AERONCA
Electric Scale version of a stylish 1940s lightplane.
The Sedan literally jumps into the sky on launch. The Speed 400
electric motors have plenty of performance potential.
The author proudly displays his replica of the classic Aeronca.
This shot gives a good reference for the size of the model.
n John H. Linke
Sedan
When World War II was becoming a memory in 1946, the
American light airplane industry expected a boom. With all the
pilots returning from their wartime exploits, many “experts” felt that
these servicemen would want to continue flying in peacetime, for
“the fun of it.”
Management at the Aeronautical Corporation of America
(Aeronca) wanted to get in on the boom with a family-type airplane.
It directed the engineering department to come up with a new fourseat
design using as much in-house inventory as possible, to keep
production costs down. It would also assure some parts
32 M ODEL AVIATION
February 2001 33
Use a combination square or a right triangle to ensure that the
forward fuselage formers are properly aligned.
Make a “kit” of parts before beginning construction. The
fuselage parts are shown laid out and ready for assembly.
The fuselage near completion, with all the formers installed, the
bottom glued in place, and the stringers positioned.
Each of the outer wing panels must be joined to the centersection.
Accuracy and alignment are critical in this step!
production costs down. It would also assure some parts commonality
with the other Aeronca models.
The four-seat Aeronca Sedan was the result of this effort.
Powered by a 145-horsepower Continental engine, the 37-footwingspan
aircraft carried its passengers in comfort at 105 mph.
Although it wasn’t particularly fast—even in its heyday—the Sedan
excelled in load-carrying.
The aircraft’s reasonable cost and all-metal wing made it a
favorite of operators in isolated areas.
Aeronca manufactured 561 Sedans from mid-1948 through March
1951. Two last airplanes were built from spares in October 1951,
thus ending Aeronca’s aircraft manufacturing business. Aeronca is
currently involved in aerospace component manufacturing.
Data from 1980 Federal Aviation Administration (FAA) records
indicate that 197 Sedans are still registered, with perhaps another
100 in Canada, which have various utility duties.
The Sedan’s standard factory color scheme was limited to three
colors throughout the years of production. The 1948 and 1949
models shared the same red and straw (cream) coloring, and the
1948 models had natural aluminum-colored wings.
Aeronca later issued a service bulletin, requiring paint on all
models’ wings. The 1949 airplanes’ wings were painted red, with
NC numbers on the top right and bottom left in the straw color. The
1950 Sedans switched to a medium blue over the straw, blue wings,
and straw numbers on the wings.
For the purist, the Sedans were numbered consecutively from
NC1000H to NC1491H. Many aircraft were exported, so surviving
aircraft may have other identification numbers or be painted in other
schemes and colors.
CONSTRUCTION
I have been influenced by the efforts of Walt Musciano in the
model’s layout and general construction features.
A few Sedans have been modeled throughout the years.
Berkeley had a kit in the 1950s, and I saw another version
advertised in early issues of Radio Control Modeler. Walt
Musciano had a Control Line model featured in his book Building
and Flying Scale Model Aircraft, and I think Scientific produced
this or a similar version in kit form.
My Electric Sedan is a simple three-channel sport flier that looks
like a full-scale airplane in the air. The electronic speed control
permits longer flights, by allowing the Speed 400 motor to be
“throttled back” for extended cruising.
The model is not a speed demon, nor is it fully aerobatic. It is
designed to be easy to fly and to fly in a scalelike fashion, and it has
generally good manners.
The wings may be attached with the dowel-and-bolt
Photos courtesy the author Graphic Design by Carla Kunz
Type: RC Electric Fun Scale
Wingspan: 413⁄8 inches
Motor: Speed 400
Functions: Speed control, elevator, rudder
Flying Weight: 21 ounces
Construction: Balsa and plywood
Covering/finish: Silkspan and dope, MonoKote®
AECRAON Sedan
34 M ODEL AVIATION
The model’s wing panels, the center-section with dihedral
braces, and the innermost wing ribs are ready to be joined.
Give the completed Sedan airframe a careful sanding. The final
finish is only as good as the woodwork beneath.
Looking into the cabin area, you can see the battery on the
forward side of the slide and the receiver on the rear face.
arrangement shown on the plans or the more-traditional doweland-
rubber band arrangement.
If you want to try out a good-flying, inexpensive Electric, this is
the one for you. It can also be powered by 1⁄2A gas engines, for those
who don’t have the desire to try clean and quiet Electric flying.
Fuselage: This is a simple balsa box, with an open, stringered rear
section. Plywood is used in areas of stress.
The model is not designed to survive a major ground impact, and
increasing wood sizes will only make it too heavy to fly well with
electric or gas power.
Wood selection is not particularly critical, but try to keep the
same density in the fuselage sides and doublers, to make the
bends easier.
The tail surfaces are made from medium-weight 3⁄32 balsa sheet.
They may also be built up for “lightness,” but be careful when
covering not to introduce warps into the lightweight structure.
The easiest way to build from scratch is to make a “kit” of
components. Cut the fuselage sides and doublers from mediumweight
1⁄16 balsa. Note that the doublers have vertical grain.
Edge-glue three-inch-wide sheets together with CyA, to make it
easy and quick.
Cut the firewall, landing gear braces, and formers 1 and 2 from
1⁄8 plywood. Don’t skimp here; these pieces hold the airplane
together! Drill 1⁄16- or 1⁄8-inch-diameter pilot holes in former 1, for
the wing hold-down dowels.
The remaining formers are cut from scrap 3⁄32 balsa, or are
laminated to 1⁄8-inch-thick using two pieces of 1⁄16 balsa.
Cut the “keel” piece—to support the vertical and horizontal
stabilizer—from 1⁄8 medium balsa. Leave it slightly long on the
forward end; it can be trimmed later.
The stringers are 3⁄32 square balsa, and they should be made from
hard balsa stock; they take some abuse during the covering process.
Taper the aft end of the keel piece, as indicated, to fit between
the fuselage sides when they are joined.
Glue the doublers in place with CyA, Ambroid cement, white
glue, or aliphatic resin—whichever is your favored method. If you
use anything other than CyA, weight the sides on a flat surface until
the glue is dry, to minimize warpage.
Mark the location of all the formers by referencing the top
view on the plan.
The down-thrust angle on the firewall is not critical; just make
sure it’s down-thrust—not upthrust. (The little Speed 400 is
“torquey” under a full battery charge, and the down-thrust
compensates for that.)
Cut the triangular stock to size, on reference to the actual sides.
Cut the wing rest from 1⁄8 balsa, and cut a slot in the windshield
triangular stock, to accept the wing rest.
Glue the triangular stock in place on both fuselage sides, and
glue the wing-rest pieces. When dry, epoxy formers 1 and 2 to one
side. Assure squareness with the side using a 90° fixture (triangle or
square). When that is dry, epoxy the other side to formers 1 and 2.
Allow to dry thoroughly.
Glue a 1⁄8-square spacer piece to the lower front side of former 1;
this positions the landing-gear (LG) brace. Cut a groove in each LG
brace to fit the gear wire, and epoxy one LG brace in place.
Cut, fit, and glue in the 1⁄16 bottom sheeting between formers 1
and 2 (cross-grain). When dry, pull the tail together carefully,
sandwiching the keel piece in position. Check squareness with a
ruler and square at the wing mount.
Use the keel as a “fixture,” to help align formers 3 and 4. Mark
the location of former 3, make sure the sides are “square,” and glue
it in place. Continue with former 4. When satisfied, glue the sides to
the keel and clamp until dry.
Cut a piece of scrap 1⁄16 or 1⁄8 plywood to fit between former 4
and the tail post. Bend the .045-inch-diameter tail wheel wire to
shape, and glue it securely to this plywood piece. Glue the tailwheel
mount in place, flush with the fuselage sides.
Cut and fit the fuselage bottom pieces cross-grain, and glue them
in place. Fit the 3⁄32 stringers in place, and glue them.
Mount the Graupner Speed 400 motor mount to the firewall. Cut a 11⁄8-
Continued on page 38
February 2001 35
Full-Size Plans Available —see page 173
36 M ODEL AVIATION
inch-diameter hole into the firewall, so the
motor can be inserted from the rear. Enlarge as
necessary, to ensure easy passage.
Epoxy the firewall in place, pulling the
nose section together with rubber bands.
Check firewall alignment before the epoxy
sets. No up-thrust or left-thrust allowed!
Cut through the fuselage sides for the
landing gear wire, sandwich the wire
between LG pieces, glue (epoxy is
recommended), and clamp.
When that is dry, cover the bottom of the
fuselage from landing gear to cowl markings on
the plan with 1⁄16 balsa; cover the forward part
with 3⁄32 balsa (cross-grain). Set aside to dry.
Cut the tail surfaces from medium 3⁄32
balsa. Sand smooth and round the edges of
the fin, rudder, horizontal stabilizer, and the
trailing edge of the elevators.
Use a 1⁄8-inch-diameter hardwood dowel to
join elevator halves. Do not hinge the rudder to
the vertical fin at this time. Hinge the elevator to
the horizontal stabilizer with over/under cloth
hinges or a MonoKote® hinge.
Position the horizontal stabilizer assembly
in the keel slot. Check alignment with the wing
rest. Ensure that the stabilizer is parallel to the
wing, 90° to the fuselage in the horizontal and
vertical plane before gluing in place.
This alignment is critical for a successful
first flight! Glue the stabilizer assembly in place
when you are satisfied with the placement.
Carefully cut scrap 1⁄16 x 1⁄4 balsa to fit
between former 4 and the tail post, above
and below the stabilizer. This will
strengthen the joint, and give the covering
material something to grab onto when you
are covering around the tail.
Install the motor. The electronic speed
control should be placed in the area behind
the firewall. Tape wires on the fuselage side,
to keep them out of the way.
Cover the rest of the nose area and the
windshield area, except at the top of the
windshield; leave a space here for drilling the
dowel holes when you fit the wing into position.
With a spoke shave, knife, and
sandpaper, shape the nose to resemble the
drawing on the plan. The 1/2-inch triangle
Continued from page 34
Aeronca Sedan
stock can take a lot of cutting, so keep at it
to get nice, big, smooth curves to the cowl
and the windshield.
Besides, your model doesn’t need to
carry all that extra balsa around! Cut the
nose block to shape. It may be made from
one piece or from several laminated
pieces. Keep it soft and light. Hollow as
indicated, and cut the 11⁄8-inch-diameter
hole for the motor.
Fit the nose block in place, cutting and
adjusting as necessary to fit around the motor
and the mount. When you are satisfied, tackglue
the nose block in place and blend it into
the rest of the nose contour.
The scale air intakes for the cylinders
and the carburetor may be cut into the
nose block or painted on. If you cut them,
strengthen the edges afterward with a
bead of CyA.
Epoxy in the 1⁄8 plywood wing-bolt
mount. Fit scrap pieces of 3⁄32 or 1⁄16 balsa
between the stringers behind former 2;
this will help prevent you from punching
a hole in the covering with the
screwdriver, as I did.
Servos will be mounted at the rear of the
cabin, just ahead of former 2.
Cut pushrods for the tail surfaces. I used
3⁄16 balsa with wire ends; clevis in the rear
and “Z” bends at the servo.
Cut a scrap 3⁄32 x 1⁄4 piece of balsa, to fit
between formers 2 and 3 and 3 and 4 on the
upper fuselage sides. Glue this scrap in
place. It will minimize distortion of the
sides when you are shrinking the covering.
Wing construction is straightforward.
The center-section is sheeted with 1⁄16
balsa on the bottom and 1⁄32 balsa on the top.
If you plan on using rubber bands to secure
the wing, use 1⁄16 balsa on the top also.
Cut all the ribs, trailing edge (TE)
pieces, 1⁄8-inch square spar, and the 1⁄4-inch
square leading edge (LE).
Lay the 1⁄16- x 1/2-inch lower LE on the
plan. Glue the 1⁄4-inch LE to this piece. Pin
the TE to the plan. Raise the tips, as indicated.
Fit the ribs, and glue them in place.
Leave rib B off until the outer panels are
joined to the center-section. Glue the spar
in place. Allow assembly to dry thoroughly
before removing it from the plan.
Build the other wing panel as the
preceding one was done. To build the
center-section, cut the 1⁄8 plywood dihedral
supports. Edge-glue 1⁄16 balsa to make up
the lower sheeting. Pin the TE to the plan.
Edge-glue the lower sheeting to the TE.
Glue the LE to the lower sheeting.
Glue (epoxy preferred) the 1⁄8 plywood
dihedral joiners to the LE and the TE.
Make sure each end of the joiner is
equidistant from the building board.
Shape the LE of each wing panel and
the center-section with spoke shave, and
sandpaper. Fit the 1⁄32 sheeting to the
center-section. Mate the outer panels to the
center-section one at a time. Fit, cut, sand,
and jiggle to fit, if necessary.
Support the tip one inch above the
board at the last A rib, and glue the
dihedral braces to the outer panel. Fit and
glue rib B. Repeat this process with the
other panel when the first is dry.
Fit and glue the LE sheeting to each
wing panel. The tips may be cut from 3⁄8
soft balsa or laminated. Glue in place.
Trim excess from the tips with a knife,
and sand the entire wing assembly. Go
easy sanding the 1⁄32 sheeting.
Fit the wing to the fuselage, ensuring
that it is parallel with the horizontal
stabilizer. Temporarily secure the wing
with tape or rubber bands. Drill a 3⁄16-
inch-diameter hole through the pilot
holes in former 1. This will leave a mark
on the bottom of the wing.
Remove the wing, and cut two pieces
of 3⁄4-inch-long scrap triangular stock.
Sand or cut a 3⁄16-inch groove in the
triangular stock, to accept the dowel.
Spot-glue the dowels to the wing, and
reposition the wing in place.
If the fit is satisfactory, remove the wing
and reglue the dowels in place. Glue triangular
stock over the dowels for reinforcement.
Fit the wing to the fuselage, and make
sure all is in alignment. Drill a 1⁄8-inchdiameter
hole through the center-section
TE and into the plywood bolt mount.
Remove the wing, and make the hole in
the plywood bolt mount with a 10-32 tap.
Drill the hole in the TE to 3⁄16-inch, and
strengthen it with CyA or plywood scrap.
Fit the wing, screw the bolt in place,
and ensure alignment. When satisfied, fit
and glue the final piece to the windshield.
Sand to contour with the center-section
LE. Remove the wing and finish shaping
the windshield.
Sand the whole fuselage with 280-grit
(or finer) paper, smoothing and slightly
rounding the bottom.
Final Assembly and Finish: Glue on the
vertical fin; use epoxy or CyA, since there
is such a small gluing area.
Alternately, the fuselage may be covered
and a small portion of the covering cut away
on the keel so the vertical fin may be glued
in place. This method is preferable, since the
full-scale Sedan had a smooth fillet line of
fabric on the tail section.
Hinge the rudder in place with
over/under hinges or MonoKote®. Cover
the open area with silkspan, silk, your
favorite iron-on film, or 1⁄32 balsa. I
covered the original model there with
silkspan, then I doped all covering and
exposed wood with nitrate. I applied two
coats of dope, and I sanded with 320-grit
between coats on the wood.
I followed that with one coat of sanding
sealer and sanded with 320-grit, I applied
two to three coats of butyrate, sanded with
400-grit, then added color.
After masking, I sprayed on a silver
base, cream, then red. I covered the wings
with aluminum MonoKote®, and the
numbers are MonoKote® Trim Sheets.
Install servos at the rear of the wing
bay. Install prefitted pushrods, and check
for free operation.
The receiver may be fitted to the rear of
the 1⁄16 plywood slide that also carries the
flight batteries. Leave enough wire on the
receiver to allow the slide to be removed for
flight-battery replacement.
With the width and depth of the fuselage
space available, the receiver may also be
taped to the sidewall or the floor with
double-stick tape.
The slide to carry the power pack is
convenient and easy to use. The slide’s
“springiness” will absorb much of the
impact in the event of a nose-first landing,
so the battery pack will not try to wipe out
everything forward of it.
I used this method for more than 50
flights on my Electric Cub, and I am very
satisfied with it.
If the battery pack must be installed in
the fuselage on the floor, reinforce the
floor locally with 1⁄32 plywood and
Velcro™ the battery to the reinforcement.
Lay a piece of foam rubber between the
battery and former 1, so something other
than the airframe absorbs impact.
All that’s left now is finish-up work.
Gear fairings may be glued to the wire.
Rough up the wire with sandpaper and keep
the upper portion of the fairings clear of the
fuselage, so they may flex on landing.
A bead of silicone may be dropped into
the fairing-fuselage junction, to simulate the
fairing on the real Sedan.
Wheel pants were available on the Sedans,
and you can make them by laminating 3⁄8 soft
balsa to thickness and carving it to shape.
Secure the wheel pants to the gear fairing
with epoxy, or solder a mount plate to the
gear leg and screw the wheel pants to the
plate with cut-down #2 sheet-metal screws.
Balance the model as indicated on the
plans. Use the flight pack to achieve final
balance, if necessary. The prototype model
balanced satisfactorily with the flight pack,
receiver, speed control, and servos in the
positions described.
All-up weight should be less than 24
ounces for best performance. The original
weighed 21 ounces, ready to fly (with a sixcell
power pack). The model flies “on the
wing”—not on the motor power—and any
increase above the recommended weight
only adds to wing loading.
Any powered aircraft’s climb
performance is the result of the amount of
power in excess of what is required for
level flight. The higher the wing loading,
the more power is required for level flight.
Even though we have built an
essentially all-sheet model, we can still
build it light enough for good performance
if we pay attention to detail.
Many Electric models don’t fly well
because modelers build in more “strength”
than is necessary for flight loads. Our
power models are subject to engine
vibration, and have historically been
designed to tolerate crashes.
Electric models have to carry expected
flight loads, and have reasonable survivability
in an unsmooth landing. The relatively heavy
battery pack that Electric models carry around
can easily wipe out the whole interior if it
breaks loose in a hard landing.
Flying: Enough editorial! Let’s fly this
thing.
Battery packs are many and varied. I
use Radio Shack 850/1,000 mAh AA Ni-
Cds. They are more than satisfactory for
fun-flying, and they are readily available.
Charge ’em up, fasten them to the slide
tray, and install the wing.
There is no need to carry an airborne
pack with a Battery Eliminator Circuit
(BEC) receiver, and this further reduces the
weight the wing must carry.
Check controls before each flight!
This airplane launches easily by hand.
Don’t throw it; ease it into the air with a
smooth follow-through. Allow the model
to accelerate to climbing speed before
trying any turns.
The model is responsive and stable.
Loops are possible, but they require some
speed before entry, as with the full-scale
Sedan. It’s the same with rudder rolls—
accelerate, nose up, full rudder. As the model
goes inverted, feed in down-elevator to keep
the nose from falling through, then release it
as the model passes the 3⁄4 position of the roll.
Enter left and right spins from a stall,
power on or power off. As soon as the model
stalls, throttle to idle, pull full aft stick, and
apply full rudder. Hold this until you are ready
to recover. Neutralize the sticks (just let go!),
and the model will recover all by itself.
Ease the throttle back to determine the best
speed at which to fly. Shut the motor off if
thermals are present, and you will be pleasantly
surprised with the Sedan’s capabilities.
The idea of this is to have a nice,
easy, relaxed flier that looks right in the
air and is easy on the pocketbook. I think
we made it, don’t you? MA
John H. Linke
4521 Nicholas St.
Omaha NE 68132
