The ShyFox - 2010/03

THE MOST ACCESSIBLE CL Racing events are Super Slow Rat (SSR) and its
evil twin, Fox Race, which are often flown combined. The reasons are many, but at the
top of the list are that the models fly well
and that the pace is within many pilots'
physical abilities.
You don't have to be in marathon condition to fly SSR/Fox safely and get a lot
of enjoyment from it. That, in combination
with the stock-engine restrictions and
airframe-size minimums, means you are
likely to experience some extremely close
racing.
The airplanes can be made rugged and
the systems are simple, so if three
contestants start the race, it is a good bet
that all of them will be in it until the end.
Being able to compete against your buddies
with a fair chance of beating them is a ton
of fun. This event might have more
bragging per mph than any other Racing
class.
When I started Racing and was looking
for another event to enter in local contests, I
noticed that the organizers rotated the
categories but that SSR/Fox was held more
often than many of the others. That meant if
I built an SSR/Fox racer, I could race more
often. That was all the motivation I needed.
My local hobby shop had no eligible
kits, so I started designing the SkyFox just
three weeks before the 2005 Northern
California Racing Championships. The
contest was to be held in Napa, California.
As my friends will confirm, I don't do
If you are going to build the ShyFox as a Fox racer, increase the enginemount
spacing compared to the plain-bearing .25s. Also, you will probably
need the full 2-ounce tank.
The nose will see more vibration and stress. Therefore, use firmer wood for
the fuselage and cheek cowl, and apply at least one layer of 2-ounce-persquare-
yard fiberglass on the front. Overlap it onto the wing center-section
planking. Use generous epoxy fillets on the wing/fuselage joint.
Install the shutoff so you can shut down the model anytime it vibrates
badly. If the airplane vibrates terribly on the ground or in the air, change
propellers or engines until it moderates, or you will get cracks around the
wing/fuselage joint.
Be aware that a Fox power plant uses different design features and materials
from more modern engines. Be sure to use fuel with plenty of castor oil, but
don’t try to run a hot Fox with a lot of varnish on the piston or liner.
At local contests, we run all castor fuel in Fox Race, which helps. If you
have starting problems and the engine fires but the propeller oscillates back and
forth, reduce the voltage to your plug. This also reduces your risk of a pit fire.
If the engine starts fine cold but won’t restart hot, work on priming, and
even try dousing the cylinder with a water bottle during each pit stop. When the
hot starts go away, you need to find an engine with a tighter piston/liner fit; that
is what the competitors who are passing you have.
If the vibration is killing your airplane, soak the cracks with thin CA and
then heated epoxy. Install an O.S. .25, and race it as a Super Slow Rat. MA
—Dave “McSlow” Hull
28 MODEL AVIATION
Keep your engine covered to shut out inevitable blowing grit that will ruin your
piston/sleeve fit. Ear protectors are a good idea. Any major problems would require you
to open the toolbox—a sure sign that you didn’t win.
ShyFox
The
anything quickly—especially building an
airplane. However, I finished the
calculations, penciled the shapes, and
started construction. I soldered the fuel tank
the day before I packed for the trip. I put a
couple coats of dope on the fuselage in the
motel room the night before the race and
decided that my ShyFox and I were ready to
give it a shot.
My racing partner, Dave Dawson,
started breaking in the engine as soon as we
arrived at the field. We got in a couple of
test flights before the contest and declared
the equipment to be ready.
From the first flight, it was obvious that
the model performed smoothly and was
simple to fly. We were competitive from the
start, nabbing a second place among some
tough competition.
In spring 2007, at the Cabin Fever
contest in Tucson, Arizona, we were beaten
by perhaps the fastest SSR design in North
Type: Profile CL Racing
Skill: Beginner builder and pilot
Wingspan: 38.06 inches
Wing area: 306 square inches
Length: 22.5 inches
Weight: 27 ounces
Engine: O.S. 25LA Stunt or Fox .35 Stunt
Construction: Balsa and plywood
Covering/finish: MonoKote wings and tail, fiberglass fuselage and vertical tail
Other: 1.5- to 2.0-ounce fuel tank, propeller, 2-inch bellcrank
America in a phenomenal race. In July of
that year, I took the ShyFox to the Nats and
garnered first place.
Two characteristics made this possible.
First, the airplane has a straightforward fuel
system and starting procedure. I had to
borrow one pitman for the heat races and
then another for the final, and each had only
five minutes to figure out how to fuel up,
prime the engine (but avoid flooding), and
get one-flip starts.
The other key feature is that this model
flies so solidly that the winds at Muncie,
Indiana, were never a factor. I could watch
for traffic instead of worrying about my
racer ballooning in the wind.
If you and your flying buddies want to
have a bunch of fun, score some plans,
shuffle through the stack of balsa at the
hobby shop to find some racing wood, and
spend a few evenings at the building board.
If you aren’t having fun, you aren’t racing.
CONSTRUCTION
Because the ShyFox was to be built in
fewer than three weeks, it had to be simple.
I like to use 1/16 ribs with capstrips. But
it takes me quite a bit of time to cut and fit
so many pieces (I’m slow, remember?), so
the drawing shows 3/32 ribs without
capstrips. And I used an aluminum enginemounting
plate with integral gear leg,
similar to the one on my Quickie Rat racer.
For someone who has not had much
experience with engines, definitely go the
SSR route. This is a stock-engine class, so
the event directors might disassemble your
power plant to see if you have “improved”
things or installed nonstock parts. If you just
can’t stand running a stock engine, move up
to Slow Rat; those rules allow fully
modified engines.
There are many different fuel systems.
03sig1.QXD_00MSTRPG.QXD 1/26/10 9:51 AM Page 28
Numerous types work well, but some are
more difficult to tune. To achieve the
correct number of laps, the tank must be
built to match your engine. The rules permit
a tank that is a large as 2 ounces, but most
.25 engines will overrun on this much fuel
and you will be disqualified for not
completing the required two pit stops.
I suggest that you run your engine on the
bench to determine how much fuel is
required to last 105-120 seconds when set
slightly rich of peak; that should be good for
35-40 laps at typical ShyFox speeds. This
should be somewhere near 1.5 ounces.
Scale the length of the tank shown on the
plans to this volume. If building a custom
tank is all that is holding you back from
racing, try one from Brodak, such as item
BH-582 or BH-566.
The fuel shutoff is an integral part of
your fuel system and is considered a safety
item in SSR/Fox; you can’t use it during the
race. But being able to shut down during a
competition can rescue a pilot from his or
her mistakes or from a pitman or the other
teams.
My model is fitted with the springloaded,
drawbar-type (the wire is “J”
shaped) shutoff, with a pull-to-actuate trip
wire. I used the small size from Dirty Dale
Long. In addition to being a safety feature,
the shutoff permits a team to put up a series
of quick needle-adjustment flights
immediately before the race.
The aluminum monowheel gear shown is
actually easy to make. Be sure to use a heattreated
alloy such as 6061-T6 or 2024-T4.
Lay the pattern on the aluminum and you
are ready to cut. I like to drill holes at each
inside corner and then saw into each hole.
I used a urethane wheel from Darrell
Albert, with a threaded (fixed) brass hub.
Other possible sources are Glenn Lee
(urethane) and Marc Warwashana (who has
replicas of Don’s Wheels in rubber or
urethane).
This gear design has virtually no give. A
rubber wheel is an advantage if your pilot
can’t make consistent soft landings.
Wing: The wing has a constant thickness of
1 inch (minimum) from root to tip, so it can
easily be constructed flat on the building
board. Place a 3/8-inch strip of balsa under
the TE and move it fore/aft until its center is
exactly 1/2 inch above the building surface
along the span. If you get this right, you will
have no washin, washout, or warps.
The best way to make the ribs is to cut
an aluminum root and tip template. Drill
matching holes in the templates, and then
drill a set of rectangular balsa rib blanks to
match. Sandwich the whole thing and start
shaping.
I like to use a block of 80-grit sandpaper
to rough down one side and then the other.
Finish shaping with 120-grit paper.
Take your stack of ribs and lay the spar
stock in the correct location. Score the spar
notches with a new razor blade or hobby
knife. Do this carefully and you will get a
straighter, stronger wing, because the spars
won’t be twisted and the fit will be nice and
snug. Cut leadout holes in the inboard ribs
using a piece of sharpened 1/4-inch brass
tubing.
It is probably overkill, but the ShyFox’s
spars and LE are reinforced with carbonfiber
(CF) strips. A .007 x 1/4-inch strip is
laminated to the inside of each spruce spar.
Make sure that the spar stock is straight
to begin with and that they are laying on a
flat bench when you glue the CF. If you
want the most reliable joint, solvent-wipe
the carbon and use epoxy. The LE is
laminated from two pieces of 1/4 x 1/2 stock,
with .007 x 1/2 CF in between.
Remember that the event rules require a
1-inch-thick wing. If you cut the spar
notches too deep, push the top spar into
them, and sand the ribs flush, your wing will
be illegal.
Add the lower TE piece and then the
upper. You might want to taper the insides
of each a bit at the TE, to get a slightly
better fit with your ribs and to make the
finished TE a bit thinner.
The inboard tip is laminated so that the
leadouts pass through the center slot,
which is long enough to allow the leadouts
to be moved forward or aft for trimming.
Set your guide at the location shown on
the plans for first flights, or you can forgo
the adjustable guide and glue in brass
guides at this location. Install the bellcrank
platform and fit-check the controls.
Notice the 1/64 plywood reinforcement on
the inside of the planking, around the
pushrod hole. Add the spar shear webs,
noting the direction of the grain.
The leadouts in the inboard wing
preclude the use of shear webs in every bay.
Don’t worry about it; the wing is plenty
strong.
Plank the top center-section and carefully
sand everything. Do not ruin the airfoil or
make the wing too thin.
My airplane has MonoKote iron-on
covering. I like to apply this material to the
wing before installation in the fuselage, so
planning is in order.
If you cover using four pieces and leave a
gap along the middle of the wing, you won’t
have to try to peel this off before attaching
the wing to the fuselage. Don’t forget to
include the fillets when you calculate these
dimensions.
Tail and Fuselage: Use firm to hard balsa
for the fuselage and good five-ply birch
plywood. Cut the blank for the maple (or
birch) engine mounts, establishing the
spacing to fit your selected engine. Cut the
plywood doublers to outline but do not cut
the wing slot yet.
Taper the TE of the doublers; it is much
easier to do so before they are installed. Glue
the engine mounts and inboard doubler to
the fuselage with 30-minute epoxy. When
cured, glue on the inboard doubler with the
front edge lined up with the front of the wing.
Use the wing rib template to carefully
trace the cutout over the fuselage centerline.
Drill a 3/16-inch hole at the LE. Using a scroll
saw or a coping saw, cautiously cut down the
center of the line.
This will give a close fit during assembly
and results in a stronger, lighter wing joint
that is properly aligned. Straight is great;
slanted is planted.
Use your engine to mark the bolt pattern,
and then mark the two holes at the rear above
the gear leg. Drill 1/8 inch in diameter through,
and then counterbore the inboard side 5/32 inch
in diameter and 1/8 inch deep.
Press the Du-Bro blind nuts into the holes.
These are the best-quality blind nuts I have
found.
Cut a piece of 3/8 x 1/2 balsa for the nose
block. This adds strength but really serves to
reduce drag.
It is easier to cut the engine-clearance
radius in this block before you cut it to length.
Epoxy in place and final-shape your engine
case using sandpaper wrapped around a
dowel.
Cut the cheek cowling block (inboard
tripler) from medium balsa. Relieve the areas
over the blind nuts, and coat with epoxy for
fuel-proofing. Install using epoxy or
carpenter’s glue.
Clamp or weight the assembly until dry,
and cut the wing hole in the tripler. Trim and
sand to final shape, blending with the tapered
plywood doublers.
Cut, drill, and install the maple tail skid
block. Epoxy the block in place. A good way
to ensure that the removable tail skid will fit is
to make two blocks with identical hole
spacing and use one as a soldering fixture.
Drill a hole in the fuselage where the
elevator joiner goes through, and cut the
horizontal stabilizer slot. The tail is set with
zero incidence to the wing. Slot the top of the
fuselage for the rudder.
An odd thing happened when I made the
tail. As usual, I went to the scrap box before
chopping up a new sheet. There was a piece
quite a bit bigger than I needed—16 inches
long.
Instead of cutting it to the plans pattern, I
cut a stabilizer/elevator set that was as long as
the piece of wood that I found. I ended up
using this larger structure and have been
pleased with it.
The model grooves well, and this
stabilizer/elevator might be one reason why.
Plans show the original size, which should
work fine, so pick the one that suits you.
I fiberglassed the prototype ShyFox
fuselage and tail for strength and durability.
Use an extremely lightweight fiberglass,
especially on the tail. I employed a 0.58-
ounce-per-square-yard plain-weave cloth. Use
an epoxy resin system that has low viscosity.
Try not to thin it, but use lacquer thinner if
you do.
This design’s rudder is present because I
like airplanes that look real. It also protects
the shutoff horn if the model flips over, if it’s
fiberglassed or made from basswood.
You can use plywood if you think you
can install and seal it before it warps.
There should be no rudder offset.
Once you have glued the rudder to the
fuselage and added the fillets, do the final
shaping and sanding. If you are
considering skipping the fiberglass
reinforcement, you should know that the
most vulnerable part of a racer’s fuselage
is aft of the wing.
If the pitman is forced to attempt a
wing catch, the tail will whip. This can
cause the fuselage to crack at the wing TE
or farther aft.
So either don’t make flying and pitting
mistakes or build in ruggedness. Light is
fast; broken is last.
Airframe: Insert the wing and horizontal
stabilizer into the fuselage. Set this on a
large, flat surface and clamp the fuselage
to a 90° block at the nose. I use a large
secondhand machinist’s knee.
When everything is correct, you should
be able to sight along the horizontal
stabilizer from the rear and see if it is
parallel to the wing. Take your time. A
fast airplane exaggerates trim problems,
and a crooked model is a slow model.
I have used KlassKote epoxy to seal
and fuel-proof the wing/fuselage joint, and
I like its durability and relative ease of
use. You can mask over the MonoKote
and paint directly over the seam for a good
look. Scuff the covering where you will
paint after you mask it, and then wipe off
thoroughly with alcohol.
I like to use sewn hinges. Insert the
joiner wire through the fuselage and install
the elevators. Align and tape the assembly
to the stabilizer.
Using 12-pound-test Spectra fishing
line, start sewing the holes nearest to the
fuselage and work your way out. Stitch a
figure-eight pattern through each set of
holes, using four passes through each hole.
Snug everything tight, but do not pull
too hard on the line when tying the knot. It
could cut you, or your wood, if you didn’t
use hardwood spars.
Sullivan Products’ Gold-N-Clevises are
strong; don’t use a lesser-quality part. Install
a jam nut against the clevis once you have
the elevator adjusted to neutral, when the
bellcrank is at midtravel. Do you feel
catching or roughness? If so, fix it now.
Install the wheel on the landing gear
plate and install the engine and plate
together. The upper engine bolts also hold
on the tank vent line and fueling port, so
make this up now.
Fit the tank and shutoff in the space
between the wing and the engine as far
forward as you can, to improve fuel draw.
Install the shutoff, and connect the fuel lines
and shutoff trip wire. Adjust the wire so that
full down-elevator trips the shutoff.
I am still trying to design a long-lasting
tail skid. In the meantime, the ShyFox uses
my standard replaceable wire skid. These
are sort of spring-loaded into the mount.
Over asphalt, the standard skids wear
down after a year of racing and the loop
breaks off. Simply make a spare while you
are bending and soldering, and don’t worry
about it.
The prototype ShyFox weighs 27
ounces, which is fairly heavy, but there is
a relationship between weight and
durability. You don’t want your airplane
falling apart near the time you get it
trimmed and going fast in practice.
Make sure the CG is within 1/8 inch of
the location shown on the plans. You can
trim the CG within a certain range to suit
your skills, but a racer should fly level
without the pilot constantly watching it.
Be sure that your adjustable leadout
guide is locked down tight, and then hang
the model with the two leadouts held
together. It should hang a bit nose-down.
Test-Flying and Racing! When you get
your racer out to the field, check it one
more time. Connect the lines and handle.
Are the lines .015-inch stranded steel and
between 59 feet, 6 inches and 60 feet, 6
inches long when measured between the
handle and the fuselage centerline?
Is up really up? Is your handle marked?
For the control setup shown, you should
start with a handle spacing of
approximately 2 inches.
Try the shutoff in flight and set the
sensitivity to suit the pilot. You will know
it is too sensitive if he or she accidentally
shuts it off when taking off into the wind
and applies a great deal of down to keep
from ballooning into the racing zone.
This seems to be the most down-control
I ever need, so we use this maneuver to set
up each new model. If you shorten the tail
skid and are slightly slow on the handle,
you need more down-control.
The engine should speed up slightly on
the last lap, although the tank shown runs
evenly to the end. The downside of this is
that the pilot won’t get much warning of the
impending pit stop, and the team should
keep track of laps during each tank. Passing
with a nearly empty tank is a risky
maneuver.
I hope you enjoy building and racing your
ShyFox. For more information about
Racing, check out the National Control Line
Racing Association AMA SIG. The dues are
low and the information contained in the
newsletter, Torque Roll, will help you
become a competitive racer.
If you have the itch and want to learn
how to race, one of the best articles to read
is “The Race … and how to fly it” by John
Kilsdonk, which was published in the May
1977 MA. AMA members can access this
issue via the Academy’s Web site, in the
“Members Only” section. MA
Dave “McSlow” Hull
[email protected]
Sources:
Brodak Manufacturing
(724) 966-2726
www.brodak.com
Dale Long
(951) 784-4328
[email protected]
Racing wheels and other specialty items:
Darrell Albert
(760) 741-2505
[email protected]
Marc Warwashana
11577 North Shore Dr.
Whitmore Lake MI 48189
[email protected]
Du-Bro Products, Inc.
(800) 848-9411
www.dubro.com
KlassKote
(612) 243-1234
www.klasskote.com
Sullivan Products (control horns are item
556)
(410) 732-3500
www.sullivanproducts.com
National Control Line Racing Association
www.nclra.org
Stock .35 Stunt engine, 2-inch bellcrank,
glow plugs:
Fox Manufacturing
(479) 646-1656
www.foxmanufacturing.com
Stock 25LA CL engine:
O.S. Engines
(217) 398-8970
www.osengines.com
Lines, line-making supplies, clips, fueling
bottles, horns, etc.:
MBS Model Supplies (Melvin Schuette)
(785) 256-2583
www.mbsmodelsupply.com
Tin-plated steel, 1/8-inch-diameter copper
tubing; 1/8-inch-diameter aluminum plate for
gear:
K&S Engineering
(773) 586-8503
www.ksmetals.com
Fiberglass cloth, EZ-Lam epoxy resin:
Aerospace Composite Products
(925) 443-5900
www.acp-composites.com
Carbon-fiber reinforcing materials:
Dave Brown Products, Inc.
(513) 738-1576
www.dbproducts.com
Fourmost Products
(503) 357-2732
www.fourmostproducts.com
AMA
(765) 287-1256
www.modelaircraft.org

THE MOST ACCESSIBLE CL Racing events are Super Slow Rat (SSR) and its
evil twin, Fox Race, which are often flown combined. The reasons are many, but at the
top of the list are that the models fly well
and that the pace is within many pilots'
physical abilities.
You don't have to be in marathon condition to fly SSR/Fox safely and get a lot
of enjoyment from it. That, in combination
with the stock-engine restrictions and
airframe-size minimums, means you are
likely to experience some extremely close
racing.
The airplanes can be made rugged and
the systems are simple, so if three
contestants start the race, it is a good bet
that all of them will be in it until the end.
Being able to compete against your buddies
with a fair chance of beating them is a ton
of fun. This event might have more
bragging per mph than any other Racing
class.
When I started Racing and was looking
for another event to enter in local contests, I
noticed that the organizers rotated the
categories but that SSR/Fox was held more
often than many of the others. That meant if
I built an SSR/Fox racer, I could race more
often. That was all the motivation I needed.
My local hobby shop had no eligible
kits, so I started designing the SkyFox just
three weeks before the 2005 Northern
California Racing Championships. The
contest was to be held in Napa, California.
As my friends will confirm, I don't do
If you are going to build the ShyFox as a Fox racer, increase the enginemount
spacing compared to the plain-bearing .25s. Also, you will probably
need the full 2-ounce tank.
The nose will see more vibration and stress. Therefore, use firmer wood for
the fuselage and cheek cowl, and apply at least one layer of 2-ounce-persquare-
yard fiberglass on the front. Overlap it onto the wing center-section
planking. Use generous epoxy fillets on the wing/fuselage joint.
Install the shutoff so you can shut down the model anytime it vibrates
badly. If the airplane vibrates terribly on the ground or in the air, change
propellers or engines until it moderates, or you will get cracks around the
wing/fuselage joint.
Be aware that a Fox power plant uses different design features and materials
from more modern engines. Be sure to use fuel with plenty of castor oil, but
don’t try to run a hot Fox with a lot of varnish on the piston or liner.
At local contests, we run all castor fuel in Fox Race, which helps. If you
have starting problems and the engine fires but the propeller oscillates back and
forth, reduce the voltage to your plug. This also reduces your risk of a pit fire.
If the engine starts fine cold but won’t restart hot, work on priming, and
even try dousing the cylinder with a water bottle during each pit stop. When the
hot starts go away, you need to find an engine with a tighter piston/liner fit; that
is what the competitors who are passing you have.
If the vibration is killing your airplane, soak the cracks with thin CA and
then heated epoxy. Install an O.S. .25, and race it as a Super Slow Rat. MA
—Dave “McSlow” Hull
28 MODEL AVIATION
Keep your engine covered to shut out inevitable blowing grit that will ruin your
piston/sleeve fit. Ear protectors are a good idea. Any major problems would require you
to open the toolbox—a sure sign that you didn’t win.
ShyFox
The
anything quickly—especially building an
airplane. However, I finished the
calculations, penciled the shapes, and
started construction. I soldered the fuel tank
the day before I packed for the trip. I put a
couple coats of dope on the fuselage in the
motel room the night before the race and
decided that my ShyFox and I were ready to
give it a shot.
My racing partner, Dave Dawson,
started breaking in the engine as soon as we
arrived at the field. We got in a couple of
test flights before the contest and declared
the equipment to be ready.
From the first flight, it was obvious that
the model performed smoothly and was
simple to fly. We were competitive from the
start, nabbing a second place among some
tough competition.
In spring 2007, at the Cabin Fever
contest in Tucson, Arizona, we were beaten
by perhaps the fastest SSR design in North
Type: Profile CL Racing
Skill: Beginner builder and pilot
Wingspan: 38.06 inches
Wing area: 306 square inches
Length: 22.5 inches
Weight: 27 ounces
Engine: O.S. 25LA Stunt or Fox .35 Stunt
Construction: Balsa and plywood
Covering/finish: MonoKote wings and tail, fiberglass fuselage and vertical tail
Other: 1.5- to 2.0-ounce fuel tank, propeller, 2-inch bellcrank
America in a phenomenal race. In July of
that year, I took the ShyFox to the Nats and
garnered first place.
Two characteristics made this possible.
First, the airplane has a straightforward fuel
system and starting procedure. I had to
borrow one pitman for the heat races and
then another for the final, and each had only
five minutes to figure out how to fuel up,
prime the engine (but avoid flooding), and
get one-flip starts.
The other key feature is that this model
flies so solidly that the winds at Muncie,
Indiana, were never a factor. I could watch
for traffic instead of worrying about my
racer ballooning in the wind.
If you and your flying buddies want to
have a bunch of fun, score some plans,
shuffle through the stack of balsa at the
hobby shop to find some racing wood, and
spend a few evenings at the building board.
If you aren’t having fun, you aren’t racing.
CONSTRUCTION
Because the ShyFox was to be built in
fewer than three weeks, it had to be simple.
I like to use 1/16 ribs with capstrips. But
it takes me quite a bit of time to cut and fit
so many pieces (I’m slow, remember?), so
the drawing shows 3/32 ribs without
capstrips. And I used an aluminum enginemounting
plate with integral gear leg,
similar to the one on my Quickie Rat racer.
For someone who has not had much
experience with engines, definitely go the
SSR route. This is a stock-engine class, so
the event directors might disassemble your
power plant to see if you have “improved”
things or installed nonstock parts. If you just
can’t stand running a stock engine, move up
to Slow Rat; those rules allow fully
modified engines.
There are many different fuel systems.
03sig1.QXD_00MSTRPG.QXD 1/26/10 9:51 AM Page 28
Numerous types work well, but some are
more difficult to tune. To achieve the
correct number of laps, the tank must be
built to match your engine. The rules permit
a tank that is a large as 2 ounces, but most
.25 engines will overrun on this much fuel
and you will be disqualified for not
completing the required two pit stops.
I suggest that you run your engine on the
bench to determine how much fuel is
required to last 105-120 seconds when set
slightly rich of peak; that should be good for
35-40 laps at typical ShyFox speeds. This
should be somewhere near 1.5 ounces.
Scale the length of the tank shown on the
plans to this volume. If building a custom
tank is all that is holding you back from
racing, try one from Brodak, such as item
BH-582 or BH-566.
The fuel shutoff is an integral part of
your fuel system and is considered a safety
item in SSR/Fox; you can’t use it during the
race. But being able to shut down during a
competition can rescue a pilot from his or
her mistakes or from a pitman or the other
teams.
My model is fitted with the springloaded,
drawbar-type (the wire is “J”
shaped) shutoff, with a pull-to-actuate trip
wire. I used the small size from Dirty Dale
Long. In addition to being a safety feature,
the shutoff permits a team to put up a series
of quick needle-adjustment flights
immediately before the race.
The aluminum monowheel gear shown is
actually easy to make. Be sure to use a heattreated
alloy such as 6061-T6 or 2024-T4.
Lay the pattern on the aluminum and you
are ready to cut. I like to drill holes at each
inside corner and then saw into each hole.
I used a urethane wheel from Darrell
Albert, with a threaded (fixed) brass hub.
Other possible sources are Glenn Lee
(urethane) and Marc Warwashana (who has
replicas of Don’s Wheels in rubber or
urethane).
This gear design has virtually no give. A
rubber wheel is an advantage if your pilot
can’t make consistent soft landings.
Wing: The wing has a constant thickness of
1 inch (minimum) from root to tip, so it can
easily be constructed flat on the building
board. Place a 3/8-inch strip of balsa under
the TE and move it fore/aft until its center is
exactly 1/2 inch above the building surface
along the span. If you get this right, you will
have no washin, washout, or warps.
The best way to make the ribs is to cut
an aluminum root and tip template. Drill
matching holes in the templates, and then
drill a set of rectangular balsa rib blanks to
match. Sandwich the whole thing and start
shaping.
I like to use a block of 80-grit sandpaper
to rough down one side and then the other.
Finish shaping with 120-grit paper.
Take your stack of ribs and lay the spar
stock in the correct location. Score the spar
notches with a new razor blade or hobby
knife. Do this carefully and you will get a
straighter, stronger wing, because the spars
won’t be twisted and the fit will be nice and
snug. Cut leadout holes in the inboard ribs
using a piece of sharpened 1/4-inch brass
tubing.
It is probably overkill, but the ShyFox’s
spars and LE are reinforced with carbonfiber
(CF) strips. A .007 x 1/4-inch strip is
laminated to the inside of each spruce spar.
Make sure that the spar stock is straight
to begin with and that they are laying on a
flat bench when you glue the CF. If you
want the most reliable joint, solvent-wipe
the carbon and use epoxy. The LE is
laminated from two pieces of 1/4 x 1/2 stock,
with .007 x 1/2 CF in between.
Remember that the event rules require a
1-inch-thick wing. If you cut the spar
notches too deep, push the top spar into
them, and sand the ribs flush, your wing will
be illegal.
Add the lower TE piece and then the
upper. You might want to taper the insides
of each a bit at the TE, to get a slightly
better fit with your ribs and to make the
finished TE a bit thinner.
The inboard tip is laminated so that the
leadouts pass through the center slot,
which is long enough to allow the leadouts
to be moved forward or aft for trimming.
Set your guide at the location shown on
the plans for first flights, or you can forgo
the adjustable guide and glue in brass
guides at this location. Install the bellcrank
platform and fit-check the controls.
Notice the 1/64 plywood reinforcement on
the inside of the planking, around the
pushrod hole. Add the spar shear webs,
noting the direction of the grain.
The leadouts in the inboard wing
preclude the use of shear webs in every bay.
Don’t worry about it; the wing is plenty
strong.
Plank the top center-section and carefully
sand everything. Do not ruin the airfoil or
make the wing too thin.
My airplane has MonoKote iron-on
covering. I like to apply this material to the
wing before installation in the fuselage, so
planning is in order.
If you cover using four pieces and leave a
gap along the middle of the wing, you won’t
have to try to peel this off before attaching
the wing to the fuselage. Don’t forget to
include the fillets when you calculate these
dimensions.
Tail and Fuselage: Use firm to hard balsa
for the fuselage and good five-ply birch
plywood. Cut the blank for the maple (or
birch) engine mounts, establishing the
spacing to fit your selected engine. Cut the
plywood doublers to outline but do not cut
the wing slot yet.
Taper the TE of the doublers; it is much
easier to do so before they are installed. Glue
the engine mounts and inboard doubler to
the fuselage with 30-minute epoxy. When
cured, glue on the inboard doubler with the
front edge lined up with the front of the wing.
Use the wing rib template to carefully
trace the cutout over the fuselage centerline.
Drill a 3/16-inch hole at the LE. Using a scroll
saw or a coping saw, cautiously cut down the
center of the line.
This will give a close fit during assembly
and results in a stronger, lighter wing joint
that is properly aligned. Straight is great;
slanted is planted.
Use your engine to mark the bolt pattern,
and then mark the two holes at the rear above
the gear leg. Drill 1/8 inch in diameter through,
and then counterbore the inboard side 5/32 inch
in diameter and 1/8 inch deep.
Press the Du-Bro blind nuts into the holes.
These are the best-quality blind nuts I have
found.
Cut a piece of 3/8 x 1/2 balsa for the nose
block. This adds strength but really serves to
reduce drag.
It is easier to cut the engine-clearance
radius in this block before you cut it to length.
Epoxy in place and final-shape your engine
case using sandpaper wrapped around a
dowel.
Cut the cheek cowling block (inboard
tripler) from medium balsa. Relieve the areas
over the blind nuts, and coat with epoxy for
fuel-proofing. Install using epoxy or
carpenter’s glue.
Clamp or weight the assembly until dry,
and cut the wing hole in the tripler. Trim and
sand to final shape, blending with the tapered
plywood doublers.
Cut, drill, and install the maple tail skid
block. Epoxy the block in place. A good way
to ensure that the removable tail skid will fit is
to make two blocks with identical hole
spacing and use one as a soldering fixture.
Drill a hole in the fuselage where the
elevator joiner goes through, and cut the
horizontal stabilizer slot. The tail is set with
zero incidence to the wing. Slot the top of the
fuselage for the rudder.
An odd thing happened when I made the
tail. As usual, I went to the scrap box before
chopping up a new sheet. There was a piece
quite a bit bigger than I needed—16 inches
long.
Instead of cutting it to the plans pattern, I
cut a stabilizer/elevator set that was as long as
the piece of wood that I found. I ended up
using this larger structure and have been
pleased with it.
The model grooves well, and this
stabilizer/elevator might be one reason why.
Plans show the original size, which should
work fine, so pick the one that suits you.
I fiberglassed the prototype ShyFox
fuselage and tail for strength and durability.
Use an extremely lightweight fiberglass,
especially on the tail. I employed a 0.58-
ounce-per-square-yard plain-weave cloth. Use
an epoxy resin system that has low viscosity.
Try not to thin it, but use lacquer thinner if
you do.
This design’s rudder is present because I
like airplanes that look real. It also protects
the shutoff horn if the model flips over, if it’s
fiberglassed or made from basswood.
You can use plywood if you think you
can install and seal it before it warps.
There should be no rudder offset.
Once you have glued the rudder to the
fuselage and added the fillets, do the final
shaping and sanding. If you are
considering skipping the fiberglass
reinforcement, you should know that the
most vulnerable part of a racer’s fuselage
is aft of the wing.
If the pitman is forced to attempt a
wing catch, the tail will whip. This can
cause the fuselage to crack at the wing TE
or farther aft.
So either don’t make flying and pitting
mistakes or build in ruggedness. Light is
fast; broken is last.
Airframe: Insert the wing and horizontal
stabilizer into the fuselage. Set this on a
large, flat surface and clamp the fuselage
to a 90° block at the nose. I use a large
secondhand machinist’s knee.
When everything is correct, you should
be able to sight along the horizontal
stabilizer from the rear and see if it is
parallel to the wing. Take your time. A
fast airplane exaggerates trim problems,
and a crooked model is a slow model.
I have used KlassKote epoxy to seal
and fuel-proof the wing/fuselage joint, and
I like its durability and relative ease of
use. You can mask over the MonoKote
and paint directly over the seam for a good
look. Scuff the covering where you will
paint after you mask it, and then wipe off
thoroughly with alcohol.
I like to use sewn hinges. Insert the
joiner wire through the fuselage and install
the elevators. Align and tape the assembly
to the stabilizer.
Using 12-pound-test Spectra fishing
line, start sewing the holes nearest to the
fuselage and work your way out. Stitch a
figure-eight pattern through each set of
holes, using four passes through each hole.
Snug everything tight, but do not pull
too hard on the line when tying the knot. It
could cut you, or your wood, if you didn’t
use hardwood spars.
Sullivan Products’ Gold-N-Clevises are
strong; don’t use a lesser-quality part. Install
a jam nut against the clevis once you have
the elevator adjusted to neutral, when the
bellcrank is at midtravel. Do you feel
catching or roughness? If so, fix it now.
Install the wheel on the landing gear
plate and install the engine and plate
together. The upper engine bolts also hold
on the tank vent line and fueling port, so
make this up now.
Fit the tank and shutoff in the space
between the wing and the engine as far
forward as you can, to improve fuel draw.
Install the shutoff, and connect the fuel lines
and shutoff trip wire. Adjust the wire so that
full down-elevator trips the shutoff.
I am still trying to design a long-lasting
tail skid. In the meantime, the ShyFox uses
my standard replaceable wire skid. These
are sort of spring-loaded into the mount.
Over asphalt, the standard skids wear
down after a year of racing and the loop
breaks off. Simply make a spare while you
are bending and soldering, and don’t worry
about it.
The prototype ShyFox weighs 27
ounces, which is fairly heavy, but there is
a relationship between weight and
durability. You don’t want your airplane
falling apart near the time you get it
trimmed and going fast in practice.
Make sure the CG is within 1/8 inch of
the location shown on the plans. You can
trim the CG within a certain range to suit
your skills, but a racer should fly level
without the pilot constantly watching it.
Be sure that your adjustable leadout
guide is locked down tight, and then hang
the model with the two leadouts held
together. It should hang a bit nose-down.
Test-Flying and Racing! When you get
your racer out to the field, check it one
more time. Connect the lines and handle.
Are the lines .015-inch stranded steel and
between 59 feet, 6 inches and 60 feet, 6
inches long when measured between the
handle and the fuselage centerline?
Is up really up? Is your handle marked?
For the control setup shown, you should
start with a handle spacing of
approximately 2 inches.
Try the shutoff in flight and set the
sensitivity to suit the pilot. You will know
it is too sensitive if he or she accidentally
shuts it off when taking off into the wind
and applies a great deal of down to keep
from ballooning into the racing zone.
This seems to be the most down-control
I ever need, so we use this maneuver to set
up each new model. If you shorten the tail
skid and are slightly slow on the handle,
you need more down-control.
The engine should speed up slightly on
the last lap, although the tank shown runs
evenly to the end. The downside of this is
that the pilot won’t get much warning of the
impending pit stop, and the team should
keep track of laps during each tank. Passing
with a nearly empty tank is a risky
maneuver.
I hope you enjoy building and racing your
ShyFox. For more information about
Racing, check out the National Control Line
Racing Association AMA SIG. The dues are
low and the information contained in the
newsletter, Torque Roll, will help you
become a competitive racer.
If you have the itch and want to learn
how to race, one of the best articles to read
is “The Race … and how to fly it” by John
Kilsdonk, which was published in the May
1977 MA. AMA members can access this
issue via the Academy’s Web site, in the
“Members Only” section. MA
Dave “McSlow” Hull
[email protected]
Sources:
Brodak Manufacturing
(724) 966-2726
www.brodak.com
Dale Long
(951) 784-4328
[email protected]
Racing wheels and other specialty items:
Darrell Albert
(760) 741-2505
[email protected]
Marc Warwashana
11577 North Shore Dr.
Whitmore Lake MI 48189
[email protected]
Du-Bro Products, Inc.
(800) 848-9411
www.dubro.com
KlassKote
(612) 243-1234
www.klasskote.com
Sullivan Products (control horns are item
556)
(410) 732-3500
www.sullivanproducts.com
National Control Line Racing Association
www.nclra.org
Stock .35 Stunt engine, 2-inch bellcrank,
glow plugs:
Fox Manufacturing
(479) 646-1656
www.foxmanufacturing.com
Stock 25LA CL engine:
O.S. Engines
(217) 398-8970
www.osengines.com
Lines, line-making supplies, clips, fueling
bottles, horns, etc.:
MBS Model Supplies (Melvin Schuette)
(785) 256-2583
www.mbsmodelsupply.com
Tin-plated steel, 1/8-inch-diameter copper
tubing; 1/8-inch-diameter aluminum plate for
gear:
K&S Engineering
(773) 586-8503
www.ksmetals.com
Fiberglass cloth, EZ-Lam epoxy resin:
Aerospace Composite Products
(925) 443-5900
www.acp-composites.com
Carbon-fiber reinforcing materials:
Dave Brown Products, Inc.
(513) 738-1576
www.dbproducts.com
Fourmost Products
(503) 357-2732
www.fourmostproducts.com
AMA
(765) 287-1256
www.modelaircraft.org

THE MOST ACCESSIBLE CL Racing events are Super Slow Rat (SSR) and its
evil twin, Fox Race, which are often flown combined. The reasons are many, but at the
top of the list are that the models fly well
and that the pace is within many pilots'
physical abilities.
You don't have to be in marathon condition to fly SSR/Fox safely and get a lot
of enjoyment from it. That, in combination
with the stock-engine restrictions and
airframe-size minimums, means you are
likely to experience some extremely close
racing.
The airplanes can be made rugged and
the systems are simple, so if three
contestants start the race, it is a good bet
that all of them will be in it until the end.
Being able to compete against your buddies
with a fair chance of beating them is a ton
of fun. This event might have more
bragging per mph than any other Racing
class.
When I started Racing and was looking
for another event to enter in local contests, I
noticed that the organizers rotated the
categories but that SSR/Fox was held more
often than many of the others. That meant if
I built an SSR/Fox racer, I could race more
often. That was all the motivation I needed.
My local hobby shop had no eligible
kits, so I started designing the SkyFox just
three weeks before the 2005 Northern
California Racing Championships. The
contest was to be held in Napa, California.
As my friends will confirm, I don't do
If you are going to build the ShyFox as a Fox racer, increase the enginemount
spacing compared to the plain-bearing .25s. Also, you will probably
need the full 2-ounce tank.
The nose will see more vibration and stress. Therefore, use firmer wood for
the fuselage and cheek cowl, and apply at least one layer of 2-ounce-persquare-
yard fiberglass on the front. Overlap it onto the wing center-section
planking. Use generous epoxy fillets on the wing/fuselage joint.
Install the shutoff so you can shut down the model anytime it vibrates
badly. If the airplane vibrates terribly on the ground or in the air, change
propellers or engines until it moderates, or you will get cracks around the
wing/fuselage joint.
Be aware that a Fox power plant uses different design features and materials
from more modern engines. Be sure to use fuel with plenty of castor oil, but
don’t try to run a hot Fox with a lot of varnish on the piston or liner.
At local contests, we run all castor fuel in Fox Race, which helps. If you
have starting problems and the engine fires but the propeller oscillates back and
forth, reduce the voltage to your plug. This also reduces your risk of a pit fire.
If the engine starts fine cold but won’t restart hot, work on priming, and
even try dousing the cylinder with a water bottle during each pit stop. When the
hot starts go away, you need to find an engine with a tighter piston/liner fit; that
is what the competitors who are passing you have.
If the vibration is killing your airplane, soak the cracks with thin CA and
then heated epoxy. Install an O.S. .25, and race it as a Super Slow Rat. MA
—Dave “McSlow” Hull
28 MODEL AVIATION
Keep your engine covered to shut out inevitable blowing grit that will ruin your
piston/sleeve fit. Ear protectors are a good idea. Any major problems would require you
to open the toolbox—a sure sign that you didn’t win.
ShyFox
The
anything quickly—especially building an
airplane. However, I finished the
calculations, penciled the shapes, and
started construction. I soldered the fuel tank
the day before I packed for the trip. I put a
couple coats of dope on the fuselage in the
motel room the night before the race and
decided that my ShyFox and I were ready to
give it a shot.
My racing partner, Dave Dawson,
started breaking in the engine as soon as we
arrived at the field. We got in a couple of
test flights before the contest and declared
the equipment to be ready.
From the first flight, it was obvious that
the model performed smoothly and was
simple to fly. We were competitive from the
start, nabbing a second place among some
tough competition.
In spring 2007, at the Cabin Fever
contest in Tucson, Arizona, we were beaten
by perhaps the fastest SSR design in North
Type: Profile CL Racing
Skill: Beginner builder and pilot
Wingspan: 38.06 inches
Wing area: 306 square inches
Length: 22.5 inches
Weight: 27 ounces
Engine: O.S. 25LA Stunt or Fox .35 Stunt
Construction: Balsa and plywood
Covering/finish: MonoKote wings and tail, fiberglass fuselage and vertical tail
Other: 1.5- to 2.0-ounce fuel tank, propeller, 2-inch bellcrank
America in a phenomenal race. In July of
that year, I took the ShyFox to the Nats and
garnered first place.
Two characteristics made this possible.
First, the airplane has a straightforward fuel
system and starting procedure. I had to
borrow one pitman for the heat races and
then another for the final, and each had only
five minutes to figure out how to fuel up,
prime the engine (but avoid flooding), and
get one-flip starts.
The other key feature is that this model
flies so solidly that the winds at Muncie,
Indiana, were never a factor. I could watch
for traffic instead of worrying about my
racer ballooning in the wind.
If you and your flying buddies want to
have a bunch of fun, score some plans,
shuffle through the stack of balsa at the
hobby shop to find some racing wood, and
spend a few evenings at the building board.
If you aren’t having fun, you aren’t racing.
CONSTRUCTION
Because the ShyFox was to be built in
fewer than three weeks, it had to be simple.
I like to use 1/16 ribs with capstrips. But
it takes me quite a bit of time to cut and fit
so many pieces (I’m slow, remember?), so
the drawing shows 3/32 ribs without
capstrips. And I used an aluminum enginemounting
plate with integral gear leg,
similar to the one on my Quickie Rat racer.
For someone who has not had much
experience with engines, definitely go the
SSR route. This is a stock-engine class, so
the event directors might disassemble your
power plant to see if you have “improved”
things or installed nonstock parts. If you just
can’t stand running a stock engine, move up
to Slow Rat; those rules allow fully
modified engines.
There are many different fuel systems.
03sig1.QXD_00MSTRPG.QXD 1/26/10 9:51 AM Page 28
Numerous types work well, but some are
more difficult to tune. To achieve the
correct number of laps, the tank must be
built to match your engine. The rules permit
a tank that is a large as 2 ounces, but most
.25 engines will overrun on this much fuel
and you will be disqualified for not
completing the required two pit stops.
I suggest that you run your engine on the
bench to determine how much fuel is
required to last 105-120 seconds when set
slightly rich of peak; that should be good for
35-40 laps at typical ShyFox speeds. This
should be somewhere near 1.5 ounces.
Scale the length of the tank shown on the
plans to this volume. If building a custom
tank is all that is holding you back from
racing, try one from Brodak, such as item
BH-582 or BH-566.
The fuel shutoff is an integral part of
your fuel system and is considered a safety
item in SSR/Fox; you can’t use it during the
race. But being able to shut down during a
competition can rescue a pilot from his or
her mistakes or from a pitman or the other
teams.
My model is fitted with the springloaded,
drawbar-type (the wire is “J”
shaped) shutoff, with a pull-to-actuate trip
wire. I used the small size from Dirty Dale
Long. In addition to being a safety feature,
the shutoff permits a team to put up a series
of quick needle-adjustment flights
immediately before the race.
The aluminum monowheel gear shown is
actually easy to make. Be sure to use a heattreated
alloy such as 6061-T6 or 2024-T4.
Lay the pattern on the aluminum and you
are ready to cut. I like to drill holes at each
inside corner and then saw into each hole.
I used a urethane wheel from Darrell
Albert, with a threaded (fixed) brass hub.
Other possible sources are Glenn Lee
(urethane) and Marc Warwashana (who has
replicas of Don’s Wheels in rubber or
urethane).
This gear design has virtually no give. A
rubber wheel is an advantage if your pilot
can’t make consistent soft landings.
Wing: The wing has a constant thickness of
1 inch (minimum) from root to tip, so it can
easily be constructed flat on the building
board. Place a 3/8-inch strip of balsa under
the TE and move it fore/aft until its center is
exactly 1/2 inch above the building surface
along the span. If you get this right, you will
have no washin, washout, or warps.
The best way to make the ribs is to cut
an aluminum root and tip template. Drill
matching holes in the templates, and then
drill a set of rectangular balsa rib blanks to
match. Sandwich the whole thing and start
shaping.
I like to use a block of 80-grit sandpaper
to rough down one side and then the other.
Finish shaping with 120-grit paper.
Take your stack of ribs and lay the spar
stock in the correct location. Score the spar
notches with a new razor blade or hobby
knife. Do this carefully and you will get a
straighter, stronger wing, because the spars
won’t be twisted and the fit will be nice and
snug. Cut leadout holes in the inboard ribs
using a piece of sharpened 1/4-inch brass
tubing.
It is probably overkill, but the ShyFox’s
spars and LE are reinforced with carbonfiber
(CF) strips. A .007 x 1/4-inch strip is
laminated to the inside of each spruce spar.
Make sure that the spar stock is straight
to begin with and that they are laying on a
flat bench when you glue the CF. If you
want the most reliable joint, solvent-wipe
the carbon and use epoxy. The LE is
laminated from two pieces of 1/4 x 1/2 stock,
with .007 x 1/2 CF in between.
Remember that the event rules require a
1-inch-thick wing. If you cut the spar
notches too deep, push the top spar into
them, and sand the ribs flush, your wing will
be illegal.
Add the lower TE piece and then the
upper. You might want to taper the insides
of each a bit at the TE, to get a slightly
better fit with your ribs and to make the
finished TE a bit thinner.
The inboard tip is laminated so that the
leadouts pass through the center slot,
which is long enough to allow the leadouts
to be moved forward or aft for trimming.
Set your guide at the location shown on
the plans for first flights, or you can forgo
the adjustable guide and glue in brass
guides at this location. Install the bellcrank
platform and fit-check the controls.
Notice the 1/64 plywood reinforcement on
the inside of the planking, around the
pushrod hole. Add the spar shear webs,
noting the direction of the grain.
The leadouts in the inboard wing
preclude the use of shear webs in every bay.
Don’t worry about it; the wing is plenty
strong.
Plank the top center-section and carefully
sand everything. Do not ruin the airfoil or
make the wing too thin.
My airplane has MonoKote iron-on
covering. I like to apply this material to the
wing before installation in the fuselage, so
planning is in order.
If you cover using four pieces and leave a
gap along the middle of the wing, you won’t
have to try to peel this off before attaching
the wing to the fuselage. Don’t forget to
include the fillets when you calculate these
dimensions.
Tail and Fuselage: Use firm to hard balsa
for the fuselage and good five-ply birch
plywood. Cut the blank for the maple (or
birch) engine mounts, establishing the
spacing to fit your selected engine. Cut the
plywood doublers to outline but do not cut
the wing slot yet.
Taper the TE of the doublers; it is much
easier to do so before they are installed. Glue
the engine mounts and inboard doubler to
the fuselage with 30-minute epoxy. When
cured, glue on the inboard doubler with the
front edge lined up with the front of the wing.
Use the wing rib template to carefully
trace the cutout over the fuselage centerline.
Drill a 3/16-inch hole at the LE. Using a scroll
saw or a coping saw, cautiously cut down the
center of the line.
This will give a close fit during assembly
and results in a stronger, lighter wing joint
that is properly aligned. Straight is great;
slanted is planted.
Use your engine to mark the bolt pattern,
and then mark the two holes at the rear above
the gear leg. Drill 1/8 inch in diameter through,
and then counterbore the inboard side 5/32 inch
in diameter and 1/8 inch deep.
Press the Du-Bro blind nuts into the holes.
These are the best-quality blind nuts I have
found.
Cut a piece of 3/8 x 1/2 balsa for the nose
block. This adds strength but really serves to
reduce drag.
It is easier to cut the engine-clearance
radius in this block before you cut it to length.
Epoxy in place and final-shape your engine
case using sandpaper wrapped around a
dowel.
Cut the cheek cowling block (inboard
tripler) from medium balsa. Relieve the areas
over the blind nuts, and coat with epoxy for
fuel-proofing. Install using epoxy or
carpenter’s glue.
Clamp or weight the assembly until dry,
and cut the wing hole in the tripler. Trim and
sand to final shape, blending with the tapered
plywood doublers.
Cut, drill, and install the maple tail skid
block. Epoxy the block in place. A good way
to ensure that the removable tail skid will fit is
to make two blocks with identical hole
spacing and use one as a soldering fixture.
Drill a hole in the fuselage where the
elevator joiner goes through, and cut the
horizontal stabilizer slot. The tail is set with
zero incidence to the wing. Slot the top of the
fuselage for the rudder.
An odd thing happened when I made the
tail. As usual, I went to the scrap box before
chopping up a new sheet. There was a piece
quite a bit bigger than I needed—16 inches
long.
Instead of cutting it to the plans pattern, I
cut a stabilizer/elevator set that was as long as
the piece of wood that I found. I ended up
using this larger structure and have been
pleased with it.
The model grooves well, and this
stabilizer/elevator might be one reason why.
Plans show the original size, which should
work fine, so pick the one that suits you.
I fiberglassed the prototype ShyFox
fuselage and tail for strength and durability.
Use an extremely lightweight fiberglass,
especially on the tail. I employed a 0.58-
ounce-per-square-yard plain-weave cloth. Use
an epoxy resin system that has low viscosity.
Try not to thin it, but use lacquer thinner if
you do.
This design’s rudder is present because I
like airplanes that look real. It also protects
the shutoff horn if the model flips over, if it’s
fiberglassed or made from basswood.
You can use plywood if you think you
can install and seal it before it warps.
There should be no rudder offset.
Once you have glued the rudder to the
fuselage and added the fillets, do the final
shaping and sanding. If you are
considering skipping the fiberglass
reinforcement, you should know that the
most vulnerable part of a racer’s fuselage
is aft of the wing.
If the pitman is forced to attempt a
wing catch, the tail will whip. This can
cause the fuselage to crack at the wing TE
or farther aft.
So either don’t make flying and pitting
mistakes or build in ruggedness. Light is
fast; broken is last.
Airframe: Insert the wing and horizontal
stabilizer into the fuselage. Set this on a
large, flat surface and clamp the fuselage
to a 90° block at the nose. I use a large
secondhand machinist’s knee.
When everything is correct, you should
be able to sight along the horizontal
stabilizer from the rear and see if it is
parallel to the wing. Take your time. A
fast airplane exaggerates trim problems,
and a crooked model is a slow model.
I have used KlassKote epoxy to seal
and fuel-proof the wing/fuselage joint, and
I like its durability and relative ease of
use. You can mask over the MonoKote
and paint directly over the seam for a good
look. Scuff the covering where you will
paint after you mask it, and then wipe off
thoroughly with alcohol.
I like to use sewn hinges. Insert the
joiner wire through the fuselage and install
the elevators. Align and tape the assembly
to the stabilizer.
Using 12-pound-test Spectra fishing
line, start sewing the holes nearest to the
fuselage and work your way out. Stitch a
figure-eight pattern through each set of
holes, using four passes through each hole.
Snug everything tight, but do not pull
too hard on the line when tying the knot. It
could cut you, or your wood, if you didn’t
use hardwood spars.
Sullivan Products’ Gold-N-Clevises are
strong; don’t use a lesser-quality part. Install
a jam nut against the clevis once you have
the elevator adjusted to neutral, when the
bellcrank is at midtravel. Do you feel
catching or roughness? If so, fix it now.
Install the wheel on the landing gear
plate and install the engine and plate
together. The upper engine bolts also hold
on the tank vent line and fueling port, so
make this up now.
Fit the tank and shutoff in the space
between the wing and the engine as far
forward as you can, to improve fuel draw.
Install the shutoff, and connect the fuel lines
and shutoff trip wire. Adjust the wire so that
full down-elevator trips the shutoff.
I am still trying to design a long-lasting
tail skid. In the meantime, the ShyFox uses
my standard replaceable wire skid. These
are sort of spring-loaded into the mount.
Over asphalt, the standard skids wear
down after a year of racing and the loop
breaks off. Simply make a spare while you
are bending and soldering, and don’t worry
about it.
The prototype ShyFox weighs 27
ounces, which is fairly heavy, but there is
a relationship between weight and
durability. You don’t want your airplane
falling apart near the time you get it
trimmed and going fast in practice.
Make sure the CG is within 1/8 inch of
the location shown on the plans. You can
trim the CG within a certain range to suit
your skills, but a racer should fly level
without the pilot constantly watching it.
Be sure that your adjustable leadout
guide is locked down tight, and then hang
the model with the two leadouts held
together. It should hang a bit nose-down.
Test-Flying and Racing! When you get
your racer out to the field, check it one
more time. Connect the lines and handle.
Are the lines .015-inch stranded steel and
between 59 feet, 6 inches and 60 feet, 6
inches long when measured between the
handle and the fuselage centerline?
Is up really up? Is your handle marked?
For the control setup shown, you should
start with a handle spacing of
approximately 2 inches.
Try the shutoff in flight and set the
sensitivity to suit the pilot. You will know
it is too sensitive if he or she accidentally
shuts it off when taking off into the wind
and applies a great deal of down to keep
from ballooning into the racing zone.
This seems to be the most down-control
I ever need, so we use this maneuver to set
up each new model. If you shorten the tail
skid and are slightly slow on the handle,
you need more down-control.
The engine should speed up slightly on
the last lap, although the tank shown runs
evenly to the end. The downside of this is
that the pilot won’t get much warning of the
impending pit stop, and the team should
keep track of laps during each tank. Passing
with a nearly empty tank is a risky
maneuver.
I hope you enjoy building and racing your
ShyFox. For more information about
Racing, check out the National Control Line
Racing Association AMA SIG. The dues are
low and the information contained in the
newsletter, Torque Roll, will help you
become a competitive racer.
If you have the itch and want to learn
how to race, one of the best articles to read
is “The Race … and how to fly it” by John
Kilsdonk, which was published in the May
1977 MA. AMA members can access this
issue via the Academy’s Web site, in the
“Members Only” section. MA
Dave “McSlow” Hull
[email protected]
Sources:
Brodak Manufacturing
(724) 966-2726
www.brodak.com
Dale Long
(951) 784-4328
[email protected]
Racing wheels and other specialty items:
Darrell Albert
(760) 741-2505
[email protected]
Marc Warwashana
11577 North Shore Dr.
Whitmore Lake MI 48189
[email protected]
Du-Bro Products, Inc.
(800) 848-9411
www.dubro.com
KlassKote
(612) 243-1234
www.klasskote.com
Sullivan Products (control horns are item
556)
(410) 732-3500
www.sullivanproducts.com
National Control Line Racing Association
www.nclra.org
Stock .35 Stunt engine, 2-inch bellcrank,
glow plugs:
Fox Manufacturing
(479) 646-1656
www.foxmanufacturing.com
Stock 25LA CL engine:
O.S. Engines
(217) 398-8970
www.osengines.com
Lines, line-making supplies, clips, fueling
bottles, horns, etc.:
MBS Model Supplies (Melvin Schuette)
(785) 256-2583
www.mbsmodelsupply.com
Tin-plated steel, 1/8-inch-diameter copper
tubing; 1/8-inch-diameter aluminum plate for
gear:
K&S Engineering
(773) 586-8503
www.ksmetals.com
Fiberglass cloth, EZ-Lam epoxy resin:
Aerospace Composite Products
(925) 443-5900
www.acp-composites.com
Carbon-fiber reinforcing materials:
Dave Brown Products, Inc.
(513) 738-1576
www.dbproducts.com
Fourmost Products
(503) 357-2732
www.fourmostproducts.com
AMA
(765) 287-1256
www.modelaircraft.org

THE MOST ACCESSIBLE CL Racing events are Super Slow Rat (SSR) and its
evil twin, Fox Race, which are often flown combined. The reasons are many, but at the
top of the list are that the models fly well
and that the pace is within many pilots'
physical abilities.
You don't have to be in marathon condition to fly SSR/Fox safely and get a lot
of enjoyment from it. That, in combination
with the stock-engine restrictions and
airframe-size minimums, means you are
likely to experience some extremely close
racing.
The airplanes can be made rugged and
the systems are simple, so if three
contestants start the race, it is a good bet
that all of them will be in it until the end.
Being able to compete against your buddies
with a fair chance of beating them is a ton
of fun. This event might have more
bragging per mph than any other Racing
class.
When I started Racing and was looking
for another event to enter in local contests, I
noticed that the organizers rotated the
categories but that SSR/Fox was held more
often than many of the others. That meant if
I built an SSR/Fox racer, I could race more
often. That was all the motivation I needed.
My local hobby shop had no eligible
kits, so I started designing the SkyFox just
three weeks before the 2005 Northern
California Racing Championships. The
contest was to be held in Napa, California.
As my friends will confirm, I don't do
If you are going to build the ShyFox as a Fox racer, increase the enginemount
spacing compared to the plain-bearing .25s. Also, you will probably
need the full 2-ounce tank.
The nose will see more vibration and stress. Therefore, use firmer wood for
the fuselage and cheek cowl, and apply at least one layer of 2-ounce-persquare-
yard fiberglass on the front. Overlap it onto the wing center-section
planking. Use generous epoxy fillets on the wing/fuselage joint.
Install the shutoff so you can shut down the model anytime it vibrates
badly. If the airplane vibrates terribly on the ground or in the air, change
propellers or engines until it moderates, or you will get cracks around the
wing/fuselage joint.
Be aware that a Fox power plant uses different design features and materials
from more modern engines. Be sure to use fuel with plenty of castor oil, but
don’t try to run a hot Fox with a lot of varnish on the piston or liner.
At local contests, we run all castor fuel in Fox Race, which helps. If you
have starting problems and the engine fires but the propeller oscillates back and
forth, reduce the voltage to your plug. This also reduces your risk of a pit fire.
If the engine starts fine cold but won’t restart hot, work on priming, and
even try dousing the cylinder with a water bottle during each pit stop. When the
hot starts go away, you need to find an engine with a tighter piston/liner fit; that
is what the competitors who are passing you have.
If the vibration is killing your airplane, soak the cracks with thin CA and
then heated epoxy. Install an O.S. .25, and race it as a Super Slow Rat. MA
—Dave “McSlow” Hull
28 MODEL AVIATION
Keep your engine covered to shut out inevitable blowing grit that will ruin your
piston/sleeve fit. Ear protectors are a good idea. Any major problems would require you
to open the toolbox—a sure sign that you didn’t win.
ShyFox
The
anything quickly—especially building an
airplane. However, I finished the
calculations, penciled the shapes, and
started construction. I soldered the fuel tank
the day before I packed for the trip. I put a
couple coats of dope on the fuselage in the
motel room the night before the race and
decided that my ShyFox and I were ready to
give it a shot.
My racing partner, Dave Dawson,
started breaking in the engine as soon as we
arrived at the field. We got in a couple of
test flights before the contest and declared
the equipment to be ready.
From the first flight, it was obvious that
the model performed smoothly and was
simple to fly. We were competitive from the
start, nabbing a second place among some
tough competition.
In spring 2007, at the Cabin Fever
contest in Tucson, Arizona, we were beaten
by perhaps the fastest SSR design in North
Type: Profile CL Racing
Skill: Beginner builder and pilot
Wingspan: 38.06 inches
Wing area: 306 square inches
Length: 22.5 inches
Weight: 27 ounces
Engine: O.S. 25LA Stunt or Fox .35 Stunt
Construction: Balsa and plywood
Covering/finish: MonoKote wings and tail, fiberglass fuselage and vertical tail
Other: 1.5- to 2.0-ounce fuel tank, propeller, 2-inch bellcrank
America in a phenomenal race. In July of
that year, I took the ShyFox to the Nats and
garnered first place.
Two characteristics made this possible.
First, the airplane has a straightforward fuel
system and starting procedure. I had to
borrow one pitman for the heat races and
then another for the final, and each had only
five minutes to figure out how to fuel up,
prime the engine (but avoid flooding), and
get one-flip starts.
The other key feature is that this model
flies so solidly that the winds at Muncie,
Indiana, were never a factor. I could watch
for traffic instead of worrying about my
racer ballooning in the wind.
If you and your flying buddies want to
have a bunch of fun, score some plans,
shuffle through the stack of balsa at the
hobby shop to find some racing wood, and
spend a few evenings at the building board.
If you aren’t having fun, you aren’t racing.
CONSTRUCTION
Because the ShyFox was to be built in
fewer than three weeks, it had to be simple.
I like to use 1/16 ribs with capstrips. But
it takes me quite a bit of time to cut and fit
so many pieces (I’m slow, remember?), so
the drawing shows 3/32 ribs without
capstrips. And I used an aluminum enginemounting
plate with integral gear leg,
similar to the one on my Quickie Rat racer.
For someone who has not had much
experience with engines, definitely go the
SSR route. This is a stock-engine class, so
the event directors might disassemble your
power plant to see if you have “improved”
things or installed nonstock parts. If you just
can’t stand running a stock engine, move up
to Slow Rat; those rules allow fully
modified engines.
There are many different fuel systems.
03sig1.QXD_00MSTRPG.QXD 1/26/10 9:51 AM Page 28
Numerous types work well, but some are
more difficult to tune. To achieve the
correct number of laps, the tank must be
built to match your engine. The rules permit
a tank that is a large as 2 ounces, but most
.25 engines will overrun on this much fuel
and you will be disqualified for not
completing the required two pit stops.
I suggest that you run your engine on the
bench to determine how much fuel is
required to last 105-120 seconds when set
slightly rich of peak; that should be good for
35-40 laps at typical ShyFox speeds. This
should be somewhere near 1.5 ounces.
Scale the length of the tank shown on the
plans to this volume. If building a custom
tank is all that is holding you back from
racing, try one from Brodak, such as item
BH-582 or BH-566.
The fuel shutoff is an integral part of
your fuel system and is considered a safety
item in SSR/Fox; you can’t use it during the
race. But being able to shut down during a
competition can rescue a pilot from his or
her mistakes or from a pitman or the other
teams.
My model is fitted with the springloaded,
drawbar-type (the wire is “J”
shaped) shutoff, with a pull-to-actuate trip
wire. I used the small size from Dirty Dale
Long. In addition to being a safety feature,
the shutoff permits a team to put up a series
of quick needle-adjustment flights
immediately before the race.
The aluminum monowheel gear shown is
actually easy to make. Be sure to use a heattreated
alloy such as 6061-T6 or 2024-T4.
Lay the pattern on the aluminum and you
are ready to cut. I like to drill holes at each
inside corner and then saw into each hole.
I used a urethane wheel from Darrell
Albert, with a threaded (fixed) brass hub.
Other possible sources are Glenn Lee
(urethane) and Marc Warwashana (who has
replicas of Don’s Wheels in rubber or
urethane).
This gear design has virtually no give. A
rubber wheel is an advantage if your pilot
can’t make consistent soft landings.
Wing: The wing has a constant thickness of
1 inch (minimum) from root to tip, so it can
easily be constructed flat on the building
board. Place a 3/8-inch strip of balsa under
the TE and move it fore/aft until its center is
exactly 1/2 inch above the building surface
along the span. If you get this right, you will
have no washin, washout, or warps.
The best way to make the ribs is to cut
an aluminum root and tip template. Drill
matching holes in the templates, and then
drill a set of rectangular balsa rib blanks to
match. Sandwich the whole thing and start
shaping.
I like to use a block of 80-grit sandpaper
to rough down one side and then the other.
Finish shaping with 120-grit paper.
Take your stack of ribs and lay the spar
stock in the correct location. Score the spar
notches with a new razor blade or hobby
knife. Do this carefully and you will get a
straighter, stronger wing, because the spars
won’t be twisted and the fit will be nice and
snug. Cut leadout holes in the inboard ribs
using a piece of sharpened 1/4-inch brass
tubing.
It is probably overkill, but the ShyFox’s
spars and LE are reinforced with carbonfiber
(CF) strips. A .007 x 1/4-inch strip is
laminated to the inside of each spruce spar.
Make sure that the spar stock is straight
to begin with and that they are laying on a
flat bench when you glue the CF. If you
want the most reliable joint, solvent-wipe
the carbon and use epoxy. The LE is
laminated from two pieces of 1/4 x 1/2 stock,
with .007 x 1/2 CF in between.
Remember that the event rules require a
1-inch-thick wing. If you cut the spar
notches too deep, push the top spar into
them, and sand the ribs flush, your wing will
be illegal.
Add the lower TE piece and then the
upper. You might want to taper the insides
of each a bit at the TE, to get a slightly
better fit with your ribs and to make the
finished TE a bit thinner.
The inboard tip is laminated so that the
leadouts pass through the center slot,
which is long enough to allow the leadouts
to be moved forward or aft for trimming.
Set your guide at the location shown on
the plans for first flights, or you can forgo
the adjustable guide and glue in brass
guides at this location. Install the bellcrank
platform and fit-check the controls.
Notice the 1/64 plywood reinforcement on
the inside of the planking, around the
pushrod hole. Add the spar shear webs,
noting the direction of the grain.
The leadouts in the inboard wing
preclude the use of shear webs in every bay.
Don’t worry about it; the wing is plenty
strong.
Plank the top center-section and carefully
sand everything. Do not ruin the airfoil or
make the wing too thin.
My airplane has MonoKote iron-on
covering. I like to apply this material to the
wing before installation in the fuselage, so
planning is in order.
If you cover using four pieces and leave a
gap along the middle of the wing, you won’t
have to try to peel this off before attaching
the wing to the fuselage. Don’t forget to
include the fillets when you calculate these
dimensions.
Tail and Fuselage: Use firm to hard balsa
for the fuselage and good five-ply birch
plywood. Cut the blank for the maple (or
birch) engine mounts, establishing the
spacing to fit your selected engine. Cut the
plywood doublers to outline but do not cut
the wing slot yet.
Taper the TE of the doublers; it is much
easier to do so before they are installed. Glue
the engine mounts and inboard doubler to
the fuselage with 30-minute epoxy. When
cured, glue on the inboard doubler with the
front edge lined up with the front of the wing.
Use the wing rib template to carefully
trace the cutout over the fuselage centerline.
Drill a 3/16-inch hole at the LE. Using a scroll
saw or a coping saw, cautiously cut down the
center of the line.
This will give a close fit during assembly
and results in a stronger, lighter wing joint
that is properly aligned. Straight is great;
slanted is planted.
Use your engine to mark the bolt pattern,
and then mark the two holes at the rear above
the gear leg. Drill 1/8 inch in diameter through,
and then counterbore the inboard side 5/32 inch
in diameter and 1/8 inch deep.
Press the Du-Bro blind nuts into the holes.
These are the best-quality blind nuts I have
found.
Cut a piece of 3/8 x 1/2 balsa for the nose
block. This adds strength but really serves to
reduce drag.
It is easier to cut the engine-clearance
radius in this block before you cut it to length.
Epoxy in place and final-shape your engine
case using sandpaper wrapped around a
dowel.
Cut the cheek cowling block (inboard
tripler) from medium balsa. Relieve the areas
over the blind nuts, and coat with epoxy for
fuel-proofing. Install using epoxy or
carpenter’s glue.
Clamp or weight the assembly until dry,
and cut the wing hole in the tripler. Trim and
sand to final shape, blending with the tapered
plywood doublers.
Cut, drill, and install the maple tail skid
block. Epoxy the block in place. A good way
to ensure that the removable tail skid will fit is
to make two blocks with identical hole
spacing and use one as a soldering fixture.
Drill a hole in the fuselage where the
elevator joiner goes through, and cut the
horizontal stabilizer slot. The tail is set with
zero incidence to the wing. Slot the top of the
fuselage for the rudder.
An odd thing happened when I made the
tail. As usual, I went to the scrap box before
chopping up a new sheet. There was a piece
quite a bit bigger than I needed—16 inches
long.
Instead of cutting it to the plans pattern, I
cut a stabilizer/elevator set that was as long as
the piece of wood that I found. I ended up
using this larger structure and have been
pleased with it.
The model grooves well, and this
stabilizer/elevator might be one reason why.
Plans show the original size, which should
work fine, so pick the one that suits you.
I fiberglassed the prototype ShyFox
fuselage and tail for strength and durability.
Use an extremely lightweight fiberglass,
especially on the tail. I employed a 0.58-
ounce-per-square-yard plain-weave cloth. Use
an epoxy resin system that has low viscosity.
Try not to thin it, but use lacquer thinner if
you do.
This design’s rudder is present because I
like airplanes that look real. It also protects
the shutoff horn if the model flips over, if it’s
fiberglassed or made from basswood.
You can use plywood if you think you
can install and seal it before it warps.
There should be no rudder offset.
Once you have glued the rudder to the
fuselage and added the fillets, do the final
shaping and sanding. If you are
considering skipping the fiberglass
reinforcement, you should know that the
most vulnerable part of a racer’s fuselage
is aft of the wing.
If the pitman is forced to attempt a
wing catch, the tail will whip. This can
cause the fuselage to crack at the wing TE
or farther aft.
So either don’t make flying and pitting
mistakes or build in ruggedness. Light is
fast; broken is last.
Airframe: Insert the wing and horizontal
stabilizer into the fuselage. Set this on a
large, flat surface and clamp the fuselage
to a 90° block at the nose. I use a large
secondhand machinist’s knee.
When everything is correct, you should
be able to sight along the horizontal
stabilizer from the rear and see if it is
parallel to the wing. Take your time. A
fast airplane exaggerates trim problems,
and a crooked model is a slow model.
I have used KlassKote epoxy to seal
and fuel-proof the wing/fuselage joint, and
I like its durability and relative ease of
use. You can mask over the MonoKote
and paint directly over the seam for a good
look. Scuff the covering where you will
paint after you mask it, and then wipe off
thoroughly with alcohol.
I like to use sewn hinges. Insert the
joiner wire through the fuselage and install
the elevators. Align and tape the assembly
to the stabilizer.
Using 12-pound-test Spectra fishing
line, start sewing the holes nearest to the
fuselage and work your way out. Stitch a
figure-eight pattern through each set of
holes, using four passes through each hole.
Snug everything tight, but do not pull
too hard on the line when tying the knot. It
could cut you, or your wood, if you didn’t
use hardwood spars.
Sullivan Products’ Gold-N-Clevises are
strong; don’t use a lesser-quality part. Install
a jam nut against the clevis once you have
the elevator adjusted to neutral, when the
bellcrank is at midtravel. Do you feel
catching or roughness? If so, fix it now.
Install the wheel on the landing gear
plate and install the engine and plate
together. The upper engine bolts also hold
on the tank vent line and fueling port, so
make this up now.
Fit the tank and shutoff in the space
between the wing and the engine as far
forward as you can, to improve fuel draw.
Install the shutoff, and connect the fuel lines
and shutoff trip wire. Adjust the wire so that
full down-elevator trips the shutoff.
I am still trying to design a long-lasting
tail skid. In the meantime, the ShyFox uses
my standard replaceable wire skid. These
are sort of spring-loaded into the mount.
Over asphalt, the standard skids wear
down after a year of racing and the loop
breaks off. Simply make a spare while you
are bending and soldering, and don’t worry
about it.
The prototype ShyFox weighs 27
ounces, which is fairly heavy, but there is
a relationship between weight and
durability. You don’t want your airplane
falling apart near the time you get it
trimmed and going fast in practice.
Make sure the CG is within 1/8 inch of
the location shown on the plans. You can
trim the CG within a certain range to suit
your skills, but a racer should fly level
without the pilot constantly watching it.
Be sure that your adjustable leadout
guide is locked down tight, and then hang
the model with the two leadouts held
together. It should hang a bit nose-down.
Test-Flying and Racing! When you get
your racer out to the field, check it one
more time. Connect the lines and handle.
Are the lines .015-inch stranded steel and
between 59 feet, 6 inches and 60 feet, 6
inches long when measured between the
handle and the fuselage centerline?
Is up really up? Is your handle marked?
For the control setup shown, you should
start with a handle spacing of
approximately 2 inches.
Try the shutoff in flight and set the
sensitivity to suit the pilot. You will know
it is too sensitive if he or she accidentally
shuts it off when taking off into the wind
and applies a great deal of down to keep
from ballooning into the racing zone.
This seems to be the most down-control
I ever need, so we use this maneuver to set
up each new model. If you shorten the tail
skid and are slightly slow on the handle,
you need more down-control.
The engine should speed up slightly on
the last lap, although the tank shown runs
evenly to the end. The downside of this is
that the pilot won’t get much warning of the
impending pit stop, and the team should
keep track of laps during each tank. Passing
with a nearly empty tank is a risky
maneuver.
I hope you enjoy building and racing your
ShyFox. For more information about
Racing, check out the National Control Line
Racing Association AMA SIG. The dues are
low and the information contained in the
newsletter, Torque Roll, will help you
become a competitive racer.
If you have the itch and want to learn
how to race, one of the best articles to read
is “The Race … and how to fly it” by John
Kilsdonk, which was published in the May
1977 MA. AMA members can access this
issue via the Academy’s Web site, in the
“Members Only” section. MA
Dave “McSlow” Hull
[email protected]
Sources:
Brodak Manufacturing
(724) 966-2726
www.brodak.com
Dale Long
(951) 784-4328
[email protected]
Racing wheels and other specialty items:
Darrell Albert
(760) 741-2505
[email protected]
Marc Warwashana
11577 North Shore Dr.
Whitmore Lake MI 48189
[email protected]
Du-Bro Products, Inc.
(800) 848-9411
www.dubro.com
KlassKote
(612) 243-1234
www.klasskote.com
Sullivan Products (control horns are item
556)
(410) 732-3500
www.sullivanproducts.com
National Control Line Racing Association
www.nclra.org
Stock .35 Stunt engine, 2-inch bellcrank,
glow plugs:
Fox Manufacturing
(479) 646-1656
www.foxmanufacturing.com
Stock 25LA CL engine:
O.S. Engines
(217) 398-8970
www.osengines.com
Lines, line-making supplies, clips, fueling
bottles, horns, etc.:
MBS Model Supplies (Melvin Schuette)
(785) 256-2583
www.mbsmodelsupply.com
Tin-plated steel, 1/8-inch-diameter copper
tubing; 1/8-inch-diameter aluminum plate for
gear:
K&S Engineering
(773) 586-8503
www.ksmetals.com
Fiberglass cloth, EZ-Lam epoxy resin:
Aerospace Composite Products
(925) 443-5900
www.acp-composites.com
Carbon-fiber reinforcing materials:
Dave Brown Products, Inc.
(513) 738-1576
www.dbproducts.com
Fourmost Products
(503) 357-2732
www.fourmostproducts.com
AMA
(765) 287-1256
www.modelaircraft.org