1

READ THROUGH THIS MANUALBEFORE STARTING CONSTRUCTION.

IT CONTAINS IMPORTANT INSTRUCTIONS AND WARNINGS CONCERNING THE

ASSEMBLY AND USE OF THIS MODEL.

Tower Hobbies® 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 Tower Hobbies’ liability exceed the original cost of the purchased kit. Further, Tower Hobbies reserves the right to change or modify this warranty without notice.

In that Tower Hobbies has no control over the final assembly or material used for final assembly, no liability shall be assumed nor accepted for any damage resulting from the use by the user of the final user-assembled product. By the act of using the user-assembled product, the user accepts all resulting liability.

If the buyer is not prepared to accept the liability associated with the use of this product, 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.

WA

RR

AN

TY

TOWA2050© 2016 Tower Hobbies.®  A subsidiary of Hobbico, Inc. 

®®

TOWER HOBBIESChampaign, Illinois

(217) 398-8970 ext. 5

RADIO4 – 5 channel

WINGSPAN45.5 in [1155 mm]

WEIGHT6.0 – 7.25 lbs. [2720 – 3290g]

WING AREA840 sq in [54.2 dm2]

LENGTH50 in [1270 mm]

airsupport@hobbico.com

I N S T R U C T I O N M A N UA L

WING LOADING16 – 20 oz/ft2 [49– 61 g/dm2]

POWER.46 – .55 2-stroke glow,.72 – .81 4-stroke glow,RimFire .55 42-60-480,

6S LiPo, 75A ESC

2

INTRODUCTION

Congratulations and thank you for purchasing the Tower

Hobbies Ultimate bipe. In spite of its aerobatic appearance, the

Ultimate is a cinch to takeoff, fl y and land and is unexpectedly

stable. But when you’re ready to lay down some aerobatics

the Ultimate is ready to respond when it’s time to move the

sticks to the corners!

Powered by a .46 2-stroke glow, the Ultimate fl ies surprisingly

well. But if aggresive aerobatics is your preference a 2-stroke

glow is not the optimum choice. With a 2-stroke the Ultimate

still performs all the expected sport aerobatic maneuvers

such as loops (inside and outside), rolls, point rolls, stalls,

spins, inverted fl ight and even knife-edge fl ight. Even if the

Ultimate doesn’t have unlimited vertical with a 2-stroke, a

2-stroke is still the lightest setup which you will actually be

able to feel when it’s in the air.

Because of the large propellers it can swing, the Ultimate

becomes a monster with a Rimfi re .55 and a 6S battery.

Performance when powered by an O.S. .72 is a close second.

For the latest technical updates or manual corrections to the

Utimate ARF visit the Tower Hobbies web site at towerhobbies.

com and visit the page for the Ultimate ARF. If there is new

technical information or changes to this model a “tech notice”

box will appear on the page.

ADDITIONAL ITEMS REQUIRED

Radio/Servos

The Ultimate can be fl own with a 4-channel radio, but a

computer radio such as the Tactic TTX650 is recommended

because of the simplicity and fl exibility a computer radio offers

in addition to the convenience of multiple model memory:

❍ Tactic TTX650 6-channel programmable radio

(TACJ2650)

❍ Tactic TR625 6-chanel receiver (TACL0625)

❍ Hobbico 2S (6.6V) LiFe receiver pack (HCAM6411)*

❍ On-off receiver switch (TACM2000)*

* If powering your Ultimate with a brushless electric motor,

you may power the receiver and servos from the BEC in

the ESC, so a receiver battery or on/off receiver switch

will be not required.

The Ultimate was designed for mini servos, but regular servos

with minimum torque of 55 oz-in [4.0 kg-cm] may be used

simply by enlarging the servo mounts in the wing and fuselage.

Tactic TSX25 mini digital high-speed 2 ball bearing servos

(TACM0225) or Tactic TSX20 mini high-speed 2 ball bearing

servos (TACM0220) are recommended.

The Ultimate may be fl own with two or four aileron servos.

With two servos, the ailerons in the top wing are operated

by pushrods connected directly to the bottom ailerons. With

four servos, each aileron is operated by its own servo. The

advantage of two servos is economy and less weight. The

advantage of four servos is increased response and precision.

TABLE OF CONTENTS

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

ADDITIONAL ITEMS REQUIRED . . . . . . . . . . . . . . . . . . 2

Radio/Servos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Glow Engine & Accessories for Glow . . . . . . . . . . . . . 3

Brushless Electric Motor . . . . . . . . . . . . . . . . . . . . . . . 3

LiPo Battery Charger . . . . . . . . . . . . . . . . . . . . . . . . . . 3

ADHESIVES. HARDWARE AND

OTHER ACCESSORIES . . . . . . . . . . . . . . . . . . . . . . . 3

KIT INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

CONTENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

PREPARATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

ASSEMBLE THE WINGS . . . . . . . . . . . . . . . . . . . . . . . . . 7

Install the Aileron Servos. . . . . . . . . . . . . . . . . . . . . . . 7

Hook Up the Ailerons. . . . . . . . . . . . . . . . . . . . . . . . . . 9

ASSEMBLE THE FUSELAGE. . . . . . . . . . . . . . . . . . . . . . 9

Install the Horizontal Stabilizer

and Vertical Stabilizer . . . . . . . . . . . . . . . . . . . . . . . . . 9

Hinge the Elevators and Rudder . . . . . . . . . . . . . . . . 11

Hook Up the Elevator and Rudder. . . . . . . . . . . . . . . 13

Mount the Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Mount the ESC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Mount the Engine. . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Install the Fuel Tank . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Hook Up the Throttle . . . . . . . . . . . . . . . . . . . . . . . . . 19

Mount the Cowl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Finish the Radio Installation. . . . . . . . . . . . . . . . . . . . 22

Mount the Main Landing Gear. . . . . . . . . . . . . . . . . . 23

Attach the Belly Pan . . . . . . . . . . . . . . . . . . . . . . . . . 24

Assemble the Canopy Hatch. . . . . . . . . . . . . . . . . . . 25

Mount the Wings . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Make the Aileron Pushrods . . . . . . . . . . . . . . . . . . . . 30

PREPARE THE MODEL FOR FLIGHT . . . . . . . . . . . . . . 30

Apply the Decals . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Set the Control Throws . . . . . . . . . . . . . . . . . . . . . . . 30

Check the C.G. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Balance the Model Laterally . . . . . . . . . . . . . . . . . . . 31

PREFLIGHT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Engine/Motor Safety Precautions . . . . . . . . . . . . . . . 31

Propeller Selection for a Brushless Motor. . . . . . . . . 32

Battery Precautions. . . . . . . . . . . . . . . . . . . . . . . . . . 33

Range Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

AMA SAFETY CODE. . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Radio Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Know Before You Fly . . . . . . . . . . . . . . . . . . . . . . . . . 34

FLYING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

3

Electric-powered

Glow-powered

SERVO CHART

Wingconfiguration

4 aileronservos

2 aileronservos

4 aileronservos

2 aileronservos

Total numberof servosrequired

6 4 7 5

The quantity and lengths of servo extensions can get

complicated depending upon whether you want to mix all four

aileron servos electronically, or mix them mechanically with

Y-harnesses, and whether you plan to remove the wings for

transport (then, you’ll want a servo wire connection from the

top aileron servos alongside one of the rear cabane struts that

can be easily connected and disconnected). The instruction

manual illustrates both two aileron servos in the bottom wing

only and four aileron servos in the top and bottom wings, but

for both options all the aileron servos were connected into

one channel with Y-harnesses as listed below.

2 Aileron Servos 4 Aileron Servos

SERVO EXTENSIONS and Y-HARNESS for

CONNECTING AILERON SERVOS INTO ONE CHANNEL

20"[508 mm]Y-harness

(1) TACM2500 (2) TACM2500

5"— 6"[130 —150 mm]

Y-harnessNot Required (1) VNRM1668

Glow Engine & Accessories for Glow

The Ultimate is suited for a .46 – .55 2-stroke or .72 – .81

4-stroke. Because the engine is side-mounted, 2-stroke

engines require a Bisson Pitts-style muffl er:

❍ O.S. FS72-a 4-stroke with muffl er (OSMG0877)

❍ *O.S. 46AXII 2-stroke with muffl er (OSMG0548)

❍ O.S. 55AX ABL 2-stroke with muffl er (OSMG0557)

❍ Bisson Pitts-style muffl er (BISG4046)

❍ 1/4" [6.4mm] R/C foam rubber (HCAQ1000)

❍ Great Planes Dead Center Hole Locator (GPMR8130)

❍ 3’ [.9m] medium silicone fuel line (GPMQ4131)

❍ Optional: Aluminum fuel line plug (GPMQ4166)

❍ Dubro Fuel Clunk Standard (DUBQ0637)

❍ Suitable propeller for your engine

* With the O.S. .46 AXII an APC 12.5 x 6 (APCQ9905)

was preferred

Brushless Electric Motor

The electric setup for the Ultimate is straightforward: a Great

Planes ElectriFly RimFire .55 on a 6S battery in the 3800mAh

range with a 75A ESC. Propeller selection depends upon your

preference and fl ying style, but we preferred the APCX 16 x

8E (full discussion on prop selection on page 32). A Castle

Creations Edge Lite 75 is also recommended and illustrated

in the instruction manual because it is compact, durable,

programmable and features data logging. The discharge

wires from the ESC require lengthening to reach the battery

and order numbers for the wire are provided below.

❍ 42-60-480 RimFire .55 (GPMG4715)

❍ Brushless motor mount for medium motors

(GPMG1255)

❍ M3 x 6 screws for mounting motor to motor mount

(DTXC8650 or HPIC0351)

❍ APC 16 x 8 thin E prop (APCQ4015)

❍ Castle Creations Edge Lite 75 (CSEM1200)

❍ (2) FlightPower 3S 3800 30C (FPWP3383) and Great

Planes Series adapter (GPMM3143)

OR❍ FlightPower 6S 3800mAh 30C (FPWP3386)

❍ Adhesive-back Velcoro for mounting batteries

(GPMQ4480)

❍ 10 gauge silicone wire to extend discharge wires

from ESC

➊ CSEC0030 3’ black

➋ CSEC0031 3’ red

➌ 3/16" heat shrink tubing (GPMM1056)

➍ T-style Star connector (HCAM4001)

LiPo Battery Charger

To charge a 6S 3800 mAh LiPo at 1C, a charger capable of

at least 95 watts is required (6S x 4.2V/cell = 25.2 V x 3.8 A =

95 Watts). The Triton2 EQ is just enough charger with 100 W

output AC and 120 W output DC (GPMM3156).

ADHESIVES. HARDWARE AND

OTHER ACCESSORIES

Other than common hobby tools here is a list of the rest of

the items required:

❍ 30-minute epoxy (GPMR6043)

❍ Epoxy brushes (GPMR8060)

❍ Mixing cups (GPMR8056)

❍ Mixing sticks (GPMR8055)

❍ Threadlocker thread locking cement (GPMR6060)

❍ Thin CA (GPMR6001)

❍ Medium CA (GPMR6007)

❍ CA applicator tips (HCAR3780)

❍ A #50 (.070") drill (for drilling out servo arms for the

pushrod wires)

❍ Optional: 1/5-scale Sport pilot (GPMQ9015)

❍ Optional: Zap Adhesives Formula 560 Canopy Glue

(PAAR3300)

4

A Robart Super Stand II (ROBP1402) is also indispensable

for working on your Ultimate.

A covering iron with a cover sock may be required for

tightening and re bonding the covering to the model that may

have loosened between the time the plane was manufactured

and the time the model was removed from the box. The 21st

Century iron is preferred because of its long cord, contoured

shoe and precisely adjustable temperature range. A trim iron

is also handy for detailed covering tasks.

❍ Coverite 21st Century Sealing Iron (COVR2700)

❍ Coverite 21st Century Cover Sock (COVR2702)

❍ Coverite 21st Century Trim Seal Tool (COVR2750)

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.

Hobbico Product Support3002 N. Apollo Drive, Suite 1 Ph: (217) 398-8970, ext. 5Champaign, IL 61822 Fax: (217) 398-7721

E-mail: airsupport@hobbico.com

Order No. Description

REPLACEMENT PARTS LIST

TOWA4050

TOWA4051

TOWA4052

TOWA4053

TOWA4054

TOWA4055

TOWA4056

TOWA4057

TOWA4058

TOWA4059

TOWA4060

TOWA4061

TOWA4062

TOWA4063

TOWA4064

TOWA4065

TOWA4066

TOWA4067

TOWA4068

Fuselage set

Upper wing set

Lower wing set

Tail surface set

Cowl

Landing gear

Wheel pants

Interplane struts

Cabanes

Canopy

Hatch

Belly pan

Thumb screw set

Lower wing bolts (2)

Spinner

Fuel tank

Decals

Tail wheel set

Engine mount set

CONTENTS

1. Cowl

2. Fuselage

3. Canopy Hatch

4. Top Wing

5. Bottom Wing

6. Horizontal Stabilizer

7. Vertical Stabilizer

8. Hardware / Wood Parts

9. Cabane Struts

10. Hardware

11. Wing Struts

12. Wheel Pants

13. Main Landing Gear

14. Canopy

15. Fuel Tank

16. Main Wheels

17. Spinner

18. Pushrods

1

7

13

4

10

16

2

814

5

11

17

3

9

15

6

12

18

5

PREPARATIONS

NOTE: If you’re already familiar with iron-on coverings, you

may fi nd that the covering on the Ultimate requires less heat

than other coverings you’ve worked with. Too much heat

causes seams and edges to separate as the covering tightens.

The optimum temperature measured on the surface of a cover

sock on a cover iron is about 280ºF [140ºC] which requires

a dial setting of about 300ºF [150ºC] or “medium” heat on

most covering irons. You can go a little higher if necessary,

but be careful around seams and overlapping edges. If the

covering blisters up and cannot be pressed back down, the

iron may be too hot, or you are leaving it in one location for

too long—try reducing the heat or moving the iron a little

faster. Another option is perforating the blister in a few areas

with a #11 hobby blade.

A covering iron with a cover sock is preferred over a heat

gun. With a covering iron you can apply heat only where

required. With a heat gun you may inadvertently overheat a

seam causing separation.

❏ 1. Use a covering iron with a cover sock to tighten any

loose covering. Wherever the covering is attached to wood,

press down on the iron to thoroughly bond the covering to

the balsa underneath. Where possible, reach inside the model

and support sheeted areas while tightening the covering to

prevent the sheeting from bending inward. If you’ll be using

the top wing aileron servos, also be sure to securely bond

the covering to the structure on the bottom of the top wing

around the aileron hatch openings. (The area of the hatch has

been outlined with a felt-tip pen for illustration in the image.)

❏ 2. Before proceeding with assembly, now would be a good

time to make sure all the hinges in the ailerons are secure.

Pull hard on each aileron to check the hinges. Apply thin CA

to any hinges that may not be secure.

Perform the steps 3 through 7 if installing aileron servos

in the top wing.

❏ 3. Use a hobby knife (or a 3/8" brass tube sharpened on

the end) to cut a hole in the bottom of the top wing where

shown for the servo wire.

❏ 4. Use a straightedge as a guide to cut the covering

approximately 3/16" [5mm] inside the edges of the aileron

hatch openings.

6

❏ 5. Slit the corners of the covering up to the corners of

the hatch opening.

❏ 6. Use a trim iron to bond the covering down inside

the openings.

❏ 7. Cut the covering from the servo arm openings and

the four screw holes in the corners of the top aileron hatch

covers. Use a trim seal tool to seal the covering around the

edges of the openings.

❏ 8. A few paper towels stacked on top of each other cut

into small squares will come in handy for wiping off excess

CA and/or epoxy as you proceed with assembly. For epoxy

clean up later, dampen the squares with denatured alcohol.

❏ 9. Glue the wood dowels into the bottom wing.

❏ 10. If powering your Ultimate with a glow engine, fuelproof

any areas that may be exposed to raw fuel or oily engine

exhaust such as the openings in the fuselage at the front

and back of the bottom wing, the front of the bottom wing,

inside the belly pan around the wing bolt holes and the back

of the fi rewall.

7

ASSEMBLE THE WINGS

Install the Aileron Servos

Part of installing the aileron servos is deciding how you are

going to connect the servos to your receiver. If you’re using

only the two servos in the bottom wing you can connect them

with a standard Y-connector and guide the male end of the Y

that goes into the receiver out the wing. Or, you may connect

the servos to separate channels in your receiver mixing them

electronically through programming in your transmitter.

But if you’re using four servos there are even more ways to mix

the servos depending on how many channels are available in

your radio. One way would be to connect each aileron servo

to separate channels in the receiver, controlling them with a

programmable mix. The advantage here would be the ability

to independently adjust each servo’s sub trim and end points

for the ultimate in precision and tuning. But then at least a

7-channel receiver would be required and all the additional

servo extensions to connect each one to the receiver.

Another way is with a standard 2-aileron wing mix found

under the “wing type” mix in most transmitters. This mixes

two aileron servos, but then you will have to “Y” the top and

bottom servos on each wing half and will not have the ability

to adjust the sub trims and end points of each servo.

But since all options (other than controlling the servos

separately with four channels) eliminate adjusting the servos

independently with end points and sub trims, we just kept it

simple and “Y’d” the servos in the top wing to each other and

“Y’d” the servos in the bottom wing to each other, then “Y’d”

the “Y’s” together inside the fuselage into a single aileron

channel. The advantage with this option is only one servo

wire coming from the top wing which is simpler and more

aesthetically pleasing.

The following instructions illustrate installing and

hooking up the ailerons in the bottom wing. If installing

servos in the top wing too, simply perform the steps

for all four servos.

❏ 1. Trim one of the 5/16" x 9/16" x 3/4" [8 x 15 x 20mm]

servo mount blocks to accommodate the servo wire where

it exits the servo case.

❏ 2. Hold two

blocks to the servo

with thin cardstock

between the blocks

and the servo and

under the servo

between the servo

and your workbench

as shown. Drill 1/16"

[1.6mm] holes into

the blocks for the

servo mounting

screws.

❏ 3. Make another

aileron servo/mount

block assembly

mirroring the first

and drill the holes

and mount to the

servo.

❏ 4. Apply 30-minute epoxy to the bottom of the mount

blocks where they contact the hatch covers. Also wipe a

fi lm of epoxy onto the hatch covers where the mount blocks

will land. Wait a few minutes for the epoxy to soak into the

mount blocks, apply more epoxy if needed, then position

the servos on the hatch covers so the servo arms will be

centered in the cutouts. Use weights or clamps to hold the

servo blocks to the hatches until the epoxy hardened.

8

If installing all four aileron servos, this is what the servos and

hatch covers should look like.

❏ 5. Connect the bottom aileron servos to your receiver

(with or without a Y-harness; whichever is your preference)

with a battery and turn on your transmitter to power up the

system so you can operate the servos.

❏ 6. Fit servo arms on the servos positioned so the arms

will be angled forward approximately as shown—it’s more

important to have the arms on each servo angled the same

than it is to have any precise angle. The arms just need to

be angled forward so the pushrods will be approximately

perpendicular with the servo arms when connected to the

control horn on the aileron.

❏ 7. Cut the unused arms from the servo arm and enlarge the

holes in the servo arm with a #50 (.070") drill for the pushrod

wires. Fasten the arms to the servos with the screws that

came with the servos.

❏ 8. Cut the covering from one of the servo wire holes in

the top of the bottom wing. Use the string in the wing to pull

one side of the 20" [508mm] Y-harness through the hole and

out one of the aileron hatch openings.

❏ 9. Connect the Y-harness to the servo and mount the

hatch/servo to the wing with M2.3 x 8 washer-head screws.

9

❏ 10. Pull the other end of the Y-harness through the other

side of the wing and mount the other hatch.

Hook Up the Ailerons

Refer to this image while mounting the aileron servos

and hooking up the ailerons.

Do the left wing fi rst…

❏ ❏ 1. Thread a clevis about fi fteen full turns onto a 4-3/4"

[120mm] aileron pushrod. Make a second assembly the

same way.

1/16" [1.5 mm]

Servo Arm

90º Connector

❏ ❏ 2. Bend and cut the pushrods to the correct length,

then connect the aileron servos to the ailerons using the

hardware shown. Drill 1/16" [1.6mm] holes into the ailerons

for the M2 x 12 screws. After installing the screws, remove

the screws, add a few drops of thin CA to the holes, allow to

harden, then reinstall the screws. Adjust the clevises on the

pushrods so the ailerons will be centered when the servos

are centered.

M2 x 10

For Bottom Ailerons Only

Small Control Horn

Centered BehindMounting Plate

❏ ❏ 3. If not installing aileron servos in the top wing, mount

a small control horn to the top surface of the bottom ailerons

in the location illustrated in the image above and in the

illustration on the bottom of the column to the left.

ASSEMBLE THE FUSELAGE

Install the Horizontal Stabilizerand Vertical Stabilizer

❏ 1. If you haven’t already done so, remove the masking tape

holding the elevators to the horizontal stabilizer. Any residual

glue from the masking tape can be removed with naptha

(lighter fl uid) and a small paper towel square. If necessary,

use your covering iron to tighten the covering.

❏ 2. Test-fi t the elevator joiner wire to the elevators. If the

elevators do not align with each other (as in the image), use

pliers to “tweak” the joiner to get the elevators aligned.

10

❏ 3. Temporarily bolt the bottom wing to the fuselage with the

two included nylon wing bolts. Slide the horizontal stabilizer

into position and view the model from behind. Check the

alignment between the stab and the wing. If necessary,

remove the stab and lightly sand the slot to align the stab

with the wing.

❏ 4. Perform a trial-run of fi nal stab alignment before doing

it with glue;

A. Center the stab laterally taking measurements from both

sides of the fuselage.

B. Once the stab is centered, insert pins into the trailing

edge tightly against both sides of the fuselage to lock the

trailing edge into place.

A = A'A

A'

C. Insert a pin into the fuselage centered over the stringer at

the front of the hatch opening. Use an inelastic string around

the pin with a line drawn on a strip of masking tape to check

rotational stab alignment. Slide the tape along the string and

rotate the stab until both tips align with the line on the tape.

11

❏ 5. Remove one of the pins from the trailing edge and slide

out the stab. Install the elevator joiner wire into the stab slot

in the fuselage, making certain to keep the correct orientation

so the elevators will align when refi tted to the joiner.

❏ 6. Add a liberal amount of 30-minute epoxy to the top and

bottom of the exposed balsa in the middle of the stab. Be

certain not to forget to install the elevator joiner wire

into the stab slot as instructed in the previous step! Slide

the stab into place removing excess epoxy as you proceed.

Reinsert the pin to align the trailing edge and make sure the

stab is properly aligned as previously described with the string

and tape. Make sure you’ve cleaned up all residual epoxy

and do not disturb the model until the epoxy has hardened.

❏ 7. Test-fi t the vertical stabilizer (fi n) into position. Make

any adjustments necessary for a good fi t and to make sure

the fi n is vertical, then permanently glue it into place with

30-minute epoxy. Use T-pins or clamps as necessary to close

any gaps between the fi n and the fi llet blocks. Any pinholes

from T-pins can be reduced later with a covering iron.

Hinge the Elevators and Rudder

❏ 1. Add a small drop of medium CA to the end of one of the

hinges. Insert the hinge halfway into one of the hinge slots in

one of the elevators—do not use any CA accelerator! This

will be just enough CA to keep the hinge from shifting while

joining the control surfaces to the stab and fi n.

❏ 2. Tack-glue the rest of the hinges into the hinge slots in

both elevators.

❏ 3. After the CA has hardened and all the hinges are in

place, test-fi t the elevators to the stab and joiner. Make sure

the surfaces move easily and smoothly.

12

❏ 4. Remove the elevators. Add epoxy into the holes in the

elevators for the joiner wires. Rejoin the elevators to the stab

and joiner wire and wipe away excess epoxy.

❏ 5. Use a thin applicator tip to apply 6 drops of thin CA

to the top and bottom of each hinge waiting a few seconds

between drops for the hinges to absorb the CA. Excess CA

that doesn’t wick into the hinges can be absorbed with the

edge of a small paper towel square.

❏ 6. Test fi t the tail gear. Same as was done with the elevator,

tack-glue the hinges into the rudder, then test-fi t the rudder

to the fi n. Make any adjustments necessary for a good fi t,

then remove the rudder and tail gear.

❏ 7. Using care not to get any epoxy into the hinge points

around the tail gear wire, insert the hinges into the fuselage

with 30-minute epoxy. Add epoxy into the hole in the rudder

for the “arm” part of the tail gear wire, then fi t the rudder to

the assembly.

❏ 8. Permanently attach the rudder to the fi n and fusealge

by gluing the hinges with thin CA.

❏ 9. After the CA on all the hinges has hardened, pull hard

on all the control surfaces to make sure they are secure and

all the hinges are thoroughly glued into place.

13

Hook Up the Elevator and Rudder

❏ 1. Thread a clevis onto two 26" [660mm] pushrods and

connect them to two large control horns. Mount the horns

to the elevator and rudder with M2 x 12 machine screws and

backing plates as shown.

❏ 2. Place the elevator and rudder servos in the servo tray

(enlarge the tray as necessary to accommodate your servos).

Install servo arms that will be perpendicular to the pushrods

as shown and cut off the unused arms.

❏ 3. With the surfaces centered, mark, bend and cut the

pushrods and connect them to the servos. You can bend

and cut the pushrods while they are in the fuselage, but it

will be easier to cut and bend them out of the fuselage (but

then the clevises will have to be temporarily removed so the

pushrods can be reinserted from the front of the guide tubes).

❏ 4. Drill 1/16" [1.6mm] holes through the servo tray and

mount the servos to the servo tray with the screws included

with the servos.

❏ 5. You can temporarily connect the servos to the receiver

and operate the servos and adjust the length of the pushrods

now, or later when performing fi nal radio setup.

Mount the Motor

If using a glow engine skip to Mount the Engine on page 16.

❏ 1. Mount the motor to an Electrifl y Brushless Motor Mount

for Medium Motors (not included), but do not use the M3

x 10 screws that came with the motor because they are

too long and may protrude into the motor and contact the

copper windings. Use M3 x 6 screws instead (DTXC8650

or HPIC0351).

❏ 2. Cut the brushless motor mount template from the

back of the instruction manual (or from the card that came

with the brushless motor mount) and tape it to the fi rewall

aligning the cross marks. Use a pin to mark the mounting

screw holes into the fi rewall.

14

❏ 3. Remove the template from the fi rewall. Drill 1/16" [1.6mm]

pilot holes through the fi rewall at the marks. Enlarge the holes

with a 13/64" (or 7/32") drill.

❏ 4. Use an M4 x 12 SHCS (socket-head cap screw) with a

stack of washers and a 3mm Allen wrench to draw the M4

blind nuts into the back of the fi rewall.

❏ 5. Mount the brushless motor mount to the fi rewall with

four M4 x 12 SHCS and M4 washers; it’s a little easier to fi rst

loosely fasten the mount with the bottom two screws, then

the top two screws before tightening them all down.

❏ 6. If necessary, ream or drill the back plate of the spinner

to fi t on the prop shaft, then fi t the back plate. Adjust the

mount so the back plate will be 4-3/4" [120mm] from the

fi rewall, then use a 3/32" Allen wrench to tentatively tighten

the screws on both sides of the mount to temporarily lock

the halves together.

Mount the ESC

❏ 1. You may copy the battery and ESC installation shown in

the manual, or do it another way if you have a different ESC.

However you mount the ESC, plan and test-fi t the battery

and ESC before cutting wires or performing any other steps

that cannot be undone. Here, the ESC has been temporarily

mounted to make sure it all fi ts and to determine the wire

length. Now, we know the ESC will fi t inside the cowl, but

the discharge wires from the ESC to the battery will have to

be lengthened.

❏ 2. Prepare your ESC as required to work with your setup.

For the Edge Lite 75 we extended the discharge wires an

additional 8-1/2" [215mm] and soldered the female 4mm

bullet connectors to the motor wires.

15

❏ 3. Mount the ESC, connect the ESC to the motor and

guide the discharge wires through the fuselage where they

can connect to the battery.

❏ 4. Attach a strip of the softer, “loop” side of adhesive-

back Velcro (not included) to the bottom of the battery and

strips of the rougher, “hook” side to the battery tray. Make

a battery strap (like one of the straps shown on page 18)

from the included Velcro strips and mount the battery to

the battery tray.

❏ 5. If the motor mount bolts protrude from the back of the

fi rewall, cut two 3" [80mm] pieces from the included 1/4" x

¼" x 8" [6 x 6 x 200mm] balsa stick. Glue the sticks to the

back of the fi rewall to prevent the bolts from puncturing the

front of the battery in the event of a crash.

❏ 6. Install the battery tray making sure the front of the tray

keys into the short balsa sticks right behind the fi rewall to

hold the front of the tray down. Fasten the battery tray with

one of the fi nger-turn ¼-20 nylon bolts included. Make sure

the discharge wires from the ESC can reach the discharge

wires from the battery.

CAUTION: If powering the receiver and servos through

the BEC in the ESC, whenever operating the radio in the

workshop, be certain to do so without the propeller

mounted. Do not operate the radio with the propeller

installed until you are outdoors when checking the motor

or fl ying the plane. If powering the servos and ESC with a

separate receiver battery, the radio may be safely operated

without concern for the propeller turning if the motor battery

is not connected to the ESC.

Skip ahead to Mount the Cowl on page 20.

16

Mount the Engine

The process for mounting a 4-stroke and a 2-stroke are the

same, but most of the instructions show a 4-stroke. Where

necessary or helpful, photos and notes for installing a 2-stroke

are also provided.

❏ 1. Mount a fl at stick or the back plate of your spinner to

the engine. Hold one of the engine mounts to the engine

sliding it along the engine until the distance between the

back of the engine mount and the back of the spinner will

be 4-3/4" [120mm].

❏ 2. Holding the mount to the engine, mark one of the holes

in the engine onto the engine mount – a Great Planes Dead-

Center Hole Locator is indispensable for this.

You can fasten the engine to the mount with the included M3

x 25 cap screws and M3 nuts, or drill and tap M3 threads

into the mount so no nuts will be required.

❏ 3. If using nuts, drill a 1/8" [3.2mm] hole through the mark

made in the previous step. If you are going to tap 3mm

threads, drill a 2.4mm (or 3/32") hole through the mark – in

either case, use a drill press if you have access to one to

ensure the hole is perpendicular to the surface of the mount.

If you don’t have a drill press, do your best to hold the drill

vertically so the hole will be perpendicular.

❏ 4. If tapping threads, use a 3mm tap to thread the hole – if

care is used you can chuck the tap in a hand drill to make

the procedure easier and faster.

❏ 5. Fasten the engine mount to the engine with an M3 x 25

cap screw, an M3 lock washer and fl at washer and an M3

nut (if you didn’t tap threads). Mark the location of the other

engine mount bolt hole onto the mount.

❏ 6. Remove the mount from the engine. Drill the 2nd hole

in the mount and fasten the mount back onto the engine.

❏ 7. Position the other mount half on the other side of the

engine and mark and drill the holes the same way, then fasten

the mount to the engine.

❏ 8. If using an O.S. FS .72 or .46AX, cut the appropriate

Engine Mount Template from the back of the instruction

manual. If using a different engine, place your engine over

the templates to see if one of them happens to match the

mount hole spacing for the engine mounts on your engine.

17

❏ 9. If neither template matches the spacing of the mount on

your engine, you can make your own template out of one of

the existing ones. Measure the distance between the holes

of the mount halves.

❏ 10. Mark “crossmarks” on the vertical lines above and

below the centerline half the distance of the measurement

you came up with in the previous step.

❏ 11. Tape the template to the fi rewall with the crossmarks

on the template aligned with the crossmarks on the fi rewall.

Push a pin into the fi rewall through the marks in the template

that align with the mounting holes in the engine mounts.

❏ 12. Remove the template from the fi rewall. Drill 1/16"

[1.6mm] pilot holes through the fi rewall at the pinpoints.

Enlarge the holes with a 13/64" (or 7/32") drill.

❏ 13. Use an M4 x 20 SHCS (socket-head cap screw) with

a stack of washers and a 3mm Allen wrench to draw the M4

blind nuts into the back of the fi rewall. Note: If the top of

the engine mount box interferes with the top two blind nuts,

grind one edge of the blind nuts so they will fi t.

18

❏ 14. Mount the engine mount to the fi rewall with four M4

x 20 SHCS and M4 washers and threadlocker. (For the O.S.

.72, the engine mounts had to be temporarily removed from

the engine to insert two of the SHCS in the mount.)

Install the Fuel Tank

❏ 1. Remove the stopper from the fuel tank and shake out

the aluminum tubes and the silicone fuel line.

❏ 2. Assemble the stopper assembly with the pickup line as

shown—the aluminum tubes can easily be cut to length by

rolling them on your workbench under a hobby knife blade.

Option: Insert the third aluminum tube through the stopper

and attach another pickup line and clunk (not included) for

a fueling/defueling line so you won’t have to detach the fuel

line from the engine to fuel and as you will with a single-line.

❏ 3. Insert the stopper into the tank with the vent line at the

top of the tank. Write TOP on top of the tank (or just insert

the stopper with the vent at the side of the tank with the

molded-in logo and capacity).

❏ 4. Cut a 2" x 5-1/2" [50 x 140mm] sheet of ¼" [6.4mm] RC

foam rubber. Make two fuel tank straps from 8" [200mm]

strips of Velcro overlapping 5" [130mm]. Fasten the fuel tank

to the fuel tank tray and connect approximately 8" of fuel

line to each line coming out of the tank.

19

❏ 5. Install the fuel tank tray into the fuselage guiding the fuel

lines out the hole in the fi rewall—make sure the front of the

tray keys into the short balsa sticks right behind the fi rewall

to hold the front of the tray down. Position the tray as far

forward as possible without causing the lines to kink against

the engine, then secure the tray with one of the fi nger-turn

¼-20 nylon bolts included.

Hook Up the Throttle

❏ 1. Plan your throttle setup. Determine where to locate the

throttle pushrod and the throttle servo (depending on the

location of the carburetor arm on the engine and locations

available for the throttle servo). The carburetor arm on both

the O.S. engines shown is above the fuel tank tray, so it’s

easiest to position the pushrod and servo above the tray

as well. The throttle servo may be installed in the servo tray

next to the elevator and rudder servos, but make sure the

servo won’t interfere with the wing bolt. If the throttle servo

will not fi t in the servo tray, perhaps the servo arm on the

elevator or rudder servo could be fl ip-fl opped allowing that

servo to be relocated to make room for the throttle servo.

Or, the throttle servo could be mounted on either side of the

engine mounting box inside the cowl.

❏ 2. Being certain to avoid the fuel tank, drill a 1/8" [3.2mm]

hole through the fi rewall in-line with the carburetor arm for

the throttle guide tube – a 1/8" [3.2mm] brass tube sharpened

on the end makes this an easy job. Otherwise, the engine

will have to be removed from the fi rewall and the hole drilled

with a regular 1/8" [3.2mm] drill.

Thread-on retainer(USE THREALOCKER!)

Screw-lock

M3 set screw

20

❏ 3. Cut the throttle guide tube and the throttle pushrod to

the correct length, then mount and connect the throttle servo

to the carburetor arm using the screw-lock assembly. Glue

one or two of the guide tube braces into position where

necessary to brace the throttle pushrod guide tube. Note:

The screw-lock assembly is a little tricky; do not over tighten

the thread-on retainer or else the screw-lock will not pivot in

the servo arm causing the throttle pushrod to bind. Because

of this, threadlocker must be used on the thread-on retainer

so it does not come off.

❏ 4. While we’re still working “under the hood,” mount the

muffl er and connect the fuel line to the carb and the vent

line to the pressure tap off the muffl er (the dangling fuel line

in the photo will be for fueling/defueling).

Mount the Cowl

Disregard the landing gear and wings that appear in following

images. Your landing gear and wings should not yet be

mounted.

❏ 1. Glue the ½" x ½" x 1" [13 x 13 x 25mm] hardwood

cowl mount blocks to front of the fuselage even with the

fuselage sides.

21

❏ 2. Position the cowl onto the fuselage over the engine/motor

and install the spinner back plate onto the prop shaft with a

prop and prop nut. (For glow engines, temporary removal of

the muffl er and needle valve may be required to fi t the cowl.).

❏ 3. Insert shims from balsa or card stock the thickness of the

desired spinner gap (approximately 3/32" [2.5mm]) between

the front of the cowl and the back plate of the spinner and

tightly tape the spinner to the cowl. Note: If you’re using a

brushless motor with the Great Planes adjustable brushless

motor mount, no need for the shims; after the cowl has been

mounted, simply adjust the mount to move the motor forward

until the desired spinner gap has been achieved.

❏ 4. Use a fi ne-point felt-tip pen to mark the aft edge of

the cowl onto both sides of the fuselage. Remove the cowl.

❏ 5. Measure the distance from the lines on the fuselage to

the middle of the cowl mount blocks. Mark dots from the aft

edge of the cowl the distance you measured.

❏ 6. Drill 1/16" [1.6mm] holes through the cowl at the marks.

❏ 7. Same as before, reinstall the cowl, spinner back plate

and shims (if used for a glow engine) and tape the cowl to

the spinner. Make sure the cowl is accurately aligned with the

spinner back plate and the stripes on the cowl are aligned

with the stripes on the fuselage.

❏ 8. Drill 1/16" [1.6mm] holes through the holes in the cowl

into the cowl mount blocks.

❏ 9. Remove the cowl. Enlarge the holes in the cowl with a

3/32" [2.4mm] drill.

22

❏ 10. If you’ve mounted an electric motor with the adjustable

brushless motor mount, move the motor forward the distance

of the desired spinner gap. Test-mount the cowl to the

fuselage with four M2.6 x 8 washer-head wood screws.

❏ 11. If you’ve mounted a glow

engine, use a Dremel 569 and/

or 570 Dremel grout removal

bit and a sanding drum to cut

holes in the cowl for the glow

plug igniter, muffler, needle

valve and fueling/defueling line.

Caution: Be certain to wear

eye and respiratory protection

when cutting fi berglass.

Finish the Radio Installation

Mount the receiver battery and on/off switch (if used) and the

receiver where practical and convenient. Review the following

steps to see the options. An optional universal mounting

tray is included for the receiver and/or receiver battery and

another optional battery tray is also included to mount a

receiver battery in the nose. If you’ve installed an electric

motor, the receiver should be mounted on the bottom of

the servo tray in the wing saddle so as not to interfere with

installation/removal of the battery tray.

❏ 1. If not using the universal mounting tray, use double-

sided foam adhesive tape or adhesive-back Velcro to mount

the receiver where desired. Use tape to hold the receiver

antennas perpendicular to each other as specifi ed in the

instructions that came with your radio control system.

❏ 2. If using the optional universal mounting tray, glue

the ½" x ½" x ¼" [13 x 13 x 6mm] hardwood tray mount

blocks into position where shown. Fit the tray and drill

1/16" [1.6mm] holes and mount the tray with four M2.3 x 8

washer-head screws.

23

❏ 3. If using the optional battery tray, mount the receiver

battery to the tray and glue it into position with two pieces

of the included ¼" x ¼" [6 x 6mm] balsa stick.

❏ 4. If using an on/off switch, use the mounting plate as

a template to cut holes in the fuselage for the switch, then

mount the switch.

Mount the Main Landing Gear

❏ 1. Fasten the wheel axles to the main landing gear with an

8mm lock nut – be certain to use threadlocker on the threads

as the threaded portion of the axles does not engage the

nylon locking part in the nuts.

1/8"[3mm]

1/4"[6mm]

❏ 2. Use a reinforced cutoff wheel and/or a metal fi le to grind

a ¼" [6mm] fl at spot 1/8" [3mm] from the end of both axles.

24

Collar

M3 x 8

M3 x 5 M3 x 5

Wheelpant

❏ 3. Refer to the image to see which is the right and which

is the left main landing gear (the gear sweeps aft). Using

threadlocker on all the screws, mount the wheels to the axles

with the wheel collars as shown, then fasten the wheel pants

with M3 x 8 Phillips screws.

❏ 4. Make sure the wheels are centered in the opening in the

pants and roll smoothly. If necessary, remove the wheel pant

and adjust the location of the wheel on the axle by moving

the wheel collars, then retighten tightly.

❏ 5. Mount the landing gear to the fuselage with six M3 x 12

Phillips screws and M3 washers and threadlocker.

Attach the Belly Pan

❏ 1. Mount the bottom wing to the fuselage with the included

¼ - 20 x 1" nylon wing bolts and 5/8" x ¾" [16 x 19mm] wing

bolt plates.

❏ 2. Carefully cut just into the covering around the wing bolt

plates. Do not cut into the wood.

❏ 3. Remove the wing bolts and the wing bolt plates. Remove

the covering from under where the wing bolt plate was.

❏ 4. Glue the wing bolt plates to the wing using the wing

bolts to hold them to the wing while the glue hardens.

25

❏ 5. Position the belly pan using tape and/or weights to hold

it in position. Use a fi ne-point felt-tip pen to mark the edges

of the belly pan onto the wing.

❏ 6. Remove the belly pan. Use a pin to perforate the covering

just inside the lines so glue will adhere.

❏ 7. Use your paper towel squares lightly dampened with

denatured alcohol to wash the ink lines from the bottom

of the wing. Glue the belly pan to the wing with 30-minute

epoxy mixed with microballoons, or just 30-minute epoxy.

Use tape and/or weights to hold the belly pan down until

the epoxy hardens.

❏ 8. Remove the bottom wing to proceed with assembly.

Assemble the Canopy Hatch

You’ll see the wings are attached in the following images, but

we determined it was easier to work on the canopy before

mounting the wings.

If using a brushless motor, the cockpit hatch may be held

to the fuselage with M3 screws and washers through both

sides of the fuselage into the tabs, or with the rubber band

hook and a rubber band. If using a glow engine, the rubber

band hook is not recommended so the screws should be

used to retain the canopy hatch.

❏ 1. If installing a pilot or if using the rubber band hook to

retain the canopy hatch, glue the cockpit fl oor doubler

to the bottom of the canopy hatch—the doubler should be

centered laterally and aft edge of the doubler should align

with the aft edges of the tabs. If using the rubber band to

retain the hatch also glue the hook into position.

❏ 2. Hold the pilot into position, then use the holes in the

cockpit fl oor doubler as a guide to drill two 1/16" [1.6mm]

holes through the cockpit fl oor and into the base of the pilot.

❏ 3. The pilot may be fastened with #4 x ½" screws and #4

washers only (not included), but if permanently gluing the

canopy on it is recommended to use screws and glue to

fasten the pilot to the cockpit fl oor.

26

❏ 4. Mount the cockpit hatch to the fuselage with a rubber

band around the hooks, or cut the covering from the screw

holes in the fuselage sides for the hatch screws and mount

the cockpit with two M3 x 14 Phillips screws and washers.

❏ 5. Tape the canopy to the cockpit making sure it is centered

all the way around—pay particular attention to the back of

the canopy where it covers the gap between the turtledeck

and the former at the back of the hatch to make sure that

gap is covered.

❏ 6. Drill 1/16" [1.6mm] holes through the canopy into

the hatch over the four hardwood screw doublers inside

the cockpit.

❏ 7. Carefully remove the tape and take off the canopy.

Enlarge the holes in the canopy with a 3/32" [2.4mm] drill. Trim

any fl ashing from the inside of the canopy around the holes.

❏ 8. If the canopy needs cleaning, wash in warm, soapy

water, then dry.

❏ 9. Fasten the canopy with four M2.6 x 8 washer-head

Phillips wood screws.

Mount the Wings

NOTE: Whenever removing the wings in the future, the

bottom wing cannot be easily removed without fi rst removing

the top wing with the outer wing struts attached to it, so

whenever the wings require removal, undo the aluminum

thumb nuts holding the bottom of the struts to the bottom

wing, then remove the top wing fi rst taking the struts with it.

❏ 1. If you’ve installed servos in the top wing, review the

wing mounting procedure and look at the images to think

about how you will route the aileron servo wire(s) from the

top wing into the fuselage and to the receiver.

❏ 2. It will be easier to cut the hole in the top of the fuselage

for the aileron wire now, before the cabanes are in position.

27

A clean way to cut the hole for the servo wire is to cut two

holes with a 1/8" [3.0mm] brass tube sharpened on the end,

then join the holes by removing material between them as

shown in the image. Or just cut carefully with a hobby knife.

Longer(bottom)

Shorter(top)

Front cabane

Aftcabane

Cross-brace

Hole

Hole

❏ 3. Being certain to use threadlocker on all the screws,

loosely fasten the forward and aft cabane struts to the

fuselage with four M3 x 8 Phillips screws. Hint: For inserting

the screws, the fuselage may be placed on its side and the

screws can be lifted on your screwdriver through the holes.

❏ 4. Loosely attach the cross-braces to the cabanes with

four more M3 x 8 Phillips screws and M4 nuts and threadlocker.

28

❏ 5. Insert the four 3 x 12mm alignment pins into the wing

struts, then securely glue them into place with a few drops

of thin CA.

❏ 6. Thread the four M3 x 35 threaded studs into both wings.

If any of the studs are diffi cult to thread in, you can thread

two knurled thumb nuts onto the stud to act as a stop-nut

and turn them to turn in the stud. The studs should stop

when they get about halfway in.

Bottom of top wing

4-5/8"[117mm]

❏ 7. Mark the recommended C.G. on the bottom of the

top wing 4-5/8" [117mm] back from the leading edge at the

middle of the wing. Also mark the forward and aft range 4"

[102mm] and 5-1/4" [133mm] back. One good way to mark

the C.G. is with narrow strips of tape so you can feel the

lines with your fi ngers when suspending the plane during

the C.G. check later.

29

❏ 8. Attach the wing struts to the top wing as shown—the

struts fi t to the wings only one way, but if you’re not sure you

can tell the top of the strut (that adjoins the top wing) is shorter

than the bottom of the strut. You may consider threadlocker

on the threads if running a glow engine, but for an electric

motor no threadlocker should be required. Of course, check

the security of the struts between fl ights.

❏ 9. Connect the aileron servos from the bottom wing to the

receiver using whatever method you’ve chosen (a Y-harness

is suggested). Guide the open end of the Y-harness (or servo

extension) up through the fuselage so it will be accessible

from inside the cabin for connecting to the extension coming

down from the top wing when the plane is upright. Mount

the bottom wing to the fuselage.

❏ 10. Attach the top wing to the cabanes while joining the

struts to the bottom with two more knurled nuts and M3 x

12 Phillips screws and M3 nuts and threadlocker through

the top of the cabanes.

❏ 11. If you’ve mounted aileron servos in the top wing, guide

the servo wire down through the hole you cut in the top of

the fuselage. Connect the wire to the wire to the Y-harness

(or servo extension) from the receiver—be certain to route

the wires where they will not interfere with the battery tray

(if you’ve installed an electric motor).

❏ 12. Use tape or a nylon tie wrap to secure the aileron servo

wire from the top wing to the cabane strut.

30

Make the Aileron Pushrods

Skip this section if you’re using four aileron servos.

1/4"[6mm]

1/4"[6mm]

5-7/8"[150mm]

❏ 1. Make two 5-7/8" [150mm] pushrods by cutting an equal

amount from both ends of a 6-3/8" [160mm] pushrod. Use

a metal fi le or a cutoff wheel to remove any burrs from the

cut ends of the wire.

❏ 2. Prepare the pushrods as shown with a clevis and silicone

retainer on both ends and a small control horn on one end.

(The clevis is in the second-from-the-outer hole in the horn.)

❏ 3. Turn the model upside-down. Connect one of the

pushrods to the aileron horn previously mounted to the bottom

aileron, then mount the other horn to the aileron on the top

wing with two more M2 x 10 screws and the back plate.

❏ 4. Adjust the length of the pushrod so the ailerons will

be in synch with each other. Operate the ailerons with your

transmitter to make sure everything moves smoothly.

❏ 5. Hook up the other aileron the same way.

PREPARE THE MODEL FOR FLIGHT

Apply the Decals

Cut the included decals from the decal sheet and apply

them to the plane.

Set the Control Throws

In addition to the C.G., the control throws have a major effect

on how the model fl ies and whether or not your fi rst fl ight will

be successful. Do not skip this important step and make sure

the throws are as specifi ed. If necessary, use programming in

your transmitter and/or change the locations of the pushrods

in the servo arms and/or control horns to adjust the throw.

CAUTION: If using a brushless motor and powering the

receiver and servos through the BEC in the ESC, the throws

should be set and checked without the propeller mounted

to the motor. If the throttle is inadvertently bumped the

motor will turn possibly causing injury or damage, so make

sure the propeller is removed while operating the radio in

the workshop.

❏ 1. Before checking the throws, be certain to set the

Fail Safe function in your transmitter so that, in the case

of signal loss (or if the transmitter is inadvertently turned off

before power is disconnected from the motor) the motor will

not turn. Refer to the instructions that came with your radio

control system to set the Fail Safe.

With Tactic radios, the Fail Safe is set by pressing the “Link”

button in the receiver while the transmitter and receiver

are powered. When signal is lost, the throttle will go to the

setting where the throttle stick was when the Link button

was pressed, so to set the Fail Safe correctly make sure the

throttle stick is all the way down (motor off) when pressing

the Link button.

31

You can check the Fail Safe by having an assistant hold the

model or by removing the prop. Run the motor and turn off

the transmitter. Be prepared for the propeller to keep turning

or even speed up in case the Fail Safe has not been set

correctly. If the Fail Safe has been correctly set the motor

will stop when the transmitter is turned off.

❏ 2. Use a box or something similar to prop up the fuselage

so the horizontal stabilizer will be level. Check and set the

control throws according to the following measurements:

NOTE: The throws are measured at the widest part of the

elevator and rudder.

RUDDER

These are the recommended control surface throws:

AILERONS

ELEVATOR

LOW RATE HIGH RATE 3D RATE

2"

[51mm]

19°

Right & Left

2-3/4"

[70mm]

27°

Right & Left

4"

[102mm]

42°

Right & Left

1/2"

[13mm]

12°

Up & Down

3/4"

[19 mm]

11°

Up & Down

3/4"

[19mm]

19°

Up & Down

1"

[25 mm]

14°

Up & Down

1"

[25mm]

24°

Up & Down

3-1/2"

[89 mm]

61°

Up & Down

As mentioned in the introduction, the Ultimate is a pretty

gentle fl yer, so extreme exponential values are not necessary.

For low and high rates approximately 20% - 25% exponential

(negative exponential for Futaba and Tactic) is preferred. But

for 3D throws more exponential may be preferred (30% - 40%).

Check the C.G.

Same as the control throws, the C.G. has a great effect on how

the model fl ies. If the C.G. is too far forward the model may

be too stable and unresponsive to control inputs. If the C.G.

is too far aft the model may be too responsive and unstable.

❏ 1. If you have not yet done so, mount the propeller and

spinner. The model should be completely ready to fl y with

all components installed (including the motor battery if

using a brushless motor or with the fuel tank empty if using

a glow engine).

❏ 2. Lift the model with your fi ngertips on the C.G. lines you

marked on the bottom of the top wing back on page 28. As

long as the model balances anywhere within the specifi ed

range it is acceptable, but less-experienced pilots should

perform fi rst fl ights with the Ultimate balanced in the middle

or forward half of the range.

❏ 3. If the Ultimate doesn’t balance where specifi ed, relocate

the receiver battery or motor battery or add stick-on lead

ballast to the nose or tail to achieve the correct C.G.

❏ 4. If you’ve made any adjustments by adding ballast or

moving components, check the C.G. again before fl ying.

Balance the Model Laterally

❏ 1. Lift the Ultimate several times by the propeller shaft

and the tail to see if one wing drops.

❏ 2. If one wing drops consistently, add weight to the

opposite tip by sticking it to the outside or strategically

concealing it inside the wing tip. An airplane that has

been laterally balanced will track better in fl ight and

maintain its heading better during maneuvers when

the plane is climbing.

PREFLIGHT

Engine/Motor Safety Precautions

Failure to follow these safety precautions may result

in severe injury to yourself and others.

● Keep all engine fuel in a safe place, away from high heat,

sparks or fl ames, as fuel is very fl ammable. Do not smoke

near the engine or fuel; and remember that engine exhaust

gives off a great deal of deadly carbon monoxide. Therefore

do not run the engine in a closed room or garage.

● Get help from an experienced pilot when learning to

operate engines.

● Use safety glasses when starting or running engines.

● Do not run the engine in an area of loose gravel or sand;

the propeller 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 propeller as you start and

run the engine.

● Keep these items away from the prop: loose clothing, shirt

sleeves, ties, scarfs, long hair or loose objects such as

pencils or screwdrivers that may fall out of shirt or jacket

pockets into the prop.

32

● Use a “chicken stick” or electric starter to start the engine.

Do not use your fi ngers to fl ip the propeller. Make certain

the glow plug clip or connector is secure so that it will not

pop off or otherwise get into the running propeller.

● Make all engine adjustments from behind the rotating

propeller.

● The engine gets hot! Do not touch it during or right after

operation. Make sure fuel lines are in good condition so

fuel will not leak onto a hot engine, causing a fi re.

● To stop a glow engine, cut off the fuel supply by closing

off the fuel line or following the engine manufacturer’s

recommendations. Do not use hands, fi ngers or any other

body part to try to stop the engine. To stop a gasoline

powered engine an on/off switch should be connected to

the engine coil. Do not throw anything into the propeller

of a running engine.

WARNING: For brushless electric motors, never have the

motor battery connected to the ESC without the transmitter

turned on – after each fl ight (or any time after running the

motor) always disconnect the battery before turning off

the transmitter. And when ready to fl y (or whenever running

the motor for any reason), always turn on the transmitter

fi rst before connecting the motor battery.

Also make certain your failsafe is programmed correctly

so in the event the receiver ever loses signal the motor

will not turn (or, if you inadvertently turn off the transmitter

before disconnecting the battery or vice-versa). Follow the

instructions that came with your radio control system to

check and set the failsafe.

Propeller Selection fora Brushless Motor

The recommended RimFire .55 is rated for 45A constant

current and 80 A surge current, so load (prop) the motor to

operate within that range. The closer to 45A the longer you

can fl y full-throttle and the closer to 80A the less you can

fl y full-throttle until the motor gets too hot.

For starters, an APC 15 x 8E (on a 6S LiPo) draws momentary,

maximum peaks of about 60 A in the air, but averages a

little less than approximately 33 A with “normal” throttle

use (resulting in a recommended fl ying time of around 5-1/2

minutes). This is a suitable propeller choice for the RimFire

.55 on a 6S battery and fl ies the Ultimate well performing the

type of aerobatic routine for which it was intended.

But we’ve also fl own the Ultimate with a 16 x 8E and a 15 x

10E. Of the props tested, the 16 x 8E is preferred, but the peak

current draw will be a little higher (around 65 A). Depending

on your fl ying style and throttle usage, this could result in

shorter or even longer fl ight time.

In any regard, keep in mind the Ultimate is not a pylon racer

(where the throttle is pegged the entire fl ight!). The Ultimate

is an aerobatic airplane and the motor is therefore propped

accordingly, so it cannot be fl own full-throttle indefi nitely

unless you prop down signifi cantly, but then the Ultimate

it will not be very aerobatic. So always use prudent throttle

management to be certain you do not overheat the motor.

Use a fl ight timer with an alarm to indicate when it’s time

to land before the battery becomes over discharged. For

starters, set a conservative time (4 minutes for example) until

FORMULASA

123456789

10

B C D E F GB / A D x .8 E / C B/1000 / (A/60)

Flight Time

(.10 ths )

Recharge

CapacitymAh/minute

Battery

Capacity

Target Capacity

to Use in Flight

Recommended

Flight Time

Avg. In-Flight

Current

33

you have fl own enough times and gathered enough data to

make the calculations for setting maximum fl ight time (see

the worksheet on page 32). When the timer sounds, land.

When you charge the battery note how much capacity it

took to recharge (indicating how much capacity (mAh) was

used for the fl ight). Strive to use no more than 80% of the

battery’s capacity.

You can also use a LiPo battery tester like the one in the

image (GPMM3205) to check the resting (unloaded) voltage.

The individual cell voltage should not be below 3.75V/cell

measured a few minutes after you land. Adjust your timer

according to the voltage remaining and/or capacity used

for the fl ight.

Use the worksheet on page 32 to determine optimum fl ight

times based on how much battery capacity was used for

a fl ight.

CAUTION: Never run the motor on the ground for more

than a few seconds. Otherwise, you may overload the

motor, battery or ESC.

Battery Precautions

Before mounting the motor and setting up the ESC and battery, read the following important battery precautions:

IMPORTANT: If using multiple battery packs that are connected with an adapter, never charge the batteries together through the adapter. Always charge each battery pack separately. Charge the batteries, then read the following precautions on how to connect multiple packs for fl ying the model:

Battery Precautions:

There are two ways to connect multiple battery packs: In Series and in Parallel.

This is a SERIES battery adapterthat connects two batteries in series.

(3-Cell) 3200 mAh

(2-Cell) 3200 mAh

11.1V

7.4V

These are two 3200mAh batteries (one 11.1V and the other 7.4V). When joined in SERIES, the result will be a 18.5V, 3200 mAh battery.

1. Connecting batteries in “Series” means to connect the +’s to the –’s and the –’s to the +’s. This combines the batteries’ Voltages, but the capacity remains the same.

This is a PARALLEL battery adapter thatconnects two batteries in parallel.

(3-Cell) 1500 mAh

(3-Cell) 1500 mAh11.1V

11.1V

These two 1500mAh batteries (both 11.1V) are being joined in PARALLEL. The result will be one 11.1V, 3000mAh battery.

2. Connecting batteries in “Parallel” means to connect the +’s to the +’s and the -’s to the -’s. This combines the batteries’ capacities, but the Voltage remains the same.

34

PARALLELadapter

(2-Cell)

(3-Cell)11.1V

7.4V

PARALLELter

(3

NEVER connect battery packs with different Voltages in Parallel–only combine in Series. Otherwise, the batteries will try to “equalize” with the larger one trying to “charge” the smaller one, thus causing heat and likely a fi re.

(3-Cell) 3200mAh11.1V

(3-Cell) 1250mAh11.1V

SERIESadapter

h

SERIESter

Also NEVER connect battery packs with different ca-pacities in Series or in Parallel.

Range Check

Don’t forget to perform your usual ground range checks as

written in the instruction manual that came with your radio

system to be certain it is operating correctly.

AMA SAFETY CODE

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 fl y my model aircraft in sanctioned events,

air shows, or model fl ying demonstrations until it has

been proven to be airworthy by having been previously,

successfully fl ight tested.

2) I will not fl 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 fl ying in the

proximity of full-scale aircraft. Where necessary, an observer

shall be utilized to supervise fl ying to avoid having models

fl y in the proximity of full-scale aircraft.

3) Where established, I will abide by the safety rules for the

fl ying site I use, and I will not willfully and deliberately fl y my

models in a careless, reckless and/or dangerous manner.

5) I will not fl y my model unless it is identifi ed with my name

and address or AMA number, on or in the model. Note: This

does not apply to models while being fl 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 ground

check before the fi rst fl ight of a new or repaired model.

2) I will not fl y my model aircraft in the presence of spectators

until I become a qualified flier, unless assisted by an

experienced helper.

3) At all fl ying sites a straight or curved line(s) must be

established in front of which all fl ying takes place with the

other side for spectators. Only personnel involved with fl ying

the aircraft are allowed at or in the front of the fl ight line.

Intentional fl ying behind the fl 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 fl 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 fl ight; nor should any part of the

model other than the landing gear, intentionally touch

the ground, except while landing.

Know Before You Fly

As a new owner of an unmanned aircraft system (UAS), you are responsible for the operation of this vehicle and the safety of those around you. Please contact your local authorities to fi nd out the latest rules and regulations.

In the United States, please visit:

knowbeforeyoufl y.org faa.gov/uas

35

UpUp

O.S. Max .46AXEngine Mount Template

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FLYING

As mentioned in the introduction, in spite of its aerobatic

design the Ultimate is an easy fl yer. If you’ve prepared your

Ultimate using suggested components as described in

the manual (whether glow or electric), the wing loading is

relatively light which facilitates its landing and general fl ying

characteristics. But no matter what is written here, you still

have to fl y a successful maiden and see for yourself to gain

confi dence, so make sure the throws and C.G. are set up as

specifi ed. Intermediate pilots should takeoff and fl y the fi rst

few minutes on low rates until the Ultimate is trimmed for

straight-and-level fl ight. Learn the Ultimate’s slow-fl ight and

stall characteristics at a high altitude where there is plenty of

time and altitude to recover. The Ultimate doesn’t exhibit any

particular fl ight characteristics that you need to be warned

about ahead of time, but we can tell you that landings will

be easier and gentler if you drag the Ultimate in with three

or four clicks of power to arrest the sink rate allowing it to

gently settle onto the runway.

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