Dynaflite butterfly User manual

Entire Contents © 2010 Hobbico,
®
Inc.
®
™
GPMA0090 Mnl 2.0
sPIECE7INGFOR%ASY4RANSPORTATION
s3LOWAND&ORGIVING&LIGHT#HARACTERISTICS
s3IMPLEAND&AST!SSEMBLY
INSTRUCTION MANUAL
READ THROUGH THIS MANUAL BEFORE STARTING CONSTRUCTION. IT CONTAINS
IMPORTANT INSTRUCTIONS AND WARNINGS CONCERNING THE ASSEMBLY AND
USE OF THIS MODEL.
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.
Champaign, Illinois [phone]
airsuppor[email protected]

2
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
BuildTheTail Surfaces. . . . . . . . . . . . . . . . . . 6
Build The Fin . . . . . . . . . . . . . . . . . . . . . . . . . 6
Build The Rudder, Stab & Elevator . . . . . . . . 7
Finish The Tail Surfaces . . . . . . . . . . . . . . . . 8
BuildThe 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
BuildThe 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
AlignThe Stab & Fin. . . . . . . . . . . . . . . . . . . 26
Align The Stab . . . . . . . . . . . . . . . . . . . . . . . 26
Align The Fin . . . . . . . . . . . . . . . . . . . . . . . . 27
Covering . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Prepare For Covering . . . . . . . . . . . . . . . . . 28
Covering Sequence. . . . . . . . . . . . . . . . . . . 28
Covering Tips . . . . . . . . . . . . . . . . . . . . . . . 28
JoinTheTail Surfaces . . . . . . . . . . . . . . . . . 31
Join The Stab, Fin & Fuse . . . . . . . . . . . . . . 31
Hinge The Control Surfaces . . . . . . . . . . . . 32
Fuelproofing . . . . . . . . . . . . . . . . . . . . . . . . . 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 Dynaflite Butterfly. The Butterfly is a “powered
sailplane” or “motor glider” and is an ideal model for
learning to fly radio controlled models – especially
if you are not able to locate an experienced flight
instructor and must try it on your own. Because
of its large wingspan and light wing loading, the
Butterfly 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 first flight
attempts for a calm day – more on that in the “Flying”
section at the end of the manual.The Butterfly 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 fly the Butterfly is to let it climb (it will
do that almost by itself with just a little guidance from
you), then throttle back and fly 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 fly traditional “40-size” sport/trainers.
Enough said. Please thoroughly read the rest of
the preliminary information, then let’s get started!

3
Protect Your Model, Yourself
and Others... Follow This
Important Safety Precaution
Your Butterfly 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 Butterfly correctly,
you could possibly injure yourself or spectators
and damage property.
To make your R/C modeling experience
totally enjoyable, we recommend that you get
assistance with assembly and your first flights
from an experienced, knowledgeable 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 flying clubs in your area
whose membership includes qualified 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
fields where qualified flight 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 unflyable 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.
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 first and each successive flight to insure
that all equipment operates correctly. You must
also make certain that the model has remained
structurally sound.
NOTE: We, as the kit manufacturer, can provide
you with a quality kit and great instructions, but
ultimately the quality and flyability of your finished
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 have any questions
about building or flying 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.dynaflite.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®brand.
❍4-Channel Aircraft Radio with three
standard servos

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❍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
Setting Up Shop
If this is your first model there are a few supplies
and tools that you should gather before you begin.
The most important item is a flat 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 fit your table from a 4’ x 8’
sheet of Celotex insulation board available from a
home improvement store.
Required Supplies and Tools
These are the building tools and adhesives that
you will need to build your Butterfly.
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”)
Optional Accessories
You can build your Butterfly 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)

5
❍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, fine grit)*
*A flat, 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 Butterfly 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)
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 fit” in the instructions,
it means you should first position the part on the
assembly without using any glue, then slightly
modify or “custom fit” the part as necessary for
the best fit.
●Whenever just “epoxy” is specified you may
use either 30-minute epoxy or 6-minute epoxy.
When 30-minute epoxy is specified 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

6
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 fingers, do not
use vigorous motion to separate them. Use CA
Debonder (GPMR6039) or acetone (nail polish
remover) or soak your fingers 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.
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 fit 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 fit perfectly
or parts that require a little time for positioning
before the glue cures. You will encounter many
other conditions that require one or the other types
of CA. For the Butterfly 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 flat building
table. Position the plan sheet so the rudder and
fin drawing is over your flat building board. (Reroll
the plan sheet inside out to make it lie flat 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 fin
drawing with wax paper so the glue will not stick.
Refer to this photo while you build the fin.
❏1. Cut the fin trailing edge from a 1/4" x 3/8"
x 36" balsa stick, then pin it over its location on
the plan. Many modelers find that they can more

7
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 fin 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
fin 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 fin “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 fin TE
and the base of the fin from the 1/4" x 3/8" balsa
stick you used in step 1.
❏6. Remove the T-pins, then lift the fin from your
building board. We will instruct you to build the
dorsal part of the fin after you position the fin 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 fin. Don’t
forget to cover the plan with wax paper.
Rudder Building Sequence
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 fin.
❏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 fin 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 fin.
❏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, first 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.
❏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.

8
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 fit 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.
❏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 flat and smooth.
A note about sanding
“built-up” tail surfaces
Be careful when you sand a balsa structure
made up of “sticks.” The part flexes and moves
while you sand and it can be difficult to keep your
sanding block flat 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
flying speed of the Butterfly, a perfectly smooth
finish 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 flat bar sander and do
not apply much pressure while you sand. Enjoy
– it’s not a racing plane – it’s a floater.
❏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.

9
❏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 fin the same way.
❏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 first cut should be a shallow
slit to establish the hinge slot location. After the first
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"
3/4"
Snip the Corners
Cut eight hinges from the hinge material supplied
as shown in the sketch. Snip the corners off so
they go into the slots easier.
❏6. Test join (remember, this means no glue)
the elevator to the stab and the rudder to the fin
with the hinges. Adjust the width of the hinge
slots if necessary.
❏7. Separate the elevator from the stab and the
rudder from the fin. 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
Build the Inner Wing Panels
Build the right wing half first 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.

10
❏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
film, 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 final landing gear installation.
❏❏3. Pin a 1/8" x
3/8" x 24" basswood
bottom inner spar
over its location
on the plan so the
tip “ends” at the
centerline between
the laminated W-4s
as shown on the plan.
Do not insert T-pins
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"
tapered balsa inner
TE over its location
on the plan so the
tip aligns with the
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.
T-Pin
Spar
Work Surface
90º
Bottom

11
❏❏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.
❏❏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 forward bottom sheeting ahead of the spar.
Use a straightedge and a sharp #11 blade to trim
the sheets so they fit between the LE and bottom
spar and the TE and bottom spar, but leave the
sheets 2-7/8" wide.
❏❏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 flush
with the balsa W-1 after the wing is removed from
the plan.
❏❏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 fit, then glue the 1/8" balsa
vertical grain shear webs between only the W-4
ribs (that’s five 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 fit, but do not glue the
remaining shear webs. Use the wing center gauge
to cut the angle for the shear web that fits between
W-1 and W-2.

12
❏❏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 fit 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 fit perfectly flush 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.

13
Note: Leave the leading edge at least 1/16" high
in front of ribs W-1, 2 and 3 to accommodate the
top sheeting. You will final sand the LE after you
join the inner panels to the outer panels and glue
the top sheeting in position.
TIP: HowTo Use A Razor Plane
We highly recommend a razor plane to shape
the LEs because it is the safest, fastest and
most accurate method to remove large quantities
of balsa.
A. Adjust your razor plane so it removes about
1/64" or less balsa at a time.
B. Position the LE of the wing panel at the edge
of your work bench so it is supported and the
bench does not interfere with the razor plane.
C. Hold the razor plane at an angle to the grain
direction as shown in the photo.
D. Work slowly and inspect your work frequently.
Before you know it you will shave the LE down
quite far.
❏21. Arrange the plan so the left inner wing panel
is over your building board, then cover it with wax
paper. Return to step 3 and build the left inner wing
panel the same way as the right. Don’t forget to
switch to the left wing panel plan so you do
not build two right panels.
Build the Outer Wing Panels
Start with the right outer wing panel so your
progress matches the photos in the manual.
3/4
"
Area to Trim Off
❏❏1.Trim the end of a 3/8" x 1-1/4" x 30" tapered
balsa outer trailing edge so it matches the angle at
W-4 shown on the plan. Mark the tip end of the TE
3/4" away from the aft edge. Use a straightedge and
a ballpoint pen to mark a line on the TE connecting
the mark you made at the tip with the forward edge
of the other end (the root) of the TE.
❏❏2. Use the line you marked (or a straightedge)
as a guide to trim the TE with a sharp #11 hobby
knife as shown on the wing plan.
❏❏3. Cover the outer panel of the right wing plan
with wax paper, then use the “crossed T-pin” method
to pin the 1/8" x 3/8" x 30" basswood bottom outer
main spar in position so the root end aligns with
the plan at W-4.
❏❏4. Position the odd numbered ribs and
W-4 on the bottom spar, then pin them to your
building board.
❏❏5. Pin the outer TE and the 3/8" x 3/4" x 30"
balsa outer LE to the building board so they tightly
contact the ribs and the ends align where indicated
on the plan at W-4.

14
❏❏6. Remove the T-pins from rib W-4. Use the
wing tip panel gauge to set W-4 at the correct
angle and glue it to the TE, bottom spar and LE.
❏❏7. One rib at a time, remove the T-pins and use
a building triangle to hold the rib vertical, then use
medium or thin CA to glue the ribs you installed to
the bottom spar, LE and TE.
❏❏8. Install, then glue the remaining ribs to the
assembly using a building triangle to make sure
they are vertical.
❏❏9. Cut, then install the gussets at W-4 from
the 3/16" x 3/4" balsa stick. Due to the taper of
the LE and TE these gussets are not exactly a
90-degree angle.
❏❏10. Add the 1/8" balsa cross-grain shear web
between W-4 and W-5. Use the die-cut 1/8 plywood
wing tip panel gauge to cut the end of the web
that contacts W-4.
❏❏11. Test fit, then use medium or thick CA to
glue the 1/8" x 3/8" x 30" basswood top outer spar
to the ribs and shear web. Don’t forget to make
sure the crossed T-pins are not in the way and you
can remove them after you permanently glue the
spar into position.
❏❏12.Test fit, then use medium CA to glue both
1/8" x 1/8" x 30" balsa outer turbulator spars in
the notches of the ribs so the ends extend past
W-4 by approximately 1/16" (you can sand them
flush later).
❏❏13. Remove the T-pins, then lift the panel
from the plan. Use a razor saw to cut the ends of
the spars, LE and TE so they extend past W-15 by
approximately 1/32" to 1/16". Use your bar sander
to sand the ends flush with W-15 and W-4.
❏❏14. Use a razor plane, a hobby carving blade
or a #11 blade to roughly carve the leading edge
the same way as you carved the inner wing panels.
❏❏15. Glue the 3/4" x 6-1/4" triangle balsa wing
tip to W-15. The aft edge of the wing tip should
align with the aft edge of the TE. It may appear
that the triangle wing tip is too short because it
does not align with the LE, but as indicated on the
plan you will shape the LE to align with the wing tip.

15
❏❏16. Roughly carve the wing tip with a razor
plane or a hobby knife. Final shape the tip and blend
it to W-15 with a bar sander and 150-grit sandpaper.
❏❏17. Carefully remove any glue blobs and blend
all the ribs to the spars, TE and LE with a bar sander
and 220-grit sandpaper.
❏18. Arrange the plan so the left outer wing panel
is on your building board, then cover it with wax
paper. Return to step 1 and build the left wing panel
the same way you built the right. Don’t forget to
switch to the left wing panel plan so you do
not build two right panels.
Join the Inner Panels
Do not permanently join the inner wing panels, but
permanently install the joiner tubes so you can
temporarily join the panels for a days flying session.
Take the panels apart when it is time to go home.
❏1. Thoroughly roughen the outside of the wing
joiner tubes with 150-grit sandpaper so the glue will
stick. Use a metal file or a powered hand tool with
a cut-off wheel to remove the burrs and chamfer
the ends of the 1/4" x 10-1/2" steel wing joiner rod.
Remove any dirt or manufacturing oil from the rod
with a cloth dampened with alcohol or other solvent.
❏2. Plug one end of both wing joiner tubes with a
piece of 3/32" or 1/8" leftover balsa, then carefully
glue the plug in position with a few drops of thin
CA. Do not allow CA to flow into the tube because
it may interfere with the joiner rod.
❏3. Without any glue, temporarily join both inner
wing panels with the joiner tubes and the joiner
rod. Hold the wing halves together and inspect
the fit between the W-1 ribs of the joining panels.
If necessary, separate the panels and use your bar
sander to adjust to the ends of the spars, LEs or
TEs so the W-1s fit together well.
❏4. With the joiner tubes and the joiner rod
in position, temporarily clamp the wing halves
together, then place a weight on one of the wing
panels to hold it down. Measure the height of the
outer W-4 from the building table. It should be
approximately 4-1/2".
❏5. Remove your clamps, then position 1/8"
leftover balsa “spacers” between the W-1s and
clamp them together. The spacers will allow both
joiner tubes to protrude 1/16" from the inner panels.
❏6. Use a stack of books, blocks of balsa or similar
to support the raised wing panel at W-4. Align the
joiner tubes so the ends meet in the center of
the wing and clamp the tubes to the shear webs.
“Spot-glue” the ends of the joiner tubes in each
wing panel with medium CA or epoxy.

16
❏7. Carefully lift the wing from your building board
so you do not break the spot-glued joints, then place
it on the leading edges. Mix a batch of 30-minute
epoxy, then thoroughly glue the joiner tubes to the
shear webs, spars and ribs. Do not disturb the
wing until the epoxy cures.
❏8. Remove the clamps and separate the wing
panels. Make the top center section sheeting for
both wing panels from the remainder of the 1/16"
x 3" balsa sheet. Test fit the sheets and confirm
that the front and rear edges are flush with the TE,
upper spar and LE. If needed, trim the tops of the
ribs. Bevel the front edge of the front sheet so it
matches the LE, then glue the sheets in position.
❏9. Use a hobby knife and your bar sander with
150-grit sandpaper to trim the edge of the sheet
so it is even with W-1. Do not trim the ends of the
joiner tubes so they are flush with W-1.
❏10. Cut both of the TEs as shown on the plan.
Cut the 1/8" x 4" hardwood dowel into two pieces,
then test fit and glue the dowels to the TEs of both
wing panels with medium CA. Use your bar sander
to true the end of the dowels so they are flush with
the ends of the wing.
❏11. Test fit the die-cut 1/16" plywood W-1 root
ribs on the ends of the wing panels and the joiner
tubes. Then, glue them in position with medium
or thick CA. If you’ve just removed the W-1’s from
their die sheet, remember to save the leftover 1/16"
plywood to be used later during final landing gear
installation.
❏❏12. Test fit the 1/8" x 1/8" x 18" basswood
turbulator spars in the notches of the right wing
panel. The ends of the spars contact the center
sheeting and the tops of the spars are even with
the sheeting as shown in the following photo. If
necessary, adjust the notches so the spars fit
flush with the tops of the ribs, then glue the spars
in position with thin or medium CA.

17
❏❏13. Glue a piece of 1/8" leftover balsa to rib
W-2 to support the turbulator spars.Trim the ends
of the spars so they are even with the end of the
panel at rib W-4.
❏14. Glue the turbulator spars in the left wing
panel the same way.
❏15. Use a bar sander and 220-grit sandpaper on
both inner wing panels to carefully remove any glue
blobs and blend all the ribs to the spars, TE and LE.
Join the Outer & Inner Wing Panels
❏1. Remove the burrs and chamfer the ends of
the four 1/16" x 5" wing panel joiner wires with
a metal file or a powered hand tool and a cut-off
wheel. Remove any oil from the wires left from the
manufacturing process with a cloth dampened with
alcohol or other solvent. Thoroughly roughen the
wires with 150-girt sandpaper so the glue will stick.
❏❏2. Test fit the right inner wing panel to the
right outer wing panel. If necessary, use your bar
sander to adjust the ends of the spars, LEs or TEs
for a good fit.
❏❏3. With the mating W-4 ribs contacting each
other and the inner wing panel laying flat on your
building table, rib W-15 of the outer panel should be
approximately 4" off the table. If necessary, adjust
the ends of the spars at the W-4s to achieve the
approximate 4" measurement.
1/16" Holes
❏❏4. Use a hobby knife or a 1/16" drill to make
two holes in both W-4 ribs to accept the wire wing
panel joiners. Bend, then test fit the joiner wires.
Adjust the bends so the wires accurately match
the “bend” in the wing and fully contact the spars.
❏❏5. Apply a thin film of epoxy to the W-4 ribs,
then join the two panels with the joiner wires.
Support the tip the same way you did when you
joined the inner panels. Place a sheet of wax paper
under the wing to protect your building board from
excess epoxy, then clamp the W-4 ribs together.
Wipe away excess epoxy before it cures. Do not
apply epoxy to the joiner wires until instructed
to do so.

18
❏❏6. After the epoxy has fully cured, carefully
prop the wing up on its leading edge, then apply
30-minute epoxy to the wing joiner wires to securely
glue them to the shear webs and spars. Use T-pins if
necessary to hold the joiner wires against the spars.
Do not disturb the wing until the epoxy cures.
❏7. Return to step 2 and join the panels of the
other wing half the same way.
Finish the Wing
❏1. Drill a 1/16" hole in the bottom spar of both
wing halves where shown on the plan for the #2 x
3/8" screws to secure the wing halves with rubber
bands. We will instruct you to install the screws
after you cover the wings.
❏2. See the Tip that follows, then shape the LEs
of both wing panels.
Tip: HowTo Final ShapeThe LEs
The Butterfly is a motor glider not a high
performance aerobatic model – it’s named the
“Butterfly” after all! It is not critical that you shape
the leading edges with the greatest precision.You
probably would not notice any difference in the
flight performance of a Butterfly with a leading
edge accurately finished by an expert builder and
a Butterfly with a leading edge roughly carved to
shape with a hobby knife. This isn’t to say that
you should not always strive for building accuracy
and a good finish, but don’t worry if your LEs
don’t look perfect. Building a straight fuselage
and flat, warp-free wings are where you should
concentrate most your building efforts.
Here are some tips that can make shaping your
LEs a little easier and faster:
A.While you shape the LEs, frequently reference
the cross-section on the plan and the drawings
of the LE gauges on the plan. If you are a
perfectionist, cut the gauges from the plan, then
use rubber cement or spray adhesive to glue
them to leftover 1/8" plywood or thin cardboard
(such as a cereal box). Cut the gauges from the
wood or cardboard you glued them to, then test
fit the gauges to the appropriate sections of the
wing to arrive at the correct shape.
B.We highly recommend a razor plane to shape
the LEs until they are nearly the shape shown on
the plan – leave enough material to final shape
by sanding.
C. Shape the LEs of the inner panels first since
they have a constant shape from W-1 to W-4.
D. After you roughly shape the LE’s by carving
(or using the razor plane), final shape the LE’s
with a bar sander and 220-grit sandpaper. Wrap
a piece of 220-grit sandpaper around the LE and
final sand by hand.
E. Once you shape the inner LE’s, use the gauges
to final shape the outer LE’s and blend the two
together where they meet.
❏3. Inspect all glue joints of both wing panels. Add
CA to all glue joints that don’t look strong.
❏4. Final sand the wings with your bar sander
and 320-grit sandpaper and blend all the ribs with
TE, LE and spars.

19
Build the Fuselage
Prepare the Fuse Sides
All the parts used during fuselage construction are
die-cut 1/8" plywood unless otherwise specified.
❏1. Carefully remove the forward and aft fuselage
sides from their die sheets, then remove slivers or
die-cutting irregularities with a bar sander.
❏2. Lay the forward fuselage sides on your work
bench opposite each other in a “mirror image.”
Mark the inside of the fuselage sides as the “right
inside” and the “left inside” with a ballpoint pen.
❏3. Remove the portion of only the right fuselage
side indicated by the perforated line with a hobby
knife and a straightedge.
❏4. Glue the aft fuselage sides to the forward
fuselage sides with medium CA.Work over the plan
covered with wax paper to make sure the pieces
align. Use a bar sander and 150-grit sandpaper to
sand the two sides so they are flat and even.
❏5. Glue a servo rail support to the inside of both
fuselage sides at the location shown in the photo.
❏6. Place one of the fuselage sides on a piece of
scrap wood, then drill a 3/16" hole at both punch
marks for the wing dowels. Press down on the
fuselage side to keep the drill from splitting the
wood as it goes through. Repeat for the other
fuselage side.
❏7. While you have your drill and bits out, drill an
11/64" hole at the forward landing gear wire punch
mark in the right fuse side and the aft punch mark
in the left fuselage side. If you do not have an 11/64"
drill, you may use a 5/32" drill but you will have to
enlarge the hole slightly with a hobby knife.
❏8. Use thin CA to glue the 1/4" x 36" balsa triangle
fuselage reinforcement stringers to the top and
bottom of the inside of both fuselage sides. Be
certain you glue the stringers to the inside
of the fuselage sides. The front of the stringers
should be 1/8" aft of the front edge of the fuselage
sides (for F-5). Make the “splice” in the stringers
as shown on the plan at the rear of the fuselage.

20
❏9. Use the above die drawing of the fuselage parts
to mark each part with a ballpoint pen exactly as
they are shown. This will insure proper orientation
of the formers during construction.
❏10. Use medium CA to glue the notched aft
fuse side joiners (F-1) to both fuselage sides so
the front edge of the notches in the joiners are 1/4"
ahead of the front edge of the notches in the fuse
sides as shown in the photo.
❏11. Use a ballpoint pen and a straightedge to
draw a line connecting the punch marks on the
front of F-4 to indicate the position of your engine
mount. Draw two vertical lines (with the grain of
the wood) on the back of F-4 1/8" from each side
to indicate the position of F-5.
❏12. Glue F-5 to F-4 with epoxy so the edges of
F-5 align with the lines on the back of F-4 and the
top edges of F-4 and F-5 are even. From now on
this assembly will be referred to as the “firewall.”
Make certain that the “F-4” and “F-5” designations
you marked are in the same orientation. If the parts
are slightly warped, clamp them to a flat table or
board with wax paper between the board and the
parts. Wipe away excess epoxy before it cures.
❏13. Center the engine mount (not included) on
the firewall so the “rails” align with the horizontal
line. Use a piece of wire sharpened at one end to
mark the location of the engine mount holes on the
firewall. Remove the mount and drill 1/8" holes at
the marks to fasten mount with 4-40 x 1/2" machine
screws and 4-40 blind nuts (not included).We used
a Hayes 061 KM-15 engine mount (HAYG1061)
on our prototype.