Great Planes GPMA0175 User Manual

P-51D MUSTANG

.40 Size

INSTRUCTION MANUAL

WARRANTY

Great Planes Model Manufacturing Co guarantees this kit to be free from defects in both material and workmanship
at the date of purchase This warranty does not cover any component parts damaged by use or modification In no case
shall Great Planes' liability exceed the original cost of the purchased kit. Further, Great Planes reserves the right
to change or modify this warranty without notice

In that Great Planes has no control over the final assembly or material used for final assembly no liability shall be
assumed nor accepted for any damage resulting from the use by the user of the final user-assembled product By the act
of using the user-assembled product, the user accepts all resulting liability

If the buyers are not prepared to accept the liability associated with the use of this product, they are advised
to return this kit immediately in new and unused condition to the place of purchase.

PO Box 788 Urbana IL 61801 [phone]

productsupport@greatplanes .com

P540P03 for GPMA0175

V1

1

Printed In USA

Entire Contents © Copyright 2001

TABLE OF CONTENTS

INTRODUCTION

Precautions
Decisions You Must Make Now ... 4
Other Items Required
Supplies and Tools Needed
Abbreviations
Types of
Get Ready to Build
Die Patterns

TAIL FEATHERS

Build the Fin and Rudder
Build the Stabilizer and Elevators .. 8

Temporarily Install the Hinges .... 9

WING ASSEMBLY

Build the Wing Panels .......... 10

Join the Wing Panels
Install Aileron Torque Rods
Sand Flat on TE

Fiberglass the Center Section ..... 16

Install Wing
Install Ailerons
Temporarily Install Wing Dowels .. 18
Install Wing Bolt Plate
Fill LG Slots
Install Landing Gear Covers
Install Retracts

FUSELAGE ASSEMBLY

Prepare Fuse Sides
Prepare the Firewall
Assemble Lower Fuselage
Drill Engine Mount
Install Pushrod Guide Tubes
Mount Wing to Fuse

Fit Fuel Tank and Fuelproofing .... 29

Assemble Aft Deck

Assemble Front Deck

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Assemble Upper Cowl

FINAL ASSEMBLY

Install Front Wing Fairing
Assemble Air Scoop Front
Install Wing Fillets
Mount Stab and Fin
Shaping and Sanding
Install Pushrods and Radio
Control Surface Throws
Install Receiver, etc.
Fit Cowl

FINISHING

Additional Fuelproofing

Balance the Airplane Laterally .... 40

Final Sanding

Covering
Glue the Hinges
Apply Decals and
Install Pilot
Glue Canopy in Place
Wing Seating
Re-install Engine & Radio
Balance
Final Hookups and Checks

PRE-FLIGHT .................. 45

Charge the Batteries
Find a Safe Place to Fly
Ground Check the Model
Range Check
Engine Safety Precautions

AMA Safety Code
FLYING

CAUTION ..................... 47

FLIGHT TRIMMING
PARTS

3-VIEW ....................... 52

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WARNING! THIS IS NOT A TOY!

THIS IS NOT A BEGINNER'S AIRPLANE!

This R/C kit and the model you will build is not a toy! It is capable of serious bodily harm and prop-

erty damage. IT IS YOUR RESPONSIBILITY AND YOURS ALONE -- to build this kit correctly,
properly install all R/C components and flying gear (engine, tank, pushrods, etc.) and to test the model and
fly it only with experienced, competent help, using common sense and in accordance with all safety stan­dards as set down in the Academy of Model Aeronautics Safety Code. It is suggested that you join the
AMA and become properly insured before you attempt to fly this model. IF YOU ARE JUST START­ING R/C MODELING, CONSULT YOUR LOCAL HOBBY SHOP OR WRITE TO THE ACADEMY
OF MODEL AERONAUTICS TO FIND AN EXPERIENCED INSTRUCTOR IN YOUR AREA.

Academy of Model Aeronautics

5151 East Memorial Drive

Muncie, IN 47302-9252 [phone]

INTRODUCTION

Congratulations! Thank you for purchasing the Great

Planes P-51D Mustang!

The Great Planes P-51D Mustang is a semi-scale (ap­proximately 1/8-scale) model of the full-size North American
P-51D. The prototype as pictured on the box cover is not a
copy of any one full-size airplane in particular. Rather, we
selected several typical trim features from several aircraft,
making a good-looking and rather "generic" trim scheme that
typifies the Mustang we all know.

Several full-size P-51 D Mustangs are shown on
the box side panel to give you an idea of the many trim
variations that have been used. If you are interested in
sport scale competition, or just want to copy a specific
full-size trim scheme, you'll be happy to know that
color photos of these and MANY other P-51D Mus­tangs are available from: Scale Model Research,
2334 Ticonderoga Way, Costa Mesa, CA 92626.

Unlike many other scale models, the Great Planes P-51D
Mustang is easy to build and fly, predictable, highly aero­batic, and has no "bad habits," making it a great sport-scale
airplane (as long as you don't get carried away with paint and
additions, making it a "lead sled")!. This model is designed
to be a great flying "sport airplane," one that you feel
comfortable with, flight after flight. It is not intended for
scale competition, but with a little extra work it should place
well in sport scale competitions at the local level.

This is not a beginner's airplane! While the P-51D is
easy to build and flies great, we must discourage you from
selecting this kit as your first R/C airplane. It is fast, highly
maneuverable, and lacks the self-recovery characteristics of
a good basic trainer such as the Great Planes PT Series
airplanes. On the other hand, if you have already learned the
basics of R/C flying and you are able to safely handle an
"aileron trainer" airplane such as the Great Planes Trainer
Series or Big Stick Series airplanes, the P-51 D is an excellent
choice.

Please inspect all parts carefully before starting to
build! If any parts are missing, broken or defective, or if
you have any questions about building or flying this
airplane, please call us at [phone] and we'll be glad
to help. If you are calling for replacement parts, please
look up the part numbers and the kit identification num­ber (stamped on the end of the carton) and have them
ready when calling.

PRECAUTIONS

1. You must build the plane according to the plans and
instructions. Do not alter or modify the model, as doing so
may result in an unsafe or unflyable model. In a few cases the
plans and instructions may differ slightly from the photos. In
those instances you should assume the plans and written
instructions are correct.

2. You must take time to build straight, true and strong.

3. You must use a proper R/C radio that is in first class
condition, the correct sized engine and correct components
(fuel tank, wheels, etc.) throughout your building process.

3

4. You must properly install all R/C and other components
so that the model operates properly on the ground and in the
air.

5. You must test the operation of the model before the first
and each successive flight to insure that all equipment is
operating, and you must make certain that the model has
remained structurally sound. Be sure to check the nylon
clevises often, and replace if they show signs of wear.

Note: We, as the kit manufacturer, can provide you with
a top quality kit and great instructions, but ultimately the
quality and flyability of your finished model depends on
how you build it; therefore, we cannot in any way
guarantee the performance of your completed model, and
no representations are expressed or implied as to the
performance or safety of your completed model.

6. You must fly the model only with the competent help of
a well experienced R/C pilot if you are not already an
experienced and knowledgeable R/C pilot at this time.

DECISIONS YOU MUST MAKE NOW

ENGINE AND MOUNT SELECTION

The recommended engine size range is as follows:

.40* - .46 cubic inch displacement 2-cycle

.60** - .70 cubic inch displacement 4-cycle
*NOTE: Performance may be marginal if a non-sch­neurle-ported .40 cu.in. 2-Cycle engine is used.
**NOTE: The O.S. Max 48 Surpass also provides
sufficient power to fly this airplane.

NOTE: If you choose to side mount a 2-Cycle engine,
we recommend using a muffler that can be almost
completely enclosed inside the cowl. The muffler used
in one of our prototypes is a Tatone #11413 Pitts Style
Muffler for .29 - .40 engines. The muffler may require
slight modification to fit your engine.

Remember: Take your time and follow directions to end
up with a well-built model that is straight and true.

Snap the two mount halves together. Slide the
mount halves apart until the engine mounting lugs
will sit flat on the beams. Adjust the mount until
the firewall centerline (or offset line) is centered
between the "tick" marks on the mount.

NOTE: If you choose to power your P-51D with a 4­cycle engine, keep in mind that the RPM of your engine
will be considerably less than that of a 2-Cycle engine;
therefore, you should select a higher pitch propeller to
keep the speed and overall performance roughly equiva­lent to that of a 2-Cycle engine. For example, a 10x6 or

10x7 prop would be used with a .40 (2-Cycle) engine; but
a 12x8,11x9 or 10x10 prop may be the best choices for
a 4-cycle engine. The 4-blade prop shown on the
prototype is a mock-up for static display purposes only.

If you mount a 2-Cycle engine inverted or upright,

a standard muffler may be used. Complete enclosure of
the engine and exhaust requires inverted installation and
a custom-made exhaust manifold.

The engine you select will determine how you build

the fuselage, so it is important that you have the engine

close at hand while building.

This kit includes the new Great Planes
Adjustable Engine mount. This mount will work on
most .40-.60 2-Cycles and .40-.70 4-cycles. Cut or
break the "spreader bar" off each mount half.
Carefully trim any extra plastic off each mount half
left by the spreader bar. The surfaces where the
spreader bars were attached need to be very
smooth to allow the mount halves to fit together.

SELECTION OF WHEELS

To save weight, we recommend using lightweight

foam rubber wheels.

2-1/2" diameter main wheels are recommended for
retracts (but 2-3/4" wheels will fit, and may be needed for
satisfactory operation on grass fields).

2-3/4" diameter main wheels arc recommended for
normal sport flying with fixed landing gear (3" wheels
may be needed for satisfactory operation on rough grass
fields).

3-1/4" scale wheels may be installed for maximum

scale realism (such as Robart UX-325 diamond-tread
scale wheels).

A 1" diameter tailwheel is recommended.

4

OTHER ITEMS REQUIRED SUPPLIES AND TOOLS NEEDED

0 Four-channel radio with 4 servos (additional channel and

retract servo required if retracts are being used).

0 Propellers (see engine instructions and above engine

notes for recommended sizes).

0 Spinner (2-3/4" diameter)
0 Fuel Tank (10 ounce)

0 5/32" Wheel Collars - 4

0 3/32" Wheel Collars - 2
0 Iron-on Covering Material
0 Fuelproof Paint* for Cowl, Canopy, Exhaust Ports &

Cannons
0 Silicone Fuel Tubing
0 Wing Seating Tape (or silicone sealer ... see instruc-

tions)
0 Latex Foam Rubber Padding (1/4" thick)

0 Dubro "E-Z Connector" (optional)
0 Plastic Pilot: Williams Bros. "Standard, 2" Scale #176"

(WWII Military Style)
0 Main Gear Retracts: (optional)

Mechanical:Dave Brown 2-Gear Main, B&D 85­degree mechanical retracts, or equivalent.
Pneumatic :Robart #606 85-degree mains, or equiva
lent (requires #188 air control kit)

*Note: Chevron "Perfect Paint" matches Super Monokote,

and is available in convenient spray cans.

0 2 oz. Thin CA Adhesive

0 2 oz. Medium or Thick CA Adhesive
0 2.5 oz. 5-Minute Epoxy
0 2.5 oz. 30-Minute Epoxy
0 Hand or Electric Drill
0 Drill Bits: 1/16", 5/64", 3/32", 7/64", 1/8", 9/64", 5/32",

3/16", 13/64". 7/32", and 1/4"
0 Sealing Iron
0 Heat Gun
0 Hobby Saw (Xacto Razor Saw)
0 Xacto Knife, #11 Blades
0 Pliers
0 Screw Drivers
0 T-Pins
0 Straightedge
0 Masking Tape (Required for construction)
0 Sandpaper (coarse, medium, fine grit)*
0 T-Bar Sanding Block (or similar)

0 Waxed Paper
0 Lightweight Balsa Filler
0 1/4-20 Tap, Tap Wrench
0 Vaseline Petroleum Jelly
0 Isopropyi Rubbing Alcohol (70%)
0 3M "77" Spray Adhesive (optional)
0 Dremel Moto Tool or similar (optional)

*NOTE: On our workbench, we have four 11" T-Bar

sanders, equipped with #50, #80, #100 and # 150-grit sandpa­per. This setup is all that is required for almost any sanding
task. We also keep some #320-grit wet-or-dry sandpaper
handy for finish sanding before covering.

COMMON ABBREVIATIONS USED IN
THIS BOOK AND ON THE PLANS:

Elev = Elevator
Fuse = Fuselage
LE = Leading Edge (front)
LG = Landing Gear
Lt = Left

Ply = Plywood

Rt = Right

Stab = Stabilizer
TE = Trailing Edge (rear)
" =Inches

TYPES OF WOOD

BASSWOOD

GET READY TO BUILD

D 1. Unroll the plan sheets. Re-roll the plans inside out
to make them lie flat.

D 2. Remove all parts from the box. As you do, figure out

the name of each pan by comparing it with the plans and the

parts list at the back of this book. Using a felt tip pen, write

the part name or size on each piece to avoid confusion later.

Use the die-cut patterns shown on page 6 to identify the die­cut parts and mark them before punching out. Save all scraps.

If any of the die-cut parts are difficult to punch out, do not
force them! Instead, first cut around the pans with an Xacto

knife. After punching out the die-cut pans, use your T-Bar or

sanding block to lightly sand the edges to remove any die-

cutting irregularities.

D 3. As you identify and mark the parts, separate them

into groups, such as fuse (fuselage), wing. Fin and stab
(stabilizer), and hardware.

5

DIE PATTERNS

6

TAIL FEATHERS

BUILD THE FIN AND RUDDER

To build the fin and rudder you'll need the following:

1/4" shaped balsa fin front
1/4" shaped balsa fin rear
1/4" shaped balsa rudder rear
1/4" x 1-1/4" x 9-1/2" balsa sheet
1/4" x 1/4" x 30" balsa stick

D 1. Tape the fuselage plan down to your flat work

surface. Tape a piece of waxed paper over the fin and rudder

portion of the plan.

D 7. Carefully draw a centerline all around the edges of
the fin and rudder (this will help to maintain symmetry when
sanding).

D 2. Working on a flat surface covered with waxed paper,
glue the fin front to the fin rear.

D 3. Using a T-bar or sanding block, sand both sides of
the fin smooth, then sand the outline of the fin to match the
plan.

D 4. Using the plan as a guide, glue the 1/4" x 1-1/4" x
9-1/2" balsa rudder front to the shaped balsa rudder rear,
lining up the top edges.

D 5. Cut a 2-1/4" length of 1/4" x 1/4" balsa, and glue it
to the top of the rudder.

D 6. Trim the edges of the rudder to match the plan, then
use your T-bar with medium grit sandpaper to sand both sides
of the rudder smooth.

D 8. Using a sanding block and coarse (50 or 80-grit)
sandpaper, sand both sides of the rudder to a taper as shown
on the plans. The trailing edge should end up approximately
3/32" wide and have a rounded shape. (Do not sand to a sharp
edge). Sand the bottom edge to a rounded shape. Sand the
leading edge to a "V-shape" as shown on the plan. Sand the
top and front edges of the fin to a rounded shape.

D 9. Check the plans and mark the location of the tailgear*
on the rudder. Drill a 7/64" hole in the rudder (the hole is
drilled slightly oversize to allow for positioning, and to create
a hard epoxy "sleeve" around the wire). Then groove the

rudder leading edge to accept the tailgear wire. (See the

photo at step 5 on page 18).

7

HINT: Using an Xacto knife, sharpen the inside of one

end of a 1/8" diameter brass tube, and use it to cut the groove
in the leading edge of the rudder.

*NOTE: The tailwheel location and installation shown
on the plan is designed for easy installation and durability.
and for the best possible ground handling characteristics.
However, if you are building your P-51 for sport scale
competition, you may want to install a tailgear (fixed or
retractable) in the "scale location" shown on the plan.
These instructions do not cover such a modification, but
the location is shown for your convenience.

D 3. Check the shaped balsa elevators and sand if neces-

sary to match the plan.

D 4. Draw a centerline all around the edges of the stab
and elevators.

D 5. Sand both sides of the elevators to a taper as shown
on the plans. The trailing edge should end up approximately
3/32" wide and have a rounded shape (do not sand to a sharp
edge). Sand the leading edge to a "V-shape" as shown on the
plan.

D 6. Temporarily tape the elevators to the stab.

BUILD THE STABILIZER AND
ELEVATORS

To build the stab and elevators you'll need the following:

1/4" shaped balsa stab front
1/4" shaped balsa stab rear
1/4" shaped balsa elevators
1/8" bent wire elevator joiner

D 1. Glue the stab front to the stab rear. Sand the
outline of the stab to match the plan, then sand both sides of
the stab smooth.

D 7. Lay the 1/8" wire elevator joiner in place on the
elevators and mark its outline using a fine point felt-tip pen.

D 8. Accurately drill holes in the elevators for the 1/8"
wire joiner. Begin by drilling a 1/16" or 5/64" pilot hole, then
drill the final hole to a depth of 7/8" with a 9/64" drill bit.
(The hole is drilled slightly oversize to allow for positioning,
and to create a hard epoxy "sleeve" around the wire).

D 9. Using an Xacto knife, sharpen the inside of one end
of a 1/8" diameter brass tube and use it to cut grooves in the
leading edge of the elevators to accept the joiner wire.

D 10. Roughen the joiner wire with coarse sandpaper, then
clean the wire thoroughly with alcohol to remove any oily
residue.

D 2. Sand the leading edge and ends to a rounded shape.

(Leave the center portion of the LE square).

D 11. Trial fit the joiner wire into the elevators, then glue
it in using 5-minute or 30-minute epoxy. Work plenty of

8

epoxy into the holes with a toothpick, then lay the elevator
leading edges along a straightedge to insure perfect align­ment.

TEMPORARILY INSTALL HINGES

(Do not glue)

NOTE: On an experimental basis, we have included

"laminated hinges" in this kit, and the following
instructions are written for this type of hinge. Our R&D
department has thoroughly tested these hinges and found
them to be easy to install and sufficiently strong and
durable for this type of airplane. However, as the kit
builder you arc reminded that you are ultimately responsible

for the structural integrity of your aircraft. If you are not
confident using this type of hinge, please feel free to
substitute your favorite hinge.

D 1. Lay the rudder and elevators on the plan and mark

the hinge locations. Place the rudder against the fin TE and
transfer the marks over to the fin. Place the elevators against
the stab TE and transfer the marks over to the stab.

C. Trial fit the hinge into the slot. If the hinge is
difficult to push in, re-insert the knife and move it back
and forth in the slot a few times to enlarge the slot.

CAUTION!!!: You must use extreme care when
cutting hinge slots with an Xacto knife, to avoid
cutting yourself! If the balsa part breaks while you
are pushing on the knife, the blade could go into
your hand before you know it! A good precaution is
to wear leather gloves while performing the follow­ing steps.

D 2. Cut the hinge slots on the accurate centerlines
which you previously drew, using an Xacto knife. The
recommended procedure for cutting hinge slots with an Xacto
knife is given below.

A. Begin by carefully cutting a very shallow slit in the
trailing edge at the hinge location. This first cut is to
establish your cut in the right place, so concentrate on
staying on the centerline and don't cut too deep!

B. Make three or four more cuts in the same line, going
slightly deeper each time. As you make these addi­tional cuts, work on going straight into the wood. Con­tinue this process while ''wiggling" the knife handle
back and forth until the blade has reached the proper
depth for the hinge.

D 3. Insert the hinges into the slots and trial fit the rudder
and elevators in place on the fin and stab. Do not glue the
hinges until you are instructed to do so later in this book.
Hinge gluing instructions are included later.

WING

NOTE: The following instructions explain how to build
the wing on a flat surface, directly on the plans. An
alternate method is to use a Great Planes Wing Jig
(available from your local hobby dealer). Many expert
modelers prefer to use a wing jig for high performance
airplanes, as it helps to insure a straight, warp-free wing,
especially if you do not have a workbench or building
board that is perfectly flat. If you choose to use the Wing
Jig, please read the instructions that are included with the

jig before beginning.

9

BUILD THE WING PANELS

NOTE: It will be helpful to build the wing on a piece of

"Celotex"* or other semi-soft (and flat) surface, into

which you may easily stick pins to firmly hold down the

wing parts while building, to avoid warps. *Available

from lumber companies and home centers.

D 1. Tape the plan to your flat work surface, and cover

the wing drawing with waxed paper (so you won't glue the
wing to the plan!). NOTE: If your work space is limited, you
may cut the left and right wing half drawings apart.

D 2. The shaped and notched wing leading edges (LE)

and trailing edges (TE) are fastened together by thin strips of

balsa. Separate them by folding until the balsa breaks, or by
cutting. Sand away the excess balsa that remains along the
edges after breaking them apart, using a T-bar with 100-grit

sandpaper.
D 3. Before using the 1/4" x 3/8" x 28" hard balsa spars,

examine them carefully for possible imperfections. Look for

knots, soft spots, diagonal grain and any other imperfections.

If possible, position each spar so the imperfections (if any) are

on the outer half of the wing panel (toward the tip), where they

will be least affected by high stress. If the spars are warped

slightly, try to "balance them out" by installing the warped

spars in opposite directions (see sketch). NOTICE: If you

feel that any of the wing parts are unusable due to severe

warps or other defects, give us a call and we'll replace the
parts.

TWO WARPED SPARS INSTALLED

THIS WAY WILL RESULT IN A

STRAIGHT WINO

NOTE: If you will be installing a retractable landing
gear, disregard Step 6.

D 6. Note that the wing plan shows the location of the
main landing gear blocks. Note also that Ribs W-3 and W-4
have partial cutouts for the grooved landing gear block. If
you are building your plane with a fixed (not retractable)
landing gear, finish cutting out the notches in these ribs. (If
you will be installing retracts, do not cut out these notches).

D 7. Glue the die-cut 1/16" ply notched landing gear
doublers to ribs W-3 and W-4 (for fixed gear only). If
installing retracts, you will later glue the other set of 1/16" ply
"nose rib doublers" to ribs W-4 and W-5. Be sure to glue them
to the correct side of the ribs, as shown on the plan (make a
right and a left set). Sand the doublers even with the edge of
the ribs.

D 8. Prepare the leading edge sheeting by trimming the
3/32" x 2-7/8" x 28" balsa sheets as shown in the following
sketch.

TWO WARPED SPARS INSTALLED

THIS WAY WILL RESULT IN A

WARPED WING

D 4. Find the four 1/8" x 3/8" x 13" hard balsa spar

doublers. Sand one end of each spar doubler to a taper as

shown in the "Wing Spar Detail" on the plan. Glue the spar

doublers to the spars, and sand off any excess glue.

D 5. Carefully punch out all the die-cut 3/32" balsa wing

ribs. Sand the edges slightly to remove any die-cutting

irregularities.

NOTE: Follow steps 9 through 36 to build the
RIGHT wing panel, then repeat these steps to
build the LEFT wing panel.

D D 9. Pin one of the spars to the plan with the spar
doubler up and toward the root. NOTE: The spars are cut

10

slightly too long. Center the spar on the plan so an equal

amount protrudes on both ends.
D D 10. Place the ribs on the spar in their approximate

position, but do not glue. NOTE: Make sure ribs W-3 and
W-4 are installed with the LG notches down, and W-l is
installed with the servo opening pointing up.

D D 11. Examine the shaped, notched balsa trailing edges.

Notice that the notches at one and of each TE are only 1-7/8"
apart. These are the notches for W-1 and W-2. Also notice
that all notches in the TE are vertical; however, rib W-l will
be installed at a slight angle using the Dihedral Gauge.
Therefore, you should now modify the notch for W-l by

cutting it to the angle of the rib. You may determine the
approximate angle of the cut by holding the Dihedral Gauge
(DG) against the TE as shown above.

D D 13. Insert the rear ends of the ribs into the notches in
the TE, then block up the TE with the 1/4" balsa TE Jig
supplied. NOTE: The narrow end of the TE jig is at rib
W-ll. Pin the jig to the building surface.

D D 14. Pin the TE to the TE Jig, making sure the ribs line

up with the plan.

D D 15. Glue ribs W-2 through W-ll to the TE. (Apply

glue sparingly, to avoid gluing the TE to the TE Jig).

D D 16. Bend (break) the leading edge at the notches
which you previously cut, then insert the front ends of the ribs

into the notches in the LE. NOTE: Position the LE as shown

here

CENTER L.E. VERTICALLY

ON FRONT OF RIBS

D D 12. Examine the shaped, notched balsa leading edges.

Notice that one end does not have notches, this is the root end.
Use a razor saw to cut notches in the leading edge as shown

in the "Leading Edge Detail" on the wing plan. These
notches will aid in "breaking" the leading edge in the correct
locations.

D D 17. Make sure the ribs are fully down on the plan and
ribs 5 -11 are inserted into the LE notches. Glue ribs 2-11
to the LE and bottom spar. Angle rib W-l slightly using the
dihedral gauge (DG). Glue W-l to the TE, LE and bottom
spar. NOTE: Thin CA glue may be used in tight-fitting

joints, but to insure strong joints we recommend that you

follow up by also applying medium or thick CA to all joints.

11

D D 18. Glue the top spar in place (with the spar doubler

facing down), making sure you do not change the angle of
W-l.

IMPORTANT: In the following steps you'll find it

necessary to remove some of the pins holding the wing
down to your building board. As you do, take other steps

as necessary to continue holding the wing down. such as

by applying weight to the top of the wing, or by relocating

the pins.

D D 21. Securely glue the die-cut 1/8" ply dowel plates

into the wing. The small dowel plate glues to the back edge
of the leading edge and to ribs W-l and W-2. The large dowel
plate is located 1" behind the small dowel plate, and is glued

to ribs W-l and W-2. NOTE: The photo shows only the small
dowel plate.

D D 19. Glue the pre-cut 3/32" balsa vertical grain shear
webs to the rear edge of the spars in all rib bays except

between ribs W-l and W-2. Also install webs on the front
of the spars between ribs 1 and 4. NOTE: You may wish to
trial fit, mark, and trim each web before gluing in. NOTE:
The webs must be securely glued to the spars, but it is not
necessary to glue the webs to the ribs.

NOTE: In the next steps, maintain straightness by
keeping the wing down on the flat surface and on the
TF Jig.

D D 20. You will now make a "pocket" for the 1/16" ply
dihedral brace by installing a 1/8" die-cut balsa (horizontal
grain) web 1/16" behind the spars. The die-cut web is very
close to the correct size, but sand it as necessary for a good fit
between W-l and W-2. Using a scrap of 1/16" ply as a
temporary spacer, glue the 1/8" web to W-l and W-2.

D D 22. Lightly sand the tops of the ribs to blend with the
notched trailing edge; then glue one of the 3/32" x 1-3/8" x
28" balsa trailing edge sheets in place. NOTE: The edge of
the TE sheet may not be exactly straight, but just position the
sheet so it slightly overlaps the TE, and any overlap can be
sanded off later.

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D D 23. Before applying the leading edge sheeting in the
next step, use your T-bar to lightly sand off the edges of the
shear webs and smoothly blend the ribs to the spar.

D D 24. Prepare the 3/32" balsa leading edge sheeting by

sanding the front edge to a slight bevel so it will fit snugly
against the back of the leading edge (this is only done in the
area from rib W-4 to the tip).

NOTE: It will be helpful to have the following items
handy for the next step... thin CA, thick CA, a wet cloth
and twelve 8-inch strips of masking tape. Read through
the following step and go through a "dry run" before
actually gluing.

bending over the ribs. Any small gaps and irregularities may
later be sanded or filled with balsa filler.

D D 25. Apply thick CA glue to the top edge of the ribs and

to the front half of the spar. Working quickly, position the
leading edge sheeting at the rear edge of the notched LE so
there is an equal amount protruding on both ends of the wing.
Using thin CA, glue the front (beveled) edge of the leading
edge sheeting to the back edge of the leading edge. Now wet
the top surface of the sheeting so it will bend easier, then
immediately bend the sheeting down onto the ribs and spar.
Hold the sheeting down with long strips of masking tape until

the glue has set.

D D 26. Using four of the 3/32" x 3" x 7-7/8" balsa sheets,

cut pieces to complete the LE sheeting from W-1 to W-4, and
glue in place. You'll have to wet this sheeting to permit

D D 27. Using the 3/32" x 3" x 7-7/8" balsa sheets and the

scraps which you trimmed from the LE sheeting, glue the top

center section sheeting in place as shown on the plan.

NOTE: If you are installing retracts, disregard steps
28 through 31.

D D 28. Remove the wing from the building board and

trial fit the long grooved hardwood LG block into the notches

in ribs W-3 and W-4 (see the landing gear detail drawing on

the wing plan for proper positioning). File the notches if nec­essary for a good fit. Now use epoxy to securely glue the
block in place.

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D D 29. Epoxy the 7/16" x 5/8" x 7/8" hardwood block to

the LG block and to the 1/16" ply doubler on rib W-3, as
shown on the plan and in the photo, then epoxy the small
hardwood gusset to the other end of the LG block and to the
1/16" ply doubler on rib W-4.

D D 30. Drill a 5/32" hole down through the grooved LG

block and the 7/8" block. Line up the drill so you are drilling
straight down through the middle of the 7/8" block.

D D 31. Trial fit the 5/32" diameter main landing gear

wire into the landing gear block at this time. Cut or file the
groove and hole in the landing gear block as necessary for a
good fit.

C. Gluo in 1/4" ply retract mounting; rails using

epoxy.

D. Trim the rails as necessary.

D D 32. Using a razor saw and a sanding block, carefully

cut off and sand all excess sheeting, spars, LE and TE even
with W-1 and W-11.

NOTE: If you will be installing retracts, now is the

time to install the 1/4" x 5/8" x 2-5/8" ply retract
mounting rails with epoxy on the bottom of the wing
between the 1/16" ply doublers on ribs W-4 and W-5, as

shown on the plan. Add 1/4" balsa triangle under the

1/4" ply rails. Installing retracts requires careful

planning and a lot of trial Fitting, customizing the

installation as necessary to accommodate your retracts;

therefore, you should take the time now to plan out your

installation. Here are some typical tasks you must

perform when installing retracts:

NOTE: All photos in this book show installation of the

Dave Brown mechanical retracts.

A. Glue in the 1/16" ply nose rib doublers to reinforce

ribs W-4 and W-5 where retracts are to be installed.

B. Trial fit the retract unit to determine the mounting

location and angles. Cut away the ribs as necessary for

clearance.

E. Install pushrod and guide tube just under the top

sheeting.

F. Fabricate wheel well from 1/16** balsa or styro-

foam cup.

G. Install retract unit and check operation.

H. Sheet bottom of wing, taking note where sheeting

will be cut away for retract.
D D 33. With the wing upside down, again use the TE jig

to support the TE. Then install the bottom TE sheeting, LE

sheeting* and Center Section sheeting, cutting and fitting the

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sheeting around the LG block as necessary. IMPORTANT
NOTE: To insure a straight wing, you must pin or weight
the TE securely down on the TE jig while the bottom
sheeting is glued in place!

*As you apply the bottom LE sheeting, remember to
mark the sheeting in the exact areas of the retract mechanism,
LG wire, and wheel well locations, so you can easily find and

trim the sheeting from these areas later.

(Retracts): Trim away the sheeting in the area of the

retract and wheel well.

NOTE ON RETRACTS: Additional instructions and

photos covering installation of retracts will be found at
the end of the Wing section, on page 20.

D D 34. From the 3/32" x 1/4" x 30" balsa sticks, cut and
glue cap strips to all exposed ribs, top and bottom. HINT:
For easier positioning of the cap strips, first mark the location
of each rib on the LE and TE sheeting.

D D 35. Trim the sheeting flush with ribs W-l and W-11
and sand the entire wing panel smooth. Sand the leading edge

to smoothly blend with the LE sheeting (see note below).

D 37. Now go back and repeat Steps 9 through 36 to build
the left wing panel.

JOIN THE WING PANELS
NOTE: Read steps 1 through 4, then make a "dry run,"

practicing these steps before actually proceeding.

D 1. Lay a piece of waxed paper down and place the two

wing panels, right side up, so that the W-l ribs are together.
Using wood scraps, make two blocks similar to that shown in
the photo, and use them to block up both wing tips 1-5/8 inch.
Sand the wing panels at the center so they will fit together
without a gap.

IMPORTANT: The shape of the leading edge
will affect the way this airplane performs snap rolls
and spins. A blunt, rounded leading edge will
"soften" the stall, making the plane very docile
when flying slowly, enabling it to flare nose-high
for very slow landings; however, this may cause
the plane to be a little sluggish when trying to enter

a snap roll or spin. A sharper leading edge will help
the plane enter snap roll and spin maneuvers more
crisply, while sacrificing only a little of the low
speed stability. The leading edge has been
approximately pre-shaped, but we recommend
that you cut out the Leading Edge Template, and
use it as a guide when sanding the leading edge to
final shape. To avoid tip stalls, make sure the

leading edges of both wing panels have the same
shape.

D 2. Trial fit the die-cut 1/16" ply dihedral brace to

make sure it will readily slide into place.

NOTE: 30-minute epoxy is strongly recommended
for the wing joining process.

D 3. Mix up a batch of 30-minute epoxy and push some
into the dihedral brace slots. Smear epoxy on the spar ends,
and on both sides of the 1/16" ply dihedral brace. Slide the
dihedral brace in place, push the wing panels together and
immediately proceed to the next step.

D D 36. Mark and cut out a 1/16" slot in W-l just behind

the spars, for the dihedral brace.

D 4. With the wing tips blocked up 1-5/8 inch, carefully
align the LE and TE of both wing panels at the center and,

15

while holding them in correct alignment, apply thin CA glue
to "lock" the panels together. Do not apply CA glue to any
area that is already coated with epoxy. Allow the epoxy to
fully harden before disturbing the wing.

D 5. Sand the wing joint smooth all around.

INSTALL AILERON TORQUE RODS

D 1. Roughen the short end of the aileron torque rods

with 100-grit sandpaper, and file the same end to a wedge
shape,

File end to
wedge shape

of petroleum jelly to the ends of the plastic tubes (to help
prevent glue from getting inside and locking up the torque
rods).

D 7. Use 5-minute epoxy or thick CA to glue the plastic
bearing tubes into the grooves in the center TE pieces. Wipe
off any excess glue and allow it to harden.

D 8. Trial fit the trailing edge / torque rod assemblies

onto the wing trailing edge. Sand the center trailing edge
pieces slightly where they join, for a good fit. Glue these
pieces in place with epoxy. HINT: Use masking tape to hold
these pieces to the wing TE, to aid in correct positioning.

D 2. Roughen the surface of the plastic bearing tubes
with 100-grit sandpaper.

D 3. Clean the torque rods and bearing tubes with alco-

hol.

D 4. Find the two grooved, tapered balsa center trailing

edge pieces. Lay them on the plan, mark and cut them off to
match the plan for length and angle at the centerline.

D 5. Trial fit the torque rods into the center TE pieces.

Determine from the plan where to cut the clearance notches,
which will permit the torque rod horns to travel freely. Also
cut small clearance notches in the wing TE. Note: The
torque rod horns must exit the TOP of the wing!

D 6. Slide the plastic bearings toward the threaded end of

the torque rods, then use a toothpick to apply a small amount

SAND "FLAT" ON TE

D 1. Study the wing plan near the wing centerline. Note
that the center portion of the TE must be sanded flat.

D 2. Sand approximately 1/4" into the TE at the center-

line. (The flat will end up approximately 3-1/4" wide at the
TE).

FIBERGLASS THE CENTER SECTION

NOTE: Because of the high stresses in the center of
this wing, fiberglass reinforcement is REQUIRED.
Please do not omit this important section!

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