Dynaflite GPMA0090 User Manual

INSTRUCTION MANUAL

sPIECE7INGFOR%ASY4RANSPORTATION
s3LOWAND&ORGIVING&LIGHT#HARACTERISTICS
s3IMPLEAND&AST!SSEMBLY

WARRANTY

Great Planes® 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 buyer is not prepared to
accept the liability associated with the use of this product, return this kit immediately in new and
unused condition to the place of purchase.

READ THROUGH THIS MANUAL BEFORE STARTING CONSTRUCTION. IT CONTAINS
IMPORTANT INSTRUCTIONS AND WARNINGS CONCERNING THE ASSEMBLY AND
USE OF THIS MODEL.

™

Champaign, Illinois [phone]

®

Entire Contents © 2010 Hobbico,® Inc.

[e-mail]

GPMA00 90 Mnl 2.0

Table of Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Precautions. . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Preparations . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Required Accessories . . . . . . . . . . . . . . . . . . 3

Setting Up Shop . . . . . . . . . . . . . . . . . . . . . . 4

Required Supplies & Tools . . . . . . . . . . . . . . 4

Optional Accessories . . . . . . . . . . . . . . . . . . 4

Building Notes . . . . . . . . . . . . . . . . . . . . . . . . 5

Common Abbreviations. . . . . . . . . . . . . . . . . 5

Types of Wood . . . . . . . . . . . . . . . . . . . . . . . . 6

Cyanoacrylate Glue. . . . . . . . . . . . . . . . . . . . 6

Build The T ail Surfaces. . . . . . . . . . . . . . . . . . 6

Build The Fin . . . . . . . . . . . . . . . . . . . . . . . . . 6

Build The Rudder, Stab & Elevator . . . . . . . . 7

Finish The Tail Surfaces . . . . . . . . . . . . . . . . 8

Build The Wing . . . . . . . . . . . . . . . . . . . . . . . . 9

Build The Inner Wing Panels . . . . . . . . . . . . . 9

Build The Outer Wing Panels . . . . . . . . . . . 13

Join The Inner Panels . . . . . . . . . . . . . . . . . 15

Join The Outer & Inner Wing Panels . . . . . . 17

Finish The Wing. . . . . . . . . . . . . . . . . . . . . . 18

Build The Fuselage. . . . . . . . . . . . . . . . . . . . 19

Prepare The Fuse Sides . . . . . . . . . . . . . . . 19

Join The Fuselage Sides. . . . . . . . . . . . . . . 21

Sheet The Fuse Bottom . . . . . . . . . . . . . . . 22

Finish The Fuselage . . . . . . . . . . . . . . . . . . 22

Install The Servos . . . . . . . . . . . . . . . . . . . . 26

Align The Stab & Fin. . . . . . . . . . . . . . . . . . . 26

Align The Stab. . . . . . . . . . . . . . . . . . . . . . . 26

Align The Fin . . . . . . . . . . . . . . . . . . . . . . . . 27

Covering . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Prepare For Covering . . . . . . . . . . . . . . . . . 28

Covering Sequence. . . . . . . . . . . . . . . . . . . 28

Covering Tips . . . . . . . . . . . . . . . . . . . . . . . 28

Join The T ail Surfaces . . . . . . . . . . . . . . . . . 31

Join The Stab, Fin & Fuse . . . . . . . . . . . . . . 31

Hinge The Control Surfaces . . . . . . . . . . . . 32

Fuelproofi ng . . . . . . . . . . . . . . . . . . . . . . . . . 33

Final Hook-Ups & Checks . . . . . . . . . . . . . . 33

Connect The Servos . . . . . . . . . . . . . . . . . . 33

Mount The Landing Gear . . . . . . . . . . . . . . 35

Finish Radio Installation . . . . . . . . . . . . . . . 35

Mount The Wing . . . . . . . . . . . . . . . . . . . . . 36

Balance Your Model. . . . . . . . . . . . . . . . . . . 36

Set The Control Throws. . . . . . . . . . . . . . . . 37

PreFlight . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

At Home . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

At The Flying Site . . . . . . . . . . . . . . . . . . . . 38

Engine Safety Precautions . . . . . . . . . . . . . 38

Flying. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Find A Safe Place To Fly . . . . . . . . . . . . . . . 38

Takeoff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Flight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Landing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Introduction

Congratulations and thank you for purchasing
the Dynafl ite Butterfl y. The Butterfl y is a “powered
sailplane” or “motor glider” and is an ideal model for
learning to fl y radio controlled models – especially
if you are not able to locate an experienced fl ight
instructor and must try it on your own. Because
of its large wingspan and light wing loading, the
Butterfl y is a gentle model that will give you plenty
of time to think and react. Because of its size and
light weight however, you must reserve fi rst fl ight
attempts for a calm day – more on that in the “Flying”
section at the end of the manual. The Butterfl y does

not require a powerful engine. Any .10 to .15 cu.

in. 2-stroke will do the job – all the engine has to
do is provide a little thrust and the large wing will
do the rest!

The way you fl y the Butterfl y is to let it climb (it will

do that almost by itself with just a little guidance from
you), then throttle back and fl y it around rather like
a sailplane. When you need more altitude just apply
throttle. This doesn’t sound like much action but

don’t worry, if you’re a beginner you’ll be busy. Most

important, you’ll develop the hand-eye coordination
required to fl y traditional “40-size” sport/trainers.
Enough said. Please thoroughly read the rest of
the preliminary information, then let’s get started!

2

Protect Your Model, Yourself
and Others... Follow This
Important Safety Precaution

Your Butterfl y is not a toy, but a sophisticated

working model that functions like a full-size
airplane. Because of its performance, if you do
not assemble and operate the Butterfl y correctly,
you could possibly injure yourself or spectators
and damage property.

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

strong.

3. You must install all R/C and other components

so that the model operates properly on the ground
and in the air.

4. You must test the operation of the model before

the fi rst and each successive fl ight to insure
that all equipment operates correctly. You must
also make certain that the model has remained
structurally sound.

To make your R/C modeling experience

totally enjoyable, we recommend that you get
assistance with assembly and your fi rst fl ights
from an experienced, kno wledgeable modeler.

You’ll learn faster and avoid risk to your model

before you’re truly ready to solo. Your local hobby
shop has information about fl ying clubs in your area
whose membership includes qualifi ed instructors.

You can also contact the national Academy of Model
Aeronautics (AMA), which has more than 2,500

chartered clubs across the country. We recommend
you join the AMA which will provide you with
insurance coverage at AMA club sites and events.

AMA Membership is required at chartered club

fi elds where qualifi ed fl ight instructors are available.

Contact the AMA at the address or toll-free phone
number below.

Academy of Model Aeronautics

5151 East Memorial Drive
Muncie, IN 47302-9252

[phone]
Fax [phone]

or via the internet at: www.modelaircraft.org

Precautions

1. You must assemble the plane according to the

instructions. Do not alter or modify the model, as
doing so may result in an unsafe or unfl yable model.
In a few cases the instructions may differ slightly
from the photos or plan. In those instances the text
should be taken as correct.

NOTE: We, as the kit manufacturer, can provide

you with a quality kit and great instructions, but
ultimately the quality and fl yability of your fi nished
model depends on how you assemble 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.

Please inventory and inspect all parts carefully
before starting to build! If any parts are missing,
broken or defective or if you ha ve any questions
about building or fl ying this model, 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 have them ready
when calling. Visit our web site at:

www.dynafl ite.com

Preparations

Required Accessories

These are the items “not included” with your kit,

that you will need to purchase separately. Items
in parentheses (OSMG2691) are suggested part
numbers recognized by distributors and hobby
shops and are listed for your ordering convenience.

GPM is the Great Planes® brand, TOP is the Top

®

Flite

brand and HCA is the Hobbico

❍ 4-Channel Aircraft Radio with three

standard servos

®

brand.

3

❍ O.S.® 10LA (OSMG0011) or O.S. 15LA

(OSMG0016)

❍ Engine Mount (Hayes 006-AS15 short

mount for O.S. LA engines) HAYG0006

❍ Propellers; Refer to your engine’s

instructions for proper size

❍ Approximately 2 rolls Top Flite MonoKote

covering; See Covering Tips (page 31)

❍ Medium Fuel Tubing (3’, GPMQ4131)

❍ 1/4" Latex Rubber Padding (HCAQ1000)

❍ 1/16" Foam Wing Seating Tape

(GPMQ4422)

❍ 4 oz. Fuel Tank

❍ (2) 2-1/4" Wheels (GPMQ4222)

❍ (4) 4-40 x 1/2" screws to secure engine

mount (GPMQ3012)

❍ (4) 4-40 blind nuts for engine mount

screws (GPMQ3324)

❍ #64 Rubber Bands (1/4 lb box –

HCAQ2020)

❍ (4) 5/32" Wheel Collars (GPMQ4306)

❍ #4 x 1/2" Screw for mounting engine to

engine mount

Required Supplies and Tools

These are the building tools and adhesives that

you will need to build your Butterfl y.

We recommend Great Planes Pro™ CA and Epoxy

❍ 2 oz. Thin CA Adhesive - (GPMR6003)

®

❍ 2 oz. Medium CA+ (GPMR6009)

❍ CA Activator - (GPMR6035)

❍ 30-Minute Epoxy - (GPMR6047)

❍ #1 Hobby Knife Handle (XACR4305)

❍ #11 Blades (Qty. 100 – HCAR0311) or (Qty.

5 – XACR2911)

❍ X-Acto® (or similar) Building Square

(XACR7726) or Building Triangle
(XACR7725)

❍ Medium T-pins (HCAR5150)

❍ Wax Paper

❍ Electric Drill

❍ Drill Bits: 1/16", 5/64", 3/32", 3/16", 11/64"

or 5/32", 15/64" or 1/4"

❍ String for aligning the stabilizer

❍ Screwdrivers (Phillips and Flat Blade)

❍ Top Flite Covering Iron (TOPR2100)

❍ A building board that you can stick pins

into (see “Setting Up Shop”)

Setting Up Shop

If this is your fi rst model there are a few supplies
and tools that you should gather before you begin.

The most important item is a fl at table that you can

build your models on. You can turn a solid core door
into a building table, but avoid hollow core doors
because they warp easily. If possible, locate your
building table in an area that is not in the way of
other projects or household activities. Cover your
building table with a board that you can stick pins
into. The back of a 2’ x 4’ ceiling tile works well or
you can cut a piece to fi t your table from a 4’ x 8’
sheet of Celotex insulation board available from a
home improvement store.

Optional Accessories

You can build your Butterfl y without these items

but they will make the job much easier and provide
you with better results. These are things you will
accumulate as your building “career” progresses
anyway.

❍ Razor Plane (MASR1510)

❍ Single-Edge Razor Blades (100,

HCAR0312)

❍ CA Applicator Tips (HCAR3780)

❍ Hot Sock™ (for your covering iron,

TOPR2175)

4

❍ 6-Minute Pro™ Epoxy (GPMR6045)

❍ Trim Seal Tool™ (TOPR2200)

❍ Heat Gun (TOPR2000)

❍ Straightedge (Fourmost Non-Slip,

FORR2149)

❍ Denatured or Isopropyl Alcohol (for epoxy

clean-up)

❍ Spare Glow Plugs (O.S. #8 for most

2-stroke engines, OSMG2691)

™

❍ HobbyLite

Balsa Filler (HCAR3401)

❍ Epoxy Brushes (GPMR8060)

❍ CA Debonder (GPMR6039)

❍ Powered hand tool with Sanding Drum and

Cut-off Wheel

❍ Bar Sander or Sanding Block and

Sandpaper (coarse, medium, fi ne grit)*

12’ Roll of adhesive-backed sandpaper,

80-grit (GPMR6180)
150-grit (GPMR6183)
220-grit (GPMR6185)

Assortment pack of 5-1/2" strips (GPMR6189)

Building Notes

● 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"

Machine screws are
designated by a number,
threads per inch and a
length.

For example 6-32 x 3/4"

● When you see the term “test fi t” in the instructions,
it means you should fi rst position the part on the

assembly without using any glue, then slightly

modify or “custom fi t” the part as necessary for
the best fi t.

*A fl at, durable, easy-to-handle sanding tool is

a necessity for building model airplanes. Great
Planes makes a complete range of Easy-Touch™
Bar Sanders and replaceable Easy-Touch
adhesive-backed sandpaper. For the Butterfl y all
that is required is the short 5-1/2" Bar Sander
(GPMR6169) and two assortment packages of
adhesive-backed sandpaper (GPMR6189).

For future reference, here’s a list of Easy-Touch
Bar Sanders and adhesive-backed sandpaper:

5-1/2" Bar Sander (GPMR6169)

11" Bar Sander (GPMR6170)
22" Bar Sander (GPMR6172)

● Whenever just “epoxy” is specifi ed you may
use either 30-minute epoxy or 6-minute epoxy.
When 30-minute epoxy is specifi ed it is highly
recommended that you use only 30-minute epoxy
because you will need either the working time
and/or the additional strength.

Common Abbreviations

Fuse = Fuselage
Stab = Horizontal Stabilizer
LE = Leading edge (front)
TE = Trailing edge (rear)
Ply = Plywood
" = Inches

5

Types Of Wood

Balsa Basswood Plywood

Cyanoacrylate Glue

The most popular type of glue modelers use for

general construction of R/C models is Cyanoacrylate
or CA glues. Modelers build with CA because
it cures fast (immediately in some cases) and
the pieces do not have to be clamped or pinned
together as they do with traditional adhesives.
CA’s do, however have their own set of special
procedures and precautions that you should follow.

Always use CA in a well ventilated area. Open some

windows or place a fan in the room to circulate the
air. Do not lean directly over your work when you
use CA and look away while it cures or “sets off.”
CA can cure immediately upon contact with skin
so if you accidentally bond your fi ngers, do not
use vigorous motion to separate them. Use CA
Debonder (GPMR6039) or acetone (nail polish
remover) or soak your fi ngers in warm water for

a few minutes. Never point the tip of a CA bottle

toward your face and be especially careful when
you unclog a CA tip. Hobbico CA Applicator Tips
(HCAR3780) are highly recommended and will
help keep the bottle from clogging. Keep paper
towels or tissues close by to immediately absorb
excess CA dropped on your model or work area.

Read all the warning labels on your CA bottle.

other conditions that require one or the other types
of CA. For the Butterfl y all you really need is thin
and medium CA.

CA Accelerator is a chemical that you can spray
over uncured CA to make it cure immediately. A

mist spray of accelerator will do the job. Do not

inhale the vapors! Some modelers “preprime” the
parts to be glued with accelerator, join them, then
add the CA. This way the CA is guaranteed to cure
immediately. This prepriming is especially handy
when you use thin CA because it will cure before all
of the glue soaks into the wood away from the glue
joint. We do not recommend you build your entire
model with this method and use accelerator only
when necessary. Often, overspray from accelerator
used hours or even days earlier on nearby glue
joints will cause the CA you use on the next step to
cure prematurely and unexpectedly – so be careful!

Build the Tail Surfaces

Build the Fin

Place your building board on top of your fl at building
table. Position the plan sheet so the rudder and
fi n drawing is over your fl at building board. (Reroll
the plan sheet inside out to make it lie fl at or use
weights or tape to hold it down.) You may separate
the wing portion from the plan or fold the plan in
half to make it easier to work with. Cover the fi n
drawing with wax paper so the glue will not stick.

There are different viscosities of CA’s intended for

different conditions you will encounter when you
build. Thin CA is great for “tack-gluing,” for glue
joints that fi t well and for parts that are already
joined but need to be permanently bonded. Medium
CA is used for general construction where you apply
glue to one part, then join it to another part. Thick
CA is great for glue joints that don’t fi t perfectly
or parts that require a little time for positioning
before the glue cures. You will encounter many

Refer to this photo while you build the fi n.

❏ 1. Cut the fi n trailing edge from a 1/4" x 3/8"

x 36" balsa stick, then pin it over its location on
the plan. Many modelers fi nd that they can more

6

accurately cut small balsa sticks (such as the ones
used in the tail surfaces) with a single-edge razor
blade rather than a hobby knife.

❏ 2. Cut the fi n leading edge from a 1/4" x 1/4" x 24"

balsa stick, then pin it over its location on the plan.

❏ 3. Cut the two base pieces and the tip of the

fi n from the same 1/4" x 1/4" balsa stick, then glue
them to the LE (leading edge) and TE (trailing edge)
with medium CA and pin them in position.

❏ 4. Cut the two fi n “ribs” from one of the 1/8" x

1/4" x 24" balsa sticks, then glue them in position

over their location on the plan.

❏ 5. Make the gusset for the corner of the fi n TE
and the base of the fi n from the 1/4" x 3/8" balsa

stick you used in step 1.

❏ 6. Remove the T-pins, then lift the fi n from your

building board. We will instruct you to build the

dorsal part of the fi n after you position the fi n on

the fuselage. Reinforce glue joints that don’t look
strong with medium CA.

Build the Rudder, Stabilizer
and Elevator

Use the following building sequence for the rudder,

stabilizer and elevator as a guide to cut the balsa
sticks and pin them to the plan, then glue them
together the same as you did for the fi n. Don’t
forget to cover the plan with wax paper.

Rudder Building Sequence

❏ 2. The TE, then the bottom from a 1/4" x 1/2"

x 12" balsa stick.

❏ 3. The “balance tab” part of the rudder and the

tip from the remainder of the 1/4" x 1/4" balsa stick
you used for the fi n and another 1/4" x 1/4" x 24"
balsa stick if needed.

❏ 4. The “ribs” from the remainder of the 1/8" x

1/4" stick you used for the fi n.

❏ 5. Remove the T-pins and lift the rudder from the

building board. Reinforce glue joints that don’t look
strong with medium CA.

Stabilizer Building Sequence

Refer to this photo while you build the stabilizer.

❏ 1. The TE, LEs, tips, then LE “brace” from two

1/4" x 3/8" x 36" balsa sticks. To make the brace for

the LE, fi rst cut the 1/4" x 3/8" piece to a length of

4-1/4", then mark a centerline. Use a straightedge

and a hobby knife with a #11 blade to cut the angle
on the brace that extends from the centerline to
both corners.

Refer to this photo while you build the rudder.

❏ 1. The LE from the remainder of the 1/4" x 3/8"

stick used in step 1 of the fi n.

❏ 2. 1/8" x 1/4" x 24" basswood stab spar.
❏ 3. The stab center (in front of and behind the

basswood spar) from the 1/4" x 1-1/2" x 3- 7/8"
balsa sheet.

❏ 4. The stab ribs from 1/8" x 1/4" x 24" balsa sticks.
❏ 5. Remove the T-pins and lift the stab from your

building board. Reinforce glue joints that don’t look
strong with medium CA.

7

Elevator Building Sequence

Refer to this photo while you build the elevator.

❏ 1. The LEs as shown on the plan, cut from a 1/4"

x 3/8" x 36" balsa stick. Use a hobby knife to cut
the “notches” for the 3/16" elevator joiner dowel.
Pin the LEs to the plan.

❏ 2. The TEs and tip ends from the remaining

1/4" x 3/8" balsa sticks from previous steps. Do

not make the elevator root ends until instructed
to do so (the roots are the ends of the elevators
nearest the fuselage).

❏ 3. Test fi t the 3/16" x 3-3/4" elevator joiner
dowel in the notches in the LEs of the elevators,

then if necessary adjust the notches so the dowel
is parallel to the TE of the stab on the plan.

❏ 4. Glue the dowel in position with epoxy. Stick

T-pins into your building board in front of the dowel

to hold it against the elevators. Slightly raise the
dowel so it is centered in the LEs, then wipe away
excess epoxy before it cures.

❏ 5. After the epoxy fully cures cut, then glue the
elevator root ends to the assembly.

❏ 6. The elevator ribs from remaining 1/8" x 1/4"

balsa sticks, then the control horn base for the right
elevator from leftover 1/4" x 3/8" balsa.

A note about sanding
“built-up” tail surfaces

Be careful when you sand a balsa structure
made up of “sticks.” The part fl exes and moves
while you sand and it can be diffi cult to keep your
sanding block fl at so you do not snag any of the
small ribs or over-sand one area and thin it more
than another area. Due to the design and slow

fl ying speed of the Butterfl y, a perfectly smooth
fi nish is not necessary. For this model, the

purpose of sanding is just to remove any glue
bumps or uneven edges. Stop sanding when
you have reduced most of the high spots. Use a
large sanding block or a fl at bar sander and do
not apply much pressure while you sand. Enjoy
– it’s not a racing plane – it’s a fl oater.

❏ 7. Remove the elevator from the plan, then add

CA to glue joints that don’t look strong.

Finish The Tail Surfaces

❏ 1. See the note below, then use your bar sander

or a sanding block and 220-grit sandpaper to even
the edges and blend the ribs, LEs and TEs of all
the tail surfaces so they are fl at and smooth.

❏ 2. Use a ballpoint pen to mark the location of

the hinges on the control surfaces as shown in
the photo.

Note: The plan shows two hinges in each elevator
but use three as indicated in the photo.

8

❏ 3. Lay the stabilizer on your building table. Use

thin card stock or business cards to raise the stab

so you can mark the hinge slots in the center of

the TE at the hinge locations. Mark the hinge slots
in the TE of the fi n the same way.

❏ 6. Test join (remember, this means no glue)

the elevator to the stab and the rudder to the fi n
with the hinges. Adjust the width of the hinge
slots if necessary.

❏ 4. Use the same procedure to mark the centerline
the entire length of the LE of the rudder and the

elevator.

Cut the Hinge Slot with a

Hobby Knife and a No. 11 Blade

❏ 5. Use a hobby knife with a #11 blade to make
the hinge slots. The fi rst cut should be a shallow

slit to establish the hinge slot location. After the fi rst
cut, make several more cuts going slightly deeper
each time. Move the knife from side to side and
widen the slot as you cut.

1"

1"

❏ 7. Separate the elevator from the stab and the

rudder from the fi n. Use the “pen-and-card stock”

technique to mark a guideline 3/32” to 1/8" from

the LE on both sides of the elevator and rudder.

The guidelines indicate where to round the LE for

control movement.

❏ 8. Use the guidelines and a sanding block or

razor plane to round the leading edges of the rudder
and elevator equally.

❏ 9. Mark a centerline on the trailing edge of the

rudder and elevator with a ballpoint pen. Use your
bar sander or sanding block and 150-grit sandpaper
to taper the rudder and elevator as shown on the
cross-section of the plan or simply round the trailing
edges the same as the leading edges.

Build the Wing

Snip the Corners

3/4"

Cut eight hinges from the hinge material supplied
as shown in the sketch. Snip the corners off so
they go into the slots easier.

Build the Inner Wing Panels

Build the right wing half fi rst so your progress

matches the photos in the manual. Lay the right
wing plan over your building board, then cover the
plan with wax paper.

9

❏ 1. Before you remove the balsa ribs from their

die sheets, use the photos to identify the ribs and
mark them with a ballpoint pen as shown. If you
plan to cover the wing with transparent MonoKote
fi lm, mark the ribs neatly all in the same location
or mark them in an inconspicuous location so the
marks will not be seen through the covering.

❏ 2. Remove all the ribs from their die sheets, then

use a bar sander and 220-grit sandpaper to remove
any slivers or die-cutting irregularities. Save the
leftover 1/16" plywood from the W-1s to be used
later during fi nal landing gear installation.

❏ ❏ 3. Pin a 1/8" x

3/8" x 24" basswood

T-Pin

bottom inner spar

over its location
on the plan so the
tip “ends” at the
centerline between
the laminated W-4s

Spar

as shown on the plan.
Do not insert T-pins

Work Surface

through the spar
but install them in a
criss-cross pattern.

❏ ❏ 4. Position rib W-3 on the bottom spar and pin

it to the building board over its location on the plan.

Position the six W-4s of the inner wing panel on

the spar and pin them to the building board as well.

Note: Substitute the third W-4 rib in from the tip

with a W-3.

❏ ❏ 5. Position a

3/8" x 1-1/4" x 21"

90º

tapered balsa inner

TE over its location

on the plan so the
tip aligns with the

Bottom

centerline at the
laminated W-4s on the plan. Securely pin the TE to
the building board so it tightly contacts the wing ribs.

❏ ❏ 6. Position a 3/8" x 3/4" x 21" balsa inner LE

over its location on the plan so the tip aligns with
the centerline at the laminated W-4s on the plan.
Securely pin the LE to the building board so it tightly
contacts the wing ribs.

10

❏ ❏ 7. Remove the T-pins in rib W-3. Use a 90-

degree triangle to hold W-3 perpendicular to the
building board, then glue it to the spar, LE and TE
with medium or thin CA. Glue the W-4s to the spar,
LE and TE the same way.

❏ ❏ 10. Use medium or thin CA to glue the sheets
in position so the outer edges align with the outer
edge of rib W-2. The sheeting will be sanded fl ush

with the balsa W-1 after the wing is removed from
the plan.

❏ ❏ 8. Use the die-cut 1/8" plywood wing center
gauge to accurately mark where the balsa W-1

contacts the LE so you know where to position W-1
after the bottom sheeting is glued in place. Mark
the TE the same way.

❏ ❏ 9. Cut three

2-7/8" wide strips
from the 1/16" x 3"
x 36" balsa sheet.
Glue two of the
strips together

to make the aft
bottom sheeting

behind the bottom
spar. The other
strip is to be used

for the forwar d bottom sheeting ahead of the spar.

Use a straightedge and a sharp #11 blade to trim
the sheets so they fi t between the LE and bottom
spar and the TE and bottom spar, but leave the
sheets 2-7/8" wide.

❏ ❏ 11. Align W-1 with the marks on the LE and

TE, then glue it in position using the wing center

gauge to set the correct angle.

❏ ❏ 12. Glue W-2 in position with thin or medium

CA. While gluing, hold W-2 perpendicular to your
building board as you did with the W-4s.

❏ ❏ 13. Trim, test fi t, then glue the 1/8" balsa
vertical grain shear webs between only the W-4

ribs (that’s fi ve shear webs). Note that the shear
webs between the W-4s are centered on the bottom
spar. You will have to temporarily remove the T-pins
that interfere with the shear webs, then replace the

T-pins through the shear web after you glue each

web into position. See the following photo.

❏ ❏ 14. Trim and test fi t, but do not glue the

remaining shear webs. Use the wing center gauge
to cut the angle for the shear web that fi ts between
W-1 and W-2.

11

❏ ❏ 15. Slide the composite wing joiner tube

into the holes of W-1, W-2 and W-3. The holes in
the ribs are slightly oversize so you can accurately
position the tube when you permanently glue it
into the wing. Position the joiner tube so it rests
against the forward edge of the holes in the ribs,
then position the shear webs so they contact the
tube yet remain vertical. Glue the shear webs to
the wing (not the joiner tube) in this position.

❏ ❏ 16. Remove the joiner tube, then test fi t the

1/8" x 3/8" x 21" basswood inner upper spar in

the notches of the ribs. Make sure none of the
crossed T-pins interfere with the top spar and you
will be able to remove them after you permanently
glue the spar into position. If necessary, trim the
shear webs that do not allow the spar to rest fully
into the notches of the ribs. Use medium or thick
CA to glue the upper spar to the assembly so the
end is even with the outer rib W-4.

❏ ❏ 17. Make two gussets from the 3/16" x 3/4" x

12" balsa sheet, then glue them in position. If you

have one, use a small building triangle to accurately
cut the gussets. Note the grain direction as shown
in the photo.

❏ ❏ 18. Remove the T-pins and lift the wing panel

from your building board. Trim the ends of the spars,
LE and TE, then use your bar sander and 150-grit
sandpaper to make the spars, LE, TE and bottom
sheeting fi t perfectly fl ush with W-1.

❏ ❏ 19. Glue W-1A into position with medium CA.

❏ ❏ 20. See the Tip that follows, then use a razor

plane, a hobby knife with a carving blade or a #11

blade to roughly carve the leading edge according

to the sketch.

12