 glow
Tank: Modeltech 360cc
Flight battery: Four cells, 4.8 volts
Radio: Spektrum DX7 system, AR7000 receiver, three DS821
and two Hitec HS-625MG servos
Spinner: Du-Bro (LXE 149) 3 inch
Construction: Balsa and light plywood
Covering/finish: Builder’s choice (Sig AeroKote is recommended.)
Photos by the author
05sig1.QXD 3/25/08 10:58 AM Page 21
22 MODEL AVIATION
The GMS .61 two-stroke engine hides inside the spacious cowl. A
four-stroke .82-1.00 would also fit this model neatly.
Stock Sig Four-Star 120 wheel pants complete this sport model’s 1930s racing look. The long and tall fuselage offers good knifeedge
performance.
Put the right fuselage side in place on the plans and secure it. Using
a square to position it, epoxy the firewall/doubler assembly flush with
the front of the fuselage side. When it has set, Formers F1 and F2 can
be cemented in place using cyanoacrylate. Position the servo tray in the
slots provided in formers F1 and F2, and secure it with cyanoacrylate.
Fashion the 11/2 x 47/16-inch rear wing anchor plate from 1/4
plywood. Do not drill it. Temporarily insert it into the slot provided in
the fuselage doubler. Test-fit the left side for perfect alignment. The
firewall assembly, the formers, the wing anchor plate, and both
fuselage sides must align properly.
When you are satisfied, remove the left side and apply epoxy to the
edge of the firewall assembly and the wing anchor plate edges that
mate with F2 and the fuselage sides. Apply cyanoacrylate to the mating
edges of F1 and F2. Put the left side back in position.
Place a book or similar weight on top to ensure a good bond, and
then take a break.
Shape the tail post from 1/2 x 3/4 x 13-inch balsa. It should taper
from 1/2 inch at the LE to 3/16 inch at the TE. It is important that this
piece be symmetrical. It will be further shaped and cut for the stabilizer
later, during fuselage assembly.
Notch the front roughly 1/8 inch deep to accept the light-plywood
fin. Refer to the plans for notch location.
With the fuselage secured to the top view of the plans, use T-pins to
temporarily hold the rear of the fuselage sides together, sandwiching
the tail post into position. The tail post should be centered over the
plans and flush with the bottom and back of the fuselage sides. Ensure
that the tail post is vertical in both axes when referenced to the fuselage
sides.
Reposition the pins until these conditions are met. Temporarily tack
the assembly together using a few drops of thin cyanoacrylate.
Remove the T-pins and recheck alignment. When you are satisfied,
flow in more thin cyanoacrylate for a permanent bond.
Install the remaining formers using cyanoacrylate. If necessary, use
rubber bands around the fuselage to ensure a full-contact fit.
Employing the plywood fin as a pattern, make doublers
approximately 3/8 inch wide from 3/16 balsa sheet. The doublers enable
a smooth transition between the planking and the fin. There is a
detailed drawing on the fuselage plans.
Cement the balsa doublers to both sides of the fin with
cyanoacrylate. Cut 1/8-inch gaps in the doubler where the fin fits into
05sig1.QXD 3/25/08 10:06 AM Page 22
the F5 and F6 notches and another at the rear
of the fin where it will be inserted into the
tail-post notch. Install the fin and secure it
with cyanoacrylate, and then sand the top of
the tail post to blend with the fin and doublers.
Cut the cockpit floor from 1/8 balsa sheet.
See the fuselage top view for the pattern.
Using cyanoacrylate, install the floor as
indicated and test-fit the dash panel. The dashpanel
pattern is somewhat oversize; you must
sand it to mount flush with the cockpit floor
and F3. Use a long sanding block to blend the
panel with the fuselage.
Install former F8. Fit it between F6 and the
tail post. See the plans for location. Trim it as
necessary for a proper fit. Ensure that F8 is at
right angles to, and level with, the top of the
notch in the fuselage sides. Take your time;
this establishes proper alignment and angle of
incidence.
I found it helpful to cut a piece of 3/8 balsa
sheet 3 inches wide and 12-15 inches long to
use as a spacer and alignment aid. Lay it on
top of F8 to use as a temporary substitute for
the stabilizer.
Position F7 as indicated on the plans, and
snug it against the temporary spacer. Adhere
F7 in place with cyanoacrylate and remove
the spacer. Trim F7 as necessary for a proper
fit.
Install the stringers using cyanoacrylate.
The front stringers extend aft to the panel.
There are no notches in the panel, so shape
the ends of the stringers for a nice butt fit
26 MODEL AVIATION
INTRODUCING
• Safe chemistry will not explode or catch fire
• Fast charge capable – 100% in 15 minutes
• 30c continuous, 60c bursts
• Exclusive Duralite Stay Balance Circuitry built-in
to every pack – no external balancing needed
• Charge through the charge lead with a Duralite Plus
Charger or through the power lead with an A123 capable
charger like the Orbit Pocketlader
• No regulator needed for most Rx applications
• Longer life cycle than lithium polymer chemistry
LITHIUM POWER SOLUTIONS FOR EVERYTHING YOU FLY
Order toll free 877-744-3685
Shop online www.duraliteflightsystems.com
PLUS
WITH STAY BALANCE
CIRCUITRY BUILT-IN
TO EVERY PACK
against it. The rear stringers should terminate
flush with the front of the tail post.
Epoxy four 1/4-20 captive nuts to the inner
LG mounting plate. Remove your fuselage
assembly from the building board, flip it over,
and use epoxy to bond the inner LG mounting
plate to the support rails. Don’t spare the
epoxy here; the LG takes considerable abuse
(at least when I’m flying).
The battery hatch came about because the
finished model needed a bit of nose weight. I
don’t like to add lead for balance when I can
reposition something to compensate. I
relocated the flight battery forward, in a foam
nest made for perfect balance with no
additional ballast. As a bonus, you have access
to the LG support assembly, engine-mount
captive nuts, and fuel tank should something
go awry.
Fashion the battery hatch from a piece of
1/8 light plywood. It should fit nicely between
the firewall, the fuselage sides, and the LG
mounting plate. It should rest on the support
rails. Drill holes at four corners for your
selected screw hardware.
I band-sawed a small amount of
downthrust and right thrust into my engine
mounts before installation. Offset the mounts
so that the spinner will be centered at the
proper location. When positioned, drill the
firewall and install the captive nuts.
Empennage: Building this area is
straightforward, and little explanation is
necessary beyond what is on the plans. The
only item that may need clarification is the
elevator joiner.
I originally intended to use a double
pushrod for elevator control. However, I had a
nice piece of .317 composite tubing left from
the wing construction, and it seemed
reasonable to use as a torque tube to join the
elevator halves. If you prefer double pushrods,
eliminate the torque tube and the clearance
notch in the rudder.
Wings: Select the right-wing full plans and
secure them to your building board. Using
cyanoacrylate, bond an RR1 rib to an RR2.
RR1 should be inboard. This assembly forms
the root rib.
Bond an R3 to an R1. The rib with no LE
notch is an R3; it should be inboard. Refer to
the plans for confirmation.
The wing will be built using the centermost
bottom spar as a reference. Cut a piece of 1/8 x
1/4 basswood to length and secure it in place
on the plans. Use a square to position the root
rib assembly on the plans with the spar snug in
its notch. Use cyanoacrylate to adhere the root
rib assembly to the spar.
Follow suit with an R1, R2 pair. Install the
remaining ribs, and adhere them to the spar
with cyanoacrylate. All ribs’ break-off stubs
should lay flat on the plans.
R2 is slightly different; it establishes a
small amount of washout in the wingtips to
improve low-speed stability. When all ribs are
in place, cut and install the three top spars. Cut
the .317-inch composite LE to length and glue
it in place with cyanoacrylate.
You should be able to insert the composite
spar as far as shown on the plans. Test-fit it. It
05sig1.QXD 3/25/08 10:09 AM Page 26
should be snug but not distort the ribs as it
passes through. Make any adjustments needed
until this condition is met, and then remove
the spar.
Remove the wing from the plans. Install
the remaining bottom spars, and then check
the assembly for straightness. It should lay
flat, resting on the centermost bottom spar and
rib break-off stubs. Correct any twist in the
wing before proceeding.
Following the diagram below the right
wing assembly drawing, shape the TE from 1/2
x 3/8 balsa. When you are finished, glue it into
position with cyanoacrylate.
Temporarily position the 1/8 light-plywood
servo plate to the bottom of the wing. Make
sure to place it at a point that is deep enough
on the chord to ensure that a standard servo’s
body does not protrude through the top. (Ask
me why I added this instruction.)
When you are satisfied with its position,
adhere the servo plate in place with
cyanoacrylate, flush with the bottom of the
ribs. Use scrap 1/8 x 1/4 spar material to make
rails to support and stiffen it.
Use cyanoacrylate to glue the 1/8 lightplywood
wingtip in place. It should be
centered between the LE and TE and at right
angles to R2. Make spar extensions and
cement them between the rib and the tip. See
the plans for positioning. Snap off the rib
stubs and sand the areas smooth.
Remove the right wing plans from the
building board and replace them with the left.
28 MODEL AVIATION
(We don’t want two right wings, do we?)
Take a deep breath and repeat the wing
instructions.
Having completed the framing of both
wings, fabricate and add the 1/4-inch plywood
dowel support webbing and the wing
mounting dowels. Ensure that the pegs will
align with the holes in F1. The detail diagram
will aid in drilling the peg holes and installing
the pegs.
Cut the .505 composite-tubing spar to
length and test-fit the joined wings. Be sure to
allow for the 1/16-inch planking. This work is
critical; it affects the final wing leveling and
wing/stabilizer angle of incidence. If the wing
is too wide, it does no harm to remove some
material from the TE where it fits within the
fuselage.
Wing Planking: The LE planking is a 1/16 x
12 x 36 balsa “wing skin.” The plans indicate
the areas that are covered with planking. Do
not trim the width until it is installed.
Thoroughly soak the balsa with Windex and
wait several minutes before attempting to
make the sharp LE bend.
When the balsa is pliable enough to make
the bend, start at the top, rear 1/8 x 1/4 spar.
Use cyanoacrylate to bond the balsa to the
spar. Clamp it along its length until the
adhesive sets.
Work slowly. Starting at the middle of the
wing and moving outward, glue, with
cyanoacrylate, the ribs, front spar, LE, etc.,
until you have the entire wing skin bonded,
top and bottom. If you do the job properly,
the planking should be tight, with no bulges.
Trim whatever planking extends beyond the
center, bottom spar.
Install the remaining planking and the rib
capstrips. It’s better to plank the entire
wingtip on both sides; it makes the covering
job easier and neater. When you have
finished both wings, prepare them to accept
covering.
Fuselage Planking: Starting with the front
deck, plank the fuselage with 3/32 sheet balsa.
I made a cardboard pattern and used it as a
guide to cut the planking for the forward
“hood,” from the firewall to F3. Soak the
planking for installation. After test-fitting, use
cyanoacrylate to install it.
Make the 3/32 balsa planking for the area
aft of the cockpit. Use a single piece to cover
from F5 to the tail post and up to the 1/8-inch
top stringer on each side. This piece should
cover the tail post and terminate at the back
of the fuselage. The bend is fairly gentle and
should pose little problem. When you are
satisfied with the fit, glue the planking in
place with cyanoacrylate. Shape and add the
pieces that go between the top stringer and
the fin doublers.
When the cyanoacrylate has set, use a
sanding block to shape the back of the tail
post so it is flat. Blend the planking into the
fin doubler and the fuselage sides.
Cut two pieces of 3/8 balsa stock 11/4
inches wide and 83/8 inches long. These fit
between F5 and the instrument panel. Shape
the fronts to fit flush with the panel. Position
them so they are 3/32 inch inboard of the
05sig1.QXD 3/25/08 10:09 AM Page 28
fuselage sides, and adhere them in place with
cyanoacrylate.
Sand both sides so they follow the contour
of the panel and F5. These provide support for
the planking around the cockpit. See photos
for clarification.
Shape and fit the planking around the
cockpit. When you are satisfied, sand
everything flush. Use balsa filler to fill any
gaps, and finish-sand the entire fuselage
smooth and even. Cut—but do not install—
the 3/32-inch bottom piece. With the fuselage
planking complete, cut the tail post for the
stabilizer. This marks the end of the planking
phase.
Ailerons: These are cut from 3/8 x 3 tapered
balsa. See the wing plans for patterns.
Before shaping the aileron LE, use
cyanoacrylate to laminate a matching piece of
1/16 hard balsa to the top to strengthen the
structure. Temporarily attach the ailerons to
the wing with a few small spots of
cyanoacrylate, and then block-sand the bottom
of the ailerons to blend with the wing TE.
Remove the ailerons using debonder, and
sand the LEs for hinging.
Pushrods, Etc.: Install the pushrod tubes.
Holes are provided in F4 to support the front
of the pushrod tubes. I crossed mine in the
middle and they exited the fuselage on the
opposite side. I used a small cable tie at the
crossover point to support and stiffen the
tubes. Once the pushrod tubes are installed,
use cyanoacrylate to glue the bottom piece in
place. Sand the joint smooth.
A 360cc tank (Global Hobby part 120074)
I had on hand was employed in the original. I
used silicone adhesive to bond the front of the
fuel tank to the inside of the firewall, with the
neck protruding through the provided hole. I
Dremeled the bottom of the hole in F1 to
match the contour of the rear of the tank (see
dotted line on F1 pattern) and used silicon
adhesive there too.
Drill a hole in the firewall and F1 for the
throttle pushrod, positioned to make a straight
run from the carburetor to the throttle servo.
The fuselage servo linkages are typical. Use
your favorite clevises, etc. The wing servos
and linkages are installed after covering.
There are large openings in the ribs that
provide passage for the wires from the servos.
Make small openings in the planking inboard,
on the top of the wing, for the servo wires to
exit.
Insert the .505 composite wing spar in one
(either) wing up to the rib just past the servo
and glue it in place inside the root rib (only)
with cyanoacrylate.
It is unnecessary to cement the wing halves
together. It is much easier to store and
transport them separately. The mounting pegs
and nylon bolts will align and secure the wings
to the fuselage, and the spar is more than
strong enough to prevent them from folding.
Cowl: For the original model I made my cowl
from laminations of 3/8 balsa. Several good
articles have been written about the subject.
I also made a balsa cowl for a second
airplane, and I sent it out for Fiberglass
Specialties to duplicate in fiberglass. These
cowls are available for purchase if you don’t
want to expend the effort to fabricate your
own. Either way, the weight difference is
slight so the balance remains unchanged.
Covering: It seems like everyone has a
favorite covering material; I am no different. I
prefer Sig AeroKote, which I used on the
entire aircraft.
I don’t care for the elaborate, multicolor
schemes festooned with sponsor logos that are
rampant on ARFs. Thus Brodak’s CL Oriental
was the inspiration for the color scheme I used
on the original Golden Era 60. The Oriental is
black and red; I opted for Black and Naval
Orange.
If you use black on the fuselage, throw a
white cloth over it if the model is going to sit
in the sun for a long period. The black
covering absorbs heat and loosens, and you
will be faced with a session with the iron and
heat gun when you get home.
Nuts and Bolts: I used Du-Bro heavy-duty
.40-.91 control horns (item 867) throughout.
They require a single hole for mounting and are
rugged and easy to install. A bonus is that they
adjust for angle as well as throw. I installed a
steerable tail-wheel assembly from Global
Hobby. It mounts easily and works well.
My Spektrum DX7 came with four JR
RC System is distributed by:
SIG Manufacturing Company, Inc.
P.O. Box 520 • Montezuma, Iowa 50171-0520
Web Site: www.sigmfg.com • Phone: (641)623-5154
* actual Flightsimulator screens shown
There are different ways to learn model flying. If an
experienced model flyer is not on site then the first steps can
be disappointing. At worst case you could crash your first
model. Especially for learning R/C helicopter flying the so
called "Dry Run" on a simulator is an inexpensive and
suggested method. The SimTransmitter
"Joystick" in combination with the FMS
Flightsimulator provides the ideal virtual
beginner airplane or helicopter "model".
Simply plug the SimTransmitter into a free USB
port and configure it as a joystick.
SimTransmitter
Order No. RCSSIM062 - $39.99
* Prices at Participating Dealers
*
05sig1.QXD 3/25/08 10:09 AM Page 31
servos. Three are used in the fuselage, and
Hitec HD servos are used for the ailerons.
The Spektrum dual receivers are mounted
on opposite fuselage sides using Velcro. They
are oriented to provide opposite antenna
polarity, as the installation instructions
mandate. Not having to provide routing and
an exit for a long 72 MHz antenna is a
pleasant change!
The double 1/4-inch plate used to mount
the LG is a work-around because of a
clearance issue. The wing extends forward
from the mounting recess and engages the LG
if additional clearance isn’t provided. I didn’t
realize this until too late, and the second plate
proved to be a quick, effective remedy.
I cut the windshield from a plastic cake
container my supermarket provided free of
charge. Ask for one. If they refuse, you can
buy a cake and eat it!
The seat and headrest are carved from
balsa block and brushed with one coat of
Insignia Orange Aero Gloss. It imparts an
almost suedelike appearance. “Leo,” the pilot,
had to have his shoulders trimmed to fit in the
narrow cockpit. I repainted him with my
wife’s acrylics to match the model.
(References to “Leo” stem from the pilot
figure’s uncanny resemblance to a friend and
fellow RCer, Leo Desmarais.)
Hinging: I used cyanoacrylate hinges
throughout, but regardless of the type you
should have at least two on each elevator half,
three on the rudder, and four—equidistant—
along each aileron. Mounting procedures vary,
depending on the type chosen, and hingeinstallation
instruction is beyond the scope of
this article.
No matter what type of hinge you use,
make sure the movable surfaces fit closely to
the fixed surfaces. Gaps give birth to control
flutter, which can end an otherwise perfect
flying day.
Assembly: Since this is probably not your
first scratch build, I’ll be brief. There is
nothing unusual about the model and
assembly is straightforward
Assuming that the covering job is finished
and the elevator is hinged, insert the stabilizer
into its slot. Make sure it’s straight using a
string from the nose to the elevator tips. Mark
the stabilizer where it joins the fuselage, top
and bottom.
Remove the stabilizer and then remove the
covering that will be within the slot.
Permanently adhere the stabilizer, with
cyanoacrylate or epoxy, and hook up the
control hardware.
Drill the LG to accept the 1/4-20 nylon
mounting bolts. If the wheel pants haven’t
been assembled and painted and the wheels
haven’t been mounted, you haven’t been
reading far enough ahead!
Assemble the wings and fit them to the
fuselage. With the wings seated, carefully drill
9/32-inch holes through the centers of the wing
reinforcement pads into the rear wing
mounting plate.
Remove the wing and then further drill the
mounting plate to accept the captive 1/4-20
nuts. Epoxy them in place on the backside.
When they are set, reinstall the wing and
insert the 1/4-20 nylon bolts. Screw them into
the mounting plate slightly more than finger
tight.
Check the wing-to-stabilizer angle of
incidence using your favorite method; I use a
Great Planes laser setup. If your build is
accurate, it should be 0°-.5°. If it isn’t, make it
so. You can correct it several degrees either
way by removing or adding material to the
rear part of the wing saddle.
Balancing and Flying: I suggest a slightly
nose-heavy configuration for the first flights.
The balance point should fall one-third back
from the LE, or approximately where the LE
planking ends. Being an RC novice, I have
left the balance point there. If you’re more
experienced, you may find that a slightly more
aft point allows for better aerobatics.
This airplane has a thin symmetrical wing,
a somewhat short tail-moment arm, and high
wing loading; therefore, it flies like a
warbird—fast and without self-righting
properties. I programmed flaperons to help
during landings. Keep power on during
approach. As does a warbird, the Golden Era
likes to come in under power.
The large control surfaces beg dual rate
and exponential programming. This will allow
the experienced pilot to burn holes in the sky
while the less confident can fly it around
without working up a sweat.
The deep fuselage makes for easy knife
edge, and the slight wingtip washout and
aileron configuration help to keep it from
falling out of the sky at relatively low speeds.
This is not a good design for a first lowwing
sport airplane. It is satisfying for the
intermediate pilot and will draw attention at
the club field.
Electric Dreams: I gave little consideration to
making this aircraft light beyond what was
necessary for good 60-power performance. It
came in at slightly more than 9 pounds dry.
An electric conversion could include fewer
doublers, thinner and less planking, more
lightening holes, and a lighter LG assembly.
Several pounds could probably be shaved off
easily, making the wing loading nearer to a
more acceptable 20 ounces per square foot.
Being an old FF Gas aficionado, I revel in
the smell of nitro fuel in the morning, and the
postflight cleanup is akin to a labor of love.
I’ll leave it to you wattage mavens to do the
converting, but I’d love to see the results! MA
Fred Randall
[email protected]
Sources:
Short kit (1/8 light-plywood parts, 1/4 plywood
parts, 3/8 balsa rudder and elevator parts):
Creative Hobbies
(508) 473-8259
www.creativehobbies.net
Balsa, plywood stock:
National Balsa Co.
(413) 277-9500
www.nationalbalsa.com/
Composite tubing;
Kite Studio
(610) 395-3560
www.kitebuilder.com/
Fiberglass cowl:
Fiberglass Specialties
(479) 359-2429
www.fiberglassspecialtiesinc.com
Hardware, accessories:
Du-Bro
(800) 848-9411
http://dubro.com
Landing gear, wheel pants, AeroKote:
Sig Manufacturing
(641) 623-5154
www.sigmfg.com
32 MODEL AVIATION
05sig1.QXD 3/25/08 10:09 AM Page 32
Edition: Model Aviation - 2008/05
Page Numbers: 18,19,20,21,22,23,24,28,31,32
I HAVE ALWAYS admired racing aircraft of the so-called “Golden Age
of Aviation”: an era that extended from the end of World War I to the
onset of World War II. It was the time of rakish designs, open cockpits,
and “flying by the seat of one’s pants.”
Aircraft designs of the time were largely grand
experiments, and from those experiments
emerged the Granville Brothers’ Gee Bee series,
the Hughes H-1 racer, the Travel Air Mystery Ship,
the Hall Bulldog, and the rest of the list, which is too
numerous to include here.
I was weary of going to our flying field and finding almost
nothing between ARF training models, sticks, and the usual bunch of 3-D
ARFs. I realized that if I wanted something with a style I liked, I’d
have to build my own.
Accordingly, I made a couple pencil sketches, loaded
ModelCAD 3000 into my PC, and sat down at my electronic
drawing board to play. The Golden Era 60 is the result.
Although this airplane is conventional in its construction, it is
unsuitable for a first scratch-building project. This article assumes
that the builder has some experience beyond ARF assembly and is
familiar with common building techniques.
Unless you get the laser-cut “short kit” I’ll tell you about, you shouldn’t attempt this build without a scroll saw
or band saw, a Dremel or other rotary tool, and the usual collection of hand tools. The judicious use of a square and
straightedge is necessary throughout construction if you expect to manufacture a straight, easy-to-trim aircraft.
If the previous paragraphs haven’t discouraged you, we can proceed.
18 MODEL AVIATION
BY FRED RANDALL
A Williams Brothers Sportsman pilot bust complements the
open cockpit. Enamel brush paint can be spray-fixed with a
fuelproof clear coat.
Grooving through the open sky, the Golden Era 60 handles as
the popular Stick models do but has the looks of a 1930s
racer.
The grunt of a .60-size engine adds thrills
to this pioneer-reminiscent building project
05sig1.QXD 3/25/08 10:33 AM Page 18
Materials: Creative Hobbies of Mendon, Massachusetts, sells a short
kit of laser-cut 1/8 light plywood, 1/4 plywood, and 3/8 balsa parts at a
reasonable cost. These accurate precut components and a full-size
rolled plans set from MA will greatly simplify construction. It
eliminates tedium, and what remains is the equivalent of building a
good kit.
Regardless of whether or not you purchase the short kit, I suggest
that you have all fabricated parts (wing ribs, fuselage formers, etc.) on
hand before starting the build.
The landing gear and wheel pants on the original are Four-Star 120
parts ordered from Sig Manufacturing. I suggest that builders use the
same parts since they are a good match appearancewise, they fit the
gear mounting plates designed into the fuselage, and using other units
may significantly change the balance point. But if you prefer to
fabricate your own landing gear, have at it!
I did not design this airplane to be superlight since it is not
intended for “3-D.” It has an allup
weight of approximately
9 pounds and a wing
loading of roughly 26
ounces per square foot.
However, it is extremely
strong. This model is
extensively planked,
including wing
May 2008 19
After a full-power run of roughly 50 feet, the model lifts off smoothly.
The wide-track gear absorbs many of the bumps in the grass.
The former positions have been marked on the fuselage sides,
and the firewall assembly has been epoxied in place.
capstrips, and composite tubing is used for the LE and the main spar.
CONSTRUCTION
Fuselage: Although I usually begin with the wings, the fuselage was
my starting point for this project.
The first task was selecting the 1/8 balsa for the fuselage sides. The
importance of matching the side sheets’ hardness and grain cannot be
stressed enough. If the balsa is poorly matched, it will be next to
impossible to make a straight fuselage.
The fuselage sides’ maximum height is approximately 7 inches. I
used matched 4-inch-wide, 1/8 balsa sheets. Cement them together with
cyanoacrylate before cutting them to shape. (In the remainder of this
document, cyanoacrylate means medium cyanoacrylate unless
otherwise specified.)
After you have cut the balsa sides to shape, use cyanoacrylate to
glue the 1/8 plywood fuselage doublers in place. Be careful; it is easier
than you can imagine to end up with two right or two left sides.
Adhere, with cyanoacrylate, the doubler to the bottom of former F1.
After the fuselage doublers have set, epoxy and clamp the two
landing-gear (LG) and hatch-support rails to the fuselage doublers.
Refer to the plans for position. Make sure to wipe off any excess epoxy
from around the perimeter with alcohol.
Epoxy the 1/8 plywood firewall doubler to the 1/4 plywood firewall.
(Epoxy means 30-minute epoxy unless otherwise specified.)
Lay the fuselage plans on your building board, protecting them with
waxed paper or the like. With the plans as a guide, use a square
referenced to the top of the fuselage sides to mark the position of all
formers on the inside of both fuselage sides.
05sig1.QXD 3/25/08 10:44 AM Page 19
20 MODEL AVIATION
Formers F1 and F2 have been put in place, and the servo plate has
been mounted between them.
With the fuselage wide open, it’s a good time to fit the fuel tank.
Silicone sealant will be used to mount the tank permanently.
The left side has been epoxied in place after a careful alignment
check. Notice how the rear wing mount is locked into cutouts in
the doubler.
Bevel the tail post and then glue it in place. Dry-fit the fin and the
remaining formers to assure good alignment.
The tail-wheel mount area is supported by a 1/8 plywood plate.
It’s recessed to allow room for balsa, which will be sanded flush
with the fuselage sides.
Scrap 3/8 balsa sheet is substituted for the stabilizer during
preliminary alignment. The forward stringers are added at
this point.
05sig1.QXD 3/25/08 11:26 AM Page 20
May 2008 21
Once the sheeting is complete, it’s a good time to test-fit the
landing gear and engine mount. The cockpit area can be detailed
at this time.
Notice the smart use of carbon-fiber tubing to form the LE and
support the wing spar. The wing will be sheeted next.
Above: The completed one-piece wing is mounted with dowel pins
and nylon bolts. The light tail structure is designed to keep the
weight mass balanced on the recommended CG.
Left: Build the cowl from wood or purchase the fiberglass
version from Fiberglass Specialties. The mounting screws are
hidden inside.
Type: RC sport
Pilot skill level:
Intermediate to expert
Wingspan: 65.25 inches
Flying weight: 10 pounds
Wing area: 792 square inches
Wing loading: 26-27 ounces/square foot
Length: 51 inches
Engine: GMS .61 glow
Tank: Modeltech 360cc
Flight battery: Four cells, 4.8 volts
Radio: Spektrum DX7 system, AR7000 receiver, three DS821
and two Hitec HS-625MG servos
Spinner: Du-Bro (LXE 149) 3 inch
Construction: Balsa and light plywood
Covering/finish: Builder’s choice (Sig AeroKote is recommended.)
Photos by the author
05sig1.QXD 3/25/08 10:58 AM Page 21
22 MODEL AVIATION
The GMS .61 two-stroke engine hides inside the spacious cowl. A
four-stroke .82-1.00 would also fit this model neatly.
Stock Sig Four-Star 120 wheel pants complete this sport model’s 1930s racing look. The long and tall fuselage offers good knifeedge
performance.
Put the right fuselage side in place on the plans and secure it. Using
a square to position it, epoxy the firewall/doubler assembly flush with
the front of the fuselage side. When it has set, Formers F1 and F2 can
be cemented in place using cyanoacrylate. Position the servo tray in the
slots provided in formers F1 and F2, and secure it with cyanoacrylate.
Fashion the 11/2 x 47/16-inch rear wing anchor plate from 1/4
plywood. Do not drill it. Temporarily insert it into the slot provided in
the fuselage doubler. Test-fit the left side for perfect alignment. The
firewall assembly, the formers, the wing anchor plate, and both
fuselage sides must align properly.
When you are satisfied, remove the left side and apply epoxy to the
edge of the firewall assembly and the wing anchor plate edges that
mate with F2 and the fuselage sides. Apply cyanoacrylate to the mating
edges of F1 and F2. Put the left side back in position.
Place a book or similar weight on top to ensure a good bond, and
then take a break.
Shape the tail post from 1/2 x 3/4 x 13-inch balsa. It should taper
from 1/2 inch at the LE to 3/16 inch at the TE. It is important that this
piece be symmetrical. It will be further shaped and cut for the stabilizer
later, during fuselage assembly.
Notch the front roughly 1/8 inch deep to accept the light-plywood
fin. Refer to the plans for notch location.
With the fuselage secured to the top view of the plans, use T-pins to
temporarily hold the rear of the fuselage sides together, sandwiching
the tail post into position. The tail post should be centered over the
plans and flush with the bottom and back of the fuselage sides. Ensure
that the tail post is vertical in both axes when referenced to the fuselage
sides.
Reposition the pins until these conditions are met. Temporarily tack
the assembly together using a few drops of thin cyanoacrylate.
Remove the T-pins and recheck alignment. When you are satisfied,
flow in more thin cyanoacrylate for a permanent bond.
Install the remaining formers using cyanoacrylate. If necessary, use
rubber bands around the fuselage to ensure a full-contact fit.
Employing the plywood fin as a pattern, make doublers
approximately 3/8 inch wide from 3/16 balsa sheet. The doublers enable
a smooth transition between the planking and the fin. There is a
detailed drawing on the fuselage plans.
Cement the balsa doublers to both sides of the fin with
cyanoacrylate. Cut 1/8-inch gaps in the doubler where the fin fits into
05sig1.QXD 3/25/08 10:06 AM Page 22
the F5 and F6 notches and another at the rear
of the fin where it will be inserted into the
tail-post notch. Install the fin and secure it
with cyanoacrylate, and then sand the top of
the tail post to blend with the fin and doublers.
Cut the cockpit floor from 1/8 balsa sheet.
See the fuselage top view for the pattern.
Using cyanoacrylate, install the floor as
indicated and test-fit the dash panel. The dashpanel
pattern is somewhat oversize; you must
sand it to mount flush with the cockpit floor
and F3. Use a long sanding block to blend the
panel with the fuselage.
Install former F8. Fit it between F6 and the
tail post. See the plans for location. Trim it as
necessary for a proper fit. Ensure that F8 is at
right angles to, and level with, the top of the
notch in the fuselage sides. Take your time;
this establishes proper alignment and angle of
incidence.
I found it helpful to cut a piece of 3/8 balsa
sheet 3 inches wide and 12-15 inches long to
use as a spacer and alignment aid. Lay it on
top of F8 to use as a temporary substitute for
the stabilizer.
Position F7 as indicated on the plans, and
snug it against the temporary spacer. Adhere
F7 in place with cyanoacrylate and remove
the spacer. Trim F7 as necessary for a proper
fit.
Install the stringers using cyanoacrylate.
The front stringers extend aft to the panel.
There are no notches in the panel, so shape
the ends of the stringers for a nice butt fit
26 MODEL AVIATION
INTRODUCING
• Safe chemistry will not explode or catch fire
• Fast charge capable – 100% in 15 minutes
• 30c continuous, 60c bursts
• Exclusive Duralite Stay Balance Circuitry built-in
to every pack – no external balancing needed
• Charge through the charge lead with a Duralite Plus
Charger or through the power lead with an A123 capable
charger like the Orbit Pocketlader
• No regulator needed for most Rx applications
• Longer life cycle than lithium polymer chemistry
LITHIUM POWER SOLUTIONS FOR EVERYTHING YOU FLY
Order toll free 877-744-3685
Shop online www.duraliteflightsystems.com
PLUS
WITH STAY BALANCE
CIRCUITRY BUILT-IN
TO EVERY PACK
against it. The rear stringers should terminate
flush with the front of the tail post.
Epoxy four 1/4-20 captive nuts to the inner
LG mounting plate. Remove your fuselage
assembly from the building board, flip it over,
and use epoxy to bond the inner LG mounting
plate to the support rails. Don’t spare the
epoxy here; the LG takes considerable abuse
(at least when I’m flying).
The battery hatch came about because the
finished model needed a bit of nose weight. I
don’t like to add lead for balance when I can
reposition something to compensate. I
relocated the flight battery forward, in a foam
nest made for perfect balance with no
additional ballast. As a bonus, you have access
to the LG support assembly, engine-mount
captive nuts, and fuel tank should something
go awry.
Fashion the battery hatch from a piece of
1/8 light plywood. It should fit nicely between
the firewall, the fuselage sides, and the LG
mounting plate. It should rest on the support
rails. Drill holes at four corners for your
selected screw hardware.
I band-sawed a small amount of
downthrust and right thrust into my engine
mounts before installation. Offset the mounts
so that the spinner will be centered at the
proper location. When positioned, drill the
firewall and install the captive nuts.
Empennage: Building this area is
straightforward, and little explanation is
necessary beyond what is on the plans. The
only item that may need clarification is the
elevator joiner.
I originally intended to use a double
pushrod for elevator control. However, I had a
nice piece of .317 composite tubing left from
the wing construction, and it seemed
reasonable to use as a torque tube to join the
elevator halves. If you prefer double pushrods,
eliminate the torque tube and the clearance
notch in the rudder.
Wings: Select the right-wing full plans and
secure them to your building board. Using
cyanoacrylate, bond an RR1 rib to an RR2.
RR1 should be inboard. This assembly forms
the root rib.
Bond an R3 to an R1. The rib with no LE
notch is an R3; it should be inboard. Refer to
the plans for confirmation.
The wing will be built using the centermost
bottom spar as a reference. Cut a piece of 1/8 x
1/4 basswood to length and secure it in place
on the plans. Use a square to position the root
rib assembly on the plans with the spar snug in
its notch. Use cyanoacrylate to adhere the root
rib assembly to the spar.
Follow suit with an R1, R2 pair. Install the
remaining ribs, and adhere them to the spar
with cyanoacrylate. All ribs’ break-off stubs
should lay flat on the plans.
R2 is slightly different; it establishes a
small amount of washout in the wingtips to
improve low-speed stability. When all ribs are
in place, cut and install the three top spars. Cut
the .317-inch composite LE to length and glue
it in place with cyanoacrylate.
You should be able to insert the composite
spar as far as shown on the plans. Test-fit it. It
05sig1.QXD 3/25/08 10:09 AM Page 26
should be snug but not distort the ribs as it
passes through. Make any adjustments needed
until this condition is met, and then remove
the spar.
Remove the wing from the plans. Install
the remaining bottom spars, and then check
the assembly for straightness. It should lay
flat, resting on the centermost bottom spar and
rib break-off stubs. Correct any twist in the
wing before proceeding.
Following the diagram below the right
wing assembly drawing, shape the TE from 1/2
x 3/8 balsa. When you are finished, glue it into
position with cyanoacrylate.
Temporarily position the 1/8 light-plywood
servo plate to the bottom of the wing. Make
sure to place it at a point that is deep enough
on the chord to ensure that a standard servo’s
body does not protrude through the top. (Ask
me why I added this instruction.)
When you are satisfied with its position,
adhere the servo plate in place with
cyanoacrylate, flush with the bottom of the
ribs. Use scrap 1/8 x 1/4 spar material to make
rails to support and stiffen it.
Use cyanoacrylate to glue the 1/8 lightplywood
wingtip in place. It should be
centered between the LE and TE and at right
angles to R2. Make spar extensions and
cement them between the rib and the tip. See
the plans for positioning. Snap off the rib
stubs and sand the areas smooth.
Remove the right wing plans from the
building board and replace them with the left.
28 MODEL AVIATION
(We don’t want two right wings, do we?)
Take a deep breath and repeat the wing
instructions.
Having completed the framing of both
wings, fabricate and add the 1/4-inch plywood
dowel support webbing and the wing
mounting dowels. Ensure that the pegs will
align with the holes in F1. The detail diagram
will aid in drilling the peg holes and installing
the pegs.
Cut the .505 composite-tubing spar to
length and test-fit the joined wings. Be sure to
allow for the 1/16-inch planking. This work is
critical; it affects the final wing leveling and
wing/stabilizer angle of incidence. If the wing
is too wide, it does no harm to remove some
material from the TE where it fits within the
fuselage.
Wing Planking: The LE planking is a 1/16 x
12 x 36 balsa “wing skin.” The plans indicate
the areas that are covered with planking. Do
not trim the width until it is installed.
Thoroughly soak the balsa with Windex and
wait several minutes before attempting to
make the sharp LE bend.
When the balsa is pliable enough to make
the bend, start at the top, rear 1/8 x 1/4 spar.
Use cyanoacrylate to bond the balsa to the
spar. Clamp it along its length until the
adhesive sets.
Work slowly. Starting at the middle of the
wing and moving outward, glue, with
cyanoacrylate, the ribs, front spar, LE, etc.,
until you have the entire wing skin bonded,
top and bottom. If you do the job properly,
the planking should be tight, with no bulges.
Trim whatever planking extends beyond the
center, bottom spar.
Install the remaining planking and the rib
capstrips. It’s better to plank the entire
wingtip on both sides; it makes the covering
job easier and neater. When you have
finished both wings, prepare them to accept
covering.
Fuselage Planking: Starting with the front
deck, plank the fuselage with 3/32 sheet balsa.
I made a cardboard pattern and used it as a
guide to cut the planking for the forward
“hood,” from the firewall to F3. Soak the
planking for installation. After test-fitting, use
cyanoacrylate to install it.
Make the 3/32 balsa planking for the area
aft of the cockpit. Use a single piece to cover
from F5 to the tail post and up to the 1/8-inch
top stringer on each side. This piece should
cover the tail post and terminate at the back
of the fuselage. The bend is fairly gentle and
should pose little problem. When you are
satisfied with the fit, glue the planking in
place with cyanoacrylate. Shape and add the
pieces that go between the top stringer and
the fin doublers.
When the cyanoacrylate has set, use a
sanding block to shape the back of the tail
post so it is flat. Blend the planking into the
fin doubler and the fuselage sides.
Cut two pieces of 3/8 balsa stock 11/4
inches wide and 83/8 inches long. These fit
between F5 and the instrument panel. Shape
the fronts to fit flush with the panel. Position
them so they are 3/32 inch inboard of the
05sig1.QXD 3/25/08 10:09 AM Page 28
fuselage sides, and adhere them in place with
cyanoacrylate.
Sand both sides so they follow the contour
of the panel and F5. These provide support for
the planking around the cockpit. See photos
for clarification.
Shape and fit the planking around the
cockpit. When you are satisfied, sand
everything flush. Use balsa filler to fill any
gaps, and finish-sand the entire fuselage
smooth and even. Cut—but do not install—
the 3/32-inch bottom piece. With the fuselage
planking complete, cut the tail post for the
stabilizer. This marks the end of the planking
phase.
Ailerons: These are cut from 3/8 x 3 tapered
balsa. See the wing plans for patterns.
Before shaping the aileron LE, use
cyanoacrylate to laminate a matching piece of
1/16 hard balsa to the top to strengthen the
structure. Temporarily attach the ailerons to
the wing with a few small spots of
cyanoacrylate, and then block-sand the bottom
of the ailerons to blend with the wing TE.
Remove the ailerons using debonder, and
sand the LEs for hinging.
Pushrods, Etc.: Install the pushrod tubes.
Holes are provided in F4 to support the front
of the pushrod tubes. I crossed mine in the
middle and they exited the fuselage on the
opposite side. I used a small cable tie at the
crossover point to support and stiffen the
tubes. Once the pushrod tubes are installed,
use cyanoacrylate to glue the bottom piece in
place. Sand the joint smooth.
A 360cc tank (Global Hobby part 120074)
I had on hand was employed in the original. I
used silicone adhesive to bond the front of the
fuel tank to the inside of the firewall, with the
neck protruding through the provided hole. I
Dremeled the bottom of the hole in F1 to
match the contour of the rear of the tank (see
dotted line on F1 pattern) and used silicon
adhesive there too.
Drill a hole in the firewall and F1 for the
throttle pushrod, positioned to make a straight
run from the carburetor to the throttle servo.
The fuselage servo linkages are typical. Use
your favorite clevises, etc. The wing servos
and linkages are installed after covering.
There are large openings in the ribs that
provide passage for the wires from the servos.
Make small openings in the planking inboard,
on the top of the wing, for the servo wires to
exit.
Insert the .505 composite wing spar in one
(either) wing up to the rib just past the servo
and glue it in place inside the root rib (only)
with cyanoacrylate.
It is unnecessary to cement the wing halves
together. It is much easier to store and
transport them separately. The mounting pegs
and nylon bolts will align and secure the wings
to the fuselage, and the spar is more than
strong enough to prevent them from folding.
Cowl: For the original model I made my cowl
from laminations of 3/8 balsa. Several good
articles have been written about the subject.
I also made a balsa cowl for a second
airplane, and I sent it out for Fiberglass
Specialties to duplicate in fiberglass. These
cowls are available for purchase if you don’t
want to expend the effort to fabricate your
own. Either way, the weight difference is
slight so the balance remains unchanged.
Covering: It seems like everyone has a
favorite covering material; I am no different. I
prefer Sig AeroKote, which I used on the
entire aircraft.
I don’t care for the elaborate, multicolor
schemes festooned with sponsor logos that are
rampant on ARFs. Thus Brodak’s CL Oriental
was the inspiration for the color scheme I used
on the original Golden Era 60. The Oriental is
black and red; I opted for Black and Naval
Orange.
If you use black on the fuselage, throw a
white cloth over it if the model is going to sit
in the sun for a long period. The black
covering absorbs heat and loosens, and you
will be faced with a session with the iron and
heat gun when you get home.
Nuts and Bolts: I used Du-Bro heavy-duty
.40-.91 control horns (item 867) throughout.
They require a single hole for mounting and are
rugged and easy to install. A bonus is that they
adjust for angle as well as throw. I installed a
steerable tail-wheel assembly from Global
Hobby. It mounts easily and works well.
My Spektrum DX7 came with four JR
RC System is distributed by:
SIG Manufacturing Company, Inc.
P.O. Box 520 • Montezuma, Iowa 50171-0520
Web Site: www.sigmfg.com • Phone: (641)623-5154
* actual Flightsimulator screens shown
There are different ways to learn model flying. If an
experienced model flyer is not on site then the first steps can
be disappointing. At worst case you could crash your first
model. Especially for learning R/C helicopter flying the so
called "Dry Run" on a simulator is an inexpensive and
suggested method. The SimTransmitter
"Joystick" in combination with the FMS
Flightsimulator provides the ideal virtual
beginner airplane or helicopter "model".
Simply plug the SimTransmitter into a free USB
port and configure it as a joystick.
SimTransmitter
Order No. RCSSIM062 - $39.99
* Prices at Participating Dealers
*
05sig1.QXD 3/25/08 10:09 AM Page 31
servos. Three are used in the fuselage, and
Hitec HD servos are used for the ailerons.
The Spektrum dual receivers are mounted
on opposite fuselage sides using Velcro. They
are oriented to provide opposite antenna
polarity, as the installation instructions
mandate. Not having to provide routing and
an exit for a long 72 MHz antenna is a
pleasant change!
The double 1/4-inch plate used to mount
the LG is a work-around because of a
clearance issue. The wing extends forward
from the mounting recess and engages the LG
if additional clearance isn’t provided. I didn’t
realize this until too late, and the second plate
proved to be a quick, effective remedy.
I cut the windshield from a plastic cake
container my supermarket provided free of
charge. Ask for one. If they refuse, you can
buy a cake and eat it!
The seat and headrest are carved from
balsa block and brushed with one coat of
Insignia Orange Aero Gloss. It imparts an
almost suedelike appearance. “Leo,” the pilot,
had to have his shoulders trimmed to fit in the
narrow cockpit. I repainted him with my
wife’s acrylics to match the model.
(References to “Leo” stem from the pilot
figure’s uncanny resemblance to a friend and
fellow RCer, Leo Desmarais.)
Hinging: I used cyanoacrylate hinges
throughout, but regardless of the type you
should have at least two on each elevator half,
three on the rudder, and four—equidistant—
along each aileron. Mounting procedures vary,
depending on the type chosen, and hingeinstallation
instruction is beyond the scope of
this article.
No matter what type of hinge you use,
make sure the movable surfaces fit closely to
the fixed surfaces. Gaps give birth to control
flutter, which can end an otherwise perfect
flying day.
Assembly: Since this is probably not your
first scratch build, I’ll be brief. There is
nothing unusual about the model and
assembly is straightforward
Assuming that the covering job is finished
and the elevator is hinged, insert the stabilizer
into its slot. Make sure it’s straight using a
string from the nose to the elevator tips. Mark
the stabilizer where it joins the fuselage, top
and bottom.
Remove the stabilizer and then remove the
covering that will be within the slot.
Permanently adhere the stabilizer, with
cyanoacrylate or epoxy, and hook up the
control hardware.
Drill the LG to accept the 1/4-20 nylon
mounting bolts. If the wheel pants haven’t
been assembled and painted and the wheels
haven’t been mounted, you haven’t been
reading far enough ahead!
Assemble the wings and fit them to the
fuselage. With the wings seated, carefully drill
9/32-inch holes through the centers of the wing
reinforcement pads into the rear wing
mounting plate.
Remove the wing and then further drill the
mounting plate to accept the captive 1/4-20
nuts. Epoxy them in place on the backside.
When they are set, reinstall the wing and
insert the 1/4-20 nylon bolts. Screw them into
the mounting plate slightly more than finger
tight.
Check the wing-to-stabilizer angle of
incidence using your favorite method; I use a
Great Planes laser setup. If your build is
accurate, it should be 0°-.5°. If it isn’t, make it
so. You can correct it several degrees either
way by removing or adding material to the
rear part of the wing saddle.
Balancing and Flying: I suggest a slightly
nose-heavy configuration for the first flights.
The balance point should fall one-third back
from the LE, or approximately where the LE
planking ends. Being an RC novice, I have
left the balance point there. If you’re more
experienced, you may find that a slightly more
aft point allows for better aerobatics.
This airplane has a thin symmetrical wing,
a somewhat short tail-moment arm, and high
wing loading; therefore, it flies like a
warbird—fast and without self-righting
properties. I programmed flaperons to help
during landings. Keep power on during
approach. As does a warbird, the Golden Era
likes to come in under power.
The large control surfaces beg dual rate
and exponential programming. This will allow
the experienced pilot to burn holes in the sky
while the less confident can fly it around
without working up a sweat.
The deep fuselage makes for easy knife
edge, and the slight wingtip washout and
aileron configuration help to keep it from
falling out of the sky at relatively low speeds.
This is not a good design for a first lowwing
sport airplane. It is satisfying for the
intermediate pilot and will draw attention at
the club field.
Electric Dreams: I gave little consideration to
making this aircraft light beyond what was
necessary for good 60-power performance. It
came in at slightly more than 9 pounds dry.
An electric conversion could include fewer
doublers, thinner and less planking, more
lightening holes, and a lighter LG assembly.
Several pounds could probably be shaved off
easily, making the wing loading nearer to a
more acceptable 20 ounces per square foot.
Being an old FF Gas aficionado, I revel in
the smell of nitro fuel in the morning, and the
postflight cleanup is akin to a labor of love.
I’ll leave it to you wattage mavens to do the
converting, but I’d love to see the results! MA
Fred Randall
[email protected]
Sources:
Short kit (1/8 light-plywood parts, 1/4 plywood
parts, 3/8 balsa rudder and elevator parts):
Creative Hobbies
(508) 473-8259
www.creativehobbies.net
Balsa, plywood stock:
National Balsa Co.
(413) 277-9500
www.nationalbalsa.com/
Composite tubing;
Kite Studio
(610) 395-3560
www.kitebuilder.com/
Fiberglass cowl:
Fiberglass Specialties
(479) 359-2429
www.fiberglassspecialtiesinc.com
Hardware, accessories:
Du-Bro
(800) 848-9411
http://dubro.com
Landing gear, wheel pants, AeroKote:
Sig Manufacturing
(641) 623-5154
www.sigmfg.com
32 MODEL AVIATION
05sig1.QXD 3/25/08 10:09 AM Page 32
Edition: Model Aviation - 2008/05
Page Numbers: 18,19,20,21,22,23,24,28,31,32
I HAVE ALWAYS admired racing aircraft of the so-called “Golden Age
of Aviation”: an era that extended from the end of World War I to the
onset of World War II. It was the time of rakish designs, open cockpits,
and “flying by the seat of one’s pants.”
Aircraft designs of the time were largely grand
experiments, and from those experiments
emerged the Granville Brothers’ Gee Bee series,
the Hughes H-1 racer, the Travel Air Mystery Ship,
the Hall Bulldog, and the rest of the list, which is too
numerous to include here.
I was weary of going to our flying field and finding almost
nothing between ARF training models, sticks, and the usual bunch of 3-D
ARFs. I realized that if I wanted something with a style I liked, I’d
have to build my own.
Accordingly, I made a couple pencil sketches, loaded
ModelCAD 3000 into my PC, and sat down at my electronic
drawing board to play. The Golden Era 60 is the result.
Although this airplane is conventional in its construction, it is
unsuitable for a first scratch-building project. This article assumes
that the builder has some experience beyond ARF assembly and is
familiar with common building techniques.
Unless you get the laser-cut “short kit” I’ll tell you about, you shouldn’t attempt this build without a scroll saw
or band saw, a Dremel or other rotary tool, and the usual collection of hand tools. The judicious use of a square and
straightedge is necessary throughout construction if you expect to manufacture a straight, easy-to-trim aircraft.
If the previous paragraphs haven’t discouraged you, we can proceed.
18 MODEL AVIATION
BY FRED RANDALL
A Williams Brothers Sportsman pilot bust complements the
open cockpit. Enamel brush paint can be spray-fixed with a
fuelproof clear coat.
Grooving through the open sky, the Golden Era 60 handles as
the popular Stick models do but has the looks of a 1930s
racer.
The grunt of a .60-size engine adds thrills
to this pioneer-reminiscent building project
05sig1.QXD 3/25/08 10:33 AM Page 18
Materials: Creative Hobbies of Mendon, Massachusetts, sells a short
kit of laser-cut 1/8 light plywood, 1/4 plywood, and 3/8 balsa parts at a
reasonable cost. These accurate precut components and a full-size
rolled plans set from MA will greatly simplify construction. It
eliminates tedium, and what remains is the equivalent of building a
good kit.
Regardless of whether or not you purchase the short kit, I suggest
that you have all fabricated parts (wing ribs, fuselage formers, etc.) on
hand before starting the build.
The landing gear and wheel pants on the original are Four-Star 120
parts ordered from Sig Manufacturing. I suggest that builders use the
same parts since they are a good match appearancewise, they fit the
gear mounting plates designed into the fuselage, and using other units
may significantly change the balance point. But if you prefer to
fabricate your own landing gear, have at it!
I did not design this airplane to be superlight since it is not
intended for “3-D.” It has an allup
weight of approximately
9 pounds and a wing
loading of roughly 26
ounces per square foot.
However, it is extremely
strong. This model is
extensively planked,
including wing
May 2008 19
After a full-power run of roughly 50 feet, the model lifts off smoothly.
The wide-track gear absorbs many of the bumps in the grass.
The former positions have been marked on the fuselage sides,
and the firewall assembly has been epoxied in place.
capstrips, and composite tubing is used for the LE and the main spar.
CONSTRUCTION
Fuselage: Although I usually begin with the wings, the fuselage was
my starting point for this project.
The first task was selecting the 1/8 balsa for the fuselage sides. The
importance of matching the side sheets’ hardness and grain cannot be
stressed enough. If the balsa is poorly matched, it will be next to
impossible to make a straight fuselage.
The fuselage sides’ maximum height is approximately 7 inches. I
used matched 4-inch-wide, 1/8 balsa sheets. Cement them together with
cyanoacrylate before cutting them to shape. (In the remainder of this
document, cyanoacrylate means medium cyanoacrylate unless
otherwise specified.)
After you have cut the balsa sides to shape, use cyanoacrylate to
glue the 1/8 plywood fuselage doublers in place. Be careful; it is easier
than you can imagine to end up with two right or two left sides.
Adhere, with cyanoacrylate, the doubler to the bottom of former F1.
After the fuselage doublers have set, epoxy and clamp the two
landing-gear (LG) and hatch-support rails to the fuselage doublers.
Refer to the plans for position. Make sure to wipe off any excess epoxy
from around the perimeter with alcohol.
Epoxy the 1/8 plywood firewall doubler to the 1/4 plywood firewall.
(Epoxy means 30-minute epoxy unless otherwise specified.)
Lay the fuselage plans on your building board, protecting them with
waxed paper or the like. With the plans as a guide, use a square
referenced to the top of the fuselage sides to mark the position of all
formers on the inside of both fuselage sides.
05sig1.QXD 3/25/08 10:44 AM Page 19
20 MODEL AVIATION
Formers F1 and F2 have been put in place, and the servo plate has
been mounted between them.
With the fuselage wide open, it’s a good time to fit the fuel tank.
Silicone sealant will be used to mount the tank permanently.
The left side has been epoxied in place after a careful alignment
check. Notice how the rear wing mount is locked into cutouts in
the doubler.
Bevel the tail post and then glue it in place. Dry-fit the fin and the
remaining formers to assure good alignment.
The tail-wheel mount area is supported by a 1/8 plywood plate.
It’s recessed to allow room for balsa, which will be sanded flush
with the fuselage sides.
Scrap 3/8 balsa sheet is substituted for the stabilizer during
preliminary alignment. The forward stringers are added at
this point.
05sig1.QXD 3/25/08 11:26 AM Page 20
May 2008 21
Once the sheeting is complete, it’s a good time to test-fit the
landing gear and engine mount. The cockpit area can be detailed
at this time.
Notice the smart use of carbon-fiber tubing to form the LE and
support the wing spar. The wing will be sheeted next.
Above: The completed one-piece wing is mounted with dowel pins
and nylon bolts. The light tail structure is designed to keep the
weight mass balanced on the recommended CG.
Left: Build the cowl from wood or purchase the fiberglass
version from Fiberglass Specialties. The mounting screws are
hidden inside.
Type: RC sport
Pilot skill level:
Intermediate to expert
Wingspan: 65.25 inches
Flying weight: 10 pounds
Wing area: 792 square inches
Wing loading: 26-27 ounces/square foot
Length: 51 inches
Engine: GMS .61 glow
Tank: Modeltech 360cc
Flight battery: Four cells, 4.8 volts
Radio: Spektrum DX7 system, AR7000 receiver, three DS821
and two Hitec HS-625MG servos
Spinner: Du-Bro (LXE 149) 3 inch
Construction: Balsa and light plywood
Covering/finish: Builder’s choice (Sig AeroKote is recommended.)
Photos by the author
05sig1.QXD 3/25/08 10:58 AM Page 21
22 MODEL AVIATION
The GMS .61 two-stroke engine hides inside the spacious cowl. A
four-stroke .82-1.00 would also fit this model neatly.
Stock Sig Four-Star 120 wheel pants complete this sport model’s 1930s racing look. The long and tall fuselage offers good knifeedge
performance.
Put the right fuselage side in place on the plans and secure it. Using
a square to position it, epoxy the firewall/doubler assembly flush with
the front of the fuselage side. When it has set, Formers F1 and F2 can
be cemented in place using cyanoacrylate. Position the servo tray in the
slots provided in formers F1 and F2, and secure it with cyanoacrylate.
Fashion the 11/2 x 47/16-inch rear wing anchor plate from 1/4
plywood. Do not drill it. Temporarily insert it into the slot provided in
the fuselage doubler. Test-fit the left side for perfect alignment. The
firewall assembly, the formers, the wing anchor plate, and both
fuselage sides must align properly.
When you are satisfied, remove the left side and apply epoxy to the
edge of the firewall assembly and the wing anchor plate edges that
mate with F2 and the fuselage sides. Apply cyanoacrylate to the mating
edges of F1 and F2. Put the left side back in position.
Place a book or similar weight on top to ensure a good bond, and
then take a break.
Shape the tail post from 1/2 x 3/4 x 13-inch balsa. It should taper
from 1/2 inch at the LE to 3/16 inch at the TE. It is important that this
piece be symmetrical. It will be further shaped and cut for the stabilizer
later, during fuselage assembly.
Notch the front roughly 1/8 inch deep to accept the light-plywood
fin. Refer to the plans for notch location.
With the fuselage secured to the top view of the plans, use T-pins to
temporarily hold the rear of the fuselage sides together, sandwiching
the tail post into position. The tail post should be centered over the
plans and flush with the bottom and back of the fuselage sides. Ensure
that the tail post is vertical in both axes when referenced to the fuselage
sides.
Reposition the pins until these conditions are met. Temporarily tack
the assembly together using a few drops of thin cyanoacrylate.
Remove the T-pins and recheck alignment. When you are satisfied,
flow in more thin cyanoacrylate for a permanent bond.
Install the remaining formers using cyanoacrylate. If necessary, use
rubber bands around the fuselage to ensure a full-contact fit.
Employing the plywood fin as a pattern, make doublers
approximately 3/8 inch wide from 3/16 balsa sheet. The doublers enable
a smooth transition between the planking and the fin. There is a
detailed drawing on the fuselage plans.
Cement the balsa doublers to both sides of the fin with
cyanoacrylate. Cut 1/8-inch gaps in the doubler where the fin fits into
05sig1.QXD 3/25/08 10:06 AM Page 22
the F5 and F6 notches and another at the rear
of the fin where it will be inserted into the
tail-post notch. Install the fin and secure it
with cyanoacrylate, and then sand the top of
the tail post to blend with the fin and doublers.
Cut the cockpit floor from 1/8 balsa sheet.
See the fuselage top view for the pattern.
Using cyanoacrylate, install the floor as
indicated and test-fit the dash panel. The dashpanel
pattern is somewhat oversize; you must
sand it to mount flush with the cockpit floor
and F3. Use a long sanding block to blend the
panel with the fuselage.
Install former F8. Fit it between F6 and the
tail post. See the plans for location. Trim it as
necessary for a proper fit. Ensure that F8 is at
right angles to, and level with, the top of the
notch in the fuselage sides. Take your time;
this establishes proper alignment and angle of
incidence.
I found it helpful to cut a piece of 3/8 balsa
sheet 3 inches wide and 12-15 inches long to
use as a spacer and alignment aid. Lay it on
top of F8 to use as a temporary substitute for
the stabilizer.
Position F7 as indicated on the plans, and
snug it against the temporary spacer. Adhere
F7 in place with cyanoacrylate and remove
the spacer. Trim F7 as necessary for a proper
fit.
Install the stringers using cyanoacrylate.
The front stringers extend aft to the panel.
There are no notches in the panel, so shape
the ends of the stringers for a nice butt fit
26 MODEL AVIATION
INTRODUCING
• Safe chemistry will not explode or catch fire
• Fast charge capable – 100% in 15 minutes
• 30c continuous, 60c bursts
• Exclusive Duralite Stay Balance Circuitry built-in
to every pack – no external balancing needed
• Charge through the charge lead with a Duralite Plus
Charger or through the power lead with an A123 capable
charger like the Orbit Pocketlader
• No regulator needed for most Rx applications
• Longer life cycle than lithium polymer chemistry
LITHIUM POWER SOLUTIONS FOR EVERYTHING YOU FLY
Order toll free 877-744-3685
Shop online www.duraliteflightsystems.com
PLUS
WITH STAY BALANCE
CIRCUITRY BUILT-IN
TO EVERY PACK
against it. The rear stringers should terminate
flush with the front of the tail post.
Epoxy four 1/4-20 captive nuts to the inner
LG mounting plate. Remove your fuselage
assembly from the building board, flip it over,
and use epoxy to bond the inner LG mounting
plate to the support rails. Don’t spare the
epoxy here; the LG takes considerable abuse
(at least when I’m flying).
The battery hatch came about because the
finished model needed a bit of nose weight. I
don’t like to add lead for balance when I can
reposition something to compensate. I
relocated the flight battery forward, in a foam
nest made for perfect balance with no
additional ballast. As a bonus, you have access
to the LG support assembly, engine-mount
captive nuts, and fuel tank should something
go awry.
Fashion the battery hatch from a piece of
1/8 light plywood. It should fit nicely between
the firewall, the fuselage sides, and the LG
mounting plate. It should rest on the support
rails. Drill holes at four corners for your
selected screw hardware.
I band-sawed a small amount of
downthrust and right thrust into my engine
mounts before installation. Offset the mounts
so that the spinner will be centered at the
proper location. When positioned, drill the
firewall and install the captive nuts.
Empennage: Building this area is
straightforward, and little explanation is
necessary beyond what is on the plans. The
only item that may need clarification is the
elevator joiner.
I originally intended to use a double
pushrod for elevator control. However, I had a
nice piece of .317 composite tubing left from
the wing construction, and it seemed
reasonable to use as a torque tube to join the
elevator halves. If you prefer double pushrods,
eliminate the torque tube and the clearance
notch in the rudder.
Wings: Select the right-wing full plans and
secure them to your building board. Using
cyanoacrylate, bond an RR1 rib to an RR2.
RR1 should be inboard. This assembly forms
the root rib.
Bond an R3 to an R1. The rib with no LE
notch is an R3; it should be inboard. Refer to
the plans for confirmation.
The wing will be built using the centermost
bottom spar as a reference. Cut a piece of 1/8 x
1/4 basswood to length and secure it in place
on the plans. Use a square to position the root
rib assembly on the plans with the spar snug in
its notch. Use cyanoacrylate to adhere the root
rib assembly to the spar.
Follow suit with an R1, R2 pair. Install the
remaining ribs, and adhere them to the spar
with cyanoacrylate. All ribs’ break-off stubs
should lay flat on the plans.
R2 is slightly different; it establishes a
small amount of washout in the wingtips to
improve low-speed stability. When all ribs are
in place, cut and install the three top spars. Cut
the .317-inch composite LE to length and glue
it in place with cyanoacrylate.
You should be able to insert the composite
spar as far as shown on the plans. Test-fit it. It
05sig1.QXD 3/25/08 10:09 AM Page 26
should be snug but not distort the ribs as it
passes through. Make any adjustments needed
until this condition is met, and then remove
the spar.
Remove the wing from the plans. Install
the remaining bottom spars, and then check
the assembly for straightness. It should lay
flat, resting on the centermost bottom spar and
rib break-off stubs. Correct any twist in the
wing before proceeding.
Following the diagram below the right
wing assembly drawing, shape the TE from 1/2
x 3/8 balsa. When you are finished, glue it into
position with cyanoacrylate.
Temporarily position the 1/8 light-plywood
servo plate to the bottom of the wing. Make
sure to place it at a point that is deep enough
on the chord to ensure that a standard servo’s
body does not protrude through the top. (Ask
me why I added this instruction.)
When you are satisfied with its position,
adhere the servo plate in place with
cyanoacrylate, flush with the bottom of the
ribs. Use scrap 1/8 x 1/4 spar material to make
rails to support and stiffen it.
Use cyanoacrylate to glue the 1/8 lightplywood
wingtip in place. It should be
centered between the LE and TE and at right
angles to R2. Make spar extensions and
cement them between the rib and the tip. See
the plans for positioning. Snap off the rib
stubs and sand the areas smooth.
Remove the right wing plans from the
building board and replace them with the left.
28 MODEL AVIATION
(We don’t want two right wings, do we?)
Take a deep breath and repeat the wing
instructions.
Having completed the framing of both
wings, fabricate and add the 1/4-inch plywood
dowel support webbing and the wing
mounting dowels. Ensure that the pegs will
align with the holes in F1. The detail diagram
will aid in drilling the peg holes and installing
the pegs.
Cut the .505 composite-tubing spar to
length and test-fit the joined wings. Be sure to
allow for the 1/16-inch planking. This work is
critical; it affects the final wing leveling and
wing/stabilizer angle of incidence. If the wing
is too wide, it does no harm to remove some
material from the TE where it fits within the
fuselage.
Wing Planking: The LE planking is a 1/16 x
12 x 36 balsa “wing skin.” The plans indicate
the areas that are covered with planking. Do
not trim the width until it is installed.
Thoroughly soak the balsa with Windex and
wait several minutes before attempting to
make the sharp LE bend.
When the balsa is pliable enough to make
the bend, start at the top, rear 1/8 x 1/4 spar.
Use cyanoacrylate to bond the balsa to the
spar. Clamp it along its length until the
adhesive sets.
Work slowly. Starting at the middle of the
wing and moving outward, glue, with
cyanoacrylate, the ribs, front spar, LE, etc.,
until you have the entire wing skin bonded,
top and bottom. If you do the job properly,
the planking should be tight, with no bulges.
Trim whatever planking extends beyond the
center, bottom spar.
Install the remaining planking and the rib
capstrips. It’s better to plank the entire
wingtip on both sides; it makes the covering
job easier and neater. When you have
finished both wings, prepare them to accept
covering.
Fuselage Planking: Starting with the front
deck, plank the fuselage with 3/32 sheet balsa.
I made a cardboard pattern and used it as a
guide to cut the planking for the forward
“hood,” from the firewall to F3. Soak the
planking for installation. After test-fitting, use
cyanoacrylate to install it.
Make the 3/32 balsa planking for the area
aft of the cockpit. Use a single piece to cover
from F5 to the tail post and up to the 1/8-inch
top stringer on each side. This piece should
cover the tail post and terminate at the back
of the fuselage. The bend is fairly gentle and
should pose little problem. When you are
satisfied with the fit, glue the planking in
place with cyanoacrylate. Shape and add the
pieces that go between the top stringer and
the fin doublers.
When the cyanoacrylate has set, use a
sanding block to shape the back of the tail
post so it is flat. Blend the planking into the
fin doubler and the fuselage sides.
Cut two pieces of 3/8 balsa stock 11/4
inches wide and 83/8 inches long. These fit
between F5 and the instrument panel. Shape
the fronts to fit flush with the panel. Position
them so they are 3/32 inch inboard of the
05sig1.QXD 3/25/08 10:09 AM Page 28
fuselage sides, and adhere them in place with
cyanoacrylate.
Sand both sides so they follow the contour
of the panel and F5. These provide support for
the planking around the cockpit. See photos
for clarification.
Shape and fit the planking around the
cockpit. When you are satisfied, sand
everything flush. Use balsa filler to fill any
gaps, and finish-sand the entire fuselage
smooth and even. Cut—but do not install—
the 3/32-inch bottom piece. With the fuselage
planking complete, cut the tail post for the
stabilizer. This marks the end of the planking
phase.
Ailerons: These are cut from 3/8 x 3 tapered
balsa. See the wing plans for patterns.
Before shaping the aileron LE, use
cyanoacrylate to laminate a matching piece of
1/16 hard balsa to the top to strengthen the
structure. Temporarily attach the ailerons to
the wing with a few small spots of
cyanoacrylate, and then block-sand the bottom
of the ailerons to blend with the wing TE.
Remove the ailerons using debonder, and
sand the LEs for hinging.
Pushrods, Etc.: Install the pushrod tubes.
Holes are provided in F4 to support the front
of the pushrod tubes. I crossed mine in the
middle and they exited the fuselage on the
opposite side. I used a small cable tie at the
crossover point to support and stiffen the
tubes. Once the pushrod tubes are installed,
use cyanoacrylate to glue the bottom piece in
place. Sand the joint smooth.
A 360cc tank (Global Hobby part 120074)
I had on hand was employed in the original. I
used silicone adhesive to bond the front of the
fuel tank to the inside of the firewall, with the
neck protruding through the provided hole. I
Dremeled the bottom of the hole in F1 to
match the contour of the rear of the tank (see
dotted line on F1 pattern) and used silicon
adhesive there too.
Drill a hole in the firewall and F1 for the
throttle pushrod, positioned to make a straight
run from the carburetor to the throttle servo.
The fuselage servo linkages are typical. Use
your favorite clevises, etc. The wing servos
and linkages are installed after covering.
There are large openings in the ribs that
provide passage for the wires from the servos.
Make small openings in the planking inboard,
on the top of the wing, for the servo wires to
exit.
Insert the .505 composite wing spar in one
(either) wing up to the rib just past the servo
and glue it in place inside the root rib (only)
with cyanoacrylate.
It is unnecessary to cement the wing halves
together. It is much easier to store and
transport them separately. The mounting pegs
and nylon bolts will align and secure the wings
to the fuselage, and the spar is more than
strong enough to prevent them from folding.
Cowl: For the original model I made my cowl
from laminations of 3/8 balsa. Several good
articles have been written about the subject.
I also made a balsa cowl for a second
airplane, and I sent it out for Fiberglass
Specialties to duplicate in fiberglass. These
cowls are available for purchase if you don’t
want to expend the effort to fabricate your
own. Either way, the weight difference is
slight so the balance remains unchanged.
Covering: It seems like everyone has a
favorite covering material; I am no different. I
prefer Sig AeroKote, which I used on the
entire aircraft.
I don’t care for the elaborate, multicolor
schemes festooned with sponsor logos that are
rampant on ARFs. Thus Brodak’s CL Oriental
was the inspiration for the color scheme I used
on the original Golden Era 60. The Oriental is
black and red; I opted for Black and Naval
Orange.
If you use black on the fuselage, throw a
white cloth over it if the model is going to sit
in the sun for a long period. The black
covering absorbs heat and loosens, and you
will be faced with a session with the iron and
heat gun when you get home.
Nuts and Bolts: I used Du-Bro heavy-duty
.40-.91 control horns (item 867) throughout.
They require a single hole for mounting and are
rugged and easy to install. A bonus is that they
adjust for angle as well as throw. I installed a
steerable tail-wheel assembly from Global
Hobby. It mounts easily and works well.
My Spektrum DX7 came with four JR
RC System is distributed by:
SIG Manufacturing Company, Inc.
P.O. Box 520 • Montezuma, Iowa 50171-0520
Web Site: www.sigmfg.com • Phone: (641)623-5154
* actual Flightsimulator screens shown
There are different ways to learn model flying. If an
experienced model flyer is not on site then the first steps can
be disappointing. At worst case you could crash your first
model. Especially for learning R/C helicopter flying the so
called "Dry Run" on a simulator is an inexpensive and
suggested method. The SimTransmitter
"Joystick" in combination with the FMS
Flightsimulator provides the ideal virtual
beginner airplane or helicopter "model".
Simply plug the SimTransmitter into a free USB
port and configure it as a joystick.
SimTransmitter
Order No. RCSSIM062 - $39.99
* Prices at Participating Dealers
*
05sig1.QXD 3/25/08 10:09 AM Page 31
servos. Three are used in the fuselage, and
Hitec HD servos are used for the ailerons.
The Spektrum dual receivers are mounted
on opposite fuselage sides using Velcro. They
are oriented to provide opposite antenna
polarity, as the installation instructions
mandate. Not having to provide routing and
an exit for a long 72 MHz antenna is a
pleasant change!
The double 1/4-inch plate used to mount
the LG is a work-around because of a
clearance issue. The wing extends forward
from the mounting recess and engages the LG
if additional clearance isn’t provided. I didn’t
realize this until too late, and the second plate
proved to be a quick, effective remedy.
I cut the windshield from a plastic cake
container my supermarket provided free of
charge. Ask for one. If they refuse, you can
buy a cake and eat it!
The seat and headrest are carved from
balsa block and brushed with one coat of
Insignia Orange Aero Gloss. It imparts an
almost suedelike appearance. “Leo,” the pilot,
had to have his shoulders trimmed to fit in the
narrow cockpit. I repainted him with my
wife’s acrylics to match the model.
(References to “Leo” stem from the pilot
figure’s uncanny resemblance to a friend and
fellow RCer, Leo Desmarais.)
Hinging: I used cyanoacrylate hinges
throughout, but regardless of the type you
should have at least two on each elevator half,
three on the rudder, and four—equidistant—
along each aileron. Mounting procedures vary,
depending on the type chosen, and hingeinstallation
instruction is beyond the scope of
this article.
No matter what type of hinge you use,
make sure the movable surfaces fit closely to
the fixed surfaces. Gaps give birth to control
flutter, which can end an otherwise perfect
flying day.
Assembly: Since this is probably not your
first scratch build, I’ll be brief. There is
nothing unusual about the model and
assembly is straightforward
Assuming that the covering job is finished
and the elevator is hinged, insert the stabilizer
into its slot. Make sure it’s straight using a
string from the nose to the elevator tips. Mark
the stabilizer where it joins the fuselage, top
and bottom.
Remove the stabilizer and then remove the
covering that will be within the slot.
Permanently adhere the stabilizer, with
cyanoacrylate or epoxy, and hook up the
control hardware.
Drill the LG to accept the 1/4-20 nylon
mounting bolts. If the wheel pants haven’t
been assembled and painted and the wheels
haven’t been mounted, you haven’t been
reading far enough ahead!
Assemble the wings and fit them to the
fuselage. With the wings seated, carefully drill
9/32-inch holes through the centers of the wing
reinforcement pads into the rear wing
mounting plate.
Remove the wing and then further drill the
mounting plate to accept the captive 1/4-20
nuts. Epoxy them in place on the backside.
When they are set, reinstall the wing and
insert the 1/4-20 nylon bolts. Screw them into
the mounting plate slightly more than finger
tight.
Check the wing-to-stabilizer angle of
incidence using your favorite method; I use a
Great Planes laser setup. If your build is
accurate, it should be 0°-.5°. If it isn’t, make it
so. You can correct it several degrees either
way by removing or adding material to the
rear part of the wing saddle.
Balancing and Flying: I suggest a slightly
nose-heavy configuration for the first flights.
The balance point should fall one-third back
from the LE, or approximately where the LE
planking ends. Being an RC novice, I have
left the balance point there. If you’re more
experienced, you may find that a slightly more
aft point allows for better aerobatics.
This airplane has a thin symmetrical wing,
a somewhat short tail-moment arm, and high
wing loading; therefore, it flies like a
warbird—fast and without self-righting
properties. I programmed flaperons to help
during landings. Keep power on during
approach. As does a warbird, the Golden Era
likes to come in under power.
The large control surfaces beg dual rate
and exponential programming. This will allow
the experienced pilot to burn holes in the sky
while the less confident can fly it around
without working up a sweat.
The deep fuselage makes for easy knife
edge, and the slight wingtip washout and
aileron configuration help to keep it from
falling out of the sky at relatively low speeds.
This is not a good design for a first lowwing
sport airplane. It is satisfying for the
intermediate pilot and will draw attention at
the club field.
Electric Dreams: I gave little consideration to
making this aircraft light beyond what was
necessary for good 60-power performance. It
came in at slightly more than 9 pounds dry.
An electric conversion could include fewer
doublers, thinner and less planking, more
lightening holes, and a lighter LG assembly.
Several pounds could probably be shaved off
easily, making the wing loading nearer to a
more acceptable 20 ounces per square foot.
Being an old FF Gas aficionado, I revel in
the smell of nitro fuel in the morning, and the
postflight cleanup is akin to a labor of love.
I’ll leave it to you wattage mavens to do the
converting, but I’d love to see the results! MA
Fred Randall
[email protected]
Sources:
Short kit (1/8 light-plywood parts, 1/4 plywood
parts, 3/8 balsa rudder and elevator parts):
Creative Hobbies
(508) 473-8259
www.creativehobbies.net
Balsa, plywood stock:
National Balsa Co.
(413) 277-9500
www.nationalbalsa.com/
Composite tubing;
Kite Studio
(610) 395-3560
www.kitebuilder.com/
Fiberglass cowl:
Fiberglass Specialties
(479) 359-2429
www.fiberglassspecialtiesinc.com
Hardware, accessories:
Du-Bro
(800) 848-9411
http://dubro.com
Landing gear, wheel pants, AeroKote:
Sig Manufacturing
(641) 623-5154
www.sigmfg.com
32 MODEL AVIATION
05sig1.QXD 3/25/08 10:09 AM Page 32
Edition: Model Aviation - 2008/05
Page Numbers: 18,19,20,21,22,23,24,28,31,32
I HAVE ALWAYS admired racing aircraft of the so-called “Golden Age
of Aviation”: an era that extended from the end of World War I to the
onset of World War II. It was the time of rakish designs, open cockpits,
and “flying by the seat of one’s pants.”
Aircraft designs of the time were largely grand
experiments, and from those experiments
emerged the Granville Brothers’ Gee Bee series,
the Hughes H-1 racer, the Travel Air Mystery Ship,
the Hall Bulldog, and the rest of the list, which is too
numerous to include here.
I was weary of going to our flying field and finding almost
nothing between ARF training models, sticks, and the usual bunch of 3-D
ARFs. I realized that if I wanted something with a style I liked, I’d
have to build my own.
Accordingly, I made a couple pencil sketches, loaded
ModelCAD 3000 into my PC, and sat down at my electronic
drawing board to play. The Golden Era 60 is the result.
Although this airplane is conventional in its construction, it is
unsuitable for a first scratch-building project. This article assumes
that the builder has some experience beyond ARF assembly and is
familiar with common building techniques.
Unless you get the laser-cut “short kit” I’ll tell you about, you shouldn’t attempt this build without a scroll saw
or band saw, a Dremel or other rotary tool, and the usual collection of hand tools. The judicious use of a square and
straightedge is necessary throughout construction if you expect to manufacture a straight, easy-to-trim aircraft.
If the previous paragraphs haven’t discouraged you, we can proceed.
18 MODEL AVIATION
BY FRED RANDALL
A Williams Brothers Sportsman pilot bust complements the
open cockpit. Enamel brush paint can be spray-fixed with a
fuelproof clear coat.
Grooving through the open sky, the Golden Era 60 handles as
the popular Stick models do but has the looks of a 1930s
racer.
The grunt of a .60-size engine adds thrills
to this pioneer-reminiscent building project
05sig1.QXD 3/25/08 10:33 AM Page 18
Materials: Creative Hobbies of Mendon, Massachusetts, sells a short
kit of laser-cut 1/8 light plywood, 1/4 plywood, and 3/8 balsa parts at a
reasonable cost. These accurate precut components and a full-size
rolled plans set from MA will greatly simplify construction. It
eliminates tedium, and what remains is the equivalent of building a
good kit.
Regardless of whether or not you purchase the short kit, I suggest
that you have all fabricated parts (wing ribs, fuselage formers, etc.) on
hand before starting the build.
The landing gear and wheel pants on the original are Four-Star 120
parts ordered from Sig Manufacturing. I suggest that builders use the
same parts since they are a good match appearancewise, they fit the
gear mounting plates designed into the fuselage, and using other units
may significantly change the balance point. But if you prefer to
fabricate your own landing gear, have at it!
I did not design this airplane to be superlight since it is not
intended for “3-D.” It has an allup
weight of approximately
9 pounds and a wing
loading of roughly 26
ounces per square foot.
However, it is extremely
strong. This model is
extensively planked,
including wing
May 2008 19
After a full-power run of roughly 50 feet, the model lifts off smoothly.
The wide-track gear absorbs many of the bumps in the grass.
The former positions have been marked on the fuselage sides,
and the firewall assembly has been epoxied in place.
capstrips, and composite tubing is used for the LE and the main spar.
CONSTRUCTION
Fuselage: Although I usually begin with the wings, the fuselage was
my starting point for this project.
The first task was selecting the 1/8 balsa for the fuselage sides. The
importance of matching the side sheets’ hardness and grain cannot be
stressed enough. If the balsa is poorly matched, it will be next to
impossible to make a straight fuselage.
The fuselage sides’ maximum height is approximately 7 inches. I
used matched 4-inch-wide, 1/8 balsa sheets. Cement them together with
cyanoacrylate before cutting them to shape. (In the remainder of this
document, cyanoacrylate means medium cyanoacrylate unless
otherwise specified.)
After you have cut the balsa sides to shape, use cyanoacrylate to
glue the 1/8 plywood fuselage doublers in place. Be careful; it is easier
than you can imagine to end up with two right or two left sides.
Adhere, with cyanoacrylate, the doubler to the bottom of former F1.
After the fuselage doublers have set, epoxy and clamp the two
landing-gear (LG) and hatch-support rails to the fuselage doublers.
Refer to the plans for position. Make sure to wipe off any excess epoxy
from around the perimeter with alcohol.
Epoxy the 1/8 plywood firewall doubler to the 1/4 plywood firewall.
(Epoxy means 30-minute epoxy unless otherwise specified.)
Lay the fuselage plans on your building board, protecting them with
waxed paper or the like. With the plans as a guide, use a square
referenced to the top of the fuselage sides to mark the position of all
formers on the inside of both fuselage sides.
05sig1.QXD 3/25/08 10:44 AM Page 19
20 MODEL AVIATION
Formers F1 and F2 have been put in place, and the servo plate has
been mounted between them.
With the fuselage wide open, it’s a good time to fit the fuel tank.
Silicone sealant will be used to mount the tank permanently.
The left side has been epoxied in place after a careful alignment
check. Notice how the rear wing mount is locked into cutouts in
the doubler.
Bevel the tail post and then glue it in place. Dry-fit the fin and the
remaining formers to assure good alignment.
The tail-wheel mount area is supported by a 1/8 plywood plate.
It’s recessed to allow room for balsa, which will be sanded flush
with the fuselage sides.
Scrap 3/8 balsa sheet is substituted for the stabilizer during
preliminary alignment. The forward stringers are added at
this point.
05sig1.QXD 3/25/08 11:26 AM Page 20
May 2008 21
Once the sheeting is complete, it’s a good time to test-fit the
landing gear and engine mount. The cockpit area can be detailed
at this time.
Notice the smart use of carbon-fiber tubing to form the LE and
support the wing spar. The wing will be sheeted next.
Above: The completed one-piece wing is mounted with dowel pins
and nylon bolts. The light tail structure is designed to keep the
weight mass balanced on the recommended CG.
Left: Build the cowl from wood or purchase the fiberglass
version from Fiberglass Specialties. The mounting screws are
hidden inside.
Type: RC sport
Pilot skill level:
Intermediate to expert
Wingspan: 65.25 inches
Flying weight: 10 pounds
Wing area: 792 square inches
Wing loading: 26-27 ounces/square foot
Length: 51 inches
Engine: GMS .61 glow
Tank: Modeltech 360cc
Flight battery: Four cells, 4.8 volts
Radio: Spektrum DX7 system, AR7000 receiver, three DS821
and two Hitec HS-625MG servos
Spinner: Du-Bro (LXE 149) 3 inch
Construction: Balsa and light plywood
Covering/finish: Builder’s choice (Sig AeroKote is recommended.)
Photos by the author
05sig1.QXD 3/25/08 10:58 AM Page 21
22 MODEL AVIATION
The GMS .61 two-stroke engine hides inside the spacious cowl. A
four-stroke .82-1.00 would also fit this model neatly.
Stock Sig Four-Star 120 wheel pants complete this sport model’s 1930s racing look. The long and tall fuselage offers good knifeedge
performance.
Put the right fuselage side in place on the plans and secure it. Using
a square to position it, epoxy the firewall/doubler assembly flush with
the front of the fuselage side. When it has set, Formers F1 and F2 can
be cemented in place using cyanoacrylate. Position the servo tray in the
slots provided in formers F1 and F2, and secure it with cyanoacrylate.
Fashion the 11/2 x 47/16-inch rear wing anchor plate from 1/4
plywood. Do not drill it. Temporarily insert it into the slot provided in
the fuselage doubler. Test-fit the left side for perfect alignment. The
firewall assembly, the formers, the wing anchor plate, and both
fuselage sides must align properly.
When you are satisfied, remove the left side and apply epoxy to the
edge of the firewall assembly and the wing anchor plate edges that
mate with F2 and the fuselage sides. Apply cyanoacrylate to the mating
edges of F1 and F2. Put the left side back in position.
Place a book or similar weight on top to ensure a good bond, and
then take a break.
Shape the tail post from 1/2 x 3/4 x 13-inch balsa. It should taper
from 1/2 inch at the LE to 3/16 inch at the TE. It is important that this
piece be symmetrical. It will be further shaped and cut for the stabilizer
later, during fuselage assembly.
Notch the front roughly 1/8 inch deep to accept the light-plywood
fin. Refer to the plans for notch location.
With the fuselage secured to the top view of the plans, use T-pins to
temporarily hold the rear of the fuselage sides together, sandwiching
the tail post into position. The tail post should be centered over the
plans and flush with the bottom and back of the fuselage sides. Ensure
that the tail post is vertical in both axes when referenced to the fuselage
sides.
Reposition the pins until these conditions are met. Temporarily tack
the assembly together using a few drops of thin cyanoacrylate.
Remove the T-pins and recheck alignment. When you are satisfied,
flow in more thin cyanoacrylate for a permanent bond.
Install the remaining formers using cyanoacrylate. If necessary, use
rubber bands around the fuselage to ensure a full-contact fit.
Employing the plywood fin as a pattern, make doublers
approximately 3/8 inch wide from 3/16 balsa sheet. The doublers enable
a smooth transition between the planking and the fin. There is a
detailed drawing on the fuselage plans.
Cement the balsa doublers to both sides of the fin with
cyanoacrylate. Cut 1/8-inch gaps in the doubler where the fin fits into
05sig1.QXD 3/25/08 10:06 AM Page 22
the F5 and F6 notches and another at the rear
of the fin where it will be inserted into the
tail-post notch. Install the fin and secure it
with cyanoacrylate, and then sand the top of
the tail post to blend with the fin and doublers.
Cut the cockpit floor from 1/8 balsa sheet.
See the fuselage top view for the pattern.
Using cyanoacrylate, install the floor as
indicated and test-fit the dash panel. The dashpanel
pattern is somewhat oversize; you must
sand it to mount flush with the cockpit floor
and F3. Use a long sanding block to blend the
panel with the fuselage.
Install former F8. Fit it between F6 and the
tail post. See the plans for location. Trim it as
necessary for a proper fit. Ensure that F8 is at
right angles to, and level with, the top of the
notch in the fuselage sides. Take your time;
this establishes proper alignment and angle of
incidence.
I found it helpful to cut a piece of 3/8 balsa
sheet 3 inches wide and 12-15 inches long to
use as a spacer and alignment aid. Lay it on
top of F8 to use as a temporary substitute for
the stabilizer.
Position F7 as indicated on the plans, and
snug it against the temporary spacer. Adhere
F7 in place with cyanoacrylate and remove
the spacer. Trim F7 as necessary for a proper
fit.
Install the stringers using cyanoacrylate.
The front stringers extend aft to the panel.
There are no notches in the panel, so shape
the ends of the stringers for a nice butt fit
26 MODEL AVIATION
INTRODUCING
• Safe chemistry will not explode or catch fire
• Fast charge capable – 100% in 15 minutes
• 30c continuous, 60c bursts
• Exclusive Duralite Stay Balance Circuitry built-in
to every pack – no external balancing needed
• Charge through the charge lead with a Duralite Plus
Charger or through the power lead with an A123 capable
charger like the Orbit Pocketlader
• No regulator needed for most Rx applications
• Longer life cycle than lithium polymer chemistry
LITHIUM POWER SOLUTIONS FOR EVERYTHING YOU FLY
Order toll free 877-744-3685
Shop online www.duraliteflightsystems.com
PLUS
WITH STAY BALANCE
CIRCUITRY BUILT-IN
TO EVERY PACK
against it. The rear stringers should terminate
flush with the front of the tail post.
Epoxy four 1/4-20 captive nuts to the inner
LG mounting plate. Remove your fuselage
assembly from the building board, flip it over,
and use epoxy to bond the inner LG mounting
plate to the support rails. Don’t spare the
epoxy here; the LG takes considerable abuse
(at least when I’m flying).
The battery hatch came about because the
finished model needed a bit of nose weight. I
don’t like to add lead for balance when I can
reposition something to compensate. I
relocated the flight battery forward, in a foam
nest made for perfect balance with no
additional ballast. As a bonus, you have access
to the LG support assembly, engine-mount
captive nuts, and fuel tank should something
go awry.
Fashion the battery hatch from a piece of
1/8 light plywood. It should fit nicely between
the firewall, the fuselage sides, and the LG
mounting plate. It should rest on the support
rails. Drill holes at four corners for your
selected screw hardware.
I band-sawed a small amount of
downthrust and right thrust into my engine
mounts before installation. Offset the mounts
so that the spinner will be centered at the
proper location. When positioned, drill the
firewall and install the captive nuts.
Empennage: Building this area is
straightforward, and little explanation is
necessary beyond what is on the plans. The
only item that may need clarification is the
elevator joiner.
I originally intended to use a double
pushrod for elevator control. However, I had a
nice piece of .317 composite tubing left from
the wing construction, and it seemed
reasonable to use as a torque tube to join the
elevator halves. If you prefer double pushrods,
eliminate the torque tube and the clearance
notch in the rudder.
Wings: Select the right-wing full plans and
secure them to your building board. Using
cyanoacrylate, bond an RR1 rib to an RR2.
RR1 should be inboard. This assembly forms
the root rib.
Bond an R3 to an R1. The rib with no LE
notch is an R3; it should be inboard. Refer to
the plans for confirmation.
The wing will be built using the centermost
bottom spar as a reference. Cut a piece of 1/8 x
1/4 basswood to length and secure it in place
on the plans. Use a square to position the root
rib assembly on the plans with the spar snug in
its notch. Use cyanoacrylate to adhere the root
rib assembly to the spar.
Follow suit with an R1, R2 pair. Install the
remaining ribs, and adhere them to the spar
with cyanoacrylate. All ribs’ break-off stubs
should lay flat on the plans.
R2 is slightly different; it establishes a
small amount of washout in the wingtips to
improve low-speed stability. When all ribs are
in place, cut and install the three top spars. Cut
the .317-inch composite LE to length and glue
it in place with cyanoacrylate.
You should be able to insert the composite
spar as far as shown on the plans. Test-fit it. It
05sig1.QXD 3/25/08 10:09 AM Page 26
should be snug but not distort the ribs as it
passes through. Make any adjustments needed
until this condition is met, and then remove
the spar.
Remove the wing from the plans. Install
the remaining bottom spars, and then check
the assembly for straightness. It should lay
flat, resting on the centermost bottom spar and
rib break-off stubs. Correct any twist in the
wing before proceeding.
Following the diagram below the right
wing assembly drawing, shape the TE from 1/2
x 3/8 balsa. When you are finished, glue it into
position with cyanoacrylate.
Temporarily position the 1/8 light-plywood
servo plate to the bottom of the wing. Make
sure to place it at a point that is deep enough
on the chord to ensure that a standard servo’s
body does not protrude through the top. (Ask
me why I added this instruction.)
When you are satisfied with its position,
adhere the servo plate in place with
cyanoacrylate, flush with the bottom of the
ribs. Use scrap 1/8 x 1/4 spar material to make
rails to support and stiffen it.
Use cyanoacrylate to glue the 1/8 lightplywood
wingtip in place. It should be
centered between the LE and TE and at right
angles to R2. Make spar extensions and
cement them between the rib and the tip. See
the plans for positioning. Snap off the rib
stubs and sand the areas smooth.
Remove the right wing plans from the
building board and replace them with the left.
28 MODEL AVIATION
(We don’t want two right wings, do we?)
Take a deep breath and repeat the wing
instructions.
Having completed the framing of both
wings, fabricate and add the 1/4-inch plywood
dowel support webbing and the wing
mounting dowels. Ensure that the pegs will
align with the holes in F1. The detail diagram
will aid in drilling the peg holes and installing
the pegs.
Cut the .505 composite-tubing spar to
length and test-fit the joined wings. Be sure to
allow for the 1/16-inch planking. This work is
critical; it affects the final wing leveling and
wing/stabilizer angle of incidence. If the wing
is too wide, it does no harm to remove some
material from the TE where it fits within the
fuselage.
Wing Planking: The LE planking is a 1/16 x
12 x 36 balsa “wing skin.” The plans indicate
the areas that are covered with planking. Do
not trim the width until it is installed.
Thoroughly soak the balsa with Windex and
wait several minutes before attempting to
make the sharp LE bend.
When the balsa is pliable enough to make
the bend, start at the top, rear 1/8 x 1/4 spar.
Use cyanoacrylate to bond the balsa to the
spar. Clamp it along its length until the
adhesive sets.
Work slowly. Starting at the middle of the
wing and moving outward, glue, with
cyanoacrylate, the ribs, front spar, LE, etc.,
until you have the entire wing skin bonded,
top and bottom. If you do the job properly,
the planking should be tight, with no bulges.
Trim whatever planking extends beyond the
center, bottom spar.
Install the remaining planking and the rib
capstrips. It’s better to plank the entire
wingtip on both sides; it makes the covering
job easier and neater. When you have
finished both wings, prepare them to accept
covering.
Fuselage Planking: Starting with the front
deck, plank the fuselage with 3/32 sheet balsa.
I made a cardboard pattern and used it as a
guide to cut the planking for the forward
“hood,” from the firewall to F3. Soak the
planking for installation. After test-fitting, use
cyanoacrylate to install it.
Make the 3/32 balsa planking for the area
aft of the cockpit. Use a single piece to cover
from F5 to the tail post and up to the 1/8-inch
top stringer on each side. This piece should
cover the tail post and terminate at the back
of the fuselage. The bend is fairly gentle and
should pose little problem. When you are
satisfied with the fit, glue the planking in
place with cyanoacrylate. Shape and add the
pieces that go between the top stringer and
the fin doublers.
When the cyanoacrylate has set, use a
sanding block to shape the back of the tail
post so it is flat. Blend the planking into the
fin doubler and the fuselage sides.
Cut two pieces of 3/8 balsa stock 11/4
inches wide and 83/8 inches long. These fit
between F5 and the instrument panel. Shape
the fronts to fit flush with the panel. Position
them so they are 3/32 inch inboard of the
05sig1.QXD 3/25/08 10:09 AM Page 28
fuselage sides, and adhere them in place with
cyanoacrylate.
Sand both sides so they follow the contour
of the panel and F5. These provide support for
the planking around the cockpit. See photos
for clarification.
Shape and fit the planking around the
cockpit. When you are satisfied, sand
everything flush. Use balsa filler to fill any
gaps, and finish-sand the entire fuselage
smooth and even. Cut—but do not install—
the 3/32-inch bottom piece. With the fuselage
planking complete, cut the tail post for the
stabilizer. This marks the end of the planking
phase.
Ailerons: These are cut from 3/8 x 3 tapered
balsa. See the wing plans for patterns.
Before shaping the aileron LE, use
cyanoacrylate to laminate a matching piece of
1/16 hard balsa to the top to strengthen the
structure. Temporarily attach the ailerons to
the wing with a few small spots of
cyanoacrylate, and then block-sand the bottom
of the ailerons to blend with the wing TE.
Remove the ailerons using debonder, and
sand the LEs for hinging.
Pushrods, Etc.: Install the pushrod tubes.
Holes are provided in F4 to support the front
of the pushrod tubes. I crossed mine in the
middle and they exited the fuselage on the
opposite side. I used a small cable tie at the
crossover point to support and stiffen the
tubes. Once the pushrod tubes are installed,
use cyanoacrylate to glue the bottom piece in
place. Sand the joint smooth.
A 360cc tank (Global Hobby part 120074)
I had on hand was employed in the original. I
used silicone adhesive to bond the front of the
fuel tank to the inside of the firewall, with the
neck protruding through the provided hole. I
Dremeled the bottom of the hole in F1 to
match the contour of the rear of the tank (see
dotted line on F1 pattern) and used silicon
adhesive there too.
Drill a hole in the firewall and F1 for the
throttle pushrod, positioned to make a straight
run from the carburetor to the throttle servo.
The fuselage servo linkages are typical. Use
your favorite clevises, etc. The wing servos
and linkages are installed after covering.
There are large openings in the ribs that
provide passage for the wires from the servos.
Make small openings in the planking inboard,
on the top of the wing, for the servo wires to
exit.
Insert the .505 composite wing spar in one
(either) wing up to the rib just past the servo
and glue it in place inside the root rib (only)
with cyanoacrylate.
It is unnecessary to cement the wing halves
together. It is much easier to store and
transport them separately. The mounting pegs
and nylon bolts will align and secure the wings
to the fuselage, and the spar is more than
strong enough to prevent them from folding.
Cowl: For the original model I made my cowl
from laminations of 3/8 balsa. Several good
articles have been written about the subject.
I also made a balsa cowl for a second
airplane, and I sent it out for Fiberglass
Specialties to duplicate in fiberglass. These
cowls are available for purchase if you don’t
want to expend the effort to fabricate your
own. Either way, the weight difference is
slight so the balance remains unchanged.
Covering: It seems like everyone has a
favorite covering material; I am no different. I
prefer Sig AeroKote, which I used on the
entire aircraft.
I don’t care for the elaborate, multicolor
schemes festooned with sponsor logos that are
rampant on ARFs. Thus Brodak’s CL Oriental
was the inspiration for the color scheme I used
on the original Golden Era 60. The Oriental is
black and red; I opted for Black and Naval
Orange.
If you use black on the fuselage, throw a
white cloth over it if the model is going to sit
in the sun for a long period. The black
covering absorbs heat and loosens, and you
will be faced with a session with the iron and
heat gun when you get home.
Nuts and Bolts: I used Du-Bro heavy-duty
.40-.91 control horns (item 867) throughout.
They require a single hole for mounting and are
rugged and easy to install. A bonus is that they
adjust for angle as well as throw. I installed a
steerable tail-wheel assembly from Global
Hobby. It mounts easily and works well.
My Spektrum DX7 came with four JR
RC System is distributed by:
SIG Manufacturing Company, Inc.
P.O. Box 520 • Montezuma, Iowa 50171-0520
Web Site: www.sigmfg.com • Phone: (641)623-5154
* actual Flightsimulator screens shown
There are different ways to learn model flying. If an
experienced model flyer is not on site then the first steps can
be disappointing. At worst case you could crash your first
model. Especially for learning R/C helicopter flying the so
called "Dry Run" on a simulator is an inexpensive and
suggested method. The SimTransmitter
"Joystick" in combination with the FMS
Flightsimulator provides the ideal virtual
beginner airplane or helicopter "model".
Simply plug the SimTransmitter into a free USB
port and configure it as a joystick.
SimTransmitter
Order No. RCSSIM062 - $39.99
* Prices at Participating Dealers
*
05sig1.QXD 3/25/08 10:09 AM Page 31
servos. Three are used in the fuselage, and
Hitec HD servos are used for the ailerons.
The Spektrum dual receivers are mounted
on opposite fuselage sides using Velcro. They
are oriented to provide opposite antenna
polarity, as the installation instructions
mandate. Not having to provide routing and
an exit for a long 72 MHz antenna is a
pleasant change!
The double 1/4-inch plate used to mount
the LG is a work-around because of a
clearance issue. The wing extends forward
from the mounting recess and engages the LG
if additional clearance isn’t provided. I didn’t
realize this until too late, and the second plate
proved to be a quick, effective remedy.
I cut the windshield from a plastic cake
container my supermarket provided free of
charge. Ask for one. If they refuse, you can
buy a cake and eat it!
The seat and headrest are carved from
balsa block and brushed with one coat of
Insignia Orange Aero Gloss. It imparts an
almost suedelike appearance. “Leo,” the pilot,
had to have his shoulders trimmed to fit in the
narrow cockpit. I repainted him with my
wife’s acrylics to match the model.
(References to “Leo” stem from the pilot
figure’s uncanny resemblance to a friend and
fellow RCer, Leo Desmarais.)
Hinging: I used cyanoacrylate hinges
throughout, but regardless of the type you
should have at least two on each elevator half,
three on the rudder, and four—equidistant—
along each aileron. Mounting procedures vary,
depending on the type chosen, and hingeinstallation
instruction is beyond the scope of
this article.
No matter what type of hinge you use,
make sure the movable surfaces fit closely to
the fixed surfaces. Gaps give birth to control
flutter, which can end an otherwise perfect
flying day.
Assembly: Since this is probably not your
first scratch build, I’ll be brief. There is
nothing unusual about the model and
assembly is straightforward
Assuming that the covering job is finished
and the elevator is hinged, insert the stabilizer
into its slot. Make sure it’s straight using a
string from the nose to the elevator tips. Mark
the stabilizer where it joins the fuselage, top
and bottom.
Remove the stabilizer and then remove the
covering that will be within the slot.
Permanently adhere the stabilizer, with
cyanoacrylate or epoxy, and hook up the
control hardware.
Drill the LG to accept the 1/4-20 nylon
mounting bolts. If the wheel pants haven’t
been assembled and painted and the wheels
haven’t been mounted, you haven’t been
reading far enough ahead!
Assemble the wings and fit them to the
fuselage. With the wings seated, carefully drill
9/32-inch holes through the centers of the wing
reinforcement pads into the rear wing
mounting plate.
Remove the wing and then further drill the
mounting plate to accept the captive 1/4-20
nuts. Epoxy them in place on the backside.
When they are set, reinstall the wing and
insert the 1/4-20 nylon bolts. Screw them into
the mounting plate slightly more than finger
tight.
Check the wing-to-stabilizer angle of
incidence using your favorite method; I use a
Great Planes laser setup. If your build is
accurate, it should be 0°-.5°. If it isn’t, make it
so. You can correct it several degrees either
way by removing or adding material to the
rear part of the wing saddle.
Balancing and Flying: I suggest a slightly
nose-heavy configuration for the first flights.
The balance point should fall one-third back
from the LE, or approximately where the LE
planking ends. Being an RC novice, I have
left the balance point there. If you’re more
experienced, you may find that a slightly more
aft point allows for better aerobatics.
This airplane has a thin symmetrical wing,
a somewhat short tail-moment arm, and high
wing loading; therefore, it flies like a
warbird—fast and without self-righting
properties. I programmed flaperons to help
during landings. Keep power on during
approach. As does a warbird, the Golden Era
likes to come in under power.
The large control surfaces beg dual rate
and exponential programming. This will allow
the experienced pilot to burn holes in the sky
while the less confident can fly it around
without working up a sweat.
The deep fuselage makes for easy knife
edge, and the slight wingtip washout and
aileron configuration help to keep it from
falling out of the sky at relatively low speeds.
This is not a good design for a first lowwing
sport airplane. It is satisfying for the
intermediate pilot and will draw attention at
the club field.
Electric Dreams: I gave little consideration to
making this aircraft light beyond what was
necessary for good 60-power performance. It
came in at slightly more than 9 pounds dry.
An electric conversion could include fewer
doublers, thinner and less planking, more
lightening holes, and a lighter LG assembly.
Several pounds could probably be shaved off
easily, making the wing loading nearer to a
more acceptable 20 ounces per square foot.
Being an old FF Gas aficionado, I revel in
the smell of nitro fuel in the morning, and the
postflight cleanup is akin to a labor of love.
I’ll leave it to you wattage mavens to do the
converting, but I’d love to see the results! MA
Fred Randall
[email protected]
Sources:
Short kit (1/8 light-plywood parts, 1/4 plywood
parts, 3/8 balsa rudder and elevator parts):
Creative Hobbies
(508) 473-8259
www.creativehobbies.net
Balsa, plywood stock:
National Balsa Co.
(413) 277-9500
www.nationalbalsa.com/
Composite tubing;
Kite Studio
(610) 395-3560
www.kitebuilder.com/
Fiberglass cowl:
Fiberglass Specialties
(479) 359-2429
www.fiberglassspecialtiesinc.com
Hardware, accessories:
Du-Bro
(800) 848-9411
http://dubro.com
Landing gear, wheel pants, AeroKote:
Sig Manufacturing
(641) 623-5154
www.sigmfg.com
32 MODEL AVIATION
05sig1.QXD 3/25/08 10:09 AM Page 32
Edition: Model Aviation - 2008/05
Page Numbers: 18,19,20,21,22,23,24,28,31,32
I HAVE ALWAYS admired racing aircraft of the so-called “Golden Age
of Aviation”: an era that extended from the end of World War I to the
onset of World War II. It was the time of rakish designs, open cockpits,
and “flying by the seat of one’s pants.”
Aircraft designs of the time were largely grand
experiments, and from those experiments
emerged the Granville Brothers’ Gee Bee series,
the Hughes H-1 racer, the Travel Air Mystery Ship,
the Hall Bulldog, and the rest of the list, which is too
numerous to include here.
I was weary of going to our flying field and finding almost
nothing between ARF training models, sticks, and the usual bunch of 3-D
ARFs. I realized that if I wanted something with a style I liked, I’d
have to build my own.
Accordingly, I made a couple pencil sketches, loaded
ModelCAD 3000 into my PC, and sat down at my electronic
drawing board to play. The Golden Era 60 is the result.
Although this airplane is conventional in its construction, it is
unsuitable for a first scratch-building project. This article assumes
that the builder has some experience beyond ARF assembly and is
familiar with common building techniques.
Unless you get the laser-cut “short kit” I’ll tell you about, you shouldn’t attempt this build without a scroll saw
or band saw, a Dremel or other rotary tool, and the usual collection of hand tools. The judicious use of a square and
straightedge is necessary throughout construction if you expect to manufacture a straight, easy-to-trim aircraft.
If the previous paragraphs haven’t discouraged you, we can proceed.
18 MODEL AVIATION
BY FRED RANDALL
A Williams Brothers Sportsman pilot bust complements the
open cockpit. Enamel brush paint can be spray-fixed with a
fuelproof clear coat.
Grooving through the open sky, the Golden Era 60 handles as
the popular Stick models do but has the looks of a 1930s
racer.
The grunt of a .60-size engine adds thrills
to this pioneer-reminiscent building project
05sig1.QXD 3/25/08 10:33 AM Page 18
Materials: Creative Hobbies of Mendon, Massachusetts, sells a short
kit of laser-cut 1/8 light plywood, 1/4 plywood, and 3/8 balsa parts at a
reasonable cost. These accurate precut components and a full-size
rolled plans set from MA will greatly simplify construction. It
eliminates tedium, and what remains is the equivalent of building a
good kit.
Regardless of whether or not you purchase the short kit, I suggest
that you have all fabricated parts (wing ribs, fuselage formers, etc.) on
hand before starting the build.
The landing gear and wheel pants on the original are Four-Star 120
parts ordered from Sig Manufacturing. I suggest that builders use the
same parts since they are a good match appearancewise, they fit the
gear mounting plates designed into the fuselage, and using other units
may significantly change the balance point. But if you prefer to
fabricate your own landing gear, have at it!
I did not design this airplane to be superlight since it is not
intended for “3-D.” It has an allup
weight of approximately
9 pounds and a wing
loading of roughly 26
ounces per square foot.
However, it is extremely
strong. This model is
extensively planked,
including wing
May 2008 19
After a full-power run of roughly 50 feet, the model lifts off smoothly.
The wide-track gear absorbs many of the bumps in the grass.
The former positions have been marked on the fuselage sides,
and the firewall assembly has been epoxied in place.
capstrips, and composite tubing is used for the LE and the main spar.
CONSTRUCTION
Fuselage: Although I usually begin with the wings, the fuselage was
my starting point for this project.
The first task was selecting the 1/8 balsa for the fuselage sides. The
importance of matching the side sheets’ hardness and grain cannot be
stressed enough. If the balsa is poorly matched, it will be next to
impossible to make a straight fuselage.
The fuselage sides’ maximum height is approximately 7 inches. I
used matched 4-inch-wide, 1/8 balsa sheets. Cement them together with
cyanoacrylate before cutting them to shape. (In the remainder of this
document, cyanoacrylate means medium cyanoacrylate unless
otherwise specified.)
After you have cut the balsa sides to shape, use cyanoacrylate to
glue the 1/8 plywood fuselage doublers in place. Be careful; it is easier
than you can imagine to end up with two right or two left sides.
Adhere, with cyanoacrylate, the doubler to the bottom of former F1.
After the fuselage doublers have set, epoxy and clamp the two
landing-gear (LG) and hatch-support rails to the fuselage doublers.
Refer to the plans for position. Make sure to wipe off any excess epoxy
from around the perimeter with alcohol.
Epoxy the 1/8 plywood firewall doubler to the 1/4 plywood firewall.
(Epoxy means 30-minute epoxy unless otherwise specified.)
Lay the fuselage plans on your building board, protecting them with
waxed paper or the like. With the plans as a guide, use a square
referenced to the top of the fuselage sides to mark the position of all
formers on the inside of both fuselage sides.
05sig1.QXD 3/25/08 10:44 AM Page 19
20 MODEL AVIATION
Formers F1 and F2 have been put in place, and the servo plate has
been mounted between them.
With the fuselage wide open, it’s a good time to fit the fuel tank.
Silicone sealant will be used to mount the tank permanently.
The left side has been epoxied in place after a careful alignment
check. Notice how the rear wing mount is locked into cutouts in
the doubler.
Bevel the tail post and then glue it in place. Dry-fit the fin and the
remaining formers to assure good alignment.
The tail-wheel mount area is supported by a 1/8 plywood plate.
It’s recessed to allow room for balsa, which will be sanded flush
with the fuselage sides.
Scrap 3/8 balsa sheet is substituted for the stabilizer during
preliminary alignment. The forward stringers are added at
this point.
05sig1.QXD 3/25/08 11:26 AM Page 20
May 2008 21
Once the sheeting is complete, it’s a good time to test-fit the
landing gear and engine mount. The cockpit area can be detailed
at this time.
Notice the smart use of carbon-fiber tubing to form the LE and
support the wing spar. The wing will be sheeted next.
Above: The completed one-piece wing is mounted with dowel pins
and nylon bolts. The light tail structure is designed to keep the
weight mass balanced on the recommended CG.
Left: Build the cowl from wood or purchase the fiberglass
version from Fiberglass Specialties. The mounting screws are
hidden inside.
Type: RC sport
Pilot skill level:
Intermediate to expert
Wingspan: 65.25 inches
Flying weight: 10 pounds
Wing area: 792 square inches
Wing loading: 26-27 ounces/square foot
Length: 51 inches
Engine: GMS .61 glow
Tank: Modeltech 360cc
Flight battery: Four cells, 4.8 volts
Radio: Spektrum DX7 system, AR7000 receiver, three DS821
and two Hitec HS-625MG servos
Spinner: Du-Bro (LXE 149) 3 inch
Construction: Balsa and light plywood
Covering/finish: Builder’s choice (Sig AeroKote is recommended.)
Photos by the author
05sig1.QXD 3/25/08 10:58 AM Page 21
22 MODEL AVIATION
The GMS .61 two-stroke engine hides inside the spacious cowl. A
four-stroke .82-1.00 would also fit this model neatly.
Stock Sig Four-Star 120 wheel pants complete this sport model’s 1930s racing look. The long and tall fuselage offers good knifeedge
performance.
Put the right fuselage side in place on the plans and secure it. Using
a square to position it, epoxy the firewall/doubler assembly flush with
the front of the fuselage side. When it has set, Formers F1 and F2 can
be cemented in place using cyanoacrylate. Position the servo tray in the
slots provided in formers F1 and F2, and secure it with cyanoacrylate.
Fashion the 11/2 x 47/16-inch rear wing anchor plate from 1/4
plywood. Do not drill it. Temporarily insert it into the slot provided in
the fuselage doubler. Test-fit the left side for perfect alignment. The
firewall assembly, the formers, the wing anchor plate, and both
fuselage sides must align properly.
When you are satisfied, remove the left side and apply epoxy to the
edge of the firewall assembly and the wing anchor plate edges that
mate with F2 and the fuselage sides. Apply cyanoacrylate to the mating
edges of F1 and F2. Put the left side back in position.
Place a book or similar weight on top to ensure a good bond, and
then take a break.
Shape the tail post from 1/2 x 3/4 x 13-inch balsa. It should taper
from 1/2 inch at the LE to 3/16 inch at the TE. It is important that this
piece be symmetrical. It will be further shaped and cut for the stabilizer
later, during fuselage assembly.
Notch the front roughly 1/8 inch deep to accept the light-plywood
fin. Refer to the plans for notch location.
With the fuselage secured to the top view of the plans, use T-pins to
temporarily hold the rear of the fuselage sides together, sandwiching
the tail post into position. The tail post should be centered over the
plans and flush with the bottom and back of the fuselage sides. Ensure
that the tail post is vertical in both axes when referenced to the fuselage
sides.
Reposition the pins until these conditions are met. Temporarily tack
the assembly together using a few drops of thin cyanoacrylate.
Remove the T-pins and recheck alignment. When you are satisfied,
flow in more thin cyanoacrylate for a permanent bond.
Install the remaining formers using cyanoacrylate. If necessary, use
rubber bands around the fuselage to ensure a full-contact fit.
Employing the plywood fin as a pattern, make doublers
approximately 3/8 inch wide from 3/16 balsa sheet. The doublers enable
a smooth transition between the planking and the fin. There is a
detailed drawing on the fuselage plans.
Cement the balsa doublers to both sides of the fin with
cyanoacrylate. Cut 1/8-inch gaps in the doubler where the fin fits into
05sig1.QXD 3/25/08 10:06 AM Page 22
the F5 and F6 notches and another at the rear
of the fin where it will be inserted into the
tail-post notch. Install the fin and secure it
with cyanoacrylate, and then sand the top of
the tail post to blend with the fin and doublers.
Cut the cockpit floor from 1/8 balsa sheet.
See the fuselage top view for the pattern.
Using cyanoacrylate, install the floor as
indicated and test-fit the dash panel. The dashpanel
pattern is somewhat oversize; you must
sand it to mount flush with the cockpit floor
and F3. Use a long sanding block to blend the
panel with the fuselage.
Install former F8. Fit it between F6 and the
tail post. See the plans for location. Trim it as
necessary for a proper fit. Ensure that F8 is at
right angles to, and level with, the top of the
notch in the fuselage sides. Take your time;
this establishes proper alignment and angle of
incidence.
I found it helpful to cut a piece of 3/8 balsa
sheet 3 inches wide and 12-15 inches long to
use as a spacer and alignment aid. Lay it on
top of F8 to use as a temporary substitute for
the stabilizer.
Position F7 as indicated on the plans, and
snug it against the temporary spacer. Adhere
F7 in place with cyanoacrylate and remove
the spacer. Trim F7 as necessary for a proper
fit.
Install the stringers using cyanoacrylate.
The front stringers extend aft to the panel.
There are no notches in the panel, so shape
the ends of the stringers for a nice butt fit
26 MODEL AVIATION
INTRODUCING
• Safe chemistry will not explode or catch fire
• Fast charge capable – 100% in 15 minutes
• 30c continuous, 60c bursts
• Exclusive Duralite Stay Balance Circuitry built-in
to every pack – no external balancing needed
• Charge through the charge lead with a Duralite Plus
Charger or through the power lead with an A123 capable
charger like the Orbit Pocketlader
• No regulator needed for most Rx applications
• Longer life cycle than lithium polymer chemistry
LITHIUM POWER SOLUTIONS FOR EVERYTHING YOU FLY
Order toll free 877-744-3685
Shop online www.duraliteflightsystems.com
PLUS
WITH STAY BALANCE
CIRCUITRY BUILT-IN
TO EVERY PACK
against it. The rear stringers should terminate
flush with the front of the tail post.
Epoxy four 1/4-20 captive nuts to the inner
LG mounting plate. Remove your fuselage
assembly from the building board, flip it over,
and use epoxy to bond the inner LG mounting
plate to the support rails. Don’t spare the
epoxy here; the LG takes considerable abuse
(at least when I’m flying).
The battery hatch came about because the
finished model needed a bit of nose weight. I
don’t like to add lead for balance when I can
reposition something to compensate. I
relocated the flight battery forward, in a foam
nest made for perfect balance with no
additional ballast. As a bonus, you have access
to the LG support assembly, engine-mount
captive nuts, and fuel tank should something
go awry.
Fashion the battery hatch from a piece of
1/8 light plywood. It should fit nicely between
the firewall, the fuselage sides, and the LG
mounting plate. It should rest on the support
rails. Drill holes at four corners for your
selected screw hardware.
I band-sawed a small amount of
downthrust and right thrust into my engine
mounts before installation. Offset the mounts
so that the spinner will be centered at the
proper location. When positioned, drill the
firewall and install the captive nuts.
Empennage: Building this area is
straightforward, and little explanation is
necessary beyond what is on the plans. The
only item that may need clarification is the
elevator joiner.
I originally intended to use a double
pushrod for elevator control. However, I had a
nice piece of .317 composite tubing left from
the wing construction, and it seemed
reasonable to use as a torque tube to join the
elevator halves. If you prefer double pushrods,
eliminate the torque tube and the clearance
notch in the rudder.
Wings: Select the right-wing full plans and
secure them to your building board. Using
cyanoacrylate, bond an RR1 rib to an RR2.
RR1 should be inboard. This assembly forms
the root rib.
Bond an R3 to an R1. The rib with no LE
notch is an R3; it should be inboard. Refer to
the plans for confirmation.
The wing will be built using the centermost
bottom spar as a reference. Cut a piece of 1/8 x
1/4 basswood to length and secure it in place
on the plans. Use a square to position the root
rib assembly on the plans with the spar snug in
its notch. Use cyanoacrylate to adhere the root
rib assembly to the spar.
Follow suit with an R1, R2 pair. Install the
remaining ribs, and adhere them to the spar
with cyanoacrylate. All ribs’ break-off stubs
should lay flat on the plans.
R2 is slightly different; it establishes a
small amount of washout in the wingtips to
improve low-speed stability. When all ribs are
in place, cut and install the three top spars. Cut
the .317-inch composite LE to length and glue
it in place with cyanoacrylate.
You should be able to insert the composite
spar as far as shown on the plans. Test-fit it. It
05sig1.QXD 3/25/08 10:09 AM Page 26
should be snug but not distort the ribs as it
passes through. Make any adjustments needed
until this condition is met, and then remove
the spar.
Remove the wing from the plans. Install
the remaining bottom spars, and then check
the assembly for straightness. It should lay
flat, resting on the centermost bottom spar and
rib break-off stubs. Correct any twist in the
wing before proceeding.
Following the diagram below the right
wing assembly drawing, shape the TE from 1/2
x 3/8 balsa. When you are finished, glue it into
position with cyanoacrylate.
Temporarily position the 1/8 light-plywood
servo plate to the bottom of the wing. Make
sure to place it at a point that is deep enough
on the chord to ensure that a standard servo’s
body does not protrude through the top. (Ask
me why I added this instruction.)
When you are satisfied with its position,
adhere the servo plate in place with
cyanoacrylate, flush with the bottom of the
ribs. Use scrap 1/8 x 1/4 spar material to make
rails to support and stiffen it.
Use cyanoacrylate to glue the 1/8 lightplywood
wingtip in place. It should be
centered between the LE and TE and at right
angles to R2. Make spar extensions and
cement them between the rib and the tip. See
the plans for positioning. Snap off the rib
stubs and sand the areas smooth.
Remove the right wing plans from the
building board and replace them with the left.
28 MODEL AVIATION
(We don’t want two right wings, do we?)
Take a deep breath and repeat the wing
instructions.
Having completed the framing of both
wings, fabricate and add the 1/4-inch plywood
dowel support webbing and the wing
mounting dowels. Ensure that the pegs will
align with the holes in F1. The detail diagram
will aid in drilling the peg holes and installing
the pegs.
Cut the .505 composite-tubing spar to
length and test-fit the joined wings. Be sure to
allow for the 1/16-inch planking. This work is
critical; it affects the final wing leveling and
wing/stabilizer angle of incidence. If the wing
is too wide, it does no harm to remove some
material from the TE where it fits within the
fuselage.
Wing Planking: The LE planking is a 1/16 x
12 x 36 balsa “wing skin.” The plans indicate
the areas that are covered with planking. Do
not trim the width until it is installed.
Thoroughly soak the balsa with Windex and
wait several minutes before attempting to
make the sharp LE bend.
When the balsa is pliable enough to make
the bend, start at the top, rear 1/8 x 1/4 spar.
Use cyanoacrylate to bond the balsa to the
spar. Clamp it along its length until the
adhesive sets.
Work slowly. Starting at the middle of the
wing and moving outward, glue, with
cyanoacrylate, the ribs, front spar, LE, etc.,
until you have the entire wing skin bonded,
top and bottom. If you do the job properly,
the planking should be tight, with no bulges.
Trim whatever planking extends beyond the
center, bottom spar.
Install the remaining planking and the rib
capstrips. It’s better to plank the entire
wingtip on both sides; it makes the covering
job easier and neater. When you have
finished both wings, prepare them to accept
covering.
Fuselage Planking: Starting with the front
deck, plank the fuselage with 3/32 sheet balsa.
I made a cardboard pattern and used it as a
guide to cut the planking for the forward
“hood,” from the firewall to F3. Soak the
planking for installation. After test-fitting, use
cyanoacrylate to install it.
Make the 3/32 balsa planking for the area
aft of the cockpit. Use a single piece to cover
from F5 to the tail post and up to the 1/8-inch
top stringer on each side. This piece should
cover the tail post and terminate at the back
of the fuselage. The bend is fairly gentle and
should pose little problem. When you are
satisfied with the fit, glue the planking in
place with cyanoacrylate. Shape and add the
pieces that go between the top stringer and
the fin doublers.
When the cyanoacrylate has set, use a
sanding block to shape the back of the tail
post so it is flat. Blend the planking into the
fin doubler and the fuselage sides.
Cut two pieces of 3/8 balsa stock 11/4
inches wide and 83/8 inches long. These fit
between F5 and the instrument panel. Shape
the fronts to fit flush with the panel. Position
them so they are 3/32 inch inboard of the
05sig1.QXD 3/25/08 10:09 AM Page 28
fuselage sides, and adhere them in place with
cyanoacrylate.
Sand both sides so they follow the contour
of the panel and F5. These provide support for
the planking around the cockpit. See photos
for clarification.
Shape and fit the planking around the
cockpit. When you are satisfied, sand
everything flush. Use balsa filler to fill any
gaps, and finish-sand the entire fuselage
smooth and even. Cut—but do not install—
the 3/32-inch bottom piece. With the fuselage
planking complete, cut the tail post for the
stabilizer. This marks the end of the planking
phase.
Ailerons: These are cut from 3/8 x 3 tapered
balsa. See the wing plans for patterns.
Before shaping the aileron LE, use
cyanoacrylate to laminate a matching piece of
1/16 hard balsa to the top to strengthen the
structure. Temporarily attach the ailerons to
the wing with a few small spots of
cyanoacrylate, and then block-sand the bottom
of the ailerons to blend with the wing TE.
Remove the ailerons using debonder, and
sand the LEs for hinging.
Pushrods, Etc.: Install the pushrod tubes.
Holes are provided in F4 to support the front
of the pushrod tubes. I crossed mine in the
middle and they exited the fuselage on the
opposite side. I used a small cable tie at the
crossover point to support and stiffen the
tubes. Once the pushrod tubes are installed,
use cyanoacrylate to glue the bottom piece in
place. Sand the joint smooth.
A 360cc tank (Global Hobby part 120074)
I had on hand was employed in the original. I
used silicone adhesive to bond the front of the
fuel tank to the inside of the firewall, with the
neck protruding through the provided hole. I
Dremeled the bottom of the hole in F1 to
match the contour of the rear of the tank (see
dotted line on F1 pattern) and used silicon
adhesive there too.
Drill a hole in the firewall and F1 for the
throttle pushrod, positioned to make a straight
run from the carburetor to the throttle servo.
The fuselage servo linkages are typical. Use
your favorite clevises, etc. The wing servos
and linkages are installed after covering.
There are large openings in the ribs that
provide passage for the wires from the servos.
Make small openings in the planking inboard,
on the top of the wing, for the servo wires to
exit.
Insert the .505 composite wing spar in one
(either) wing up to the rib just past the servo
and glue it in place inside the root rib (only)
with cyanoacrylate.
It is unnecessary to cement the wing halves
together. It is much easier to store and
transport them separately. The mounting pegs
and nylon bolts will align and secure the wings
to the fuselage, and the spar is more than
strong enough to prevent them from folding.
Cowl: For the original model I made my cowl
from laminations of 3/8 balsa. Several good
articles have been written about the subject.
I also made a balsa cowl for a second
airplane, and I sent it out for Fiberglass
Specialties to duplicate in fiberglass. These
cowls are available for purchase if you don’t
want to expend the effort to fabricate your
own. Either way, the weight difference is
slight so the balance remains unchanged.
Covering: It seems like everyone has a
favorite covering material; I am no different. I
prefer Sig AeroKote, which I used on the
entire aircraft.
I don’t care for the elaborate, multicolor
schemes festooned with sponsor logos that are
rampant on ARFs. Thus Brodak’s CL Oriental
was the inspiration for the color scheme I used
on the original Golden Era 60. The Oriental is
black and red; I opted for Black and Naval
Orange.
If you use black on the fuselage, throw a
white cloth over it if the model is going to sit
in the sun for a long period. The black
covering absorbs heat and loosens, and you
will be faced with a session with the iron and
heat gun when you get home.
Nuts and Bolts: I used Du-Bro heavy-duty
.40-.91 control horns (item 867) throughout.
They require a single hole for mounting and are
rugged and easy to install. A bonus is that they
adjust for angle as well as throw. I installed a
steerable tail-wheel assembly from Global
Hobby. It mounts easily and works well.
My Spektrum DX7 came with four JR
RC System is distributed by:
SIG Manufacturing Company, Inc.
P.O. Box 520 • Montezuma, Iowa 50171-0520
Web Site: www.sigmfg.com • Phone: (641)623-5154
* actual Flightsimulator screens shown
There are different ways to learn model flying. If an
experienced model flyer is not on site then the first steps can
be disappointing. At worst case you could crash your first
model. Especially for learning R/C helicopter flying the so
called "Dry Run" on a simulator is an inexpensive and
suggested method. The SimTransmitter
"Joystick" in combination with the FMS
Flightsimulator provides the ideal virtual
beginner airplane or helicopter "model".
Simply plug the SimTransmitter into a free USB
port and configure it as a joystick.
SimTransmitter
Order No. RCSSIM062 - $39.99
* Prices at Participating Dealers
*
05sig1.QXD 3/25/08 10:09 AM Page 31
servos. Three are used in the fuselage, and
Hitec HD servos are used for the ailerons.
The Spektrum dual receivers are mounted
on opposite fuselage sides using Velcro. They
are oriented to provide opposite antenna
polarity, as the installation instructions
mandate. Not having to provide routing and
an exit for a long 72 MHz antenna is a
pleasant change!
The double 1/4-inch plate used to mount
the LG is a work-around because of a
clearance issue. The wing extends forward
from the mounting recess and engages the LG
if additional clearance isn’t provided. I didn’t
realize this until too late, and the second plate
proved to be a quick, effective remedy.
I cut the windshield from a plastic cake
container my supermarket provided free of
charge. Ask for one. If they refuse, you can
buy a cake and eat it!
The seat and headrest are carved from
balsa block and brushed with one coat of
Insignia Orange Aero Gloss. It imparts an
almost suedelike appearance. “Leo,” the pilot,
had to have his shoulders trimmed to fit in the
narrow cockpit. I repainted him with my
wife’s acrylics to match the model.
(References to “Leo” stem from the pilot
figure’s uncanny resemblance to a friend and
fellow RCer, Leo Desmarais.)
Hinging: I used cyanoacrylate hinges
throughout, but regardless of the type you
should have at least two on each elevator half,
three on the rudder, and four—equidistant—
along each aileron. Mounting procedures vary,
depending on the type chosen, and hingeinstallation
instruction is beyond the scope of
this article.
No matter what type of hinge you use,
make sure the movable surfaces fit closely to
the fixed surfaces. Gaps give birth to control
flutter, which can end an otherwise perfect
flying day.
Assembly: Since this is probably not your
first scratch build, I’ll be brief. There is
nothing unusual about the model and
assembly is straightforward
Assuming that the covering job is finished
and the elevator is hinged, insert the stabilizer
into its slot. Make sure it’s straight using a
string from the nose to the elevator tips. Mark
the stabilizer where it joins the fuselage, top
and bottom.
Remove the stabilizer and then remove the
covering that will be within the slot.
Permanently adhere the stabilizer, with
cyanoacrylate or epoxy, and hook up the
control hardware.
Drill the LG to accept the 1/4-20 nylon
mounting bolts. If the wheel pants haven’t
been assembled and painted and the wheels
haven’t been mounted, you haven’t been
reading far enough ahead!
Assemble the wings and fit them to the
fuselage. With the wings seated, carefully drill
9/32-inch holes through the centers of the wing
reinforcement pads into the rear wing
mounting plate.
Remove the wing and then further drill the
mounting plate to accept the captive 1/4-20
nuts. Epoxy them in place on the backside.
When they are set, reinstall the wing and
insert the 1/4-20 nylon bolts. Screw them into
the mounting plate slightly more than finger
tight.
Check the wing-to-stabilizer angle of
incidence using your favorite method; I use a
Great Planes laser setup. If your build is
accurate, it should be 0°-.5°. If it isn’t, make it
so. You can correct it several degrees either
way by removing or adding material to the
rear part of the wing saddle.
Balancing and Flying: I suggest a slightly
nose-heavy configuration for the first flights.
The balance point should fall one-third back
from the LE, or approximately where the LE
planking ends. Being an RC novice, I have
left the balance point there. If you’re more
experienced, you may find that a slightly more
aft point allows for better aerobatics.
This airplane has a thin symmetrical wing,
a somewhat short tail-moment arm, and high
wing loading; therefore, it flies like a
warbird—fast and without self-righting
properties. I programmed flaperons to help
during landings. Keep power on during
approach. As does a warbird, the Golden Era
likes to come in under power.
The large control surfaces beg dual rate
and exponential programming. This will allow
the experienced pilot to burn holes in the sky
while the less confident can fly it around
without working up a sweat.
The deep fuselage makes for easy knife
edge, and the slight wingtip washout and
aileron configuration help to keep it from
falling out of the sky at relatively low speeds.
This is not a good design for a first lowwing
sport airplane. It is satisfying for the
intermediate pilot and will draw attention at
the club field.
Electric Dreams: I gave little consideration to
making this aircraft light beyond what was
necessary for good 60-power performance. It
came in at slightly more than 9 pounds dry.
An electric conversion could include fewer
doublers, thinner and less planking, more
lightening holes, and a lighter LG assembly.
Several pounds could probably be shaved off
easily, making the wing loading nearer to a
more acceptable 20 ounces per square foot.
Being an old FF Gas aficionado, I revel in
the smell of nitro fuel in the morning, and the
postflight cleanup is akin to a labor of love.
I’ll leave it to you wattage mavens to do the
converting, but I’d love to see the results! MA
Fred Randall
[email protected]
Sources:
Short kit (1/8 light-plywood parts, 1/4 plywood
parts, 3/8 balsa rudder and elevator parts):
Creative Hobbies
(508) 473-8259
www.creativehobbies.net
Balsa, plywood stock:
National Balsa Co.
(413) 277-9500
www.nationalbalsa.com/
Composite tubing;
Kite Studio
(610) 395-3560
www.kitebuilder.com/
Fiberglass cowl:
Fiberglass Specialties
(479) 359-2429
www.fiberglassspecialtiesinc.com
Hardware, accessories:
Du-Bro
(800) 848-9411
http://dubro.com
Landing gear, wheel pants, AeroKote:
Sig Manufacturing
(641) 623-5154
www.sigmfg.com
32 MODEL AVIATION
05sig1.QXD 3/25/08 10:09 AM Page 32
Edition: Model Aviation - 2008/05
Page Numbers: 18,19,20,21,22,23,24,28,31,32
I HAVE ALWAYS admired racing aircraft of the so-called “Golden Age
of Aviation”: an era that extended from the end of World War I to the
onset of World War II. It was the time of rakish designs, open cockpits,
and “flying by the seat of one’s pants.”
Aircraft designs of the time were largely grand
experiments, and from those experiments
emerged the Granville Brothers’ Gee Bee series,
the Hughes H-1 racer, the Travel Air Mystery Ship,
the Hall Bulldog, and the rest of the list, which is too
numerous to include here.
I was weary of going to our flying field and finding almost
nothing between ARF training models, sticks, and the usual bunch of 3-D
ARFs. I realized that if I wanted something with a style I liked, I’d
have to build my own.
Accordingly, I made a couple pencil sketches, loaded
ModelCAD 3000 into my PC, and sat down at my electronic
drawing board to play. The Golden Era 60 is the result.
Although this airplane is conventional in its construction, it is
unsuitable for a first scratch-building project. This article assumes
that the builder has some experience beyond ARF assembly and is
familiar with common building techniques.
Unless you get the laser-cut “short kit” I’ll tell you about, you shouldn’t attempt this build without a scroll saw
or band saw, a Dremel or other rotary tool, and the usual collection of hand tools. The judicious use of a square and
straightedge is necessary throughout construction if you expect to manufacture a straight, easy-to-trim aircraft.
If the previous paragraphs haven’t discouraged you, we can proceed.
18 MODEL AVIATION
BY FRED RANDALL
A Williams Brothers Sportsman pilot bust complements the
open cockpit. Enamel brush paint can be spray-fixed with a
fuelproof clear coat.
Grooving through the open sky, the Golden Era 60 handles as
the popular Stick models do but has the looks of a 1930s
racer.
The grunt of a .60-size engine adds thrills
to this pioneer-reminiscent building project
05sig1.QXD 3/25/08 10:33 AM Page 18
Materials: Creative Hobbies of Mendon, Massachusetts, sells a short
kit of laser-cut 1/8 light plywood, 1/4 plywood, and 3/8 balsa parts at a
reasonable cost. These accurate precut components and a full-size
rolled plans set from MA will greatly simplify construction. It
eliminates tedium, and what remains is the equivalent of building a
good kit.
Regardless of whether or not you purchase the short kit, I suggest
that you have all fabricated parts (wing ribs, fuselage formers, etc.) on
hand before starting the build.
The landing gear and wheel pants on the original are Four-Star 120
parts ordered from Sig Manufacturing. I suggest that builders use the
same parts since they are a good match appearancewise, they fit the
gear mounting plates designed into the fuselage, and using other units
may significantly change the balance point. But if you prefer to
fabricate your own landing gear, have at it!
I did not design this airplane to be superlight since it is not
intended for “3-D.” It has an allup
weight of approximately
9 pounds and a wing
loading of roughly 26
ounces per square foot.
However, it is extremely
strong. This model is
extensively planked,
including wing
May 2008 19
After a full-power run of roughly 50 feet, the model lifts off smoothly.
The wide-track gear absorbs many of the bumps in the grass.
The former positions have been marked on the fuselage sides,
and the firewall assembly has been epoxied in place.
capstrips, and composite tubing is used for the LE and the main spar.
CONSTRUCTION
Fuselage: Although I usually begin with the wings, the fuselage was
my starting point for this project.
The first task was selecting the 1/8 balsa for the fuselage sides. The
importance of matching the side sheets’ hardness and grain cannot be
stressed enough. If the balsa is poorly matched, it will be next to
impossible to make a straight fuselage.
The fuselage sides’ maximum height is approximately 7 inches. I
used matched 4-inch-wide, 1/8 balsa sheets. Cement them together with
cyanoacrylate before cutting them to shape. (In the remainder of this
document, cyanoacrylate means medium cyanoacrylate unless
otherwise specified.)
After you have cut the balsa sides to shape, use cyanoacrylate to
glue the 1/8 plywood fuselage doublers in place. Be careful; it is easier
than you can imagine to end up with two right or two left sides.
Adhere, with cyanoacrylate, the doubler to the bottom of former F1.
After the fuselage doublers have set, epoxy and clamp the two
landing-gear (LG) and hatch-support rails to the fuselage doublers.
Refer to the plans for position. Make sure to wipe off any excess epoxy
from around the perimeter with alcohol.
Epoxy the 1/8 plywood firewall doubler to the 1/4 plywood firewall.
(Epoxy means 30-minute epoxy unless otherwise specified.)
Lay the fuselage plans on your building board, protecting them with
waxed paper or the like. With the plans as a guide, use a square
referenced to the top of the fuselage sides to mark the position of all
formers on the inside of both fuselage sides.
05sig1.QXD 3/25/08 10:44 AM Page 19
20 MODEL AVIATION
Formers F1 and F2 have been put in place, and the servo plate has
been mounted between them.
With the fuselage wide open, it’s a good time to fit the fuel tank.
Silicone sealant will be used to mount the tank permanently.
The left side has been epoxied in place after a careful alignment
check. Notice how the rear wing mount is locked into cutouts in
the doubler.
Bevel the tail post and then glue it in place. Dry-fit the fin and the
remaining formers to assure good alignment.
The tail-wheel mount area is supported by a 1/8 plywood plate.
It’s recessed to allow room for balsa, which will be sanded flush
with the fuselage sides.
Scrap 3/8 balsa sheet is substituted for the stabilizer during
preliminary alignment. The forward stringers are added at
this point.
05sig1.QXD 3/25/08 11:26 AM Page 20
May 2008 21
Once the sheeting is complete, it’s a good time to test-fit the
landing gear and engine mount. The cockpit area can be detailed
at this time.
Notice the smart use of carbon-fiber tubing to form the LE and
support the wing spar. The wing will be sheeted next.
Above: The completed one-piece wing is mounted with dowel pins
and nylon bolts. The light tail structure is designed to keep the
weight mass balanced on the recommended CG.
Left: Build the cowl from wood or purchase the fiberglass
version from Fiberglass Specialties. The mounting screws are
hidden inside.
Type: RC sport
Pilot skill level:
Intermediate to expert
Wingspan: 65.25 inches
Flying weight: 10 pounds
Wing area: 792 square inches
Wing loading: 26-27 ounces/square foot
Length: 51 inches
Engine: GMS .61 glow
Tank: Modeltech 360cc
Flight battery: Four cells, 4.8 volts
Radio: Spektrum DX7 system, AR7000 receiver, three DS821
and two Hitec HS-625MG servos
Spinner: Du-Bro (LXE 149) 3 inch
Construction: Balsa and light plywood
Covering/finish: Builder’s choice (Sig AeroKote is recommended.)
Photos by the author
05sig1.QXD 3/25/08 10:58 AM Page 21
22 MODEL AVIATION
The GMS .61 two-stroke engine hides inside the spacious cowl. A
four-stroke .82-1.00 would also fit this model neatly.
Stock Sig Four-Star 120 wheel pants complete this sport model’s 1930s racing look. The long and tall fuselage offers good knifeedge
performance.
Put the right fuselage side in place on the plans and secure it. Using
a square to position it, epoxy the firewall/doubler assembly flush with
the front of the fuselage side. When it has set, Formers F1 and F2 can
be cemented in place using cyanoacrylate. Position the servo tray in the
slots provided in formers F1 and F2, and secure it with cyanoacrylate.
Fashion the 11/2 x 47/16-inch rear wing anchor plate from 1/4
plywood. Do not drill it. Temporarily insert it into the slot provided in
the fuselage doubler. Test-fit the left side for perfect alignment. The
firewall assembly, the formers, the wing anchor plate, and both
fuselage sides must align properly.
When you are satisfied, remove the left side and apply epoxy to the
edge of the firewall assembly and the wing anchor plate edges that
mate with F2 and the fuselage sides. Apply cyanoacrylate to the mating
edges of F1 and F2. Put the left side back in position.
Place a book or similar weight on top to ensure a good bond, and
then take a break.
Shape the tail post from 1/2 x 3/4 x 13-inch balsa. It should taper
from 1/2 inch at the LE to 3/16 inch at the TE. It is important that this
piece be symmetrical. It will be further shaped and cut for the stabilizer
later, during fuselage assembly.
Notch the front roughly 1/8 inch deep to accept the light-plywood
fin. Refer to the plans for notch location.
With the fuselage secured to the top view of the plans, use T-pins to
temporarily hold the rear of the fuselage sides together, sandwiching
the tail post into position. The tail post should be centered over the
plans and flush with the bottom and back of the fuselage sides. Ensure
that the tail post is vertical in both axes when referenced to the fuselage
sides.
Reposition the pins until these conditions are met. Temporarily tack
the assembly together using a few drops of thin cyanoacrylate.
Remove the T-pins and recheck alignment. When you are satisfied,
flow in more thin cyanoacrylate for a permanent bond.
Install the remaining formers using cyanoacrylate. If necessary, use
rubber bands around the fuselage to ensure a full-contact fit.
Employing the plywood fin as a pattern, make doublers
approximately 3/8 inch wide from 3/16 balsa sheet. The doublers enable
a smooth transition between the planking and the fin. There is a
detailed drawing on the fuselage plans.
Cement the balsa doublers to both sides of the fin with
cyanoacrylate. Cut 1/8-inch gaps in the doubler where the fin fits into
05sig1.QXD 3/25/08 10:06 AM Page 22
the F5 and F6 notches and another at the rear
of the fin where it will be inserted into the
tail-post notch. Install the fin and secure it
with cyanoacrylate, and then sand the top of
the tail post to blend with the fin and doublers.
Cut the cockpit floor from 1/8 balsa sheet.
See the fuselage top view for the pattern.
Using cyanoacrylate, install the floor as
indicated and test-fit the dash panel. The dashpanel
pattern is somewhat oversize; you must
sand it to mount flush with the cockpit floor
and F3. Use a long sanding block to blend the
panel with the fuselage.
Install former F8. Fit it between F6 and the
tail post. See the plans for location. Trim it as
necessary for a proper fit. Ensure that F8 is at
right angles to, and level with, the top of the
notch in the fuselage sides. Take your time;
this establishes proper alignment and angle of
incidence.
I found it helpful to cut a piece of 3/8 balsa
sheet 3 inches wide and 12-15 inches long to
use as a spacer and alignment aid. Lay it on
top of F8 to use as a temporary substitute for
the stabilizer.
Position F7 as indicated on the plans, and
snug it against the temporary spacer. Adhere
F7 in place with cyanoacrylate and remove
the spacer. Trim F7 as necessary for a proper
fit.
Install the stringers using cyanoacrylate.
The front stringers extend aft to the panel.
There are no notches in the panel, so shape
the ends of the stringers for a nice butt fit
26 MODEL AVIATION
INTRODUCING
• Safe chemistry will not explode or catch fire
• Fast charge capable – 100% in 15 minutes
• 30c continuous, 60c bursts
• Exclusive Duralite Stay Balance Circuitry built-in
to every pack – no external balancing needed
• Charge through the charge lead with a Duralite Plus
Charger or through the power lead with an A123 capable
charger like the Orbit Pocketlader
• No regulator needed for most Rx applications
• Longer life cycle than lithium polymer chemistry
LITHIUM POWER SOLUTIONS FOR EVERYTHING YOU FLY
Order toll free 877-744-3685
Shop online www.duraliteflightsystems.com
PLUS
WITH STAY BALANCE
CIRCUITRY BUILT-IN
TO EVERY PACK
against it. The rear stringers should terminate
flush with the front of the tail post.
Epoxy four 1/4-20 captive nuts to the inner
LG mounting plate. Remove your fuselage
assembly from the building board, flip it over,
and use epoxy to bond the inner LG mounting
plate to the support rails. Don’t spare the
epoxy here; the LG takes considerable abuse
(at least when I’m flying).
The battery hatch came about because the
finished model needed a bit of nose weight. I
don’t like to add lead for balance when I can
reposition something to compensate. I
relocated the flight battery forward, in a foam
nest made for perfect balance with no
additional ballast. As a bonus, you have access
to the LG support assembly, engine-mount
captive nuts, and fuel tank should something
go awry.
Fashion the battery hatch from a piece of
1/8 light plywood. It should fit nicely between
the firewall, the fuselage sides, and the LG
mounting plate. It should rest on the support
rails. Drill holes at four corners for your
selected screw hardware.
I band-sawed a small amount of
downthrust and right thrust into my engine
mounts before installation. Offset the mounts
so that the spinner will be centered at the
proper location. When positioned, drill the
firewall and install the captive nuts.
Empennage: Building this area is
straightforward, and little explanation is
necessary beyond what is on the plans. The
only item that may need clarification is the
elevator joiner.
I originally intended to use a double
pushrod for elevator control. However, I had a
nice piece of .317 composite tubing left from
the wing construction, and it seemed
reasonable to use as a torque tube to join the
elevator halves. If you prefer double pushrods,
eliminate the torque tube and the clearance
notch in the rudder.
Wings: Select the right-wing full plans and
secure them to your building board. Using
cyanoacrylate, bond an RR1 rib to an RR2.
RR1 should be inboard. This assembly forms
the root rib.
Bond an R3 to an R1. The rib with no LE
notch is an R3; it should be inboard. Refer to
the plans for confirmation.
The wing will be built using the centermost
bottom spar as a reference. Cut a piece of 1/8 x
1/4 basswood to length and secure it in place
on the plans. Use a square to position the root
rib assembly on the plans with the spar snug in
its notch. Use cyanoacrylate to adhere the root
rib assembly to the spar.
Follow suit with an R1, R2 pair. Install the
remaining ribs, and adhere them to the spar
with cyanoacrylate. All ribs’ break-off stubs
should lay flat on the plans.
R2 is slightly different; it establishes a
small amount of washout in the wingtips to
improve low-speed stability. When all ribs are
in place, cut and install the three top spars. Cut
the .317-inch composite LE to length and glue
it in place with cyanoacrylate.
You should be able to insert the composite
spar as far as shown on the plans. Test-fit it. It
05sig1.QXD 3/25/08 10:09 AM Page 26
should be snug but not distort the ribs as it
passes through. Make any adjustments needed
until this condition is met, and then remove
the spar.
Remove the wing from the plans. Install
the remaining bottom spars, and then check
the assembly for straightness. It should lay
flat, resting on the centermost bottom spar and
rib break-off stubs. Correct any twist in the
wing before proceeding.
Following the diagram below the right
wing assembly drawing, shape the TE from 1/2
x 3/8 balsa. When you are finished, glue it into
position with cyanoacrylate.
Temporarily position the 1/8 light-plywood
servo plate to the bottom of the wing. Make
sure to place it at a point that is deep enough
on the chord to ensure that a standard servo’s
body does not protrude through the top. (Ask
me why I added this instruction.)
When you are satisfied with its position,
adhere the servo plate in place with
cyanoacrylate, flush with the bottom of the
ribs. Use scrap 1/8 x 1/4 spar material to make
rails to support and stiffen it.
Use cyanoacrylate to glue the 1/8 lightplywood
wingtip in place. It should be
centered between the LE and TE and at right
angles to R2. Make spar extensions and
cement them between the rib and the tip. See
the plans for positioning. Snap off the rib
stubs and sand the areas smooth.
Remove the right wing plans from the
building board and replace them with the left.
28 MODEL AVIATION
(We don’t want two right wings, do we?)
Take a deep breath and repeat the wing
instructions.
Having completed the framing of both
wings, fabricate and add the 1/4-inch plywood
dowel support webbing and the wing
mounting dowels. Ensure that the pegs will
align with the holes in F1. The detail diagram
will aid in drilling the peg holes and installing
the pegs.
Cut the .505 composite-tubing spar to
length and test-fit the joined wings. Be sure to
allow for the 1/16-inch planking. This work is
critical; it affects the final wing leveling and
wing/stabilizer angle of incidence. If the wing
is too wide, it does no harm to remove some
material from the TE where it fits within the
fuselage.
Wing Planking: The LE planking is a 1/16 x
12 x 36 balsa “wing skin.” The plans indicate
the areas that are covered with planking. Do
not trim the width until it is installed.
Thoroughly soak the balsa with Windex and
wait several minutes before attempting to
make the sharp LE bend.
When the balsa is pliable enough to make
the bend, start at the top, rear 1/8 x 1/4 spar.
Use cyanoacrylate to bond the balsa to the
spar. Clamp it along its length until the
adhesive sets.
Work slowly. Starting at the middle of the
wing and moving outward, glue, with
cyanoacrylate, the ribs, front spar, LE, etc.,
until you have the entire wing skin bonded,
top and bottom. If you do the job properly,
the planking should be tight, with no bulges.
Trim whatever planking extends beyond the
center, bottom spar.
Install the remaining planking and the rib
capstrips. It’s better to plank the entire
wingtip on both sides; it makes the covering
job easier and neater. When you have
finished both wings, prepare them to accept
covering.
Fuselage Planking: Starting with the front
deck, plank the fuselage with 3/32 sheet balsa.
I made a cardboard pattern and used it as a
guide to cut the planking for the forward
“hood,” from the firewall to F3. Soak the
planking for installation. After test-fitting, use
cyanoacrylate to install it.
Make the 3/32 balsa planking for the area
aft of the cockpit. Use a single piece to cover
from F5 to the tail post and up to the 1/8-inch
top stringer on each side. This piece should
cover the tail post and terminate at the back
of the fuselage. The bend is fairly gentle and
should pose little problem. When you are
satisfied with the fit, glue the planking in
place with cyanoacrylate. Shape and add the
pieces that go between the top stringer and
the fin doublers.
When the cyanoacrylate has set, use a
sanding block to shape the back of the tail
post so it is flat. Blend the planking into the
fin doubler and the fuselage sides.
Cut two pieces of 3/8 balsa stock 11/4
inches wide and 83/8 inches long. These fit
between F5 and the instrument panel. Shape
the fronts to fit flush with the panel. Position
them so they are 3/32 inch inboard of the
05sig1.QXD 3/25/08 10:09 AM Page 28
fuselage sides, and adhere them in place with
cyanoacrylate.
Sand both sides so they follow the contour
of the panel and F5. These provide support for
the planking around the cockpit. See photos
for clarification.
Shape and fit the planking around the
cockpit. When you are satisfied, sand
everything flush. Use balsa filler to fill any
gaps, and finish-sand the entire fuselage
smooth and even. Cut—but do not install—
the 3/32-inch bottom piece. With the fuselage
planking complete, cut the tail post for the
stabilizer. This marks the end of the planking
phase.
Ailerons: These are cut from 3/8 x 3 tapered
balsa. See the wing plans for patterns.
Before shaping the aileron LE, use
cyanoacrylate to laminate a matching piece of
1/16 hard balsa to the top to strengthen the
structure. Temporarily attach the ailerons to
the wing with a few small spots of
cyanoacrylate, and then block-sand the bottom
of the ailerons to blend with the wing TE.
Remove the ailerons using debonder, and
sand the LEs for hinging.
Pushrods, Etc.: Install the pushrod tubes.
Holes are provided in F4 to support the front
of the pushrod tubes. I crossed mine in the
middle and they exited the fuselage on the
opposite side. I used a small cable tie at the
crossover point to support and stiffen the
tubes. Once the pushrod tubes are installed,
use cyanoacrylate to glue the bottom piece in
place. Sand the joint smooth.
A 360cc tank (Global Hobby part 120074)
I had on hand was employed in the original. I
used silicone adhesive to bond the front of the
fuel tank to the inside of the firewall, with the
neck protruding through the provided hole. I
Dremeled the bottom of the hole in F1 to
match the contour of the rear of the tank (see
dotted line on F1 pattern) and used silicon
adhesive there too.
Drill a hole in the firewall and F1 for the
throttle pushrod, positioned to make a straight
run from the carburetor to the throttle servo.
The fuselage servo linkages are typical. Use
your favorite clevises, etc. The wing servos
and linkages are installed after covering.
There are large openings in the ribs that
provide passage for the wires from the servos.
Make small openings in the planking inboard,
on the top of the wing, for the servo wires to
exit.
Insert the .505 composite wing spar in one
(either) wing up to the rib just past the servo
and glue it in place inside the root rib (only)
with cyanoacrylate.
It is unnecessary to cement the wing halves
together. It is much easier to store and
transport them separately. The mounting pegs
and nylon bolts will align and secure the wings
to the fuselage, and the spar is more than
strong enough to prevent them from folding.
Cowl: For the original model I made my cowl
from laminations of 3/8 balsa. Several good
articles have been written about the subject.
I also made a balsa cowl for a second
airplane, and I sent it out for Fiberglass
Specialties to duplicate in fiberglass. These
cowls are available for purchase if you don’t
want to expend the effort to fabricate your
own. Either way, the weight difference is
slight so the balance remains unchanged.
Covering: It seems like everyone has a
favorite covering material; I am no different. I
prefer Sig AeroKote, which I used on the
entire aircraft.
I don’t care for the elaborate, multicolor
schemes festooned with sponsor logos that are
rampant on ARFs. Thus Brodak’s CL Oriental
was the inspiration for the color scheme I used
on the original Golden Era 60. The Oriental is
black and red; I opted for Black and Naval
Orange.
If you use black on the fuselage, throw a
white cloth over it if the model is going to sit
in the sun for a long period. The black
covering absorbs heat and loosens, and you
will be faced with a session with the iron and
heat gun when you get home.
Nuts and Bolts: I used Du-Bro heavy-duty
.40-.91 control horns (item 867) throughout.
They require a single hole for mounting and are
rugged and easy to install. A bonus is that they
adjust for angle as well as throw. I installed a
steerable tail-wheel assembly from Global
Hobby. It mounts easily and works well.
My Spektrum DX7 came with four JR
RC System is distributed by:
SIG Manufacturing Company, Inc.
P.O. Box 520 • Montezuma, Iowa 50171-0520
Web Site: www.sigmfg.com • Phone: (641)623-5154
* actual Flightsimulator screens shown
There are different ways to learn model flying. If an
experienced model flyer is not on site then the first steps can
be disappointing. At worst case you could crash your first
model. Especially for learning R/C helicopter flying the so
called "Dry Run" on a simulator is an inexpensive and
suggested method. The SimTransmitter
"Joystick" in combination with the FMS
Flightsimulator provides the ideal virtual
beginner airplane or helicopter "model".
Simply plug the SimTransmitter into a free USB
port and configure it as a joystick.
SimTransmitter
Order No. RCSSIM062 - $39.99
* Prices at Participating Dealers
*
05sig1.QXD 3/25/08 10:09 AM Page 31
servos. Three are used in the fuselage, and
Hitec HD servos are used for the ailerons.
The Spektrum dual receivers are mounted
on opposite fuselage sides using Velcro. They
are oriented to provide opposite antenna
polarity, as the installation instructions
mandate. Not having to provide routing and
an exit for a long 72 MHz antenna is a
pleasant change!
The double 1/4-inch plate used to mount
the LG is a work-around because of a
clearance issue. The wing extends forward
from the mounting recess and engages the LG
if additional clearance isn’t provided. I didn’t
realize this until too late, and the second plate
proved to be a quick, effective remedy.
I cut the windshield from a plastic cake
container my supermarket provided free of
charge. Ask for one. If they refuse, you can
buy a cake and eat it!
The seat and headrest are carved from
balsa block and brushed with one coat of
Insignia Orange Aero Gloss. It imparts an
almost suedelike appearance. “Leo,” the pilot,
had to have his shoulders trimmed to fit in the
narrow cockpit. I repainted him with my
wife’s acrylics to match the model.
(References to “Leo” stem from the pilot
figure’s uncanny resemblance to a friend and
fellow RCer, Leo Desmarais.)
Hinging: I used cyanoacrylate hinges
throughout, but regardless of the type you
should have at least two on each elevator half,
three on the rudder, and four—equidistant—
along each aileron. Mounting procedures vary,
depending on the type chosen, and hingeinstallation
instruction is beyond the scope of
this article.
No matter what type of hinge you use,
make sure the movable surfaces fit closely to
the fixed surfaces. Gaps give birth to control
flutter, which can end an otherwise perfect
flying day.
Assembly: Since this is probably not your
first scratch build, I’ll be brief. There is
nothing unusual about the model and
assembly is straightforward
Assuming that the covering job is finished
and the elevator is hinged, insert the stabilizer
into its slot. Make sure it’s straight using a
string from the nose to the elevator tips. Mark
the stabilizer where it joins the fuselage, top
and bottom.
Remove the stabilizer and then remove the
covering that will be within the slot.
Permanently adhere the stabilizer, with
cyanoacrylate or epoxy, and hook up the
control hardware.
Drill the LG to accept the 1/4-20 nylon
mounting bolts. If the wheel pants haven’t
been assembled and painted and the wheels
haven’t been mounted, you haven’t been
reading far enough ahead!
Assemble the wings and fit them to the
fuselage. With the wings seated, carefully drill
9/32-inch holes through the centers of the wing
reinforcement pads into the rear wing
mounting plate.
Remove the wing and then further drill the
mounting plate to accept the captive 1/4-20
nuts. Epoxy them in place on the backside.
When they are set, reinstall the wing and
insert the 1/4-20 nylon bolts. Screw them into
the mounting plate slightly more than finger
tight.
Check the wing-to-stabilizer angle of
incidence using your favorite method; I use a
Great Planes laser setup. If your build is
accurate, it should be 0°-.5°. If it isn’t, make it
so. You can correct it several degrees either
way by removing or adding material to the
rear part of the wing saddle.
Balancing and Flying: I suggest a slightly
nose-heavy configuration for the first flights.
The balance point should fall one-third back
from the LE, or approximately where the LE
planking ends. Being an RC novice, I have
left the balance point there. If you’re more
experienced, you may find that a slightly more
aft point allows for better aerobatics.
This airplane has a thin symmetrical wing,
a somewhat short tail-moment arm, and high
wing loading; therefore, it flies like a
warbird—fast and without self-righting
properties. I programmed flaperons to help
during landings. Keep power on during
approach. As does a warbird, the Golden Era
likes to come in under power.
The large control surfaces beg dual rate
and exponential programming. This will allow
the experienced pilot to burn holes in the sky
while the less confident can fly it around
without working up a sweat.
The deep fuselage makes for easy knife
edge, and the slight wingtip washout and
aileron configuration help to keep it from
falling out of the sky at relatively low speeds.
This is not a good design for a first lowwing
sport airplane. It is satisfying for the
intermediate pilot and will draw attention at
the club field.
Electric Dreams: I gave little consideration to
making this aircraft light beyond what was
necessary for good 60-power performance. It
came in at slightly more than 9 pounds dry.
An electric conversion could include fewer
doublers, thinner and less planking, more
lightening holes, and a lighter LG assembly.
Several pounds could probably be shaved off
easily, making the wing loading nearer to a
more acceptable 20 ounces per square foot.
Being an old FF Gas aficionado, I revel in
the smell of nitro fuel in the morning, and the
postflight cleanup is akin to a labor of love.
I’ll leave it to you wattage mavens to do the
converting, but I’d love to see the results! MA
Fred Randall
[email protected]
Sources:
Short kit (1/8 light-plywood parts, 1/4 plywood
parts, 3/8 balsa rudder and elevator parts):
Creative Hobbies
(508) 473-8259
www.creativehobbies.net
Balsa, plywood stock:
National Balsa Co.
(413) 277-9500
www.nationalbalsa.com/
Composite tubing;
Kite Studio
(610) 395-3560
www.kitebuilder.com/
Fiberglass cowl:
Fiberglass Specialties
(479) 359-2429
www.fiberglassspecialtiesinc.com
Hardware, accessories:
Du-Bro
(800) 848-9411
http://dubro.com
Landing gear, wheel pants, AeroKote:
Sig Manufacturing
(641) 623-5154
www.sigmfg.com
32 MODEL AVIATION
05sig1.QXD 3/25/08 10:09 AM Page 32
Edition: Model Aviation - 2008/05
Page Numbers: 18,19,20,21,22,23,24,28,31,32
I HAVE ALWAYS admired racing aircraft of the so-called “Golden Age
of Aviation”: an era that extended from the end of World War I to the
onset of World War II. It was the time of rakish designs, open cockpits,
and “flying by the seat of one’s pants.”
Aircraft designs of the time were largely grand
experiments, and from those experiments
emerged the Granville Brothers’ Gee Bee series,
the Hughes H-1 racer, the Travel Air Mystery Ship,
the Hall Bulldog, and the rest of the list, which is too
numerous to include here.
I was weary of going to our flying field and finding almost
nothing between ARF training models, sticks, and the usual bunch of 3-D
ARFs. I realized that if I wanted something with a style I liked, I’d
have to build my own.
Accordingly, I made a couple pencil sketches, loaded
ModelCAD 3000 into my PC, and sat down at my electronic
drawing board to play. The Golden Era 60 is the result.
Although this airplane is conventional in its construction, it is
unsuitable for a first scratch-building project. This article assumes
that the builder has some experience beyond ARF assembly and is
familiar with common building techniques.
Unless you get the laser-cut “short kit” I’ll tell you about, you shouldn’t attempt this build without a scroll saw
or band saw, a Dremel or other rotary tool, and the usual collection of hand tools. The judicious use of a square and
straightedge is necessary throughout construction if you expect to manufacture a straight, easy-to-trim aircraft.
If the previous paragraphs haven’t discouraged you, we can proceed.
18 MODEL AVIATION
BY FRED RANDALL
A Williams Brothers Sportsman pilot bust complements the
open cockpit. Enamel brush paint can be spray-fixed with a
fuelproof clear coat.
Grooving through the open sky, the Golden Era 60 handles as
the popular Stick models do but has the looks of a 1930s
racer.
The grunt of a .60-size engine adds thrills
to this pioneer-reminiscent building project
05sig1.QXD 3/25/08 10:33 AM Page 18
Materials: Creative Hobbies of Mendon, Massachusetts, sells a short
kit of laser-cut 1/8 light plywood, 1/4 plywood, and 3/8 balsa parts at a
reasonable cost. These accurate precut components and a full-size
rolled plans set from MA will greatly simplify construction. It
eliminates tedium, and what remains is the equivalent of building a
good kit.
Regardless of whether or not you purchase the short kit, I suggest
that you have all fabricated parts (wing ribs, fuselage formers, etc.) on
hand before starting the build.
The landing gear and wheel pants on the original are Four-Star 120
parts ordered from Sig Manufacturing. I suggest that builders use the
same parts since they are a good match appearancewise, they fit the
gear mounting plates designed into the fuselage, and using other units
may significantly change the balance point. But if you prefer to
fabricate your own landing gear, have at it!
I did not design this airplane to be superlight since it is not
intended for “3-D.” It has an allup
weight of approximately
9 pounds and a wing
loading of roughly 26
ounces per square foot.
However, it is extremely
strong. This model is
extensively planked,
including wing
May 2008 19
After a full-power run of roughly 50 feet, the model lifts off smoothly.
The wide-track gear absorbs many of the bumps in the grass.
The former positions have been marked on the fuselage sides,
and the firewall assembly has been epoxied in place.
capstrips, and composite tubing is used for the LE and the main spar.
CONSTRUCTION
Fuselage: Although I usually begin with the wings, the fuselage was
my starting point for this project.
The first task was selecting the 1/8 balsa for the fuselage sides. The
importance of matching the side sheets’ hardness and grain cannot be
stressed enough. If the balsa is poorly matched, it will be next to
impossible to make a straight fuselage.
The fuselage sides’ maximum height is approximately 7 inches. I
used matched 4-inch-wide, 1/8 balsa sheets. Cement them together with
cyanoacrylate before cutting them to shape. (In the remainder of this
document, cyanoacrylate means medium cyanoacrylate unless
otherwise specified.)
After you have cut the balsa sides to shape, use cyanoacrylate to
glue the 1/8 plywood fuselage doublers in place. Be careful; it is easier
than you can imagine to end up with two right or two left sides.
Adhere, with cyanoacrylate, the doubler to the bottom of former F1.
After the fuselage doublers have set, epoxy and clamp the two
landing-gear (LG) and hatch-support rails to the fuselage doublers.
Refer to the plans for position. Make sure to wipe off any excess epoxy
from around the perimeter with alcohol.
Epoxy the 1/8 plywood firewall doubler to the 1/4 plywood firewall.
(Epoxy means 30-minute epoxy unless otherwise specified.)
Lay the fuselage plans on your building board, protecting them with
waxed paper or the like. With the plans as a guide, use a square
referenced to the top of the fuselage sides to mark the position of all
formers on the inside of both fuselage sides.
05sig1.QXD 3/25/08 10:44 AM Page 19
20 MODEL AVIATION
Formers F1 and F2 have been put in place, and the servo plate has
been mounted between them.
With the fuselage wide open, it’s a good time to fit the fuel tank.
Silicone sealant will be used to mount the tank permanently.
The left side has been epoxied in place after a careful alignment
check. Notice how the rear wing mount is locked into cutouts in
the doubler.
Bevel the tail post and then glue it in place. Dry-fit the fin and the
remaining formers to assure good alignment.
The tail-wheel mount area is supported by a 1/8 plywood plate.
It’s recessed to allow room for balsa, which will be sanded flush
with the fuselage sides.
Scrap 3/8 balsa sheet is substituted for the stabilizer during
preliminary alignment. The forward stringers are added at
this point.
05sig1.QXD 3/25/08 11:26 AM Page 20
May 2008 21
Once the sheeting is complete, it’s a good time to test-fit the
landing gear and engine mount. The cockpit area can be detailed
at this time.
Notice the smart use of carbon-fiber tubing to form the LE and
support the wing spar. The wing will be sheeted next.
Above: The completed one-piece wing is mounted with dowel pins
and nylon bolts. The light tail structure is designed to keep the
weight mass balanced on the recommended CG.
Left: Build the cowl from wood or purchase the fiberglass
version from Fiberglass Specialties. The mounting screws are
hidden inside.
Type: RC sport
Pilot skill level:
Intermediate to expert
Wingspan: 65.25 inches
Flying weight: 10 pounds
Wing area: 792 square inches
Wing loading: 26-27 ounces/square foot
Length: 51 inches
Engine: GMS .61 glow
Tank: Modeltech 360cc
Flight battery: Four cells, 4.8 volts
Radio: Spektrum DX7 system, AR7000 receiver, three DS821
and two Hitec HS-625MG servos
Spinner: Du-Bro (LXE 149) 3 inch
Construction: Balsa and light plywood
Covering/finish: Builder’s choice (Sig AeroKote is recommended.)
Photos by the author
05sig1.QXD 3/25/08 10:58 AM Page 21
22 MODEL AVIATION
The GMS .61 two-stroke engine hides inside the spacious cowl. A
four-stroke .82-1.00 would also fit this model neatly.
Stock Sig Four-Star 120 wheel pants complete this sport model’s 1930s racing look. The long and tall fuselage offers good knifeedge
performance.
Put the right fuselage side in place on the plans and secure it. Using
a square to position it, epoxy the firewall/doubler assembly flush with
the front of the fuselage side. When it has set, Formers F1 and F2 can
be cemented in place using cyanoacrylate. Position the servo tray in the
slots provided in formers F1 and F2, and secure it with cyanoacrylate.
Fashion the 11/2 x 47/16-inch rear wing anchor plate from 1/4
plywood. Do not drill it. Temporarily insert it into the slot provided in
the fuselage doubler. Test-fit the left side for perfect alignment. The
firewall assembly, the formers, the wing anchor plate, and both
fuselage sides must align properly.
When you are satisfied, remove the left side and apply epoxy to the
edge of the firewall assembly and the wing anchor plate edges that
mate with F2 and the fuselage sides. Apply cyanoacrylate to the mating
edges of F1 and F2. Put the left side back in position.
Place a book or similar weight on top to ensure a good bond, and
then take a break.
Shape the tail post from 1/2 x 3/4 x 13-inch balsa. It should taper
from 1/2 inch at the LE to 3/16 inch at the TE. It is important that this
piece be symmetrical. It will be further shaped and cut for the stabilizer
later, during fuselage assembly.
Notch the front roughly 1/8 inch deep to accept the light-plywood
fin. Refer to the plans for notch location.
With the fuselage secured to the top view of the plans, use T-pins to
temporarily hold the rear of the fuselage sides together, sandwiching
the tail post into position. The tail post should be centered over the
plans and flush with the bottom and back of the fuselage sides. Ensure
that the tail post is vertical in both axes when referenced to the fuselage
sides.
Reposition the pins until these conditions are met. Temporarily tack
the assembly together using a few drops of thin cyanoacrylate.
Remove the T-pins and recheck alignment. When you are satisfied,
flow in more thin cyanoacrylate for a permanent bond.
Install the remaining formers using cyanoacrylate. If necessary, use
rubber bands around the fuselage to ensure a full-contact fit.
Employing the plywood fin as a pattern, make doublers
approximately 3/8 inch wide from 3/16 balsa sheet. The doublers enable
a smooth transition between the planking and the fin. There is a
detailed drawing on the fuselage plans.
Cement the balsa doublers to both sides of the fin with
cyanoacrylate. Cut 1/8-inch gaps in the doubler where the fin fits into
05sig1.QXD 3/25/08 10:06 AM Page 22
the F5 and F6 notches and another at the rear
of the fin where it will be inserted into the
tail-post notch. Install the fin and secure it
with cyanoacrylate, and then sand the top of
the tail post to blend with the fin and doublers.
Cut the cockpit floor from 1/8 balsa sheet.
See the fuselage top view for the pattern.
Using cyanoacrylate, install the floor as
indicated and test-fit the dash panel. The dashpanel
pattern is somewhat oversize; you must
sand it to mount flush with the cockpit floor
and F3. Use a long sanding block to blend the
panel with the fuselage.
Install former F8. Fit it between F6 and the
tail post. See the plans for location. Trim it as
necessary for a proper fit. Ensure that F8 is at
right angles to, and level with, the top of the
notch in the fuselage sides. Take your time;
this establishes proper alignment and angle of
incidence.
I found it helpful to cut a piece of 3/8 balsa
sheet 3 inches wide and 12-15 inches long to
use as a spacer and alignment aid. Lay it on
top of F8 to use as a temporary substitute for
the stabilizer.
Position F7 as indicated on the plans, and
snug it against the temporary spacer. Adhere
F7 in place with cyanoacrylate and remove
the spacer. Trim F7 as necessary for a proper
fit.
Install the stringers using cyanoacrylate.
The front stringers extend aft to the panel.
There are no notches in the panel, so shape
the ends of the stringers for a nice butt fit
26 MODEL AVIATION
INTRODUCING
• Safe chemistry will not explode or catch fire
• Fast charge capable – 100% in 15 minutes
• 30c continuous, 60c bursts
• Exclusive Duralite Stay Balance Circuitry built-in
to every pack – no external balancing needed
• Charge through the charge lead with a Duralite Plus
Charger or through the power lead with an A123 capable
charger like the Orbit Pocketlader
• No regulator needed for most Rx applications
• Longer life cycle than lithium polymer chemistry
LITHIUM POWER SOLUTIONS FOR EVERYTHING YOU FLY
Order toll free 877-744-3685
Shop online www.duraliteflightsystems.com
PLUS
WITH STAY BALANCE
CIRCUITRY BUILT-IN
TO EVERY PACK
against it. The rear stringers should terminate
flush with the front of the tail post.
Epoxy four 1/4-20 captive nuts to the inner
LG mounting plate. Remove your fuselage
assembly from the building board, flip it over,
and use epoxy to bond the inner LG mounting
plate to the support rails. Don’t spare the
epoxy here; the LG takes considerable abuse
(at least when I’m flying).
The battery hatch came about because the
finished model needed a bit of nose weight. I
don’t like to add lead for balance when I can
reposition something to compensate. I
relocated the flight battery forward, in a foam
nest made for perfect balance with no
additional ballast. As a bonus, you have access
to the LG support assembly, engine-mount
captive nuts, and fuel tank should something
go awry.
Fashion the battery hatch from a piece of
1/8 light plywood. It should fit nicely between
the firewall, the fuselage sides, and the LG
mounting plate. It should rest on the support
rails. Drill holes at four corners for your
selected screw hardware.
I band-sawed a small amount of
downthrust and right thrust into my engine
mounts before installation. Offset the mounts
so that the spinner will be centered at the
proper location. When positioned, drill the
firewall and install the captive nuts.
Empennage: Building this area is
straightforward, and little explanation is
necessary beyond what is on the plans. The
only item that may need clarification is the
elevator joiner.
I originally intended to use a double
pushrod for elevator control. However, I had a
nice piece of .317 composite tubing left from
the wing construction, and it seemed
reasonable to use as a torque tube to join the
elevator halves. If you prefer double pushrods,
eliminate the torque tube and the clearance
notch in the rudder.
Wings: Select the right-wing full plans and
secure them to your building board. Using
cyanoacrylate, bond an RR1 rib to an RR2.
RR1 should be inboard. This assembly forms
the root rib.
Bond an R3 to an R1. The rib with no LE
notch is an R3; it should be inboard. Refer to
the plans for confirmation.
The wing will be built using the centermost
bottom spar as a reference. Cut a piece of 1/8 x
1/4 basswood to length and secure it in place
on the plans. Use a square to position the root
rib assembly on the plans with the spar snug in
its notch. Use cyanoacrylate to adhere the root
rib assembly to the spar.
Follow suit with an R1, R2 pair. Install the
remaining ribs, and adhere them to the spar
with cyanoacrylate. All ribs’ break-off stubs
should lay flat on the plans.
R2 is slightly different; it establishes a
small amount of washout in the wingtips to
improve low-speed stability. When all ribs are
in place, cut and install the three top spars. Cut
the .317-inch composite LE to length and glue
it in place with cyanoacrylate.
You should be able to insert the composite
spar as far as shown on the plans. Test-fit it. It
05sig1.QXD 3/25/08 10:09 AM Page 26
should be snug but not distort the ribs as it
passes through. Make any adjustments needed
until this condition is met, and then remove
the spar.
Remove the wing from the plans. Install
the remaining bottom spars, and then check
the assembly for straightness. It should lay
flat, resting on the centermost bottom spar and
rib break-off stubs. Correct any twist in the
wing before proceeding.
Following the diagram below the right
wing assembly drawing, shape the TE from 1/2
x 3/8 balsa. When you are finished, glue it into
position with cyanoacrylate.
Temporarily position the 1/8 light-plywood
servo plate to the bottom of the wing. Make
sure to place it at a point that is deep enough
on the chord to ensure that a standard servo’s
body does not protrude through the top. (Ask
me why I added this instruction.)
When you are satisfied with its position,
adhere the servo plate in place with
cyanoacrylate, flush with the bottom of the
ribs. Use scrap 1/8 x 1/4 spar material to make
rails to support and stiffen it.
Use cyanoacrylate to glue the 1/8 lightplywood
wingtip in place. It should be
centered between the LE and TE and at right
angles to R2. Make spar extensions and
cement them between the rib and the tip. See
the plans for positioning. Snap off the rib
stubs and sand the areas smooth.
Remove the right wing plans from the
building board and replace them with the left.
28 MODEL AVIATION
(We don’t want two right wings, do we?)
Take a deep breath and repeat the wing
instructions.
Having completed the framing of both
wings, fabricate and add the 1/4-inch plywood
dowel support webbing and the wing
mounting dowels. Ensure that the pegs will
align with the holes in F1. The detail diagram
will aid in drilling the peg holes and installing
the pegs.
Cut the .505 composite-tubing spar to
length and test-fit the joined wings. Be sure to
allow for the 1/16-inch planking. This work is
critical; it affects the final wing leveling and
wing/stabilizer angle of incidence. If the wing
is too wide, it does no harm to remove some
material from the TE where it fits within the
fuselage.
Wing Planking: The LE planking is a 1/16 x
12 x 36 balsa “wing skin.” The plans indicate
the areas that are covered with planking. Do
not trim the width until it is installed.
Thoroughly soak the balsa with Windex and
wait several minutes before attempting to
make the sharp LE bend.
When the balsa is pliable enough to make
the bend, start at the top, rear 1/8 x 1/4 spar.
Use cyanoacrylate to bond the balsa to the
spar. Clamp it along its length until the
adhesive sets.
Work slowly. Starting at the middle of the
wing and moving outward, glue, with
cyanoacrylate, the ribs, front spar, LE, etc.,
until you have the entire wing skin bonded,
top and bottom. If you do the job properly,
the planking should be tight, with no bulges.
Trim whatever planking extends beyond the
center, bottom spar.
Install the remaining planking and the rib
capstrips. It’s better to plank the entire
wingtip on both sides; it makes the covering
job easier and neater. When you have
finished both wings, prepare them to accept
covering.
Fuselage Planking: Starting with the front
deck, plank the fuselage with 3/32 sheet balsa.
I made a cardboard pattern and used it as a
guide to cut the planking for the forward
“hood,” from the firewall to F3. Soak the
planking for installation. After test-fitting, use
cyanoacrylate to install it.
Make the 3/32 balsa planking for the area
aft of the cockpit. Use a single piece to cover
from F5 to the tail post and up to the 1/8-inch
top stringer on each side. This piece should
cover the tail post and terminate at the back
of the fuselage. The bend is fairly gentle and
should pose little problem. When you are
satisfied with the fit, glue the planking in
place with cyanoacrylate. Shape and add the
pieces that go between the top stringer and
the fin doublers.
When the cyanoacrylate has set, use a
sanding block to shape the back of the tail
post so it is flat. Blend the planking into the
fin doubler and the fuselage sides.
Cut two pieces of 3/8 balsa stock 11/4
inches wide and 83/8 inches long. These fit
between F5 and the instrument panel. Shape
the fronts to fit flush with the panel. Position
them so they are 3/32 inch inboard of the
05sig1.QXD 3/25/08 10:09 AM Page 28
fuselage sides, and adhere them in place with
cyanoacrylate.
Sand both sides so they follow the contour
of the panel and F5. These provide support for
the planking around the cockpit. See photos
for clarification.
Shape and fit the planking around the
cockpit. When you are satisfied, sand
everything flush. Use balsa filler to fill any
gaps, and finish-sand the entire fuselage
smooth and even. Cut—but do not install—
the 3/32-inch bottom piece. With the fuselage
planking complete, cut the tail post for the
stabilizer. This marks the end of the planking
phase.
Ailerons: These are cut from 3/8 x 3 tapered
balsa. See the wing plans for patterns.
Before shaping the aileron LE, use
cyanoacrylate to laminate a matching piece of
1/16 hard balsa to the top to strengthen the
structure. Temporarily attach the ailerons to
the wing with a few small spots of
cyanoacrylate, and then block-sand the bottom
of the ailerons to blend with the wing TE.
Remove the ailerons using debonder, and
sand the LEs for hinging.
Pushrods, Etc.: Install the pushrod tubes.
Holes are provided in F4 to support the front
of the pushrod tubes. I crossed mine in the
middle and they exited the fuselage on the
opposite side. I used a small cable tie at the
crossover point to support and stiffen the
tubes. Once the pushrod tubes are installed,
use cyanoacrylate to glue the bottom piece in
place. Sand the joint smooth.
A 360cc tank (Global Hobby part 120074)
I had on hand was employed in the original. I
used silicone adhesive to bond the front of the
fuel tank to the inside of the firewall, with the
neck protruding through the provided hole. I
Dremeled the bottom of the hole in F1 to
match the contour of the rear of the tank (see
dotted line on F1 pattern) and used silicon
adhesive there too.
Drill a hole in the firewall and F1 for the
throttle pushrod, positioned to make a straight
run from the carburetor to the throttle servo.
The fuselage servo linkages are typical. Use
your favorite clevises, etc. The wing servos
and linkages are installed after covering.
There are large openings in the ribs that
provide passage for the wires from the servos.
Make small openings in the planking inboard,
on the top of the wing, for the servo wires to
exit.
Insert the .505 composite wing spar in one
(either) wing up to the rib just past the servo
and glue it in place inside the root rib (only)
with cyanoacrylate.
It is unnecessary to cement the wing halves
together. It is much easier to store and
transport them separately. The mounting pegs
and nylon bolts will align and secure the wings
to the fuselage, and the spar is more than
strong enough to prevent them from folding.
Cowl: For the original model I made my cowl
from laminations of 3/8 balsa. Several good
articles have been written about the subject.
I also made a balsa cowl for a second
airplane, and I sent it out for Fiberglass
Specialties to duplicate in fiberglass. These
cowls are available for purchase if you don’t
want to expend the effort to fabricate your
own. Either way, the weight difference is
slight so the balance remains unchanged.
Covering: It seems like everyone has a
favorite covering material; I am no different. I
prefer Sig AeroKote, which I used on the
entire aircraft.
I don’t care for the elaborate, multicolor
schemes festooned with sponsor logos that are
rampant on ARFs. Thus Brodak’s CL Oriental
was the inspiration for the color scheme I used
on the original Golden Era 60. The Oriental is
black and red; I opted for Black and Naval
Orange.
If you use black on the fuselage, throw a
white cloth over it if the model is going to sit
in the sun for a long period. The black
covering absorbs heat and loosens, and you
will be faced with a session with the iron and
heat gun when you get home.
Nuts and Bolts: I used Du-Bro heavy-duty
.40-.91 control horns (item 867) throughout.
They require a single hole for mounting and are
rugged and easy to install. A bonus is that they
adjust for angle as well as throw. I installed a
steerable tail-wheel assembly from Global
Hobby. It mounts easily and works well.
My Spektrum DX7 came with four JR
RC System is distributed by:
SIG Manufacturing Company, Inc.
P.O. Box 520 • Montezuma, Iowa 50171-0520
Web Site: www.sigmfg.com • Phone: (641)623-5154
* actual Flightsimulator screens shown
There are different ways to learn model flying. If an
experienced model flyer is not on site then the first steps can
be disappointing. At worst case you could crash your first
model. Especially for learning R/C helicopter flying the so
called "Dry Run" on a simulator is an inexpensive and
suggested method. The SimTransmitter
"Joystick" in combination with the FMS
Flightsimulator provides the ideal virtual
beginner airplane or helicopter "model".
Simply plug the SimTransmitter into a free USB
port and configure it as a joystick.
SimTransmitter
Order No. RCSSIM062 - $39.99
* Prices at Participating Dealers
*
05sig1.QXD 3/25/08 10:09 AM Page 31
servos. Three are used in the fuselage, and
Hitec HD servos are used for the ailerons.
The Spektrum dual receivers are mounted
on opposite fuselage sides using Velcro. They
are oriented to provide opposite antenna
polarity, as the installation instructions
mandate. Not having to provide routing and
an exit for a long 72 MHz antenna is a
pleasant change!
The double 1/4-inch plate used to mount
the LG is a work-around because of a
clearance issue. The wing extends forward
from the mounting recess and engages the LG
if additional clearance isn’t provided. I didn’t
realize this until too late, and the second plate
proved to be a quick, effective remedy.
I cut the windshield from a plastic cake
container my supermarket provided free of
charge. Ask for one. If they refuse, you can
buy a cake and eat it!
The seat and headrest are carved from
balsa block and brushed with one coat of
Insignia Orange Aero Gloss. It imparts an
almost suedelike appearance. “Leo,” the pilot,
had to have his shoulders trimmed to fit in the
narrow cockpit. I repainted him with my
wife’s acrylics to match the model.
(References to “Leo” stem from the pilot
figure’s uncanny resemblance to a friend and
fellow RCer, Leo Desmarais.)
Hinging: I used cyanoacrylate hinges
throughout, but regardless of the type you
should have at least two on each elevator half,
three on the rudder, and four—equidistant—
along each aileron. Mounting procedures vary,
depending on the type chosen, and hingeinstallation
instruction is beyond the scope of
this article.
No matter what type of hinge you use,
make sure the movable surfaces fit closely to
the fixed surfaces. Gaps give birth to control
flutter, which can end an otherwise perfect
flying day.
Assembly: Since this is probably not your
first scratch build, I’ll be brief. There is
nothing unusual about the model and
assembly is straightforward
Assuming that the covering job is finished
and the elevator is hinged, insert the stabilizer
into its slot. Make sure it’s straight using a
string from the nose to the elevator tips. Mark
the stabilizer where it joins the fuselage, top
and bottom.
Remove the stabilizer and then remove the
covering that will be within the slot.
Permanently adhere the stabilizer, with
cyanoacrylate or epoxy, and hook up the
control hardware.
Drill the LG to accept the 1/4-20 nylon
mounting bolts. If the wheel pants haven’t
been assembled and painted and the wheels
haven’t been mounted, you haven’t been
reading far enough ahead!
Assemble the wings and fit them to the
fuselage. With the wings seated, carefully drill
9/32-inch holes through the centers of the wing
reinforcement pads into the rear wing
mounting plate.
Remove the wing and then further drill the
mounting plate to accept the captive 1/4-20
nuts. Epoxy them in place on the backside.
When they are set, reinstall the wing and
insert the 1/4-20 nylon bolts. Screw them into
the mounting plate slightly more than finger
tight.
Check the wing-to-stabilizer angle of
incidence using your favorite method; I use a
Great Planes laser setup. If your build is
accurate, it should be 0°-.5°. If it isn’t, make it
so. You can correct it several degrees either
way by removing or adding material to the
rear part of the wing saddle.
Balancing and Flying: I suggest a slightly
nose-heavy configuration for the first flights.
The balance point should fall one-third back
from the LE, or approximately where the LE
planking ends. Being an RC novice, I have
left the balance point there. If you’re more
experienced, you may find that a slightly more
aft point allows for better aerobatics.
This airplane has a thin symmetrical wing,
a somewhat short tail-moment arm, and high
wing loading; therefore, it flies like a
warbird—fast and without self-righting
properties. I programmed flaperons to help
during landings. Keep power on during
approach. As does a warbird, the Golden Era
likes to come in under power.
The large control surfaces beg dual rate
and exponential programming. This will allow
the experienced pilot to burn holes in the sky
while the less confident can fly it around
without working up a sweat.
The deep fuselage makes for easy knife
edge, and the slight wingtip washout and
aileron configuration help to keep it from
falling out of the sky at relatively low speeds.
This is not a good design for a first lowwing
sport airplane. It is satisfying for the
intermediate pilot and will draw attention at
the club field.
Electric Dreams: I gave little consideration to
making this aircraft light beyond what was
necessary for good 60-power performance. It
came in at slightly more than 9 pounds dry.
An electric conversion could include fewer
doublers, thinner and less planking, more
lightening holes, and a lighter LG assembly.
Several pounds could probably be shaved off
easily, making the wing loading nearer to a
more acceptable 20 ounces per square foot.
Being an old FF Gas aficionado, I revel in
the smell of nitro fuel in the morning, and the
postflight cleanup is akin to a labor of love.
I’ll leave it to you wattage mavens to do the
converting, but I’d love to see the results! MA
Fred Randall
[email protected]
Sources:
Short kit (1/8 light-plywood parts, 1/4 plywood
parts, 3/8 balsa rudder and elevator parts):
Creative Hobbies
(508) 473-8259
www.creativehobbies.net
Balsa, plywood stock:
National Balsa Co.
(413) 277-9500
www.nationalbalsa.com/
Composite tubing;
Kite Studio
(610) 395-3560
www.kitebuilder.com/
Fiberglass cowl:
Fiberglass Specialties
(479) 359-2429
www.fiberglassspecialtiesinc.com
Hardware, accessories:
Du-Bro
(800) 848-9411
http://dubro.com
Landing gear, wheel pants, AeroKote:
Sig Manufacturing
(641) 623-5154
www.sigmfg.com
32 MODEL AVIATION
05sig1.QXD 3/25/08 10:09 AM Page 32
Edition: Model Aviation - 2008/05
Page Numbers: 18,19,20,21,22,23,24,28,31,32
I HAVE ALWAYS admired racing aircraft of the so-called “Golden Age
of Aviation”: an era that extended from the end of World War I to the
onset of World War II. It was the time of rakish designs, open cockpits,
and “flying by the seat of one’s pants.”
Aircraft designs of the time were largely grand
experiments, and from those experiments
emerged the Granville Brothers’ Gee Bee series,
the Hughes H-1 racer, the Travel Air Mystery Ship,
the Hall Bulldog, and the rest of the list, which is too
numerous to include here.
I was weary of going to our flying field and finding almost
nothing between ARF training models, sticks, and the usual bunch of 3-D
ARFs. I realized that if I wanted something with a style I liked, I’d
have to build my own.
Accordingly, I made a couple pencil sketches, loaded
ModelCAD 3000 into my PC, and sat down at my electronic
drawing board to play. The Golden Era 60 is the result.
Although this airplane is conventional in its construction, it is
unsuitable for a first scratch-building project. This article assumes
that the builder has some experience beyond ARF assembly and is
familiar with common building techniques.
Unless you get the laser-cut “short kit” I’ll tell you about, you shouldn’t attempt this build without a scroll saw
or band saw, a Dremel or other rotary tool, and the usual collection of hand tools. The judicious use of a square and
straightedge is necessary throughout construction if you expect to manufacture a straight, easy-to-trim aircraft.
If the previous paragraphs haven’t discouraged you, we can proceed.
18 MODEL AVIATION
BY FRED RANDALL
A Williams Brothers Sportsman pilot bust complements the
open cockpit. Enamel brush paint can be spray-fixed with a
fuelproof clear coat.
Grooving through the open sky, the Golden Era 60 handles as
the popular Stick models do but has the looks of a 1930s
racer.
The grunt of a .60-size engine adds thrills
to this pioneer-reminiscent building project
05sig1.QXD 3/25/08 10:33 AM Page 18
Materials: Creative Hobbies of Mendon, Massachusetts, sells a short
kit of laser-cut 1/8 light plywood, 1/4 plywood, and 3/8 balsa parts at a
reasonable cost. These accurate precut components and a full-size
rolled plans set from MA will greatly simplify construction. It
eliminates tedium, and what remains is the equivalent of building a
good kit.
Regardless of whether or not you purchase the short kit, I suggest
that you have all fabricated parts (wing ribs, fuselage formers, etc.) on
hand before starting the build.
The landing gear and wheel pants on the original are Four-Star 120
parts ordered from Sig Manufacturing. I suggest that builders use the
same parts since they are a good match appearancewise, they fit the
gear mounting plates designed into the fuselage, and using other units
may significantly change the balance point. But if you prefer to
fabricate your own landing gear, have at it!
I did not design this airplane to be superlight since it is not
intended for “3-D.” It has an allup
weight of approximately
9 pounds and a wing
loading of roughly 26
ounces per square foot.
However, it is extremely
strong. This model is
extensively planked,
including wing
May 2008 19
After a full-power run of roughly 50 feet, the model lifts off smoothly.
The wide-track gear absorbs many of the bumps in the grass.
The former positions have been marked on the fuselage sides,
and the firewall assembly has been epoxied in place.
capstrips, and composite tubing is used for the LE and the main spar.
CONSTRUCTION
Fuselage: Although I usually begin with the wings, the fuselage was
my starting point for this project.
The first task was selecting the 1/8 balsa for the fuselage sides. The
importance of matching the side sheets’ hardness and grain cannot be
stressed enough. If the balsa is poorly matched, it will be next to
impossible to make a straight fuselage.
The fuselage sides’ maximum height is approximately 7 inches. I
used matched 4-inch-wide, 1/8 balsa sheets. Cement them together with
cyanoacrylate before cutting them to shape. (In the remainder of this
document, cyanoacrylate means medium cyanoacrylate unless
otherwise specified.)
After you have cut the balsa sides to shape, use cyanoacrylate to
glue the 1/8 plywood fuselage doublers in place. Be careful; it is easier
than you can imagine to end up with two right or two left sides.
Adhere, with cyanoacrylate, the doubler to the bottom of former F1.
After the fuselage doublers have set, epoxy and clamp the two
landing-gear (LG) and hatch-support rails to the fuselage doublers.
Refer to the plans for position. Make sure to wipe off any excess epoxy
from around the perimeter with alcohol.
Epoxy the 1/8 plywood firewall doubler to the 1/4 plywood firewall.
(Epoxy means 30-minute epoxy unless otherwise specified.)
Lay the fuselage plans on your building board, protecting them with
waxed paper or the like. With the plans as a guide, use a square
referenced to the top of the fuselage sides to mark the position of all
formers on the inside of both fuselage sides.
05sig1.QXD 3/25/08 10:44 AM Page 19
20 MODEL AVIATION
Formers F1 and F2 have been put in place, and the servo plate has
been mounted between them.
With the fuselage wide open, it’s a good time to fit the fuel tank.
Silicone sealant will be used to mount the tank permanently.
The left side has been epoxied in place after a careful alignment
check. Notice how the rear wing mount is locked into cutouts in
the doubler.
Bevel the tail post and then glue it in place. Dry-fit the fin and the
remaining formers to assure good alignment.
The tail-wheel mount area is supported by a 1/8 plywood plate.
It’s recessed to allow room for balsa, which will be sanded flush
with the fuselage sides.
Scrap 3/8 balsa sheet is substituted for the stabilizer during
preliminary alignment. The forward stringers are added at
this point.
05sig1.QXD 3/25/08 11:26 AM Page 20
May 2008 21
Once the sheeting is complete, it’s a good time to test-fit the
landing gear and engine mount. The cockpit area can be detailed
at this time.
Notice the smart use of carbon-fiber tubing to form the LE and
support the wing spar. The wing will be sheeted next.
Above: The completed one-piece wing is mounted with dowel pins
and nylon bolts. The light tail structure is designed to keep the
weight mass balanced on the recommended CG.
Left: Build the cowl from wood or purchase the fiberglass
version from Fiberglass Specialties. The mounting screws are
hidden inside.
Type: RC sport
Pilot skill level:
Intermediate to expert
Wingspan: 65.25 inches
Flying weight: 10 pounds
Wing area: 792 square inches
Wing loading: 26-27 ounces/square foot
Length: 51 inches
Engine: GMS .61 glow
Tank: Modeltech 360cc
Flight battery: Four cells, 4.8 volts
Radio: Spektrum DX7 system, AR7000 receiver, three DS821
and two Hitec HS-625MG servos
Spinner: Du-Bro (LXE 149) 3 inch
Construction: Balsa and light plywood
Covering/finish: Builder’s choice (Sig AeroKote is recommended.)
Photos by the author
05sig1.QXD 3/25/08 10:58 AM Page 21
22 MODEL AVIATION
The GMS .61 two-stroke engine hides inside the spacious cowl. A
four-stroke .82-1.00 would also fit this model neatly.
Stock Sig Four-Star 120 wheel pants complete this sport model’s 1930s racing look. The long and tall fuselage offers good knifeedge
performance.
Put the right fuselage side in place on the plans and secure it. Using
a square to position it, epoxy the firewall/doubler assembly flush with
the front of the fuselage side. When it has set, Formers F1 and F2 can
be cemented in place using cyanoacrylate. Position the servo tray in the
slots provided in formers F1 and F2, and secure it with cyanoacrylate.
Fashion the 11/2 x 47/16-inch rear wing anchor plate from 1/4
plywood. Do not drill it. Temporarily insert it into the slot provided in
the fuselage doubler. Test-fit the left side for perfect alignment. The
firewall assembly, the formers, the wing anchor plate, and both
fuselage sides must align properly.
When you are satisfied, remove the left side and apply epoxy to the
edge of the firewall assembly and the wing anchor plate edges that
mate with F2 and the fuselage sides. Apply cyanoacrylate to the mating
edges of F1 and F2. Put the left side back in position.
Place a book or similar weight on top to ensure a good bond, and
then take a break.
Shape the tail post from 1/2 x 3/4 x 13-inch balsa. It should taper
from 1/2 inch at the LE to 3/16 inch at the TE. It is important that this
piece be symmetrical. It will be further shaped and cut for the stabilizer
later, during fuselage assembly.
Notch the front roughly 1/8 inch deep to accept the light-plywood
fin. Refer to the plans for notch location.
With the fuselage secured to the top view of the plans, use T-pins to
temporarily hold the rear of the fuselage sides together, sandwiching
the tail post into position. The tail post should be centered over the
plans and flush with the bottom and back of the fuselage sides. Ensure
that the tail post is vertical in both axes when referenced to the fuselage
sides.
Reposition the pins until these conditions are met. Temporarily tack
the assembly together using a few drops of thin cyanoacrylate.
Remove the T-pins and recheck alignment. When you are satisfied,
flow in more thin cyanoacrylate for a permanent bond.
Install the remaining formers using cyanoacrylate. If necessary, use
rubber bands around the fuselage to ensure a full-contact fit.
Employing the plywood fin as a pattern, make doublers
approximately 3/8 inch wide from 3/16 balsa sheet. The doublers enable
a smooth transition between the planking and the fin. There is a
detailed drawing on the fuselage plans.
Cement the balsa doublers to both sides of the fin with
cyanoacrylate. Cut 1/8-inch gaps in the doubler where the fin fits into
05sig1.QXD 3/25/08 10:06 AM Page 22
the F5 and F6 notches and another at the rear
of the fin where it will be inserted into the
tail-post notch. Install the fin and secure it
with cyanoacrylate, and then sand the top of
the tail post to blend with the fin and doublers.
Cut the cockpit floor from 1/8 balsa sheet.
See the fuselage top view for the pattern.
Using cyanoacrylate, install the floor as
indicated and test-fit the dash panel. The dashpanel
pattern is somewhat oversize; you must
sand it to mount flush with the cockpit floor
and F3. Use a long sanding block to blend the
panel with the fuselage.
Install former F8. Fit it between F6 and the
tail post. See the plans for location. Trim it as
necessary for a proper fit. Ensure that F8 is at
right angles to, and level with, the top of the
notch in the fuselage sides. Take your time;
this establishes proper alignment and angle of
incidence.
I found it helpful to cut a piece of 3/8 balsa
sheet 3 inches wide and 12-15 inches long to
use as a spacer and alignment aid. Lay it on
top of F8 to use as a temporary substitute for
the stabilizer.
Position F7 as indicated on the plans, and
snug it against the temporary spacer. Adhere
F7 in place with cyanoacrylate and remove
the spacer. Trim F7 as necessary for a proper
fit.
Install the stringers using cyanoacrylate.
The front stringers extend aft to the panel.
There are no notches in the panel, so shape
the ends of the stringers for a nice butt fit
26 MODEL AVIATION
INTRODUCING
• Safe chemistry will not explode or catch fire
• Fast charge capable – 100% in 15 minutes
• 30c continuous, 60c bursts
• Exclusive Duralite Stay Balance Circuitry built-in
to every pack – no external balancing needed
• Charge through the charge lead with a Duralite Plus
Charger or through the power lead with an A123 capable
charger like the Orbit Pocketlader
• No regulator needed for most Rx applications
• Longer life cycle than lithium polymer chemistry
LITHIUM POWER SOLUTIONS FOR EVERYTHING YOU FLY
Order toll free 877-744-3685
Shop online www.duraliteflightsystems.com
PLUS
WITH STAY BALANCE
CIRCUITRY BUILT-IN
TO EVERY PACK
against it. The rear stringers should terminate
flush with the front of the tail post.
Epoxy four 1/4-20 captive nuts to the inner
LG mounting plate. Remove your fuselage
assembly from the building board, flip it over,
and use epoxy to bond the inner LG mounting
plate to the support rails. Don’t spare the
epoxy here; the LG takes considerable abuse
(at least when I’m flying).
The battery hatch came about because the
finished model needed a bit of nose weight. I
don’t like to add lead for balance when I can
reposition something to compensate. I
relocated the flight battery forward, in a foam
nest made for perfect balance with no
additional ballast. As a bonus, you have access
to the LG support assembly, engine-mount
captive nuts, and fuel tank should something
go awry.
Fashion the battery hatch from a piece of
1/8 light plywood. It should fit nicely between
the firewall, the fuselage sides, and the LG
mounting plate. It should rest on the support
rails. Drill holes at four corners for your
selected screw hardware.
I band-sawed a small amount of
downthrust and right thrust into my engine
mounts before installation. Offset the mounts
so that the spinner will be centered at the
proper location. When positioned, drill the
firewall and install the captive nuts.
Empennage: Building this area is
straightforward, and little explanation is
necessary beyond what is on the plans. The
only item that may need clarification is the
elevator joiner.
I originally intended to use a double
pushrod for elevator control. However, I had a
nice piece of .317 composite tubing left from
the wing construction, and it seemed
reasonable to use as a torque tube to join the
elevator halves. If you prefer double pushrods,
eliminate the torque tube and the clearance
notch in the rudder.
Wings: Select the right-wing full plans and
secure them to your building board. Using
cyanoacrylate, bond an RR1 rib to an RR2.
RR1 should be inboard. This assembly forms
the root rib.
Bond an R3 to an R1. The rib with no LE
notch is an R3; it should be inboard. Refer to
the plans for confirmation.
The wing will be built using the centermost
bottom spar as a reference. Cut a piece of 1/8 x
1/4 basswood to length and secure it in place
on the plans. Use a square to position the root
rib assembly on the plans with the spar snug in
its notch. Use cyanoacrylate to adhere the root
rib assembly to the spar.
Follow suit with an R1, R2 pair. Install the
remaining ribs, and adhere them to the spar
with cyanoacrylate. All ribs’ break-off stubs
should lay flat on the plans.
R2 is slightly different; it establishes a
small amount of washout in the wingtips to
improve low-speed stability. When all ribs are
in place, cut and install the three top spars. Cut
the .317-inch composite LE to length and glue
it in place with cyanoacrylate.
You should be able to insert the composite
spar as far as shown on the plans. Test-fit it. It
05sig1.QXD 3/25/08 10:09 AM Page 26
should be snug but not distort the ribs as it
passes through. Make any adjustments needed
until this condition is met, and then remove
the spar.
Remove the wing from the plans. Install
the remaining bottom spars, and then check
the assembly for straightness. It should lay
flat, resting on the centermost bottom spar and
rib break-off stubs. Correct any twist in the
wing before proceeding.
Following the diagram below the right
wing assembly drawing, shape the TE from 1/2
x 3/8 balsa. When you are finished, glue it into
position with cyanoacrylate.
Temporarily position the 1/8 light-plywood
servo plate to the bottom of the wing. Make
sure to place it at a point that is deep enough
on the chord to ensure that a standard servo’s
body does not protrude through the top. (Ask
me why I added this instruction.)
When you are satisfied with its position,
adhere the servo plate in place with
cyanoacrylate, flush with the bottom of the
ribs. Use scrap 1/8 x 1/4 spar material to make
rails to support and stiffen it.
Use cyanoacrylate to glue the 1/8 lightplywood
wingtip in place. It should be
centered between the LE and TE and at right
angles to R2. Make spar extensions and
cement them between the rib and the tip. See
the plans for positioning. Snap off the rib
stubs and sand the areas smooth.
Remove the right wing plans from the
building board and replace them with the left.
28 MODEL AVIATION
(We don’t want two right wings, do we?)
Take a deep breath and repeat the wing
instructions.
Having completed the framing of both
wings, fabricate and add the 1/4-inch plywood
dowel support webbing and the wing
mounting dowels. Ensure that the pegs will
align with the holes in F1. The detail diagram
will aid in drilling the peg holes and installing
the pegs.
Cut the .505 composite-tubing spar to
length and test-fit the joined wings. Be sure to
allow for the 1/16-inch planking. This work is
critical; it affects the final wing leveling and
wing/stabilizer angle of incidence. If the wing
is too wide, it does no harm to remove some
material from the TE where it fits within the
fuselage.
Wing Planking: The LE planking is a 1/16 x
12 x 36 balsa “wing skin.” The plans indicate
the areas that are covered with planking. Do
not trim the width until it is installed.
Thoroughly soak the balsa with Windex and
wait several minutes before attempting to
make the sharp LE bend.
When the balsa is pliable enough to make
the bend, start at the top, rear 1/8 x 1/4 spar.
Use cyanoacrylate to bond the balsa to the
spar. Clamp it along its length until the
adhesive sets.
Work slowly. Starting at the middle of the
wing and moving outward, glue, with
cyanoacrylate, the ribs, front spar, LE, etc.,
until you have the entire wing skin bonded,
top and bottom. If you do the job properly,
the planking should be tight, with no bulges.
Trim whatever planking extends beyond the
center, bottom spar.
Install the remaining planking and the rib
capstrips. It’s better to plank the entire
wingtip on both sides; it makes the covering
job easier and neater. When you have
finished both wings, prepare them to accept
covering.
Fuselage Planking: Starting with the front
deck, plank the fuselage with 3/32 sheet balsa.
I made a cardboard pattern and used it as a
guide to cut the planking for the forward
“hood,” from the firewall to F3. Soak the
planking for installation. After test-fitting, use
cyanoacrylate to install it.
Make the 3/32 balsa planking for the area
aft of the cockpit. Use a single piece to cover
from F5 to the tail post and up to the 1/8-inch
top stringer on each side. This piece should
cover the tail post and terminate at the back
of the fuselage. The bend is fairly gentle and
should pose little problem. When you are
satisfied with the fit, glue the planking in
place with cyanoacrylate. Shape and add the
pieces that go between the top stringer and
the fin doublers.
When the cyanoacrylate has set, use a
sanding block to shape the back of the tail
post so it is flat. Blend the planking into the
fin doubler and the fuselage sides.
Cut two pieces of 3/8 balsa stock 11/4
inches wide and 83/8 inches long. These fit
between F5 and the instrument panel. Shape
the fronts to fit flush with the panel. Position
them so they are 3/32 inch inboard of the
05sig1.QXD 3/25/08 10:09 AM Page 28
fuselage sides, and adhere them in place with
cyanoacrylate.
Sand both sides so they follow the contour
of the panel and F5. These provide support for
the planking around the cockpit. See photos
for clarification.
Shape and fit the planking around the
cockpit. When you are satisfied, sand
everything flush. Use balsa filler to fill any
gaps, and finish-sand the entire fuselage
smooth and even. Cut—but do not install—
the 3/32-inch bottom piece. With the fuselage
planking complete, cut the tail post for the
stabilizer. This marks the end of the planking
phase.
Ailerons: These are cut from 3/8 x 3 tapered
balsa. See the wing plans for patterns.
Before shaping the aileron LE, use
cyanoacrylate to laminate a matching piece of
1/16 hard balsa to the top to strengthen the
structure. Temporarily attach the ailerons to
the wing with a few small spots of
cyanoacrylate, and then block-sand the bottom
of the ailerons to blend with the wing TE.
Remove the ailerons using debonder, and
sand the LEs for hinging.
Pushrods, Etc.: Install the pushrod tubes.
Holes are provided in F4 to support the front
of the pushrod tubes. I crossed mine in the
middle and they exited the fuselage on the
opposite side. I used a small cable tie at the
crossover point to support and stiffen the
tubes. Once the pushrod tubes are installed,
use cyanoacrylate to glue the bottom piece in
place. Sand the joint smooth.
A 360cc tank (Global Hobby part 120074)
I had on hand was employed in the original. I
used silicone adhesive to bond the front of the
fuel tank to the inside of the firewall, with the
neck protruding through the provided hole. I
Dremeled the bottom of the hole in F1 to
match the contour of the rear of the tank (see
dotted line on F1 pattern) and used silicon
adhesive there too.
Drill a hole in the firewall and F1 for the
throttle pushrod, positioned to make a straight
run from the carburetor to the throttle servo.
The fuselage servo linkages are typical. Use
your favorite clevises, etc. The wing servos
and linkages are installed after covering.
There are large openings in the ribs that
provide passage for the wires from the servos.
Make small openings in the planking inboard,
on the top of the wing, for the servo wires to
exit.
Insert the .505 composite wing spar in one
(either) wing up to the rib just past the servo
and glue it in place inside the root rib (only)
with cyanoacrylate.
It is unnecessary to cement the wing halves
together. It is much easier to store and
transport them separately. The mounting pegs
and nylon bolts will align and secure the wings
to the fuselage, and the spar is more than
strong enough to prevent them from folding.
Cowl: For the original model I made my cowl
from laminations of 3/8 balsa. Several good
articles have been written about the subject.
I also made a balsa cowl for a second
airplane, and I sent it out for Fiberglass
Specialties to duplicate in fiberglass. These
cowls are available for purchase if you don’t
want to expend the effort to fabricate your
own. Either way, the weight difference is
slight so the balance remains unchanged.
Covering: It seems like everyone has a
favorite covering material; I am no different. I
prefer Sig AeroKote, which I used on the
entire aircraft.
I don’t care for the elaborate, multicolor
schemes festooned with sponsor logos that are
rampant on ARFs. Thus Brodak’s CL Oriental
was the inspiration for the color scheme I used
on the original Golden Era 60. The Oriental is
black and red; I opted for Black and Naval
Orange.
If you use black on the fuselage, throw a
white cloth over it if the model is going to sit
in the sun for a long period. The black
covering absorbs heat and loosens, and you
will be faced with a session with the iron and
heat gun when you get home.
Nuts and Bolts: I used Du-Bro heavy-duty
.40-.91 control horns (item 867) throughout.
They require a single hole for mounting and are
rugged and easy to install. A bonus is that they
adjust for angle as well as throw. I installed a
steerable tail-wheel assembly from Global
Hobby. It mounts easily and works well.
My Spektrum DX7 came with four JR
RC System is distributed by:
SIG Manufacturing Company, Inc.
P.O. Box 520 • Montezuma, Iowa 50171-0520
Web Site: www.sigmfg.com • Phone: (641)623-5154
* actual Flightsimulator screens shown
There are different ways to learn model flying. If an
experienced model flyer is not on site then the first steps can
be disappointing. At worst case you could crash your first
model. Especially for learning R/C helicopter flying the so
called "Dry Run" on a simulator is an inexpensive and
suggested method. The SimTransmitter
"Joystick" in combination with the FMS
Flightsimulator provides the ideal virtual
beginner airplane or helicopter "model".
Simply plug the SimTransmitter into a free USB
port and configure it as a joystick.
SimTransmitter
Order No. RCSSIM062 - $39.99
* Prices at Participating Dealers
*
05sig1.QXD 3/25/08 10:09 AM Page 31
servos. Three are used in the fuselage, and
Hitec HD servos are used for the ailerons.
The Spektrum dual receivers are mounted
on opposite fuselage sides using Velcro. They
are oriented to provide opposite antenna
polarity, as the installation instructions
mandate. Not having to provide routing and
an exit for a long 72 MHz antenna is a
pleasant change!
The double 1/4-inch plate used to mount
the LG is a work-around because of a
clearance issue. The wing extends forward
from the mounting recess and engages the LG
if additional clearance isn’t provided. I didn’t
realize this until too late, and the second plate
proved to be a quick, effective remedy.
I cut the windshield from a plastic cake
container my supermarket provided free of
charge. Ask for one. If they refuse, you can
buy a cake and eat it!
The seat and headrest are carved from
balsa block and brushed with one coat of
Insignia Orange Aero Gloss. It imparts an
almost suedelike appearance. “Leo,” the pilot,
had to have his shoulders trimmed to fit in the
narrow cockpit. I repainted him with my
wife’s acrylics to match the model.
(References to “Leo” stem from the pilot
figure’s uncanny resemblance to a friend and
fellow RCer, Leo Desmarais.)
Hinging: I used cyanoacrylate hinges
throughout, but regardless of the type you
should have at least two on each elevator half,
three on the rudder, and four—equidistant—
along each aileron. Mounting procedures vary,
depending on the type chosen, and hingeinstallation
instruction is beyond the scope of
this article.
No matter what type of hinge you use,
make sure the movable surfaces fit closely to
the fixed surfaces. Gaps give birth to control
flutter, which can end an otherwise perfect
flying day.
Assembly: Since this is probably not your
first scratch build, I’ll be brief. There is
nothing unusual about the model and
assembly is straightforward
Assuming that the covering job is finished
and the elevator is hinged, insert the stabilizer
into its slot. Make sure it’s straight using a
string from the nose to the elevator tips. Mark
the stabilizer where it joins the fuselage, top
and bottom.
Remove the stabilizer and then remove the
covering that will be within the slot.
Permanently adhere the stabilizer, with
cyanoacrylate or epoxy, and hook up the
control hardware.
Drill the LG to accept the 1/4-20 nylon
mounting bolts. If the wheel pants haven’t
been assembled and painted and the wheels
haven’t been mounted, you haven’t been
reading far enough ahead!
Assemble the wings and fit them to the
fuselage. With the wings seated, carefully drill
9/32-inch holes through the centers of the wing
reinforcement pads into the rear wing
mounting plate.
Remove the wing and then further drill the
mounting plate to accept the captive 1/4-20
nuts. Epoxy them in place on the backside.
When they are set, reinstall the wing and
insert the 1/4-20 nylon bolts. Screw them into
the mounting plate slightly more than finger
tight.
Check the wing-to-stabilizer angle of
incidence using your favorite method; I use a
Great Planes laser setup. If your build is
accurate, it should be 0°-.5°. If it isn’t, make it
so. You can correct it several degrees either
way by removing or adding material to the
rear part of the wing saddle.
Balancing and Flying: I suggest a slightly
nose-heavy configuration for the first flights.
The balance point should fall one-third back
from the LE, or approximately where the LE
planking ends. Being an RC novice, I have
left the balance point there. If you’re more
experienced, you may find that a slightly more
aft point allows for better aerobatics.
This airplane has a thin symmetrical wing,
a somewhat short tail-moment arm, and high
wing loading; therefore, it flies like a
warbird—fast and without self-righting
properties. I programmed flaperons to help
during landings. Keep power on during
approach. As does a warbird, the Golden Era
likes to come in under power.
The large control surfaces beg dual rate
and exponential programming. This will allow
the experienced pilot to burn holes in the sky
while the less confident can fly it around
without working up a sweat.
The deep fuselage makes for easy knife
edge, and the slight wingtip washout and
aileron configuration help to keep it from
falling out of the sky at relatively low speeds.
This is not a good design for a first lowwing
sport airplane. It is satisfying for the
intermediate pilot and will draw attention at
the club field.
Electric Dreams: I gave little consideration to
making this aircraft light beyond what was
necessary for good 60-power performance. It
came in at slightly more than 9 pounds dry.
An electric conversion could include fewer
doublers, thinner and less planking, more
lightening holes, and a lighter LG assembly.
Several pounds could probably be shaved off
easily, making the wing loading nearer to a
more acceptable 20 ounces per square foot.
Being an old FF Gas aficionado, I revel in
the smell of nitro fuel in the morning, and the
postflight cleanup is akin to a labor of love.
I’ll leave it to you wattage mavens to do the
converting, but I’d love to see the results! MA
Fred Randall
[email protected]
Sources:
Short kit (1/8 light-plywood parts, 1/4 plywood
parts, 3/8 balsa rudder and elevator parts):
Creative Hobbies
(508) 473-8259
www.creativehobbies.net
Balsa, plywood stock:
National Balsa Co.
(413) 277-9500
www.nationalbalsa.com/
Composite tubing;
Kite Studio
(610) 395-3560
www.kitebuilder.com/
Fiberglass cowl:
Fiberglass Specialties
(479) 359-2429
www.fiberglassspecialtiesinc.com
Hardware, accessories:
Du-Bro
(800) 848-9411
http://dubro.com
Landing gear, wheel pants, AeroKote:
Sig Manufacturing
(641) 623-5154
www.sigmfg.com
32 MODEL AVIATION
05sig1.QXD 3/25/08 10:09 AM Page 32