Great Planes GPMA1325 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-assemb led 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.

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

GPMZ0253 for GPMA1325 V1.0© Copyright 2001

1610 Interstate Drive Champaign, IL 61822

[phone], Ext 2

[e-mail]

INSTRUCTION MANUAL

A. R. F.

Almost Ready to Fly

Wingspan: 61.5" [1,560mm]
Wing area: 712.5" [46 sq dm]
Weight: 7 lbs [3,630g]
Wing loading: 25.9 oz/sq ft [79 g/sq cm]
Length: 53" [1,345mm]
Radio: 4-ch (five servos)
Engine: .61 two-stroke, .91 four-stroke [10cc 2-stroke, 15cc 4-stroke]

INTRODUCTION................................................................2

IMPORTANT SAFETY PRECAUTIONS............................2

ADDITIONAL ITEMS REQUIRED.....................................3

Muffler ................................................................................3

Hardware and Accessories................................................4

Adhesives and Building Supplies.......................................4

Optional Supplies and Tools...............................................4

IMPORTANT BUILDING NOTES.......................................4

ORDERING REPLACEMENT PARTS ...............................4

KIT CONTENTS .................................................................5

PREPARATIONS................................................................6

BUILD THE WING..............................................................6

Hook up the Ailerons..........................................................6

Join the Wing......................................................................7

BUILD THE FUSELAGE....................................................8

Mount the Wing..................................................................8

Mount the Stab and Fin......................................................9

Mount the Wheel Pants and Landing Gear......................12

Finish the Cockpit.............................................................13

Mount the Engine.............................................................15

Mount the Cowl................................................................15

FINAL ASSEMBLY ..........................................................17

Install the Radio ...............................................................17

Finishing Touches.............................................................19

GET THE MODEL READY TO FLY..................................19

Check the Control Directions ...........................................19

Set the Control Throws.....................................................19

Balance the Model (C.G.).................................................20

Balance the Model Laterally.............................................21

PREFLIGHT.....................................................................21

Identify Your Model...........................................................21

Charge the Batteries........................................................21

Balance Propellers...........................................................21

Ground Check..................................................................21

Range Check....................................................................21

ENGINE SAFETY PRECAUTIONS.................................21

AMA SAFETY CODE ......................................................22

CHECK LIST ....................................................................22

FLYING.............................................................................23

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

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

Landing..............................................................Back Cover

Thank you for purchasing the Great Planes Shoestring ARF.
Those who know the full-size Shoestring and are familiar
with its history are likely to be racers who may hav e resisted
the idea of building an ARF. On the other hand, such a
beautiful plane can't be resisted no matter how it is
constructed! The Shoestring is nostalgic and modern at the
same time.While the Shoestring made its name as a pylon
racer in 1949 and into the fifties, even today the Shoestring
looks just as “mean”as any other modern-day racer.Though
it is an ARF, the Shoestring can still be “scaled-out” if one
wishes to go the extra mile by adding home-made details
such as landing gear fairings and an air scoop. Note: The
Shoestring is covered in TopFlite Red (TOPQ0201, 6’ roll)
and Cub Yellow (TOPQ0220, 6’roll) MonoKote film.

The full-size Shoestring has a wingspan of 19' (228"). This
model has a wingspan of 61.5". That makes it slightly larger
than quarter-scale (1:3.7 to be exact) and eligible to participate
in IMAA events.

For the latest technical updates or manual corrections for
the Shoestring, visit the web site listed below and select the
Great Planes Shoestring ARF. A “tech notice” box will
appear in the upper left corner of the page if there is new
technical information or changes.

http://www.greatplanes.com/airplanes/index.html

1. The Shoestring ARF 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, the Shoestring, if not assembled and operated
correctly, could possibly cause injury to yourself or
spectators and damage property.

2. You must assemble the model according to the
instructions. Do not alter or modify the model, as doing so

may result in an unsafe or unflyable model. In a few cases the
instructions may differ slightly from the photos. In those
instances the written instructions should be considered correct.

3. You must take time to build straight, true and strong.

4. You must use an R/C radio system that is in first-class

condition, and a correctly sized engine and components
(fuel tank, wheels, etc.) throughout the building process.

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

PRO TECT YOUR MODEL,YOURSELF

& OTHERS...FOLLOW THESE

IMPORTANT SAFETY PRECAUTIONS

INTRODUCTIONTABLE OF CONTENTS

2

6. You must check the operation of the model before every

flight to insure that all equipment is operating and that the
model has remained structurally sound. Be sure to check
clevises or other connectors often and replace them if they
show any signs of wear or fatigue.

7. If you are not already an experienced R/C pilot, you
should fly the model only with the help of a competent,
experienced R/C pilot.

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

Remember:Take y our time and follow the instructions to
end up with a well-built model that is straight and true.

If you have not flown this type of model before, we
recommend that you get the assistance of an experienced
pilot for your first flights. If you're not a member of a club,
your local hobby shop has information about clubs in your
area whose membership includes experienced pilots.

In addition to joining an R/C club, we strongly recommend
you join the AMA (Academy of Model Aeronautics). AMA
membership is required to fly at AMA sanctioned clubs.
There are over 2,500 AMA chartered clubs across the
country. Among other benefits, the AMA provides insurance
to its members who fly at AMA sites and events .Additionally,
training programs and instructors are available at AMA club
sites to help you get started the right way. Contact the AMA
at the address or toll-free phone number below:

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 Shoestring ARF is an excellent sport­scale model.Though it isn't particularly large, it is larger than
quarter-scale making it eligible to fly in IMAA events. The

IMAA (International Miniature Aircraft Association) is an
organization that promotes non-competitive flying of giant­scale models. If you plan to attend an IMAA event, contact
the IMAA for a copy of the IMAA Safety Code at the
address or telephone number below.

IMAA

205 S. Hilldale Road

Salina, KS 67401

[phone]

Conveniently, the O.S.®MAX .61FX engine fits inside the
cowl. Engines with similar proportions will fit as well.
However, the cowl will have to be trimmed to fit the exhaust
system. On our prototype, we used the B.C.M. (Bisson
Custom Mufflers) #04061 Pitts muffler for the O.S. .61 FX
(BISG4061). Another muffler that will work is the Slimline
#3217 (SLIG2217) Pitts Style (for O.S. .61 SF, FP, FX). To
use these mufflers, a portion of the included Great Planes
60-120 engine mount will have to be trimmed to
accommodate the muffler.See page 17 for details.

This is the list of hardware and accessories required to finish
the Shoestring ARF. Order numbers are provided in
parentheses for your convenience.

❏ Four-channel radio with five servos (two aileron servos)
❏ .61 two-stroke to .91 four-stroke engine
❏ Muffler
❏ Suitable propellers (refer to the engine manufacturer's

recommendations)

❏ 3' Medium fuel tubing (GPMQ4131)
❏ Y-harness for dual aileron servos (HCAM2500 for Futaba

®

J)

❏ 1/4-scale pilot (optional, WBRQ2626)
❏ R/C foam rubber (1/4" - HCA Q1000, or 1/2" - HCA Q1050)
❏ Easy Fueler fuel filler valve for glow fuel (GPMQ4160)
❏ Switch and charge jack mounting set (GPMM1000)
❏ 1/4" yellow Kwik Stripe striping tape (for canopy trim,

GPMQ1450)

Hardware and Accessories

Muffler

ADDITIONAL ITEMS REQUIRED

IMAA Information

Note: We, as the kit manufacturer, provide you with a top

quality kit and instructions, but ultimately the quality and
flyability of your finished model depends on how y ou b uild it;
therefore, we cannot in an y w ay guarantee the performance
of your completed model, and no representations are
expressed or implied as to the performance or safety of y our
completed model.

3

To order replacement par ts for the Great Planes Shoestring ARF, use the order numbers in the Replacement Parts List
that follows. Replacement par ts are available only as listed. Not all parts are available separately (an aileron cannot be
purchased separately, but is only available with the wing kit).Replacement par ts are not available from Product Support,
but can be purchased from hobby shops or mail order/Internet order firms. Hardware items (screws, nuts, bolts) are also
available from these outlets. If you need assistance locating a dealer to purchase par ts, visit www.greatplanes.com and
click on “Where to Buy.” If this kit is missing parts, contact Great Planes Product Support.

Replacement Parts List

Order Number Description How to Purchase

Missing pieces ......................Contact Product Support

Instruction manual.................Contact Product Suppor t

Full-size plans.......................Not available

GPMA2210......................................Wing Kit

GPMA2211......................................Fuse Kit

GPMA2212......................................Tail Set Contact Your Hobby

GPMA2213......................................Cowl Supplier to Purchase

GPMA2214......................................Canopy These Items

GPMA2215......................................Landing Gear

GPMA2216......................................Wheel Pants

In addition to common household tools and hobby tools, this
is the “short list”of the most important items required to build
the Shoestring. Great Planes Pro™CA and Epoxy glue
are recommended.

❏ 1/2 oz. Thin Pro CA (GPMR6001)
❏ 1/2 oz. Medium Pro CA (GPMR6007)
❏ 30-Minute Epoxy (GPMR6047)
❏ Drill bits, 1/16", 5/64", 3/32", 1/8", #29 (or 9/64") and 8-32

tap (or Great Planes 8-32 tap and drill set, GPMR8103),
3/16", #11 (or 13/64"), 7/64" (or 1/4"), 7/32"

Here is a list of additional optional items we used to
assemble the Shoestring ARF.

❏ 21

ST

Century®sealing iron (COVR2700)

❏ 21

ST

Century iron cover (COVQ2702)

❏ Milled Fiberglass (GPMR6165)
❏ Microballoons (TOPR1090)
❏ Builders Triangle Set (HCAR0480)
❏ Dead Center

™

Engine Mount Hole Locator (GPMR8130)

❏ Threadlocker (GPMR6060)
❏ K & S #801 K e vlar thread (f or stab alignment K+SR4575)
❏ Denatured Alcohol (for epoxy clean up)
❏ Curved Tip Scissors for Trimming Canopy (HCAR0667)
❏ R/C-56 Canopy Glue (JOZR5007)
❏ Great Planes CG Machine

™

(GPMR2400)

❏ Great Planes AccuThrow

™

Deflection Gauge (for measuring

control throws, GPMR2405)

❏ Top Flite Precision Magnetic Prop Balancer

™

(TOPQ5700)

• There are two types of screws used in this kit:
Sheet metal screws are designated by a number and a

length. For example #6 x 3/4"

This is a number six screw that is 3/4" long.

Machine screws are designated by a number, threads per
inch, and a length. For example 4-40 x 3/4"

This is a number four screw that is 3/4" long with

forty threads per inch.

• Whenever the term

glue

is written you should rely upon
your experience to decide what type of glue to use.When a
specific type of adhesive works best for that step, the
instructions will make a recommendation.

• Whenever just

epoxy

is specified you may use

either

30-minute epoxy or6-minute epoxy.When 30-minute epoxy
is specified it is highly recommended that you use only 30­minute (or 45-minute) epoxy, because you will need the
working time and/or the additional strength.

• Photos and sketches are placed before the step they
refer to. Frequently you can study photos in following steps
to get another view of the same parts.

IMPORTANT BUILDING NOTES

Optional Supplies and Tools

Adhesives and Building Supplies

4

ORDERING REPLACEMENT PARTS

................

5

1 Wing with Ailerons
2 Fuselage
3 Stab with Elevators
4 Fin with Rudder
5 Painted Cowl
6 Painted Canopy
7 Cockpit
8 Painted Wheel Pants (2)
9 Painted Aluminum Landing

Gear (2)

10 1/4" x 1-1/8" x 10-3/4"

Wing Joiner

11 Fuel Tank with Hardware
12 Tail Gear with Wheel
13 Plywood Servo Tray
14 Engine Mount
15 3" Wheel (2)
16 1/8" Plywood Wing Bolt Plate
17 .074" x 36" Elevator and

Rudder Pushrods

18 Wing Dowels

1/8" x 7/8" x 6" Ply strip (wheel pant mounts)
(4) 1/2" x 1/2" x 5/8" Maple blocks (cowl mnts)
1/4" x 3/4" x 5" Balsa stick (fuel tank support)
3" Spinner
(2) 2" x 3/16" Bolt-on axles
(4) 3/16" Wheel collars
(4) 6-32 Set screws for wheel collars
(2) 5/16" -24 Lock nuts (for axles)
(2) 1/4-20 x 2" Nylon wing bolts
(4) Large control horns
(6) 6-32 Blind nuts (preinstalled)
(2) 1/4-20 Blind nuts (preinstalled)

(8) 8-32 x 1" SHCS (socket-head cap screws)

(4-engine mnt to firewall, 4-engine to mnt)
(4) Faslinks
(5) Nylon clevis
(1) 2" x 9" CA hinge strip
(4) 8-32 Blind nuts (engine mount)
(6) 6-32 x 3/4" Screws (landing gear)
(4) 2-56 x 5/8" Screws (elev, rudd control horns)
(4) #2 x 1/2" Screws (aileron control horns)
(4) #2 x 3/8" Screws (wheel pants)
(5) Silicone retainers (clevises)
(4) #8 Flat washers (engine mount)

(1) 3/32" Wheel collar (tail wheel)
(1) 4-40 Set screw (tail wheel)
(1) Brass body screw-lock conn.(throttle servo)
(1) Nylon retainer (screw-lock connector)
(1) 4-40 x 1/4" SHCS (screw-lock connector)
(2) .074" x 6" Pushrod (ailerons)
(1) 3/16" x 12" Guide tube (throttle)
(1) .074" x 18" Pushrod (throttle)
(8) #8 Lock washers (engine, engine mount)
(1) Elevator joiner wire
(4) #4 x 3/8" Screws (cowl)
(4) #4 Washers (cowl)

Kit Contents

(Photographed)

Kit Contents (Not Photographed)

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

Inch Scale

Metric Scale

To convert inches to millimeters, multiply inches by 25.4

Before starting to build, use the Kit Contents list to take an inventory of your 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 Great Planes Product Support. When reporting defective or missing parts, use
the part names exactly as they are written in the Kit Contents list on this page.

Great Planes Product Support:

Phone: [phone]

Fax: [phone]

E-mail: [e-mail]

KIT CONTENTS

3

1

8

15

9

5

2

7

1

11

14

12

13

16

10

18

17

4

6

❏ 1. If you have not done so already, remove the major

parts of the kit from the box (wings, fuse, wheel pants, cowl,
tail parts, etc.) and inspect them for damage.If any parts are
damaged or missing, contact Product Support at the
address or telephone number listed on the front cover.

❏ 2. Remove the masking tape and separate the ailerons

from the wing, the rudder from the fin and the elevators from
the stab. Use a covering iron with a covering sock on high
heat to tighten the covering. Apply pressure over sheeted
areas to thoroughly bond the covering to the wood. Hint:
Poke three or four pin holes in the covering between the
“ribs” in the tail surfaces and ailerons. This will allow air to
escape while tightening the covering.

Do the right wing first so yours matches the photos the
first time through. You can do one wing at a time, or
work on them together.

❏❏1. Drill a 3/32" hole, 1/2" deep in the center of each

hinge slot to allow the CA to “wick” in. Follow-up with a #11
blade to clean-out the slots. Hint: If you have one, use a
high-speed rotary tool to drill the holes.

❏❏2. Use a sharp #11 blade to cut a strip of covering

from the hinge slots in the wing and aileron.

❏❏3.Cut three 3/4" x 1" hinges from the CA hinge strip.

Snip off the corners so they go in easier.

❏❏4. Test fit the ailerons to the wing with the hinges. If

the hinges don't remain centered, stick a pin through the
middle of the hinge to hold it in position.

❏❏5. Remove any pins you may have inserted into the

hinges. Adjust the aileron so there is a small gap between
the LE of the aileron and the wing. The gap should be
small—just enough to see light through or to slip a piece of
paper through.

1"
1"

3/4"

AWAY FROM THE SLOT

CUT THE COVERING

DRILL A 3/32" HOLE

1/2" DEEP, IN CENTER

OF HINGE SLOT

Hook Up the Ailerons

BUILD THE WING

PREPARATIONS

6

❏❏6. Apply six drops of thin CA to the top and bottom of

each hinge. Do not use CA accelerator. After the CA has
fully hardened, test the hinges by pulling on the aileron.

❏❏7.Cut the covering 1/8" inside the opening in the wing

for the aileron servo.Use a trim iron to seal the covering to
the edges of the opening. Cut the covering from the hole in
the bottom of the wing for the aileron servo wire.

❏❏8. Tie the string inside the wing to the aileron servo

wire. Pull the servo wire out of the end of the wing with the
string. Drill 1/16" holes in the wing for the servo mounting
screws, then mount the aileron servo using the screws that
came with it.

❏❏9. Dr ill 1/16" holes into the bottom of the aileron for

mounting the nylon control horn. Before mounting the horn,
use a pin to poke several holes through the covering in the

mounting location. Saturate the holes with thin CA, wipe
away residual CA and allow to fully harden. Mount the
aileron control horn to the aileron with two #2 x 1/2" screws.

❏❏10. Enlarge the hole in the servo arm with a Hobbico

Servo Horn Drill (or a #48 or 5/64" drill bit). Connect the
aileron to the servo with a 6" pushrod, a FasLink, a clevis
and a silicone retainer.

❏ 11. If you haven't yet done so, go back to step 1 and

assemble the other wing the same way.

❏ 1. Trim the covering from the ribs on the end of both

wings.This is easily done with a sanding block and medium­grit sandpaper as shown.

❏ 2. Test fit the wing halves with the hardwood joiner. Be

certain the joiner is installed upright (the bottom of the joiner
has an angle for wing dihedral).

Join the Wing

FasLink

2-56 (.074") Pushrod Wire

Servo Horn

7

❏ 3. Prepare 1/2 oz. of 30-minute epoxy. Add 1/2 oz. of

microballoons.Working quickly, thoroughly coat the inside of
both wing halves where the joiner fits and one half of the
joiner with the epoxy and microballoons mixture. Making
certain the joiner is upright, insert the coated end into one of
the wing halves. Coat the other end of the joiner with the
remainder of the epoxy and microballoons mixture.Proceed
immediately to the next step.

❏ 4. Prepare an additional 1/4 oz. of 30-minute epoxy only

(no microballoons). Coat the ribs on both ends of the wing
with the epoxy. Join the wing halves tightly, holding them
together. Use a paper towel to wipe away excess epoxy that
comes out of the wing. Tightly hold the wing together with
masking tape, making certain both halves are in full contact
and that the leading edges and trailing edges align. Wipe
away e xcess epo xy and do not disturb the wing until the epoxy
has fully hardened.

❏ 5. Connect the servo wires to a Y-harness (HCAM2500

for Futaba). Secure the connection between the servo wire
and the Y-harness with heat shrink tubing, tape or clips
suitable for that purpose.

❏ 1.Inspect the blind nuts that are pressed into the bottom

of the wing nut plate inside the fuselage. If the nuts are not
securely pressed into the plate, remove them. Apply a dab
of 30-minute epoxy to the flange around the blind nuts, then
reinsert them into the plate. Use a metal 1/4-20 bolt and a
large washer to draw the blind nuts all the way up into the
wood by tightening the bolt to the top of the plate.

❏ 2. Cut the covering from the holes in the leading edge of

the wing for the dowels and near the trailing edge for the
wing bolts. Temporarily fit the 1/4" wing dowels into the
leading edge of the wing.

❏ 3. T est fit the wing to the fuse and bolt it into position with

the 1/4-20 nylon wing bolts. If necessary, enlarge or adjust
the wing bolt holes in the wing so the wing bolts will align
with the blind nuts.

❏ 4. Unscrew the wing bolts about 1/2". Place the 1/8"

plywood wing bolt plate on the wing centered on the wing
bolts. Mar k the location of the wing bolts on the plate.

❏ 5. Drill 17/64" (or 1/4") holes through the center of the

wing bolt plate at the marks (see the photo at step 7).

Mount the Wing

BUILD THE FUSELAGE

8