Great Planes GPMA0160 User Manual
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 userassembled product, the user accepts all resulting liability.
If the buyer is not prepared to accept the liability associated
with the use of this product, the buyer is advised to return
this kit immediately in new and unused condition to the place
of purchase.
To make a w arranty claim send the def ectiv e part or item to Hobby
Services at the address below:
Hobby Services
3002 N. Apollo Dr. Suite 1
Champaign, IL 61822
USA
Include a letter stating your name, return shipping address, as
much contact information as possible (daytime telephone number,
fax number, e-mail address), a detailed description of the problem
and a photocopy of the purchase receipt. Upon receipt of the
package the problem will be evaluated as quickly as possible.
READ THROUGH THIS MANUAL BEFORE STARTING
CONSTRUCTION. IT CONT AINS IMPOR TANT
INSTRUCTIONS
AND WARNINGS CONCERNING THE ASSEMBLY AND
USE OF THIS MODEL.
CUB4P03 for GPMA0160 V3.0 Printed in USA Entire Contents © Copyright 2003
Champaign, IL
(217) 398-8970, Ext. 5
airsupport@greatplanes.com
INSTRUCTION MANUAL
Wingspan (Standard): 76.5 in [1,945mm]
Wingspan (Clipped): 61.5 in [1,560mm]
Wing Area (Standard): 820 sq in [58.9dm
2
]
Wing Area (Clipped): 653 sq in [42.1dm
2
]
Weight: 6.5-7.5 lbs [2950-300g]
Wing Loading: 18-21 oz/sq ft [55-64g/dm
2
]
Length: 49 in [1,245mm]
Radio: 4-channel transmitter with 4 standard servos
Engine: .40-.61 cu. in. [6.5-10cc] two-stroke
.48-.80 cu. in. [8-13cc] four-stroke
.40 SIZE!
WARRANTY
MADE IN
USA
INTRODUCTION................................................................2
Precautions..................................................................3
DECISIONS YOU MUST MAKE ........................................3
Engine Selection..........................................................3
Wing Configuration ......................................................4
Muffler Selection..........................................................4
REQUIRED ITEMS ............................................................4
Required Accessories..................................................4
Adhesives & Building Supplies....................................4
Covering Tools .............................................................4
Optional Supplies & Tools............................................4
IMPORTANT BUILDING NOTES.......................................5
COMMON ABBREVIATIONS............................................5
TYPES OF WOOD.............................................................6
GET READY TO BUILD.....................................................6
DIE-CUT PATTERNS .........................................................6
TAIL FEATHERS ................................................................8
Build the Rudder..........................................................8
Build the Fin .................................................................9
Build the Stabilizer.......................................................9
Build the Elevators .....................................................10
Cut the Hinge Slots....................................................11
WING ASSEMBLY...........................................................11
Build the Wing Panels................................................11
Joining the Wing Panels ............................................15
Install the Aileron Linkage .........................................17
Install LE and TE Sheeting........................................18
Install Center Sheeting ..............................................20
Build the Ailerons .......................................................21
Install Ailerons ...........................................................22
FUSELAGE ASSEMBLY .................................................23
Prepare Fuse Parts....................................................23
Assemble Fuselage...................................................25
Install Engine Mount and Fuel Tank ..........................28
Final Fuselage Assembly...........................................29
Mount Stabilizer and Fin............................................30
Install Main Landing Gear..........................................32
Mount the Wing to the Fuse......................................33
Install Servos, Horns, and Pushrods.........................34
Control Throws...........................................................35
FINAL ASSEMBLY ..........................................................35
Install Wing Struts (Optional).....................................35
Install Receiver, Switch, and Battery.........................36
Install Cowl.................................................................37
Additional Fuelproofing..............................................38
Balance the Airplane Laterally...................................38
Final Sanding.............................................................38
Covering.....................................................................38
Apply Decals and Trim...............................................39
Glue the Hinges.........................................................39
Build the Cockpit Floor (Optional)..............................39
Painting the Pilot (Optional).......................................40
Building the Seats (Optional).....................................40
Build the Landing Gear Suspension (Optional).........40
Build the Dummy Engines .........................................41
Other Scale Details ....................................................42
Install the Windshield .................................................42
Install the Side Windows............................................43
Balance Your Model ...................................................43
Final Hookups and Checks........................................43
PREFLIGHT.....................................................................44
Charge the Batteries ..................................................44
Find a Safe Place to Fly............................................44
Ground Check the Model...........................................44
Range Check Your Radio...........................................44
Engine Safety Precautions ........................................44
AMA SAFETY CODE ......................................................45
FLYING.............................................................................45
2-VIEW DRAWING...........................................Back Cover
Thank you for purchasing the Great Planes Piper J-3 Cub!
This J-3 Cub kit is a 1/5.5 (18%) scale model of a full-size J-3
Cub and retains the real plane’s great flying characteristics.
You will find the J-3 Cub easy to build and fly, very
predictable and fairly aerobatic, yet it has no bad habits.
Although the model is sufficiently close to scale that it can
place well in sport-scale competition, traditional Great
Planes interlocking construction makes it simple to build a
great-looking and straight airplane that is sturdy enough to
take along every time you go to the flying field.
If you have chosen this kit as your first R/C model, it is
important that you find an experienced modeler to help you
throughout the building and flying of this plane. He should
thoroughly check the plane over bef ore flying it and help y ou
with the first flights.The J-3 Cub is a big airplane 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 a “trainer”airplane, the J-
3 Cub is an excellent choice.
Scale Model Research has photo sets and drawings of full
scale Piper Cubs available. These can help provide good
documentation for scale detailing and contests. Their
address is 3114 Yukon Avenue , Costa Mesa, CA 92626 and
their phone number is (714) 979-8058.
For the latest technical updates or manual corrections to the
Piper J-3 Cub .40, visit the web site listed below and select
the Great Planes Piper J-3 Cub .40.If there is new technical
information or changes to this kit a “tech notice” box will
appear in the upper left corner of the page.
http://www.greatplanes.com/airplanes/index.html
INTRODUCTION
TABLE OF CONTENTS
2
1.Your Piper J-3 Cub .40 should not be considered a toy , b ut
rather a sophisticated, working model that functions very
much like a full-size airplane. Because of its performance
capabilities, the Piper J-3 Cub .40, if not assembled and
operated correctly, could possibly cause injury to yourself or
spectators and damage to property.
2. You must assemble the model according to the
instructions. Do not alter or modify the model, as doing
so may result in an unsafe or unflyable model. In a few
cases the instructions may differ slightly from the photos.In
those instances the written instructions should be
considered as correct.
3.You must take time to build straight, true and strong.
4. You must use an R/C radio system that is in first-class
condition, and a correctly sized engine and components
(fuel tank, wheels, etc.) throughout the building process.
5. You must correctly install all R/C and other components
so that the model operates correctly on the ground and in
the air.
6.You must check the operation of the model before every
flight to insure that all equipment is operating and that the
model has remained structurally sound. Be sure to check
clevises or other connectors often and replace them if they
show any signs of wear or fatigue.
7. If you are not already an experienced R/C pilot, you
should fly the model only with the help of a competent,
experienced R/C pilot.
8.While this kit has been flight tested to exceed normal use,
if the plane will be used for extremely high stress flying,
such as racing, the modeler is responsible for taking steps
to reinforce the high stress points.
Remember:T ake your time and f ollo w the instructions to
end up with a well-built model that is straight and true.
Before starting to build, compare the parts in this kit
with the Parts List, and note any missing parts. Also
inspect all parts to make sure they are of acceptable
quality. If any parts are missing, broken or defective, or
if you have any questions about building or flying this
airplane, please contact Great Planes at the address or
telephone number below. If you are contacting us for
replacement parts, please be sure to provide the full kit
name (Piper J-3 Cub .40) and the part numbers as listed
in the Parts List.
Great Planes Product Support:
3002 N Apollo Drive, Suite 1
Champaign, IL 61822
Telephone: (217) 398-8970
Fax:(217) 398-7721
E-mail:
productsupport@greatplanes.com
You can also check our web site at
www.greatplanes.com
for the latest Piper J-3 Cub .40 updates.
If you have not flown this type of model before, we
recommend that you get the assistance of an experienced
pilot in your R/C club for your first flights. If you’re not a
member of a club, your local hobby shop has information
about clubs in your area whose membership includes
experienced pilots.
In addition to joining an R/C club, we strongly recommend y ou
join the AMA (Academy of Model Aeronautics). AMA
membership is required to fly at AMA sanctioned clubs.There
are over 2,500 AMA chartered clubs across the country.
Among other benefits, the AMA provides insurance to its
members who fly at sanctioned sites and events .Additionally,
training programs and instructors are available at AMA club
sites to help you get started the right way. Contact the AMA at
the address or toll-free phone number below:
The engine you select will determine where the throttle
pushrod is routed and also how the cowl is cut out, so it
is important that you have the engine close at hand
while building.
The recommended engine size range is as follows:
.40 - .61 cubic inch displacement 2-cycle
.48 - .80 cubic inch displacement 4-cycle
Engine Selection
DECISIONS YOU MUST MAKE
Academy of Model Aeronautics
5151 East Memorial Drive
Muncie, IN 47302
Tele: (800) 435-9262
Fax (765) 741-0057
Or via the Internet at:
http://www.modelaircraft.org
We, as the kit manufacturer, provide you with a top
quality, thoroughly tested kit and 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.
PRO TECT YOUR MODEL,YOURSELF
& OTHERS...FOLLOW THESE
IMPORTANT SAFETY PRECAUTIONS
3
For the best scale effect, an OS .48 Surpass 4-cycle is
ideal. For maximum aerobatics, an OS .70 Surpass 4-cycle
is all the power you will need.
This kit includes a Great Planes EM4070 engine mount
that fits most .40 - .60 2-cycle engines and most 40 - .70
4-cycle engines.
This kit includes everything you need to build either the
standard or the clipped wing for your Cub. Both versions fly
extremely well and are equally easy to construct. The
standard wing makes the Cub a real “Floater” giving you
plenty of time to think about your maneuvers. The clipped
wing allows things to happen a bit quicker.Snaps, rolls and
spins can be performed faster and more precisely. Either
way, the model flies much like the real plane.
If you install a 2-cycle engine, we recommend using a
muffler that can be partially enclosed inside the cowl. The
muffler shown in the instruction book photos is a Slimline
#3217 Pitts Style Muffler for OS MAX .61SF and .60FP
engines. If you use a OS .40SF or .46SF use a Slimline
#3218 Pitts Style Muffler or similar. Most standard mufflers
will require an extension to clear the fuselage sides.
❏ Engine, prop nut, and suitable propellers
❏ 4-Channel radio with 4 standard ser vos
❏ 1/4" [6mm] R/C foam rubber (HCAQ1000)
❏ 10 or 12 oz. Fuel tank (GPMQ4104 or GPMQ4105)
❏ 3' [900mm] Standard silicone fuel tubing (GPMQ4131)
❏ 3-3/8" Main wheels, Cub Style (GPMQ4230)
❏ 1-1/4" Tail wheel (GPMQ4242)
❏ (4) 3/16" Wheel Collars (GPMQ4308)
❏ (2) 3/32" Wheel Collars (GPMQ4302)
❏ (2) Rolls Top Flite
®
MonoKote®covering (TOPQ0220,
Cub Yellow)
In addition to common household tools (screwdrivers, drill,
etc.), this is the “short list” of the most important items
required to build the Piper J-3 Cub .40.
We recommend
Great Planes Pro™CA and Epoxy glue.
❏ 2 oz. Thin Pro CA (GPMR6003)
❏ 2 oz. Medium Pro CA+ (GPMR6009)
❏ Pro 6-minute epoxy (GPMR6045)
❏ HobbyLite
™
balsa-colored balsa filler (HCAR3401)
❏ Plan Protector
™
(GPMR6167) or wax paper
❏ Dr ill bits: 1/16" [1.6mm], 5/64" [2.0mm], 3/32" [2.4mm],
7/64" [2.8mm], 1/8" [3.2mm], 9/64" [3.6mm],
11/64" [4.4mm], 3/16" [4.8mm], 1/4" [6.4mm]
❏ Small metal file
❏ Stick-on segmented lead weights (GPMQ4485)
❏ Silver solder w/flux (GPMR8070)
❏ #1 Hobby knife (HCAR0105)
❏ #11 Blades (100-pack, HCAR0311)
❏ Single-edge razor blades (10-pack, HCAR0212)
❏ Small T-pins (100, HCAR5100)
❏ Medium T-pins (100, HCAR5150)
❏ Sanding tools and sandpaper assor tment (see
Expert
Tip–Easy-Touch™Bar Sander
section on page 5)
❏ Top Flite
®
MonoKote®sealing iron (TOPR2100)
❏ Top Flite MonoKote heat gun (TOPR2000)
Here is a list of optional tools mentioned in the manual that
will help you build the Piper J-3 Cub .40.
❏ Pro Aliphatic resin (2 oz. [60g], GPMR6160)
❏ 2 oz. [57g] Spray CA activator (GPMR6035)
❏ CA applicator tips (HCAR3780)
❏ CA debonder (GPMR6039)
❏ Epoxy brushes (6, GPMR8060)
❏ Mixing sticks (50, GPMR8055)
❏ Mixing cups (GPMR8056)
❏ Razor plane (MASR1510)
❏ Builder’s triangle set (HCAR0480)
❏ 36" Metal r uler (HCAR0475)
❏ Cur ved-tip canopy scissors (for trimming plastic parts,
(HCAR0667)
Optional Supplies & Tools
Covering T ools
Adhesives & Building Supplies
Required Accessories
REQUIRED ITEMS
Muffler Selection
Wing Configuration
4
❏ Pliers with wire cutter (HCAR0630)
❏ Robar t Super Stand II (ROBP1402)
❏ 18" x 24" [460 x 610mm] Builder’s cutting mat (HCAR0455)
❏ 16" x 48" [410 x 1220mm] Building board (GPMR6950)
❏ Masking tape (TOPR8018)
❏ Threadlocker
™
thread locking cement (GPMR6060)
❏ Denatured alcohol (for epoxy clean up)
❏ Z-bend pliers (HCAR2000)
❏ Rotar y tool such as Dremel
®
Moto-Tool
®
❏ Rotar y tool reinforced cut-off wheel (GPMR8200)
❏ Ser vo horn dr ill (HCAR0698)
❏ Dead Center
™
Engine Mount Hole Locator (GPMR8130)
❏ AccuThrow
™
Deflection Gauge (GPMR2405)
❏ Slot Machine
™
hinge slotting tool (110V, GPMR4010)
❏ CG Machine
™
(GPMR2400)
❏ Laser incidence meter (GPMR4020)
❏ Precision Magnetic Prop Balancer
™
(TOPQ5700)
EASY-TOUCH™BAR SANDER
A flat, durable, easy to handle sanding tool is a necessity f or
building a well finished model. Great Planes makes a
complete range of Easy-Touch Bar Sanders and replaceable
Easy-Touch Adhesive-backed Sandpaper.While building the
P-38 Profile, two 5-1/2" [140mm] Bar Sanders and two 11"
[280mm] Bar Sanders equipped with 80-grit and 150-grit
Adhesive-backed Sandpaper were used.
Here’s the complete list of Easy-Touch Bar Sanders and
Adhesive Backed Sandpaper:
5-1/2" Bar Sander (GPMR6169)
11" Bar Sander (GPMR6170)
22" Bar Sander (GPMR6172)
33" Bar Sander (GPMR6174)
44" Bar Sander (GPMR6176)
11" Contour Multi-Sander (GPMR6190)
12' roll Adhesive-backed 80-grit sandpaper (GPMR6180)
150-grit (GPMR6183)
180-grit (GPMR6184)
220-grit (GPMR6185)
Assortment pack of 5-1/2" strips (GPMR6189)
We also use Top Flite 320-grit (TOPR8030, 4 sheets) and
400-grit (TOPR8032, 4 sheets) wet-or-dry sandpaper for
finish sanding.
• There are two types of screws used in this kit:
Sheet metal screws are designated by a number and a length.
For example #6 x 3/4"
This is a number six screw that is 3/4" long.
Machine screws are designated by a number, threads
0per inch, and a length. SHCS is just an abbreviation for
“socket head cap screw”and that is a machine screw with a
socket head.
For example 4-40 x 3/4".
This is a number four screw that is 3/4" long
with forty threads per inch.
• When you see the term
test fit
in the instructions, it
means that you should first position the part on the
assembly without using any glue, then slightly modify or
custom fit the part as necessar y for the best fit.
• Whenever the term
glue
is written you should rely upon
your experience to decide what type of glue to use.When a
specific type of adhesive works best for that step, the
instructions will make a recommendation.
• Whenever just
epoxy
is specified you may use
either
30-minute (or 45-minute) epoxy or6-minute epoxy. When
30-minute epoxy is specified it is highly recommended that
you use only 30-minute (or 45-minute) epoxy, because you
will need the working time and/or the additional strength.
•
Photos
and
sketches
are placed before the step they
refer to. Frequently you can study photos in following steps
to get another view of the same parts.
Fuse = Fuselage
Stab = Horizontal Stabilizer
Fin = Ver tical Fin
LE = Leading Edge
TE = Trailing Edge
LG = Landing Gear
Ply = Plywood
" = Inches
mm = Millimeters
SHCS = Socket Head Cap Screw
COMMON ABBREVIATIONS
IMPORTANT BUILDING NOTES
5
1.Unroll the plan sheet.Re-roll it inside out to make it lie flat.
2. Remove all parts from the box. As you do, figure out the
name of each part by comparing it with the plans and the
parts list included with this kit. Using a felt-tip or ballpoint
pen, lightly write the part name or size on each piece to
avoid confusion later. Use the die-cut drawings shown on
page 7 to identify the die-cut parts and mark them before
removing them from the sheet. Save all scraps. If any of
the die-cut parts are difficult to punch out, do not force
them! Instead, cut around the parts with a hobby knife.After
punching out the die-cut parts, use your Bar Sander or
sanding block to lightly sand the edges to remove any diecutting irregularities or slivers.
GET READY TO BUILDTYPES OF WOOD
6
DIE-CUT DRAWINGS
7
1/64" = .4 mm
1/32" = .8 mm
1/16" = 1.6 mm
3/32" = 2.4 mm
1/8" = 3.2 mm
5/32" = 4.0 mm
3/16" = 4.8 mm
1/4" = 6.4 mm
METRIC CONVERSIONS
3/8" = 9.5 mm
1/2" = 12.7 mm
5/8" = 15.9 mm
3/4" = 19.0 mm
1" = 25.4 mm
2" = 50.8 mm
3" = 76.2 mm
6" = 152.4 mm
12" = 304.8 mm
18" = 457.2 mm
21" = 533.4 mm
24" = 609.6 mm
30" = 762.0 mm
36" = 914.4 mm
DIE-CUT DRAWINGS
8
❏ 1. Tape waxed paper over the Rudder drawing on the
fuse plans. Remove the die-cut 1/4” balsa par ts R2,R3,R4
and R5 from CUB4RO1. Place all the parts over the plan in
their locations and check the joints for good fits.Use a T-bar
or other flat sanding block to make any necessary
adjustments.Pin the parts to the building board after proper
alignment and fitting has been done.
❏ 2. Cut the rudder LE from the 1/4" x 3/4" x 24" balsa
strip (CUB4SO3). NOTE: Look over the three CUB4S03’s
and mark the straightest one to be used later for the stab
TE. Fit the LE into the notch in R3 and against the edge of
R5. Cut the horizontal frame section from the 1/4" x 3/4"
balsa strip and fit it in position. Pin the LE and horizontal
frame section in place and securely glue all joints with thin
CA. Wipe any excess glue off with a paper towel before it
cures (this will make sanding much easier).NOTE:Leave all
the parts pinned to the building board.
❏ 3. Cut the four Ribs from the 3/16” x 1/4” x 24” balsa
stick (CUB4SO4). Fit the ribs into the rudder frame and
securely glue them in place with thin CA.
❏ 4. Remove the Rudder from the building board and
inspect all the glue joints on the bottom side.Add thin CA to
all the tight fitting joints and thick CA to any open joints.
NOTE: The process of re-gluing the joints on the bottom
side is necessary on the thick balsa parts. This will ensure
the complete wicking of the CA throughout the entire joint.
❏ 5. Place the Rudder on a flat work surface and lightly
sand both sides flat and smooth using a T-Bar or good flat
sanding block with medium grit sandpaper.
❏ 6. Carefully draw a centerline on the LE and TE of the
rudder. This will help you to maintain symmetry when
sanding these edges.
❏ 7. Using a flat sanding block, sand the top and theTE of
the rudder to a rounded shape. Sand the LE to a “V-shape”
as shown on the plans.
Build the Rudder
TAIL FEATHERS
❏ 8. Check the plans and mark the location of the tailgear
on the rudder.Drill a 7/64” hole in the rudder 3/4” deep (the
hole is drilled slightly oversize to allow room to create a hard
epoxy “sleeve”around the wire).Then groove the rudder LE
to accept the tailgear wire.
Using a hobby knife, sharpen the inside of one end of a
1/8" diameter brass tube, and use it to cut the groove in
the LE of the rudder as shown below.
❏ 1. Tape waxed paper over the Fin drawing on the fuse
plans. Remove the 1/4” die-cut balsa R1 from (CUB4RO1).
Place R1 on the plan and pin in place.
❏ 2.Cut the remaining fin frame parts from the 1/4" x 3/4"
x 24" balsa strip (CUB4SO3). Pin the par ts in place and
make sure all the joints are good and tight.Securely glue all
the joints with thin CA. Note: The bottom end of the trailing
edge stops at the top edge of the horizontal stabilizer.
❏ 3. Cut three Ribs from the 3/16" x 1/4" x 24" balsa stick
(CUB4SO4).Fit one rib in place and glue it with thin CA.Add
two more ribs for additional bracing above the lower frame.
❏ 4. Remove the Fin from the building board and inspect all
the glue joints.Glue all the tight fitting joints on the bottom side
of the fin with thin CA and add thick CA to any open joints.
❏ 5. Place the Fin on a flat work surface and lightly sand
both sides flat and smooth.
❏ 6. Draw a centerline on the LE and TE of the fin. The
lines will assist you in the final shaping of the LE and hinge
positioning on the TE.
❏ 7. Sand the LE only to a rounded shape to match the
cross-section shown on the plans. NOTE: The trailing edge,
bottom edge and top edge must not be rounded or V -shaped.
Instead, just sand these edges flat and square.
❏ 1. Tape waxed paper over the Stabilizer drawing on the
fuse plan.Remove the die-cut 1/4" balsa parts S1, S2 and S3
from (CUB4SO1) and the two S4’s from (CUB4S02). Place
S2 and S3 over the plan to check their fit together.Sand the
parts as necessar y to ensure a good fitting joint. Pin S2 and
S3 in place over the plans and glue them together.
Build the Stabilizer
Build the Fin
9
❏ 2. Position the S1 and the two S4’s over their locations
on the plans. Check the fits of the joints and sand them if
necessary. Pin them in place.
❏ 3.Cut the Stabilizer TE from the 1/4" X 3/4" X 24" balsa
strip (CUB4S03). Fit the TE between the S4’s and glue it in
place with thin CA.
❏ 4. Cut the Ribs from the 3/16" x 1/4" x 24" balsa stick
(CUB4S04). Fit the Ribs in the stabilizer frame and glue
them in place with thin CA.
❏ 5. Remove the stabilizer from the building board and
inspect all the glue joints. Glue all the tight fitting joints on
the bottom side of the stab with thin CA and add thick CA to
any open joints.
❏ 6. Place the stabilizer on a flat work surface and lightly
sand both sides flat and smooth.
❏ 7. Draw a centerline on the TE of the stabilizer. The
centerline will be used later to assist in positioning the hinges.
❏ 8. Sand the LE only of the stabilizer to a nice rounded
shape as shown on the plans.
❏ 1.Tape waxed paper over the Elevator drawing on the
fuse plan.Remove S5,S6,and S7 from the 1/4" die-cut balsa
sheet CUB4S02. Position the parts over the plans and
check the fit of the joints. Sand the parts as necessar y to
ensure good fitting joints. Pin the parts in place over the
plans and glue them together with thin CA.
❏ 2. Cut the Elevator LE from the 1/4" x 3/4" x 24" balsa
strip (CUB4S03) and pin it in place. Glue all the joints with
thin CA.
❏ 3. Cut the elevator Ribs from the 3/16" x 1/4" x 24" balsa
stick (CUB4SO4).Fit the ribs in the elevator frame and glue
with thin CA.
❏ 4. Remove the elevators from the building board and
inspect all the glue joints. Glue all the tight fitting joints with
thin CA and add thick CA to any open joints.
❏ 5. Place the elevators on a flat wor k surface and lightly
sand both sides flat and smooth using a T-bar or other good
flat sanding block.
❏ 6. Carefully draw a centerline all around the edges of
the elevators.
❏ 7. Temporarily pin the elevators to the plan. Lay the 1/8"
wire elevator joiner (WBNT194) in place on the elevators
and mark its outline using a soft leaded pencil. NOTE: Mark
the elevator joiner wire outline very lightly so that it will not
be seen through the covering material.
❏8.Accurately drill a 1/16" diameter pilot hole approximately
3/4" deep at each location. Then drill the final hole with a
9/64" drill bit to a depth of 7/8". (The hole is drilled slightly
oversize to allow for positioning, and to allow room to create
a hard epoxy “sleeve”around the wire.NOTE:The joiner wire
must be centered on the centerline of the stabilizer.The holes
must be drilled perpendicular to the LE and parallel to the top
and bottom surfaces of the elevators.
❏ 9. Use the shar pened 1/8" diameter brass tube to cut
grooves in the leading edge of the elevators to accept the
joiner wire.
❏ 10. Sand the LE to a “V”-shape and the entire TE to a
rounded shape.Check the plans for the proper cross-sections.
Build the Elevators
10
❏ 11.Test fit the joiner wire into both elevators.Position the
elevators against a straight edge to chec k f or str aightness of
the LE with the joiner wire installed. Adjust the holes if
needed to achieve a straight LE.
❏ 12. Roughen the joiner wire with coarse sandpaper,
then clean the wire thoroughly with alcohol to remove any
oily residue.
❏ 13.Glue the joiner in place using 30-minute epoxy.When
gluing, lay the elevators on a flat surface with the leading
edges along a straightedge to ensure perfect alignment.
NOTE: A strip of Ultra-Grip hinges are supplied in this
kit. If you choose to use the “pinned”-type hinges, you
should cut the hinge slots at this time. However, if you
choose to use the Ultra-Grip hinges that are furnished
in this kit, you may wait until after covering before
cutting the hinge slots. The strip of Ultra-Grip hinges
must be cut as shown in the sketch below.
❏ 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.
❏ 2. Cut the hinge slots on the centerlines which you
previously drew, using a hobby knife following the
recommended hinge slotting technique listed below. NOTE:
For pinned hinges use a slotting fork and slotting hook.
❏ A. Begin by carefully cutting a very shallow slit 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.
❏ 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.
❏ 3. Inser t 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 after you have covered the model.
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.
NOTE: You may build one of two different wings from
this kit. The standard scale wing or the clipped wing
version.You will need to decide now which version you
would like to build. Regardless of your decision, the
wings LE's and TE's will require trimming. Carefully
study the LE and TE trim diagram on the wing plan. Lay
the LE and TE directly over the plan and trim
accordingly. No change to the plans is necessary for the
standard scale wing. If you decide to build the clipped
wing version, cut the plans on the dashed lines. Slide
the outer halves of each wing panel over the inner
halves and match the registration marks between the
Build the Wing Panels
WING ASSEMBLY
CAUTION!!!: You must use extreme care when
cutting hinge slots with a hobby 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 y ou know it! A good precaution is
to wear leather gloves while performing the
following steps,and always cut
away
from yourself .
Cut the Hinge Slots
11
1"
1"
3/4"
first two #3 ribs. Keep the plans aligned and tape the
inner and outer halves together. The plans are now
ready to use for the clipped wing version.
❏1.T ape the plan to your flat work surface .Align a straightedge
on the wing centerline and draw a continuous line extending out
past the leading and trailing edges.Do this for both the right and
left wing panel plans. This centerline will be used at various
times during the wing construction. Cover the wing drawing with
waxed paper (so you won’t glue the wing to the plan!).
❏ 2. Before using the 3/8" x 3/8" x 33-1/2" bass woodSpars
(CUB4W06), 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 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.
❏ 3. Carefully punch out all the die-cut 3/32" balsa #3 and
#5 ribs (CUB4W02) and the die-cut 1/8" balsa #2, #4,#6, #7
and #8 ribs (CUB4W01, CUB4W03 and CUB4W04). Sand
the edges slightly to remove any die-cutting irregularities.
❏❏4. Place one of the 3/8" x 3/8" x 33-1/2" Basswood
Spars (CUB4W09) on the wing plan and pin the spar down
with crossed T-pins as shown in the follo wing sk etch.NOTE:
Align the end of the spar with the outboard edge of rib #7.
The spars are cut slightly too long, and the excess will be
cut off later at the center of the wing.
❏❏5. Place the 1/16" x 1-3/8" x 36" balsa TE Sheeting
(CUB4W13) on the plans but do not pin it yet.Align one end
of the sheeting with the wing centerline.
❏❏6. Place three of the #3 ribs and one of the #4 r ibs on
the spar in their locations shown on the plans, but do not
glue. Slide the TE sheeting to the forward edge of the
notches in the bottom of the ribs. The TE sheeting is used
only as a shim for the rib ends at this point.
❏❏7.Carefully check the notches on the TE (CUB4W11).
The 1/8" wide notches are to be positioned over the #1 and
#2 rib locations on the plans. Align the outboard end of the
TE with the aft end of the #4 rib.Insert the aft ends of the #3
ribs into the notches in the TE.Make sure the ribs are down
against the sheeting and building board and glue the ribs to
the spar and the TE with thin CA.The TE sheeting should
hold the ribs 1/16" above the work surface.
❏❏8. Slide the bottom sheeting back against the TE and
align it with the inboard end of the TE. Glue the bottom
sheeting to the TE and the ribs.
NOTE: Follow steps 4 through 30 to build the LEFT
wing panel, then repeat these steps to build the
RIGHT wing panel.
12
T-Pin
Spar
Work Surface
❏❏9. Carefully inspect the notches in the die-cut 1/8"
balsa Outboard TE (CUB4F03). The 1/8" wide notches are
to be aligned with the #6 rib locations. Insert the tab on the
die-cut outboard TE into the slot at the aft end of the #4 rib,
with the notches facing up.
❏❏10.Place the outboard #5 rib on the spar at the proper
location and insert the aft end of the rib into the proper notch
in the outboard TE.Do not glue yet!
❏❏11. Use a straightedge to keep the outboard TE straight
as shown in the photo and glue it to the bottom TE sheeting with
thin CA. Be careful not to glue the straightedge to the sheeting.
❏❏12. Position the notched LE so the 1/8" wide notches
are near the #2, #4, #6, #6 and #7 positions. Place it on the
ribs so the ribs are centered vertically on the LE to allow for
the LE sheeting which will be installed later.Glue it in place
with thin CA.
❏❏13. Install the remaining #5 and #6 ribs. Glue them to
the LE, the spar, the outboard TE and the bottom TE
sheeting. Make sure they are centered on the LE and down
against the bottom TE sheeting.
❏❏14.Trim the bottom sheeting in the aileron area, along
the #4 rib and the outboard TE to the end of the sheet.
Maintain a straight cut past the #7 rib location.You may want
to slide a thin piece of hard plastic under the bottom sheeting
to avoid cutting into the plans when making this cut.
❏❏15.Position the #7 rib in place over the plans and onto
the tab at the end of the outboard TE.Glue the rib to the LE,
the front and top edges of the spar, the outboard TE and
the bottom TE sheeting.Trim the bottom sheeting even with
the outboard edge of the #7 rib.
❏❏16. Insert the 3/8" x 3/8" basswood Top Spar
(CUB4W09) into the notches in the ribs. Align the end of the
spar to the outboard edge of the #7 rib. Glue the spar to all
the ribs, with the spar against the front of the notch in the #7
rib.Make sure the top surface of the spar is level with the top
edges of the ribs. NOTE: Check to make sure the spar is
positioned properly to ensure a straight wing (see step 2).
❏❏17. Install a die-cut 1/8" plywood Wing Tip Brace
(CUB4W09) at the rear of the spars through the notches in
13
the #7 rib. Align the top notch in the wing tip brace with the
#8 rib on the plans and glue the brace in place. Make sure
the “legs” of the brace are parallel with the spars.
❏❏18. If you are currently building the left wing panel,
assemble the wing tips over the right wing panel plan.Place
the die-cut 3/16" balsa Wing Tip parts T1, T2 and T3
(CUB4W08) over the plans and check all joints for proper
fits. Sand the par ts if necessary for good fitting joints. Pin
them in place and glue the pieces together with thin CA.
❏❏19. Remove the Wing Tip from the building board and
inspect all the glue joints on the bottom side. Add thin CA to
all the tight fitting joints and add thick CA to all the open joints.
❏❏20. Place the Wing Tip on a flat work surface and
lightly sand both sides flat and smooth.
❏❏21. Sand the front edge of the Wing Tip to match the
angle of the LE.Test fit the wing tip into the slot at the front of
rib #7 and align the aft end of the wing tip with the aft end of rib
#7. Glue the wing tip to the LE, the wing tip brace and rib #7.
❏❏22.Insert rib #8 into the notch in the wing tip brace so
the ends of the rib rest on the wing tip.Align the rib over the
plans and glue it in place. Sand the top and bottom outside
edges of the wing tip to remove the sharp corner where the
leading edge sheeting will be attached later.
❏❏23. Install rib #2 by sliding it in between the spars and
twisting it into place. Center it on the LE and glue it with thin
CA. Do not glue it to the spars yet! Note: Maintain a 1/16"
gap between the bottom edge of the rib and the work surface
to allow for the center sheeting which will be installed later.
Use a scrap piece of 1/16" balsa to hold the rib up off the
work surface.
❏❏24. Securely glue eight (six for the clipped wing Cub)
of the pre-cut 1/16" x 2-7/8" x 1-7/16" balsa vertical grain
shear webs (CUB4W20) to the rear surface of the spars,
starting between the two #5 ribs near the wing tip end of the
wing and working towards the center of the wing.Medium or
thick CA works best for this. Securely glue a shear web to
the front surfaces of the spars in the two rib bays between
the #3 r ibs as shown in the next photo.
❏❏25.Install the 1/8" x 1/4" x 33-1/2" balsa T op Forwar d
Spar (CUB4W12) in the forward rib notches, starting with
the #7 rib. Press the spar down fir mly into the notches and
glue it in place with thin CA. Trim the forward spar and LE
even with the inboard side of the #2 rib and even with the
outboard side of the #7 rib.
❏❏26.Position f our 1/4" x 3/8" x 1-1/2" balsa Hinge Blocks
(CUB4W21) against the Outboard TE at the locations shown
on the plans and glue them in place with CA. Notice that they
are centered vertically on the outboard TE and not placed
down against the bottom TE sheeting.
14
❏❏27. Place the die-cut 1/8" balsa triangular Gusset
(CUB4W01) in the corner formed by the #4 rib and the
tapered TE.Securely glue it in place.
(Photo taken at a later stage of completion.)
❏❏28. Glue the 1/2" x 3/4" x 1" basswood Wing Strut
Mounting Blocks (CUB4W22) to the outboard side of the
second #6 rib.They should be flush with the bottom of the rib
and positioned as shown on the plans.Cut four 1" long pieces
of 3/8" balsa Triangle (CUB4W24) and glue one piece on top
of each mounting block. There are six of these blocks
included in this kit, two of which are (CUB4F20). The strut
mounting blocks must be down flat on the building surface
when gluing it to the rib.The front block will be flush with the
bottom of the rib, but the aft block will be 3/32" below the
bottom edge of the rib because the balsa sheeting has not yet
been installed in the bellcrank bay.
❏❏29. Use the die-cut 1/8" ply Spar Gauge (CUB4F09)
to mark where to cut the spars and TE off. Hold the gauge
flat against the work surface and line it up with the centerline
on the plans. Mar k along the almost vertical edge and then
cut the spars off along these lines. This will make the top
spar slightly shorter than the bottom spar to allow for the
dihedral angle.In addition to the spars, mark and cut off the
bottom TE sheet and the tapered TE at the wing centerline.
❏❏30.Remove the wing panel from the work surface and
install the 1/8" x 1/4" x 33-1/2" Bottom Forward Spar
(CUB4W12) following the same procedure used in step 25.
❏ 31. Go back to step 4 and build the other wing panel.
❏1. Using the die-cut 1/8" ply Front Spar Joiner(CUB4W07)
and the die-cut 1/16" ply Forward and Aft Main Spar Joiners
(CUB4W05), test fit (DO NOT GLUE) the two wing panels
together. With the center of the wings resting on the work
surface, block up both wing tips 5/8" (1/2" for the clipped wing)
as measured from the work surface to the bottom of rib #7.
Check the fit of the spars and the TE to make sure they meet
up nicely without producing any sweep in the wing. Take the
panels apart and sand the spars or TE’s if necessary to achieve
the correct alignment. NOTE: The holes in the die-cut 1/8"
plywoodFront Spar Joiner and the holes in the die-cut1/16" ply
Forward Main Spar Joiner must be centered on the centerline
of the wing.Make sure you trim the ends of the spar joiners as
needed to allow the wing panels to come together and the
spars to touch. It is typical to have to trim 1/16"from the ends
of the joiners.It is also likely likely that you will have to deepen
the notches in the #2 ribs slightly to allow the joiners to slide
fully into place.
❏ 2. Glue the three die-cut 1/8" plywood Dihedral Braces
(CUB4W07) together as shown in the photo.
Joining the Wing Panels
15
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