Great Planes GPMA1240 User Manual

WARRANTY

Great Planes

®

Model Manufacturing Co. guarantees this kit to be free from defects in both material and workmanship at the date of
purchase. This warranty does not cover any component parts damaged by use or modification. In no case shall Great Planes'
liability exceed the original cost of the purchased kit. Further, Great Planes reserves the right to change or modify this warranty

without notice.
In that Great Planes has no control over the final assembly or material used for final assembly, no liability shall be assumed nor

accepted for any damage resulting from the use by the user of the final user-assembled product. By the act of using the user­assembled product, the user accepts all resulting liability.

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

While this kit has been flight tested to exceed normal use, if the plane will be used for extremely high stress flying, such as racing, the
modeler is responsible for taking steps to reinforce the high stress points.

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

GPMZ0212 for GPMA1240 V1.0© Copyright 1998

P.O. Box 788 Urbana, IL 61803 [phone]

INSTRUCTION MANUAL

Important Safety Precaution......................................................2

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

Precautions .................................................................................2

Decisions You Must Make..........................................................3

Engine Selection....................................................................3

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

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

Building Supplies and Tools...................................................3

Optional Supplies and Tools ..................................................3

General Inspection ................................................................4

Pushrod Template #1.............................................................4

Pushrod Template #2.............................................................4

Inch/Metric Ruler ...................................................................4

Parts List................................................................................5

Begin Construction ....................................................................6

Fuelproof the Fuselage..........................................................6

Join the Wing Halves.............................................................6

Mount the Engine & Install the Fuel Tank ..............................7

Mount the Stab & Fin.............................................................9

Mount the Landing Gear......................................................11

Join The Control Surfaces.......................................................13

Rudder Assembly ................................................................13

Hookup the Ailerons ............................................................14

Install the Elevator Pushrod.................................................15

Install the Rudder Pushrod..................................................16

Final Assembly..........................................................................16

Install the Wing Belly Pan....................................................16

Mount the Canopy ...............................................................17

Mount the Servo Tray..........................................................17

Final Radio Installation ........................................................18

Get Your Model Ready To Fly ..................................................19

Balance Y our Model.............................................................19

Balance the Model Laterally................................................19

Final Hookups & Checks .....................................................19

Set the Control Throws........................................................20

Preflight .....................................................................................20

Identify Y our Model..............................................................20

Charge Y our Batteries.........................................................20

Balance Y our Propellers......................................................21

Find a Safe Place to Fly ......................................................21

Ground Check Your Model ..................................................21

Range Check Your Radio ....................................................21

Check List............................................................................21

Engine Safety Precautions..................................................22

AMA Safety Code (excerpt)......................................................22

General................................................................................22

Radio Control.......................................................................23

Flying .........................................................................................23

Takeoff .................................................................................23

Flying...................................................................................23

Landing................................................................................23

Flight Log...................................................................Back Cover

Your Extra 300 ARF is not a toy, but rather a sophisticated,
working model that functions very much like a full size
airplane. Because of its realistic performance, the

Extra 300 ARF, if not assembled and operated correctly,
could possibly cause injury to yourself or spectators and
damage property.

To make your R/C modeling experience totally enjoyable,
we recommend that you get experienced, knowledgeable
help from an instructor with assembly and during your first
flights. You’ll learn faster and avoid risking 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. Through any one of them,
instructor training programs and insured newcomer training
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

Tele. [phone]

Fax [phone]

Or via the internet at: http://www.modelaircraft.org

The Great Planes Extra 300 ARF is a high performance
sport airplane that closely resembles the full size Extra 300
both in appearance and performance. However, the Extra
300 ARF is very stable and predictable, allowing even
intermediate skill level pilots to enjoy it.

This is not a beginner’s airplane! While the Extra 300
ARF is easy to assemble and flies great, we must

discourage
you from selecting this kit as your first R/C airplane. It
lacks the self-recovery characteristics of good basic
trainers such as the Great Planes PT™Series. On the
other hand, if you have already learned the basics of R/C
flying, and you are able to safely handle a .40-size low
wing airplane, the Extra 300 ARF is an excellent choice to
try your skills at flying a sport airplane.

1. You must assemble the model according to the
instructions. Do not alter or modify the model, as doing so
may result in an unsafe or unflyable model. In a few cases
the instructions may differ slightly from the photos. In those
instances the written instructions should be considered
as correct.

2. Take time to build straight, true and strong.

3. Use an R/C radio system that is in first-class condition,
and a correctly sized engine and components (fuel tank,
wheels, etc.) throughout your building process.

PRECAUTIONS

INTRODUCTION

PROTECT YOUR MODEL,YOURSELF &

OTHERS...FOLLOW THIS IMPORTANT

SAFETY PRECAUTION

TABLE OF CONTENTS

2

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

5. You must test the operation of the model before every
flight to insure that all equipment is operating and you must
make certain that the model has remained structurally
sound. Be sure to check clevises or other connectors often
and replace them if they show signs of wear or fatigue.

Remember: Take your time and follow directions to end
up with a well-built model that is straight and true.
Please inspect all parts carefully before starting to build!
If any parts are missing, broken or defective, or if you
have any questions about building or flying this
airplane, please call us at [phone]. If you are
calling for replacement parts, please reference the part
numbers and the kit identification number (stamped on
the end of the carton) and have them ready when

calling.

We can also be reached by E-Mail at:

[e-mail]

Items in parentheses (GPMQ4243) 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.

❏ Four-Channel Radio W/Five Servos
❏ “Y” Harness For Aileron Servos
❏ Engine – See Engine Selection
❏ Spare Glow Plugs (O.S. #8 For Most 2-Stroke

Engines, OSMG2691)

❏ Propeller (Top Flite

®

Power Point™–Refer To Your

Engine’s Instructions For Proper Size)

❏ 3' Medium 3/32" Fuel Tubing (GPMQ4131)
❏ 1/4" Latex Foam Rubber Padding (HCAQ1000)
❏ Fueling System (Great Planes Top Fueler,

GPMQ4160)

❏ (2) Flexible Cable Pushrod (GPMQ3702)
❏ 1/5 Scale Pilot (Williams Bros. Sportsman Pilot,

WBRQ2485)

These are the building tools that are required. We

recommend Great Planes Pro™CA and Epoxy glue.

❏ 2 oz. Pro CA (Thin, GPMR6003)
❏ 2 oz. Pro CA+ (Medium, GPMR6009)
❏ CAAccelerator (GPMR6035)
❏ 30-Minute Pro Epoxy (GPMR6047)
❏ 1/4" Red Striping Tape(GPMQ1330)
❏ #1 Hobby Knife Handle (HCAR0105)
❏ #11 Blades (HCAR0311, 100 Qty)
❏ Builders Triangle Set (HCAR0480)
❏ Masking T ape (TOPR8018)
❏ Electric Power Drill
❏ Slip-Joint & Needle Nose Pliers
❏ Monofilament String For Stabilizer Alignment
❏ Screwdrivers (Flat Blade & Phillips)
❏ Pro Thread Locking Compound (GPMR6060)
❏ Isopropyl Alcohol (70%)
❏ Drill Bits: 1/16", 5/64", 3/32", 7/64", 1/8", 3/16", 11/64",

15/64", 1/4"

❏ T op Flite Trim Seal Tool

™

(TOPR2200)

❏ Felt-Tip Pen
❏ Sandpaper: 80, 220 & 320-grit
❏ Metal File

❏ 6-Minute Pro Epoxy (GPMR6045)
❏ CAApplicator Tips (HCAR3780)
❏ Canopy Glue (JOZR5007)
❏ Epoxy Brushes (GPMR8060)
❏ Epoxy Mixing Sticks (GPMR8055, Qty. 50)
❏ CA Debonder (GPMR6039)
❏ Trim Seal Tool (TOPR2200)
❏ Dremel

®

Moto-Tool™Or Similar W/Cut-Off Wheel

❏ Hot Sock

™

(TOPR2175)

❏ Dead Center

™

Engine Mount Hole Locator

(GPMR8130)

❏ 3/32" Brass Tube
❏ Curved Tip Canopy Scissors For Canopy

Trimming (HCAR0667)

❏ LustreKote

™

Paint For Aluminum Landing Gear

(White Primer TOPR7801, Missile Red TOPR7201)

❏ Switch and Charge Jack (GPMM1000)

Optional Supplies and Tools

Building Supplies and Tools

Required Accessories

PREPARATIONS

Engine Selection

There are several engines that will work well in your
Extra 300 ARF. We recommend a hot 2-stroke such as an
O.S.®.46FX or SuperTigre™G45. If you prefer a 4-stroke,
an O.S. FS-70 is the ticket. Your choice of 2-stroke or
4-stroke will determine the location of the throttle servo
and throttle pushrod exit on the firewall, so plan ahead.

DECISIONS YOU MUST MAKE

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

3

4

1. Closely inspect the fuselage, wing panels, rudder assembly and stabilizer assembly for damage. If you find any
damage, contact the place of purchase, or Hobby Services at Great Planes for a replacement.

2. Eliminate any wrinkles you find in the covering by shrinking them away with a heat gun, then apply pressure to the area
with a covering iron and a hot sock. This will securely bond the covering to the wood so the wrinkles will be less likely to
reappear in the future.

General Inspection

Pushrod Template #1

Pushrod Template #2

Refer to these Pushrod Templates when instructed in this manual.

Inch Scale

0" 1" 2" 3" 4" 5" 6" 7"

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180

Metric Scale

5

Key# Description Qty

1

Fuselage 1

2 Left Wing Panel w/Aileron 1
3 Right Wing Panel w/Aileron 1
4 Cowl 1
5 Adjustable Engine Mount 2
6 Wing Belly Pan 1
7 Canopy 1
8 Right Wheel Pant Halves 2
9 Left Wheel Pant Halves 2
0 Aluminum Landing Gear 1

-Main Wheels 2
=

Stabilizer 1

q Elevator Assembly 2
w Rudder 1
e Vertical Fin 1
rTail Wheel Assembly 1
t Tail Wheel Bracket 1
yCowl Mounting Blocks 4
u Servo Tray 1
i Belly Pan Formers 1
o Wing Joiners 1

Parts Not Shown In Photo

Description Qty

Propeller Spinner (Red) 1
1" Fiberglass Tape 1
CA Hinge Strip (2" x 9") 1
Hardware Bag 1
Decal Sheet 1

Replacement Parts

If needed, replacement parts for Extra 300 ARF are

available

through your hobby supplier.

Wing Set............................................................GPMA2170

Fuselage Kit ......................................................GPMA2171

Tail Fin Set.........................................................GPMA2172

Canopy..............................................................GPMA2173

Cowl ..................................................................GPMA2174

Wheel Pants......................................................GPMA2175

Landing Gear Set..............................................GPMA2156

Parts List

61093185141519

12

2

20

178

21

41617

11

13

❏ 1. Coat the firewall and all other bare wood around the

firewall with fuelproof paint or 30-minute epoxy thinned with
alcohol. Fuelproof other areas of bare wood in the fuselage
that may be exposed to fuel or engine exhaust such as the
fuel tank area and the front and back of the wing saddle.
Avoid getting epoxy in the threads of the blind nuts in the
back of the firewall.

❏ 2. Set the fuselage aside while the paint dries and you

work on the wing.

❏❏1. Cut the covering 1/8" inside the edges of the

opening in the bottom of the right wing panel for the aileron
servo. Use your Top Flite MonoKote Trim Iron to seal the
covering to the sides of the opening.

Note: Inside the wing you’ll notice a piece of string with a
piece of wood tied to it. Don’t remove the string because
you will use it to pull your aileron servo cord through the
wing later.

❏❏2. Cut the covering from the half-inch hole in the top

of the wing sheeting near the root (for your servo cords to
exit) and from the hole near the TE for the wing bolt.

❏3. Repeat this procedure for the left wing panel.

❏4. Use 30-minute epoxy to glue both 1/8" x 15/16" x 5-

1/4"

plywood wing joiners together. Wipe away any excess

epoxy .

❏ 5. Test fit the wing halves with the wing joiner. If

necessary, sand any high spots on the root end of the wing
panels so there is no gap when you join them.

Make a dry run of the following step without using any
glue so you will know how to clamp your wing together.

❏ 6. Thoroughly coat the joiner pockets and the mating

ends of both wing halves with 30-minute epoxy. Set the
wing halves aside and proceed quickly. Coat all surfaces of
one half of the wing joiner with 30-minute epoxy and place
it in one of the wing halves. Coat the other half of the joiner
with 30-minute epoxy and join the other wing. Use a piece
of balsa or cardboard to wipe away excess epoxy. Use two
C-clamps to hold the front of the wing together and use
masking tape to tightly tape the rest of the wing together.

Join the Wing Halves

Fuelproof the Fuselage

BEGIN CONSTRUCTION

6

Insert short dowels or a couple of screwdrivers into the
wing bolt holes and wrap the dowels with rubber bands for
additional clamping power at the rear of the wing. Be
certain the trailing edges align. Use a tissue dampened with
alcohol to wipe away any more epoxy that oozes out of the
wing, then set the wing on one of its tips leaning against

a

wall. Do not disturb the wing until the epoxy has fully

cured.

❏ 1. Cut the spreader bar from both engine mount halves

and trim any remaining plastic so the halves slide together.
Temporarily mount your engine mount to the firewall as
shown in the sketch with four 6-32 x 1" SHCS (socket head
cap screws), #6 lock washers and #6 flat washers but don’t
tighten the screws all the way yet.

❏ 2. Adjust the engine mount so it will fit your engine.

Tighten the engine mount screws. Temporarily place the
back plate of the spinner included with this kit on your
engine. Refer to the following photo. Position your engine
on the mount so the spinner back plate is 5-1/8" from the
firewall. Hold your engine to the mount with small clamps or
something similar.

❏3. Mark the location of the engine mounting holes on the

engine mount. We use the Great Planes Dead Center

Engine

Mount Hole Locator (GPMR8130) shown in the photo.

❏ 4. Remove your engine from the mount and drill 7/64"

holes at the marks you made. Add a drop of household oil
to the holes in the mount (so it will be easier for you to
install the screws), then mount your engine to the mount
with four #6 x 1" screws and #6 flat washers. Hint: If you
have a drill press (or if you can borrow your friend’s),
remove the engine mount from the firewall and drill the
holes using the drill press.

Note: Some modelers prefer to mount their engines with
machine screws (not included) rather then the sheet metal
screws supplied with this kit. The Great Planes Adjustable
Engine Mounts accept threads well, so if this is your choice
use the appropriate drill and tap for the screws you intend
to use. 4-40 Screws are acceptable but use 6-32 screws if
they will fit into your engine. Tap the threads into the holes
and mount your engine.

❏ 5. Remove the spinner back plate from your engine,

then slip the cowl over the front of the fuse. If the head of
your engine interferes with the cowl, you can temporarily
remove the head, or cut a hole in the cowl just large
enough to accommodate the engine. After the cowl is
mounted, you can enlarge the hole to allow some
clearance for a more finished appearance.

❏ 6. Reinstall the spinner. Align the front of the cowl with

the spinner and tape it to the fuselage. Use the stripes on
the cowl and the fuselage as a cue for alignment.

❏ 7. Position one of the 1/2" x 1/2" x 3/4" hardwood cowl

mounting blocks at the aft edge of the left side of the cowl

near the top. Use a ballpoint pen to mark the aft edge of the
cowl on the cowl mounting block. Mark the remaining three
cowl mounting blocks the same way for the left side of the
cowl near the bottom and the right side of the cowl near the
bottom and the top.

❏ 8. Trim the cowl mounting blocks along the lines you

marked in step 7.

Mount the Engine & Install the Fuel Tank

7

❏ 9. Cut the covering from the front edge of the fuse for

the cowl mounting blocks and glue them in position.

❏ 10. Reposition the cowl on the fuse and mount the

spinner to your engine. Align the cowl with the spinner and
the fuse and tape it in position. View the cowl carefully to
make sure the cowl is centered horizontally and vertically
on the spinner.

❏ 11. Drill a 5/64" (or 3/32") hole through the cowl and one

of the cowl mounting blocks. Screw a #4 x 1/2" SMS (sheet
metal screw) through the cowl just far enough into the cowl
mounting block to temporarily hold that part of the cowl in
place. One at a time, drill a hole and insert a screw into the
remaining three cowl mounting blocks the same way.

❏ 12. Remove the spinner and cowl. Roughen the inside

of the cowl around the four screw holes with 80-grit

sandpaper. Cut four 1" pieces from the strip of glass cloth
and glue them to the inside of the cowl over the mounting
holes with 30-minute epoxy as shown in the photo. Set the
cowl aside while the epoxy cures. Use a small amount of
epoxy to fuelproof the cowl mounting blocks.

❏ 13. Mark the firewall where the throttle pushrod guide

tube will enter. This location may vary depending on your
engine. Make sure the guide tube will not interfere with the
fuel tank. Ideally, the hole should be 3/16" above the
bottom edge of the firewall so it can rest on top of the fuel
tank floor behind the firewall. Drill a 1/8" hole through the
firewall for the throttle pushrod guide tube.

❏ 14. Drill a 1/8" hole through the former where shown in

the photo. Roughen the outside of the guide tube so glue
will stick, then insert the throttle pushrod guide tube
through the firewall and the former. You will cut the guide
tube to the correct length when you install the servos.

❏ 15. Cut the clear pick up tube included with this kit to a

length of 2-7/8". Assemble the fuel tank as shown in the
sketch using the straight nipple. After you assemble the
tank hold it up to the light and make sure the clunk does
not contact the rear of the tank. If necessary, disassemble
the tank and shorten the pick up tube.

8

10oz. (300cc)