GREAT PLANES TWINSTAR EP User manual

Champaign, Illinois
[phone], Ext 5
airsuppor[email protected]
GPMA1609 v1.1
READ THROUGH THIS MANUAL BEFORE STARTING CONSTRUCTION. IT CONTAINS IMPORTANT
INSTRUCTIONS AND WARNINGS CONCERNING THE ASSEMBLY AND USE OF THIS MODEL.
WARRANTY
Great Planes®Model Manufacturing Co. guarantees this kit to
be free from defects in both material and workmanship at the
date of purchase. This warranty does not cover any component
parts damaged by use or modication. 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 nal assembly or
material used for nal assembly, no liability shall be assumed nor
accepted for any damage resulting from the use by the user of
the nal 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, the buyer is advised to return
this kit immediately in new and unused condition to the
place of purchase.
To make a warranty claim send the defective 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.
© 2015 Great Planes Model Mfg. A subsidiary of Hobbico,
®Inc.
SPECIFICATIONS
INSTRUCTION MANUAL
Wingspan: 47.5 in [1205 mm ]
Wing Area: 392 in2 [25.3 dm2]
Weight: 4-4.25 lb
[1810-1930 g ]
Wing
Loading:
24-25 oz/ft2
[73-76 g/dm2]
Radio: 4-channel minimum with 4 servos
and standard size receiver
Motor: RimFire .10 (35-30-1250) x 2
Length: 42.5 in [1080 mm]

2
INTRODUCTION
Congratulations on your purchase of the Twinstar EP! Now
you can experience dual motor ight in a smaller package.
It's perfect for practicing up for scale twin engine models
or just to have some fun throwing it around in the air. The
Twinstar EP is plenty thrusty and capable of aerobatics and
is also extremely easy to y. This would be a good 2nd or
3rd plane after a trainer has been mastered and you have
some low wing experience. Best of all, this model can be
tossed in the backseat of a car fully assembled to get a
quick ight over lunch.
For the latest technical updates or manual corrections to the
Great Planes Twinstar EP visit the Great Planes web site at
www.greatplanes.com.
Open the “Airplanes” link, then select the Twinstar EP. If there
is new technical information or changes to this model a “tech
notice” box will appear in the upper left corner of the page.
AMA
We urge you to join the AMA (Academy of Model Aeronautics)
and a local R/C club. The AMA is the governing body of model
aviation and membership is required to y at AMA clubs.
Though joining the AMA provides many benets, one of the
primary reasons to join is liability protection. Coverage is not
limited to ying at contests or on the club eld. It even applies
to ying at public demonstrations and air shows. Failure to
comply with the Safety Code (excerpts printed in the back of
the manual) may endanger insurance coverage. Additionally,
training programs and instructors are available at AMA club
sites to help you get started the right way. There are over
2,500 AMA chartered clubs across the country. Contact the
AMA at the address or toll-free phone number below.
Academy of Model Aeronautics
5151 East Memorial Drive
Muncie, IN 47302-9252
Tele. [phone]
Fax [phone]
Or via the Internet at: http://www.modelaircraft.org
IMPORTANT!!! Two of the most important things you can
do to preserve the radio controlled aircraft hobby are to
avoid ying near full-scale aircraft and avoid ying near or
over groups of people.
SAFETY PRECAUTIONS
Protect Your Model, Yourself & Others...
Follow These Important Safety Precautions
1. Always disconnect the power on the model before
switching off the transmitter. Without a signal to the
receiver, the ESC may command the motor to rotate
which could cause injury to yourself or surrounding
property. Always turn the transmitter on before plugging
the ight battery into the ESC.
2. Your Twinstar EP should not be considered a toy, but rather
a sophisticated, working model that functions very much like
a full-size airplane. Because of its performance capabilities,
TABLE OF CONTENTS
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
AMA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
SAFETY PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . 3
DECISIONS YOU MUST MAKE . . . . . . . . . . . . . . . . . . . . 3
Radio Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Brushless Motor Recommendations . . . . . . . . . . . . . . 3
ADDITIONAL ITEMS REQUIRED . . . . . . . . . . . . . . . . . . . 3
Adhesives and Building Supplies . . . . . . . . . . . . . . . . 3
Optional Supplies and Tools . . . . . . . . . . . . . . . . . . . . 4
Building Stand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
IMPORTANT BUILDING NOTES . . . . . . . . . . . . . . . . . . . 4
KIT INSPECTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
KIT CONTENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
ORDERING REPLACEMENT PARTS . . . . . . . . . . . . . . . . 5
PREPARATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Check the Pre-Installed Hinges . . . . . . . . . . . . . . . . . . 6
ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Build the Wing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Assemble the Fuselage . . . . . . . . . . . . . . . . . . . . . . . 12
Apply the Decals . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
GET THE MODEL READY TO FLY . . . . . . . . . . . . . . . . . 17
Check the Control Directions. . . . . . . . . . . . . . . . . . . 17
Set the Control Directions . . . . . . . . . . . . . . . . . . . . . 17
Balance the Model (C.G.). . . . . . . . . . . . . . . . . . . . . . 18
Balance the Model Laterally . . . . . . . . . . . . . . . . . . . 19
PREFLIGHT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Identify Your Model . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Charge the Batteries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Balance Propellers. . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Range Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
MOTOR SAFETY PRECAUTIONS . . . . . . . . . . . . . . . . . 20
AMA SAFETY CODE (excerpts) . . . . . . . . . . . . . . . . . . . 20
General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Radio Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
CHECK LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
FLYING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Takeoff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Flight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Landing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

3
the Twinstar EP, if not assembled and operated correctly,
could possibly cause injury to yourself or spectators and
damage to property.
3. 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 unyable model. In a few
cases the instructions may differ slightly from the photos.
In those instances the written instructions should be
considered as correct.
4. You must take time to build straight, true and strong.
5. You must use an R/C radio system that is in rst-class
condition, and a correctly sized motor and components
(battery, servos, etc.) throughout the building process.
6. You must correctly install all R/C and other components so
that the model operates correctly on the ground and in the air.
7. You must check the operation of the model before every
ight to ensure 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.
8. If you are not an experienced pilot or have not own
this type of model before, we recommend that you get
the assistance of an experienced pilot in your R/C club for
your rst ights. 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.
9. While this kit has been ight tested to exceed normal use,
if the plane will be used for extremely high stress ying, or if
a motor larger than one in the recommended range is used,
the modeler is responsible for taking steps to reinforce the
high stress points and/or substituting hardware more suitable
for the increased stress.
We, as the kit manufacturer, provide you with a top quality,
thoroughly tested kit and instructions, but ultimately the
quality and yability of your nished 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.
REMEMBER: Take your time and follow the instructions
to end up with a well-built model that is straight and true.
DECISIONS YOU MUST MAKE
This is a partial list of items required to nish the Twinstar EP
that may require planning or decision making before starting
to build. Order numbers are provided in parentheses.
Radio Equipment
The Twinstar EP requires a minimum 4-channel radio
system with four 39 oz.-in. [2.8 kg-cm] minimum torque
micro sized servos.
Because the motors are mounted on the wings, rudder
authority is important. We recommend the Futaba S3150
mini servo as an optional higher torque servo for the rudder
and it is shown in the building section of this manual.
In addition, two 12" [305mm] servo extensions are required
for the aileron servos. Two Y-harnesses will also be required
for the ailerons and the ESCs.
Recommended part numbers for the radio components are
provided below:
❍Futaba S3115 Micro Precision Servo (FUTM0415)
❍Futaba S3150 Slim Digital Servo (FUTM0303)
❍Hobbico 12" Extension Futaba J (HCAM2100)
❍Futaba Dual Servo Extension 6" J (FUTM4130)
Brushless Motor Recommendations
We recommend two RimFire .10 brushless motors and two
25A ESCs. Other motors may work ne. However, the motor
mount holes are spaced for the RimFire .10 and this motor
has been extensively ight tested and performs well in the
Twinstar EP. Two 8x8E electric propellers are recommended
with the RimFire .10. Many batteries will work as a ight
battery. We suggest the 11.1V 3800mAh FP30 FlightPower
pack. Part numbers are provided below:
❍Great Planes RimFire .10 35-30-1250 Outrunner
Brushless (GPMG4595)
❍Great Planes Silver Series 25A Brushless ESC 5V/2A
BEC (GPMM1820)
❍APC 8x8 Thin Electric Propeller (APCQ4116)
❍FlightPower LiPo FP30 3S 11.1V 3800mAh 30C
(FPWP3383)
If you need a charger for your ight battery, we suggest either
the Triton EQ or Triton 2 EQ. Both are very versatile chargers
that can charge virtually any hobby battery currently available.
❍Great Planes ElectriFly Triton EQ AC/DC Charger
(GPMM3155)
❍Great Planes ElectriFly Triton2 EQ AC/DC Charger
(GPMM3156)
ADDITIONAL ITEMS REQUIRED
Adhesives and Building Supplies
This is the list of Adhesives and Building Supplies that are
required to nish the Twinstar EP:
❍1/2 oz. [15g] Thin Pro CA (GPMR6001)
❍Pro 6-minute or 30-minute epoxy (GPMR6045 or
GPMR6047)
❍Threadlocker thread locking cement (GPMR6060)
❍Denatured alcohol (for epoxy clean up)
❍Drill bits: 1/16" [1.6mm], 5/64" [2mm]
❍Rotary tool with cutting bit
❍Revell Premium Soft Handle Knife w/Blades (5)
(RMXR6900)
❍Top Flite MonoKote sealing iron (TOPR2100)
❍Top Flite Hot Sock iron cover (TOPR2175)
❍Panel Line Pen (TOPQ2510)
❍Small clamps
❍Masking tape
❍Household oil

4
Optional Supplies and Tools
Here is a list of optional tools that will help you build the
Twinstar EP:
❍1/2 oz. [15g] Thick Pro CA- (GPMR6013)
❍1/2 oz. [15g] Medium Pro CA+ (GPMR6007)
❍2 oz. [57g] spray CA activator (GPMR6035)
❍4 oz. [113g] aerosol CA activator (GPMR6034)
❍CA applicator tips (HCAR3780)
❍CA debonder (GPMR6039)
❍Epoxy brushes 6, (GPMR8060)
❍Mixing sticks (GPMR8055)
❍Mixing cups (GPMR8056)
❍Pliers with wire cutter (HCAR0630)
❍T.A. Emerald Performance Duster Compressed Air
(TAEC1060)
❍Servo horn drill (HCAR0698)
❍Hobby Heat micro torch II (HCAR0755)
❍Dead Center™ Engine Mount Hole Locator
(GPMR8130)
❍DuraTrax Ultimate Body Reamer (DTXR1157)
❍Precision Magnetic Prop Balancer (TOPQ5700)
❍AccuThrow Deection Gauge (GPMR2405)
❍CG Machine™ (GPMR2400)
❍Hobbico Flexible 18" Ruler Stainless Steel
(HCAR0460)
❍Top Flite MonoKote trim seal iron (TOPR2200)
❍Top Flite MonoKote heat gun (TOPR2000)
❍Hobbico Pin Vise 1/16 Collet w/6 Bits (HCAR0696)
❍Hobbico 8-Piece Ball Tip Hex L Wrench SAE
(HCAR0520)
❍Hobbico 7-Piece Ball Tip Hex L Wrench Metric
(HCAR0521)
❍Great Planes Clevis Installation Tool (GPMR8030)
❍Great Planes Precision Prop Reamer Standard
(GPMQ5006)
Building Stand
A building stand or cradle comes in handy during the build.
We use the Robart Super Stand II (ROBP1402) for all our
projects in R&D, and it can be seen in pictures in this manual.
IMPORTANT BUILDING NOTES
●When you see the term test t in the instructions, it means
that you should rst position the part on the assembly
without using any glue, then slightly modify or custom
t the part as necessary for the best t.
●Whenever the term glue is written you should rely upon
your experience to decide what type of glue to use. When
a specic type of adhesive works best for that step, the
instructions will make a recommendation.
●Whenever just epoxy is specied you may use either
30-minute epoxy or 6-minute epoxy. When 30-minute
epoxy is specied it is highly recommended that you use
only 30-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.
●The stabilizer and wing incidences and motor thrust angles
have been factory-built into this model.
●The Twinstar EP is factory-covered with Top Flite MonoKote
lm. Should repairs ever be required, MonoKote can be
patched with additional MonoKote purchased separately.
Following are the colors used on this model and order
numbers for six foot rolls.
Royal Blue TOPQ0221 Black TOPQ0208
Jet White TOPQ0204 Missile Red TOPQ0201
KIT INSPECTION
Before starting to build, take an inventory of this kit to make
sure it is complete, and inspect the parts to make sure they
are of acceptable quality. If any parts are missing or are not of
acceptable quality, or if you need assistance with assembly,
contact Product Support. When reporting defective or
missing parts, use the part names exactly as they are written
in the Kit Contents list.
Great Planes Product Support
3002 N Apollo Drive, Suite 1 Ph: [phone], ext. 5
Champaign, IL 61822 Fax: [phone]
E-mail: [email protected]
ORDERING REPLACEMENT PARTS
Replacement parts for the Great Planes Twinstar EP ARF are
available using the order numbers in the Replacement Parts
List that follows. The fastest, most economical service can
be provided by your hobby dealer or mail-order company.

5
To locate a hobby dealer, visit the Hobbico web site at www.
hobbico.com. Choose “Where to Buy” at the bottom of the menu
on the left side of the page. Follow the instructions provided
on the page to locate a U.S., Canadian or International dealer.
Parts may also be ordered directly from Hobby Services by
calling [phone], or via facsimile at [phone], but
full retail prices and shipping and handling charges will apply.
Illinois and Nevada residents will also be charged sales tax.
If ordering via fax, include a Visa®or MasterCard®number
and expiration date for payment.
Mail parts orders Hobby Services
and payments by 3002 N Apollo Drive, Suite 1
personal check to: Champaign IL 61822
Be certain to specify the order number exactly as listed in
the Replacement Parts List. Payment by credit card or
personal check only; no C.O.D.
If additional assistance is required for any reason contact
Product Support by e-mail at productsupport@greatplanes.
com, or by telephone at [phone].
Order No. Description
WING SET TWINSTAR EP ARF
FUSELAGE TWINSTAR EP ARF
TAIL SET TWINSTAR EP ARF
SPINNER TWINSTAR EP ARF
NACELLE FRAME L/R TWINSTAR EP
NACELLE COVER (2) TWINSTAR EP
LANDING GEAR TWINSTAR EP ARF
NOSE CONE TWINSTAR EP ARF
DECAL SET TWINSTAR ARF
BATTERY HATCH TWINSTAR EP ARF
ESC Y-HARNESS TWINSTAR EP ARF
GPMA4390
GPMA4391
GPMA4392
GPMA4393
GPMA4394
GPMA4395
GPMA4396
GPMA4397
GPMA4398
GPMA4399
GPMA4400
REPLACEMENT PARTS LIST
KIT CONTENTS
Kit Contents 1 Nose Cone
2 Battery Hatch
3 Fuselage
4 Horizontal Stabilizer and Elevator
5 Vertical Fin and Rudder
6 Wing Joiner
7 Right Wing Panel with Aileron
8 Nacelle Covers
9 Nacelle Frames
10 Left Wing Panel with Aileron
11 Nylon Spinner
12 Wheels
13 Nose Gear
14 Main Gear
1
3
4
10
5
11
12
13
14
2
7
8
9
6

6
PREPARATIONS
❏ 1. If you have not done so already, remove the major parts
of the kit from the box and inspect for damage. If any parts
are damaged or missing, contact Product Support at the
address or telephone number listed in the “Kit Inspection”
section on page 4.
❏ 2. Use a covering iron with a covering sock on high heat
to tighten the covering if necessary. Apply pressure over
sheeted areas to thoroughly bond the covering to the wood.
Take care when applying heat onto trim covering applied over
the base color. Move the iron at a rate slow enough to get
the covering hot but not so slow that the top color shrinks
on top of the base color causing the edges to pull away.
Check the Pre-Installed Hinges
This model has all of the control surfaces pre-hinged at the
factory. No additional glue is typically necessary; however, all
of the hinged surfaces must be carefully checked to conrm
they are securely attached. This procedure should be part
of your pre-ight check each and every time you y.
❏ 1. Grasp each control surface at one end, taking care
not to dent or puncture the covering or the wood structure
beneath. Pull the control surface away from the hinge line.
Move your hand along the surface and repeat the check for
the entire length of the surface.
❏ 2. If you nd a control surface with loose hinges, you will
need to add thin CA glue to the hinges. Push the control
surface back into place. Deect the control surface all the
way in one direction in order to expose the center of the
hinge. Apply 6 to 7 drops of thin CA glue to each hinge. Do
NOT use accelerator! The CA glue must be allowed to slowly
wick into the hinge and surrounding wood. When the glue has
dried, ip the model over and add 6 or 7 drops to the other
side of each hinge. It is recommended that you reinforce
every hinge on the model with CA glue if you found even
one loose hinge. Conrm the control surfaces move freely
and are well secured.
ASSEMBLY
Build the Wing
CUT OFF
UNUSED
ARMS
❏ 1. Center your aileron servos with your radio system. Test
t four-armed servo arms onto the servos to determine

7
their best orientation so that the arms are closest to being
perpendicular with the servo case. Cut three arms from each
servo arm leaving one arm on each servo that matches the
photo. Enlarge the hole closest to 9/16" [14.3 mm] to the
center of the servo arm of each remaining arm with a 5/64"
[ 2 mm] drill bit. Attach a 12" [305 mm] servo extension to each
servo. Secure the connection using the pieces of included
heat shrink tubing. Install the rubber grommets and eyelets
onto the servo mounting tabs.
❏ 2. Tie the string ends that are taped inside the wings at
the aileron servo bays to the servo extension connectors.
❏ 3. Pull the strings through the root ribs. Be careful not to
damage the wing ribs as you pull the servo leads through them.
❏ 4. Fit the servos into the servo openings and drill 1/16"
[1.6mm] holes through the mounting tabs on the servo cases
into the rails. Thread a servo mounting screw (included with
the servo) into each hole and remove it. Apply a drop of thin
CA to each hole to harden the surrounding wood. When the
CA has hardened, install the servos into the openings as
shown using the screws supplied with the servos.
❏ 5. Thread a nylon clevis onto two 6" [150mm] aileron
pushrods 20 complete turns.
Hinge Line Hinge Line
Correct Incorrect
❏ 6. Separate the back plates from two control horns using
a knife or sprue cutters. Connect the clevises on the aileron

8
pushrods to the outer holes of the control horns. Position
the control horns over the hardwood plates in the ailerons
(if you cannot see them, hold the aileron at a shallow angle
in good lighting or use a small pin to puncture the covering)
being sure the pushrods are lined up with the enlarged holes
in the aileron servo arms.
❏ 7. Use a felt-tip pen to mark the location of the control
horn mounting holes onto both ailerons.
Drill 5/64" [2mm] holes at the marks you made. Thread 2-56
x 1/2" [13mm] machine screws into each hole and secure the
control horns into place with the control horn back plates.
❏ 8. With the ailerons in the neutral position (use tape or
small clamps to hold them in place), mark the pushrod wires
where they cross the enlarged holes in the servo arms.
Servo Arm
1/16" [ 1.6 mm]
Pushrod Wire
FasLink
❏ 9. Make a 90 degree bend at the mark on each pushrod
and cut off the excess pushrod 1/4" [6mm] beyond the bends.
Attach the pushrods to the servo arms using nylon FasLinks.
Thread the clevises in or out on the pushrods as necessary
to center the ailerons with the servo arms still perpendicular
to the servo cases. (Never center the servo with the power
on.) When satised, slide silicone clevis retainers onto the
ends of the clevises to secure them.

9
❏ 10. Locate the plywood nacelle frames. Coat the wing
pockets and aft ends with epoxy and t the frames into the
cutouts in the wings. Wipe away any excess epoxy with a
paper towel wetted with denatured alcohol. Use tape to hold
them in place. With epoxy still wet, put a thin coating on the
inside wall in the location shown on each frame. This will
provide a smooth surface to mount the ESC.
❏ 11. Install the aluminum X-mount onto the motors using
the screws included with the motors and thread locking
compound. Install the prop adapters using the screws
included with the motors and thread locking compound.
❏ 12. Mount the motors to the nacelle rewalls using 3 x12 mm
machine screws, 3mm at washers, and thread locking
compound. Be sure that the motor leads are towards the
top of the wing.

10
❏ 13. Feed one of the female ends of the battery Y-harness
through the forward wing sheeting hole in one wing panel.
Manuever it through the wing ribs and into the nacelle frame.
❏ 14. Connect an ESC to the battery Y-harness end you
inserted through the wing. Use one of the included tie
straps to secure the connectors together as shown. Use a
piece of the included double-sided foam tape to stick the
ESC to the inside of the nacelle frame where you applied
the epoxy coating.
❏ 15. Feed the other female end of the battery Y-harness
through the wing sheeting hole in the other wing panel
and into the nacelle frame. Connect the ESC to the battery

11
Y-harness and secure it with a tie strap. Look ahead to the
photo in step 16 and feed the ESC receiver leads through
the same holes as the battery harness and the aileron servo
leads through the aft wing sheeting holes.
❏ 16. Use epoxy to laminate the two wing joiner pieces
together. Use a paper towel dampened with denatured
alcohol to clean up any excess epoxy from around the joiner.
Use sping clamps or weight the joiner with something heavy
while the epoxy cures. When the epoxy is cured test t the
joiner into each wing panel, making sure it can slide in all the
way without difculty. Sand the joiner if necessary. Mix up a
batch of 30-minute epoxy and coat both wing roots, joiner
pockets and the joiner. Slide the wing panels together and
use tape to hold the panels tightly together while the epoxy
cures. Clean up excess epoxy with denatured alcohol.
CHECK THE MOTOR ROTATION
Before installing the nacelle covers in the next step, we
recommend temporarily connecting the ESCs to your
receiver and power up the system. Use the transmitter
to operate the motors. Check to ensure that both motors
are rotating counter-clockwise when looking at them
head on. If not, disconnect any two of the three motor
leads for the motor running the incorrect direction and
swap their positions. Run the motors again to conrm
the correct rotation.
❏ 17. Position the ABS nacelle covers over the frames. Align
them so the prop adapter is centered within the nacelle covers
and the prop adapter faces are about 5/64" [2mm] in front
of the covers. Use tape to temporarily hold the covers in
place. Drill ve 1/16" [1.6mm] holes evenly spaced around the
perimeter of each cover in the locations shown. Remove the
covers from the wing panels and thread a #2 x 3/8" [9.5mm]
self-tapping screw into each hole and then remove it. Apply
a few drops of thin CA glue to every hole and let it harden
without the use of accelerator. Install the covers onto the
wing panels using ten #2x 3/8" [9.5mm] screws.

12
❏ 18. Use a sharp hobby knife to trim the covering from two
of the elliptical cutouts in the bottom of the nacelle frames.
This will allow cool air to pass over the motors and ESCs and
then exit the nacelle frames.
❏ 19. Fit the main landing gear wires into the slots in the
wing. Place nylon landing gear straps into the cutouts in
order to mark the locations for the screw holes. Drill 5/64"
[ 2 mm] holes at the marks you made. Thread a #4 x 3/8"
[9.5 mm] washer head screw into each hole and then remove
it. Apply a drop or two of thin CA to each hole to harden the
surrounding wood. Let the glue harden without accelerator.
Install the straps in place using four washer head screws.
Repeat for the other side.
❏ 20. Slide a 3.5mm wheel collar followed by the wheel, then
another 3.5mm wheel collar. Use a felt tip pen to mark the
position of each collar onto the axle. Grind a at spot onto the
axle for each wheel collar set screw (look at the at spots on
the nose gear for an example). Install the wheel collars and
wheels back onto the axles and secure the collars with 3mm
set screws and thread locking compound. Check that the
wheel rotates smoothly. Add a drop or two of oil if necessary.
Assemble the Fuselage
❏ 1. Mount the steering
nose block onto the front
of the fuselage using four
3x12mm machine screws,
four 3mm at washers and
thread locking compound.
❏ 2. Install a brass screw lock connector into the outer hole of
the nylon steering arm with a nylon retainer. Loosely thread a
3mm set screw into the screw lock connector. Loosely thread
a 3x6mm machine screw into the steering arm. Assemble
the nose gear into the steering block as shown. Tighten a
wheel collar with a 3mm set screw at the top to secure the
nose gear in place. Install the nose wheel onto the axle as
you did the main wheels.
❏ 3. Temporarily mount the wing to the fuselage using the
two 10-24 x 2" [51mm] nylon wing bolts.

13
❏ 4. Fit the vertical n and horizontal stabilizer into place.
Use a felt tip marker to trace around the fuselage onto the tail
parts top and bottom and left and right side. Trace around the
n onto the fuse. Remove the tail parts and trim the covering
away 1/16" [1.6mm] inside your lines as shown.
HOW TO CUT COVERING FROM BALSA
Use a soldering iron to cut the covering from the stab. The
tip of the soldering iron doesn’t have to be sharp, but a
ne tip does work best. Allow the iron to heat fully.
Use a straightedge to guide the soldering iron at a rate
that will just melt the covering and not burn into the wood.
The hotter the soldering iron, the faster it must travel to
melt a ne cut. Peel off the covering.
❏ 5. Re-insert the horizontal stabilizer and vertical n into
the fuse. With the wing in place, stand behind the model
approximately 10 feet [3m] and conrm that the stab sits
parallel with the wing. If not, weight can be added to the high
side while gluing the stab in place, or the stab pocket can
be lightly sanded until the stab and wing sit parallel. When
satised, remove the stab and n and coat the exposed
wood with 30-minute epoxy (although messy, a more reliable
glue joint can be attained if you also coat the inside edges of
the stab pocket). Reinstall the stab and n. Wipe away any
excess epoxy with denatured alcohol and let the epoxy cure
undisturbed. When cured, the wing can be removed from
the fuselage and set aside as it will not be needed until the
nal set up of the plane.
Install servo arms onto the elevator and rudder servos as
shown. A brass screw lock connector is needed for the
nose gear pushrod. Enlarge the holes for the rudder and
elavator pushrods using a 5/64" [2mm] drill bit. We chose
a high torque servo for the rudder for more responsive yaw
control in ight.

14
❏ 6. Thread a nylon clevis onto a 27" [685 mm] pushrod.
Attach the clevis to a control horn and slide the pushrod into
the outer pushrod tube on the right side of the fuse. As you
did with the ailerons, align the control horn over the elevator
hinge line and mark the location of the screw holes. Drill
5/64" [2mm] holes at your marks and install the horn using
two 2-56 x 3/8" [ 9.8 mm] machine screws and the control
horn backplate.
❏ 7. Install the rudder control horn in the same manner as
you did the elevator control horn.
❏ 8. Install the rudder and elevator servos onto the tail servo
tray using the hardware included with the servos. Use the
position of the tail pushrods as they exit the pushrod tubes
to determine the location of the servos on the tray. The
servos should be aligned so that the pushrods overlap the
enlarged holes in the servo arms. Be sure to harden the wood
surrounding the mounting screw holes with thin CA. Center
the servos with the radio.
❏ 9. Use tape or clamps to temporarily hold the elevator and
rudder in the neutral position. Mark the pushrods where they
cross the enlarged holes in the servo arms. Make a 90º bend
at the marks. As you did with the ailerons, cut the pushrods
and connect them to the servos using two FasLinks. Cut
off the threaded portion from the remaining 18" [457mm]
pushrod. Slide it through the two screw lock connectors for
the nose gear steering arm and rudder servo. Align the nose
wheel so it’s pointing straight, then tighten the set screws
in the screw lock connectors. You may need to adjust the
pushrod once you taxi the plane.

15
❏ 10. Mix up a small batch of epoxy and apply a thin coat to
the battery tray and the side of the fuselage by the elevator
servo for the purpose of attaching the receiver.
❏ 11. When the epoxy from the previous step has completely
cured, use a piece of the included self-adhesive hook and
loop material to attach the receiver as shown.
❏ 12. Cut the included 4"[100 mm] length of white tube into
two equal pieces. Use CA to glue the pieces 90 degrees to
each other near the receiver. Feed the antenna wires into the
tubes. Note: some receivers may have only one antenna or
no exposed antennas at all. Consult your radio manual for
requirements for positioning the antenna(s).

16
❏ 13. Mark the location of the nose gear wire onto the nose
cone when you hold it up in place. Use a rotary tool to cut
a slot for the wire. The nose cone can be glued, screwed
(screws not included) or taped on. We prefer using tape on
this model because it allows easy access to the nose gear
as well as looking better. If you decide to glue it on then we
recommend RTV silicone.
❏ 14. Cut a length of non-adhesive hook and loop material 5"
[127mm]. Overlap the mating ends approximately 1" [25mm]
to make a strap. Put a piece of hook material from the self-
ahesive hook and loop material and stick it to the battery
tray. Fish the strap you made through the middle slots in
the battery tray.
❏ 15. If you have already used your radio to check the
operation of the motors, install the propellers and spinners
onto the motor shafts.
❏ 16. Congratulations on the completion of the Twinstar EP!
Now it’s time to put on the decals, balance the plane and
conrm the control throws.

17
Apply the Decals
❏ 1. Be certain the model is clean and free from oily
ngerprints and dust. Prepare a dishpan or small bucket
with a mixture of liquid dish soap and warm water—about one
teaspoon of soap per gallon of water. Submerse the decal
in the soap and water and peel off the paper backing. Note:
Even though the decals have a “sticky-back” and are not the
water transfer type, submersing them in soap & water allows
accurate positioning and reduces air bubbles underneath.
❏ 2. Position decal on the model where desired. Holding the
decal down, use a paper towel to wipe most of the water away.
❏ 3. Use a piece of soft balsa or something similar to
squeegee remaining water from under the decal. Apply the
rest of the decals the same way.
GET THE MODEL READY TO FLY
Check the Control Directions
❏ 1. Apply the loop side of the self-adhesive hook and loop
material to your ight battery. Install the pack in the battery
compartment and strap it down.
❏ 2. Turn on the transmitter, plug in the battery and center the
trims (remember the ight battery should never be plugged in
if the transmitter is off!). If necessary, remove the servo arms
from the servos and reposition them so they are centered.
Reinstall the screws that hold on the servo arms.
❏ 3. With the transmitter still on and the ight battery plugged
in, check all the control surfaces to see if they are centered.
If necessary, adjust the clevises on the pushrods to center
the control surfaces.
FULL
THROTTLE
RUDDER
MOVES
RIGHT
ELEVATOR
MOVES DOWN
RIGHT AILERON
MOVES UP
LEFT AILERON
MOVES DOWN
4-CHANNEL RADIO SET UP (STANDARD MODE 2)
❏ 4. Make certain that the control surfaces and the throttle
respond in the correct direction as shown in the diagram.
If any of the controls respond in the wrong direction, use
the servo reversing in the transmitter to reverse the servos
connected to those controls. Be certain the control surfaces
have remained centered. Adjust if necessary.
Set the Control Directions
Use a Great Planes AccuThrow (or a ruler) to accurately
measure and set the control throw of each control surface
as indicated in the chart that follows. If your radio does not
have dual rates, we recommend setting the throws at the
low rate setting.
NOTE: The throws are measured at the widest part of the
elevators, rudder and ailerons.

18
These are the recommended control surface throws:
ELEVATOR
HIGHLOW
3/8"
[ 9.5 mm ]
20°
1/4"
[6.4 mm]
14°
7/16"
[11mm]
21°
1/4"
[ 6 mm ]
11°
1-1/16"
[27mm]
30°
13/16"
[21mm]
23°
RUDDER
AILERONS
Up & Down
Up & Down
Right & Left
IMPORTANT: The Twinstar EP has been extensively
own and tested to arrive at the throws at which it ies
best. Flying your model at these throws will provide you
with the greatest chance for successful rst ights. If, after
you have become accustomed to the way the Twinstar
ies, you would like to change the throws to suit your taste,
that is ne. However, too much control throw could make
the model difcult to control, so remember, “more is not
always better.”
The pushrod farther out
means More Throw
The pushrod closer in
means Less Throw
The pushrod farther out
means Less Throw
The pushrod closer in
means More Throw
At the Servos
At the Control Surfaces
❏ 1. If necessary, adjust the location of the pushrod on the
servo arms with your ATVs remaining set at 100%. Increase
or decrease the throw according to the measurements in the
control throws chart.
If you built your model using the servo arm hole measurements
given to you then your control throws should match or be close
to the recommended control throws. If not, the pushrod may
be moved inward on the control horn to increase the throw,
but it’s better to go farther out on the servo arm because
this will introduce less free play than the alternative. Only
after moving the pushrod all the way out on the servo arm,
if you still can’t get the throw required, you’ll have to resort
to moving the pushrod closer in on the control horn. Note: If
you have a computer radio, it is always desirable to set your
ATVs to 100% (or as near 100% as possible to achieve the
control throw required).
“Closest in”
on servo arm
“Farthest out”
on control horn
Preferred Pushrod Hookup
Balance the Model (C.G.)
More than any other factor, the C.G. (balance point) can
have the greatest effect on how a model ies, and may
determine whether or not your rst ight will be successful.
If you value this model and wish to enjoy it for many ights,
DO NOT OVERLOOK THIS IMPORTANT PROCEDURE.
A model that is not properly balanced will be unstable and
possibly unyable.
At this stage the model should be in ready-to-y condition with
all of the systems in place including the engine or brushless
motor, landing gear, and the radio system (and battery pack
if applicable).
❏ 1. Use a felt-tip pen or 1/8" [3mm]-wide tape to accurately
mark the C.G. on the top of the wing on both sides of the
fuselage. The C.G. is located 2-1/2" [64mm] back from the
leading edge of the wing.
This is where your model should balance for the rst ights.
Later, you may wish to experiment by shifting the C.G. up
to 5/16" [8mm] forward or 5/16" [8mm] back to change
the ying characteristics. Moving the C.G. forward may
improve the smoothness and stability, but the model may
then require more speed for takeoff and make it more
difcult to slow for landing. Moving the C.G. aft makes
the model more maneuverable, but could also cause it to
become too difcult to control. In any case, start at the
recommended balance point and do not at any time
balance the model outside the specied range.

19
❏ 2. With the wing attached to the fuselage and all parts of
the model installed (ready to y), place the model on a Great
Planes CG Machine upside down, or lift it at the balance
point you marked.
❏ 3. If the tail drops, the model is “tail heavy” and the battery
pack and/or receiver must be shifted forward or weight must
be added to the nose to balance. If the nose drops, the
model is “nose heavy” and the battery pack and/or receiver
must be shifted aft or weight must be added to the tail to
balance. If possible, relocate the battery pack and receiver
to minimize or eliminate any additional ballast required. If
additional weight is required, use Great Planes (GPMQ4485)
“stick-on” lead. A good place to add stick-on nose weight
is to the front of the fuselage above the nose gear steering
block (don’t attach weight to the cowl—it is not intended to
support weight). Begin by placing incrementally increasing
amounts of weight on the bottom of the front of the fuse until
the model balances. Once you have determined the amount
of weight required, it can be permanently attached. If required,
tail weight may be added by cutting open the bottom of the
fuselage and gluing it permanently inside.
Note: Do not rely upon the adhesive on the back of the lead
weight to permanently hold it in place. Over time, fuel and
exhaust residue may soften the adhesive and cause the
weight to fall off. Use #2 sheet metal screws, RTV silicone
or epoxy to permanently hold the weight in place.
❏ 4. IMPORTANT: If you found it necessary to add any
weight, recheck the C.G. after the weight has been installed.
Balance the Model Laterally
❏ 1. With the wing level, have an assistant help you lift the
model by the underside front of the fuselage behind the nose
gear and the bottom of the fuse under the TE of the n. Do
this several times.
❏ 2. If one wing always drops when you lift the model, it
means that side is heavy. Balance the airplane by adding
weight to the other wing tip. An airplane that has been
laterally balanced will track better in loops and other
maneuvers.
PREFLIGHT
Identify Your Model
No matter if you y at an AMA sanctioned R/C club site or if
you y somewhere on your own, you should always have your
name, address, telephone number and AMA number on or
inside your model. It is required at all AMA R/C club ying sites
and AMA sanctioned ying events. Fill out the identication
tag on page 23 and place it on or inside your model.
Charge the Batteries
Follow the battery charging instructions that came with your
radio control system to charge the batteries. You should always
charge your transmitter the night before you go ying, and
at other times as recommended by the radio manufacturer.
CAUTION: Unless the instructions that came with your
radio system state differently, the initial charge on new
transmitter batteries should be done for 15 hours using
the slow-charger that came with the radio system.
This will “condition” the batteries so that the next charge
may be done using the fast-charger of your choice. If the
initial charge is done with a fast-charger the batteries may
not reach their full capacity and you may be ying with
batteries that are only partially charged.
Balance Propellers
Carefully balance your propeller and spare propellers before
you y. An unbalanced prop can be the single most signicant
cause of vibration that can damage your model. Not only will
motor mounting screws loosen, possibly with disastrous effect,
but vibration may also damage your radio receiver and battery.
We use a Top Flite Precision Magnetic Prop Balancer
(TOPQ5700) in the workshop and keep a Great Planes
Fingertip Prop Balancer (GPMQ5000) in our ight box.
Range Check
Ground check the operational range of your radio before the
rst ight of the day. With the transmitter antenna collapsed
and the receiver and transmitter on, you should be able to walk
at least 100 feet away from the model and still have control
(if using a 2.4GHz radio system, refer to the radio manual for
the range checking procedure). Have an assistant stand by

20
your model and, while you work the controls, tell you what the
control surfaces are doing. Repeat this test with the motor
running at various speeds with an assistant holding the
model, using hand signals to show you what is happening. If
the control surfaces do not respond correctly, do not y! Find
and correct the problem rst. Look for loose servo connections
or broken wires, corroded wires on old servo connectors, or
a damaged receiver crystal from a previous crash.
MOTOR SAFETY PRECAUTIONS
Failure to follow these safety precautions may result
in severe injury to yourself and others.
●Always disconnect the power on the model before
switching off the transmitter. Without a signal to the
receiver, the ESC may command the motor to rotate which
could cause injury to yourself or surrounding property.
Always turn the transmitter on before plugging the ight
battery into the ESC.
●Get help from an experienced pilot when learning to
operate electric motors.
●Use safety glasses when running electric motors.
●Do not run the motors in an area of loose gravel or sand;
the propellers may throw such material in your face or eyes.
●Keep your face and body as well as all spectators away from
the plane of rotation of the propellers as you run the motors.
●Keep these items away from the props: loose clothing,
shirt sleeves, ties, scarves and ascots, long hair or loose
objects such as pencils or screwdrivers that may fall out
of shirt or jacket pockets into the props.
●The motors gets hot! Do not touch them during or right
after operation.
AMA SAFETY CODE (excerpts)
Read and abide by the following excerpts from the Academy
of Model Aeronautics Safety Code. For the complete Safety
Code refer to Model Aviation magazine, the AMA web site
or the Code that came with your AMA license.
General
1) I will not y my model aircraft in sanctioned events, air
shows, or model ying demonstrations until it has been
proven to be airworthy by having been previously, successfully
ight tested.
2) I will not y my model aircraft higher than approximately
400 feet within 3 miles of an airport without notifying the
airport operator. I will give right-of-way and avoid ying in the
proximity of full-scale aircraft. Where necessary, an observer
shall be utilized to supervise ying to avoid having models y
in the proximity of full-scale aircraft.
3) Where established, I will abide by the safety rules for the
ying site I use, and I will not willfully and deliberately y my
models in a careless, reckless and/or dangerous manner.
5) I will not y my model unless it is identied with my name
and address or AMA number, on or in the model. Note: This
does not apply to models while being own indoors.
7) I will not operate models with pyrotechnics (any device
that explodes, burns, or propels a projectile of any kind).
Radio Control
1) I will have completed a successful radio equipment range
check before the rst ight of a new or repaired model.
2) I will not y my model aircraft in the presence of spectators
until I become a qualified flier, unless assisted by an
experienced helper.
3) At all ying sites a straight or curved line(s) must be
established in front of which all ying takes place with the
other side for spectators. Only personnel involved with ying
the aircraft are allowed at or in the front of the ight line.
Intentional ying behind the ight line is prohibited.
4) I will operate my model using only radio control frequencies
currently allowed by the Federal Communications Commission.
5) I will not knowingly operate my model within three
miles of any pre-existing ying site except in accordance
with the frequency sharing agreement listed [in the
complete AMA Safety Code].
9) Under no circumstances may a pilot or other person
touch a powered model in ight; nor should any part of the
model other than the landing gear, intentionally touch
the ground, except while landing.
CHECK LIST
During the last few moments of preparation your mind
may be elsewhere anticipating the excitement of the rst
ight. Because of this, you may be more likely to overlook
certain checks and procedures that should be performed
before the model is own. To help avoid this, a check list
is provided to make sure these important areas are not
overlooked. Many are covered in the instruction manual,
so where appropriate, refer to the manual for complete
instructions. Be sure to check the items off as they are
completed (that’s why it’s called a check list!).
❏ 1. Check the C.G. according to the measurements
provided in the manual.
❏ 2. Be certain the battery and receiver are securely
mounted in the fuse. Simply stufng them into place
with foam rubber is not sufcient.
❏ 3. Extend your receiver antenna (if applicable).
❏ 4. Balance your model laterally as explained in
the instructions.
❏ 5. Use threadlocking compound to secure critical
fasteners such as the set screws that hold the wheel
collars to the axles, screw-lock pushrod connectors, etc.
❏ 6. Add a drop of oil to the axles so the wheels will
turn freely.
❏ 7. Make sure all hinges are securely glued in place.
❏ 8. Reinforce holes for wood screws with thin CA
where appropriate (servo mounting screws, cowl
mounting screws, etc.).