Tower Hobbies Sbach User manual

Brand: Tower Hobbies

Model: Sbach

Category: Remote controlled toys

Type: User manual

READ THROUGH THIS MANUAL

BEFORE STARTING CONSTRUCTION.

IT CONTAINS IMPORTANT

INSTRUCTIONS AND WARNINGS

CONCERNING THE ASSEMBLY

AND USE OF THIS MODEL.

WING LOADING

19 – 2 0 oz / f t 2 [58–62 g/dm2]

WEIGHT

4.0 – 4.3lbs [1814–1928g]

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

modication. 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 nal assembly or

material used for nal assembly, no liability shall be assumed nor accept-

ed for any damage resulting from the use by the user of the nal user-assem-

bled 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, visit: towerhobbies/support

WARRANTY

TOWA2026

® A subsidiary of Hobbico, Inc.

®®

RADIO

4 – 5 channels, 4 servos

WING AREA

482.0 in2 [31.1 dm2]

WINGSPAN

49.6 in [1260 mm]

LENGTH

47. 5 in [1207 mm]

INSTRUCTION MANUAL

POWER

1.65" [42mm] diameter, 925W

RimFire .32 (42-50-800)

3300–4000 mAh 4S LiPo 75A ESC

(not included)

INTRODUCTION

Congratulations and thank you for purchasing the Tower

Hobbies Sbach EP. While the Sbach is primarily an aerobatic,

3D-type of plane, its contemporary and sleek lines make

it appealing to all kinds of pilots, both intermediate and

advanced. The Sbach can serve all as its light wing-loading

and large control surfaces make it an aerobatic machine,

while its long moments and large  ying surfaces make it a

smooth- ying, everyday sport model, too.

For the latest technical updates or manual corrections,  nd the

Sbach EP on the Tower Hobbies web site at www.towerhobbies.

com. 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

A minimum 4-channel radio with four mini servos and 4 –

5-channel receiver are required to  y the Sbach:

❍ Futaba R617FS 7-channel FASST receiver (FUTL7627)

The Sbach is intended to be  own with mini servos in the 20g

range such as Futaba S3150 or Futaba S3172SV mini servos.

❍ (4) Futaba S3150 digital servos (FUTM0303)

(4) Futaba S3172SV mini servos (FUTM0125)

❍ (4) 6" [150mm] servo extensions are required for the

ailerons (one on each servo and one in each channel

in the receiver).

❍ (4) Tactic servo extensions for Futaba (TACM2090)

(4) Tactic servo extensions Universal (TACM2092)

Brushless Electric Motor

The electric setup for the Sbach is straightforward: a

Great Planes Electrifly Rimfire .32 on a 13 x 8 E or 14 x

7E prop with a 75A ESC powered by a 4S 3800mAh LiPo.

A Castle Creations Edge Lite 75 ESC* is illustrated in the

instruction manual.

❍ RimFire .32 42-50-800 (GPMG4700)

❍ APC 13 x 8 thin E prop (APCQ3080)

APC 14 x 7 thin E prop (APCQ4045)

❍ Castle Creations Edge Lite 75 ESC (CSEM1200)

❍ 3300mAh – 4000mAh 4S LiPo:

FlightPower 4S 3300mAh 25C (FPWP2334)

FlightPower 4S 3600mAh 50C (FPWP5364)

FlightPower 4S 3800mAh 30C (FPWP3384)

* If setting the BEC voltage in the Castle Creations Edge Lite 75 ESC

higher than the factory default 5.0V, it is recommended to use a

separate BEC regulator such as the Castle Creations 10A BEC

regulator (CSEM0005) to power the radio system on-board the aircraft.

LiPo Battery Charger

To charge a 4S 3800mAh LiPo at 1C, a charger capable of

about 65 Watts output power is required (4S x 4.2V/cell =

16.8V x 3.8A = 63 Watts). The Triton EQ2 (GPMM3156) is

more than enough charger with 100W output AC and 120W

output DC.

Adhesives, Hardware &

Other Accessories

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

the items required:

❍ 6-minute epoxy (TOWR3806)

❍ 30-minute epoxy (TOWR3810)

TABLE OF CONTENTS

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

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

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

Brushless Electric Motor . . . . . . . . . . . . . . . . . . . . . . . 2

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

Adhesives, Hardware & Other Accessories . . . . . . . . . 3

KIT INSPECTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

KIT CONTENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

PREPARATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

ASSEMBLE THE WING. . . . . . . . . . . . . . . . . . . . . . . . . . . 5

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

Install the Horizontal Stabilizer. . . . . . . . . . . . . . . . . . . 9

Glue in the Horizontal Stabilizer. . . . . . . . . . . . . . . . . 12

Hinge the Elevators and Rudder . . . . . . . . . . . . . . . . 12

Hook Up the Elevator and Rudder. . . . . . . . . . . . . . . 14

Mount the Motor and ESC. . . . . . . . . . . . . . . . . . . . . 15

Final Radio Installation. . . . . . . . . . . . . . . . . . . . . . . . 20

FINAL ASSEMBLY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Mount the Landing Gear . . . . . . . . . . . . . . . . . . . . . . 20

Mount the Cowl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

PREPARE THE MODEL FOR FLIGHT . . . . . . . . . . . . . . 24

Set the Control Throws . . . . . . . . . . . . . . . . . . . . . . . 24

Check the C.G. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Balance the Model Laterally . . . . . . . . . . . . . . . . . . . 25

PREFLIGHT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Motor Safety Precautions . . . . . . . . . . . . . . . . . . . . . 25

Motor/Propeller Discussion . . . . . . . . . . . . . . . . . . . . . .

Battery Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Range Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

AMA SAFETY CODE (excerpts) . . . . . . . . . . . . . . . . . . . 27

General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Radio Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

FLYING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

❍ Epoxy brushes (GPMR8060)

❍ Mixing cups (GPMR8056)

❍ Mixing sticks (GPMR8055)

❍ Threadlocker thread locking cement (GPMR6060)

❍ Thin CA (GPMR6001)

❍ Medium CA (GPMR6007)

❍ CA applicator tips (HCAR3780)

❍ CA accelerator (GPMR6035)

❍ Great Planes Standard Precision Prop Reamer

(GPMQ5006)

❍ Optional: Z-bend pliers (HCAR2000) (see step 15 on

page 14)

❍ Drills: 1/16" [1.6mm], 1/8" [3.2mm], 5/32" [4.0mm], #49

(.073")

A Robart

Super Stand

II (ROBP1402)

is also handy

for working

on your

Sbach.

A covering iron with a cover sock may be required for

tightening and re bonding 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:

❍ Coverite 21st Century Sealing Iron (COVR2700)

❍ Coverite 21st Century Cover Sock (COVR2702)

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. Visit: towerhobbies/support

PARTS LIST

Order No. Description

Wing

Fuselage

Tail Surfaces

Cowl

Hatch

Landing Gear

Wheel Pants

Spinner

Decals

Wing Tube

TOWA5030

TOWA5031

TOWA5032

TOWA5033

TOWA5034

TOWA5035

TOWA5036

TOWA5037

TOWA5038

TOWA5039

KIT CONTENTS

1. Cowl

2. Fuselage

3. Left Wing Half

4. Right Wing Half

5. Horizontal Stabilizer

6. Rudder

7. Wheel Pants

8. Main Wheels

9. Tailwheel Assembly

10. Wing Joiner

11. Pushrods

12. Main Landing Gear

13. Spinner

14. Nylon Parts

15. Hardware

16. Elevator Joiner &

Rudder Torque Rod

17. Hardware

12 13 14

CANOPY REMOVAL/INSTALLATION

The canopy hatch is held in place with tabs in the back and

springs over dowels in the front. To remove the canopy, push

forward to disengage the tabs, then lift the rear up and pull

the canopy back and out to disengage the dowels. (If you feel

too much pressure is required to push the canopy forward,

the tabs could be shortened slightly to shorten the “throw”

that the canopy has to be pushed.)

PREPARATION

Between the time the covering was applied to your model

and the time it arrives in your hands it is normal for the

covering to loosen and wrinkle – especially if it has been a

long time and/or the air is dry at your location (causing the

structure to contract and the covering to loosen). But this is

easy to  x using the proper tools and techniques.

The best way to renew the covering job is with a covering

iron with a protective cover sock not only to tighten the

covering, but also to thoroughly bond the covering to the

wood underneath. The preferred tool is a 21st Century cover

iron with a cover sock set to about 300°F [150°C]. This

translates to about 280°F [140°C] measured on the surface

of the cover sock.

Begin with the wings. You may also do the fuselage and tail

surfaces now, or wait until they are needed for assembly later.

❏ 1. Over unsupported covering, glide the iron across, but

where the  lm is over structure apply pressure to bond the

covering down. Adjust the heat setting as necessary so the

covering tightens, shrinks and bonds to the wood, but not

so hot as to cause seams to pull apart.

❏ 2. Where possible, support the structure underneath with

your free hand to prevent the sheeting from bending inward.

❏ 3. OPTIONAL: When you get to the ailerons, elevators

and rudder, puncture three or four pinholes through the

covering on the bottom of those surfaces between each

of the braces or “ribs.” This will allow heated, expanding

air to escape so the covering will tighten. These pinholes

may appear obtrusive at  rst, but when the covering is

heated the pinholes virtually disappear. Heat the side of the

covering without the pinholes  rst.

❏ 4. Stack a few paper towels on top of each other and cut

them into small squares. These small paper towel squares

come in handy for dabbing up excess CA or wiping up

epoxy when dampened with denatured alcohol.

❏ 5. NOTE: All machine-thread screws that thread into

metal (hex nuts, blind nuts, wheel collars, etc.) should

be lightly wetted with threadlocker.

❏ 6. NOTE: The procedure for preparing the holes in

wood for all wood screws is as follows:

A. Drill the hole with the drill speci ed in the step.

B. Install, then remove the screw to form “threads” in

the hole.

C. Add a drop or two of thin CA to harden the hole.

D. Allow the CA to harden, then install the screw(s)

with the hardware that is being mounted/installed/

attached (servos, control horns, etc.).

ASSEMBLE THE WING

Hook up the Ailerons

Refer to this image while hooking up the aileron.

S3171SV

S3171SV #49 [.073"]

Drill

5/8" [16mm]

90°

❏ 1.

Connect the aileron servo to your radio so you can power

the servo. Position the servo arm so it will be perpendicular

to the servo, then cut off the unused arms. Drill out the holes

in the arm with a #49 (.073") drill.

Horn all the way to

leading edge of aileron.

90° Pushrod Connector

1/16"

[1.6mm]

❏ 2. Hook up the aileron with the hardware shown; note

that the aileron horn is mounted all the way to the forward

edge of the aileron. Using care not to drill through the top

of the aileron, drill 1/16" [1.6mm] holes for the servo and

horn mounting screws. Don’t forget to temporarily remove

the screws and harden the holes with thin CA. Connect

the pushrod to a hole about 5/8" [16mm] out on the servo

arm and the middle hole in the aileron horn. This geometry

should provide the correct 3D throw with the transmitter

servo end points dialed to about 110%.

3. Prepare the other wing with the aileron servo the

same way.

❏ 4. Use 6 or 30-minute epoxy to glue the nylon alignment

pins into both wings with approximately 1/4" [6mm]

protruding from the wing.

❏ 5. Test- t, but do not glue the  berglass wing tabs into

the ends of the wings.

❏ 6. Fit the wings to the fuselage with the wing tube. Make

sure the tabs insert into the fuselage and the holes in the

tabs align with the holes in the brackets for the tab screws

in the fuselage. Make any adjustments necessary.

7. Remove the wings and tabs. Use 30-minute epoxy to glue

the tabs into the ends of the wing and wipe away excess

epoxy. Before the epoxy hardens, reinstall the wings back

onto the fuselage and position the tabs so the slotted holes

will be centered over the holes in the brackets. Momentarily

remove the wings to be sure there is no excess epoxy

around the tabs that would inadvertently stick the wing to

the fuselage. Reinstall the wings and immediately proceed

to the next step.

❏ 8. Before the epoxy has hardened, fasten the tabs

with an M3 x 10 SHCS (socket-head cap screw) and M3

lock washers and  at washers. Push the wings snugly to

the fuselage and allow the epoxy to fully harden before

removing the wings.

ASSEMBLE THE FUSELAGE

Installl the Horizontal Stabilizer

❏ 1. If you haven’t yet done so, tighten the covering over

the fuselage and the tail surfaces. Be certain to seal the

bottom fuselage covering to the front of the former so the

covering cannot pull away.

❏ 2. Test- t the elevators to the stabilizer with the hinges

and the joiner wire—you may insert T-pins through the

middle of any hinges that don’t remain centered.

❏ 3. View the elevators from whatever perspective

necessary to see that they are aligned with each other. If

necessary, remove the joiner and lightly “tweak” with pliers

to align the elevators.

❏ 4. Temporarily mount the elevator servo, then remove

it (it’s easier to drill the holes for the elevator servo now,

before the stab has been glued in).

❏ 5. Mount the wings to the fuselage. Slide the horizontal

stabilizer into position. View the model from the rear to see

if the stab is parallel with the wing.

❏ 6. If necessary, remove the stab and carefully sand the

stab saddle where necessary to align the stab with the wing.

❏ 7. Now that the stab is level with the wing, center the

stab laterally by using a ruler to equalize the distance from

both ends of the stab to the fuselage.

❏ 8. Once centered, stick T-pins into the trailing edge of

the stab on both sides of the fuselage to lock the trailing

edge into place.

❏ 9. Tie a loop around one end of an approximately 48"

[1200mm] non-elastic line. Fold a piece of masking tape

over the other end of the line. Mark a line on the tape.

❏ 10. Insert a pin into the middle of the fuselage crutch

across the top of the former as shown. Loop the line over

the pin.

❏ 11. Hold the line with the tape to one corner of the stab.

Swing the line over to the corner on the other end of the

stab. Adjust the stab and slide the tape along the line until

the stab is centered and equalized.

❏ 12. Once you’re satis ed with stab alignment, use a

 ne-point felt-tip pen to mark the outline of the fuselage all

the way around both sides of the horizontal stabilizer. Even

though the ink and most of the covering on top of the stab

are black, you’ll still be able to see the line indicating where

the covering will be cut and removed in the next step.

❏ 13. Cut the covering 1/32" [1mm] inside the lines you

marked around the stab. A hobby knife may be used if

the blade is brand new and sharp so little pressure will be

required for cutting, but extreme care must be used to cut

only through the covering and not into the sheeting

otherwise, the stab will be weakened. The best way is with

a soldering iron with a cutting-type of tip. A heat setting of

about 500F [260C] seems to work well.

❏ 14. Wipe away any residual ink with a paper towel square

dampened with denatured alcohol, then peel the covering

from the stab.

Glue in the Horizontal Stabilizer

❏ 1. Gather your small paper towel squares and denatured

alcohol for epoxy clean up. Small balsa sticks chopped

up from 1/16" [1.5mm] balsa sheet are also handy for

“squeegeeing” away most of the epoxy before using the

paper towel squares.

❏ 2. Don’t forget to place the elevator joiner wire into the

fuselage. It can be held out of the way with a rubber band

as shown in following images.

CAUTION: Have everything ready and on-hand for gluing

in the stab. Work quickly and ef ciently because some

30-minute epoxies may harden faster than others and

time  ies when trying to work with precision—you don’t

want the epoxy hardening up before you have the stab

accurately aligned. ❏ 3. Mix up approximately 1/4 oz. of 30-minute epoxy.

Apply epoxy all the way around the stab saddle on both

sides of the fuselage and to the top and bottom of the stab.

❏ 4. Slide the stab into position. Wipe away excess epoxy

with the balsa sticks and paper towel squares dampened

with denatured alcohol. Double-check alignment, place any

weight on the stab if required for alignment and allow the

epoxy to harden before proceeding.

Hinge the Elevators and Rudder

1. Once more, test- t the elevators to the stab with the joiner

wire and hinges to make certain all the hinges and the joiner

wire go in and everything  ts together well.

❏ 2.

Apply 30-minute epoxy into the groove and in the holes

for the joiner wire in the elevators. Wipe away excess epoxy.

❏ 3. Apply epoxy to the joiner wire. Then,  t the elevators

to the stab and joiner wire with the hinges – use the T-pins if

necessary to keep the hinges centered.

❏ 4. Use a thin, metal ruler or similar tool to push the joiner

wire all the way into the elevators.

❏ 5. Permanently glue in the hinges with four or  ve drops

of thin CA on the top and bottom of all the hinges – allow

a few seconds between drops for the CA to fully wick into

the hinges.

❏ 6. Retrieve the 50mm threaded rod, two wood washers,

two M2 washers, two M2 nuts, and two torque rod horns for

the rudder torque rod.

❏ 7. Cut a small circle of covering from both sides of the

rudder around the hole for the torque rod.

❏ 8. Use 30-minute epoxy to permanently glue the torque

rod centered into the rudder with the wood washers, metal

washers and M2 nuts as shown.

❏ 9. Thread the torque rod horns onto the rudder torque

rod so they are equidistant from the hinge line, then  t the

rudder to the vertical stabilizer/fuselage with the hinges and

permanently glue them in.

Hook up the Rudder and Elevators

❏ 1. Cut the included rudder pull/pull line into two equal

lengths.

❏ 2. Loop one of the lines through the torque rod horn two

or three times. (It may be easier to push the line through if

you  rst wet the end with thin CA.)

❏ 3. Install a brass cable swage over both ends of the

line. Position the swage about 1" [25mm] from the torque

rod horn.

❏ 4. Tighten the loops and squeeze the tube with pliers.

❏ 5. Cut off the short end of the line near the swage.

6. Guide the line through the slot and down through the

fuselage.

7. Attach the other line to the horn on the other side of the

rudder the same way.

❏ 8. Tape both sides of the rudder to hold it centered with

the fuselage.

❏ 9. Thread two brass couplers onto two clevises ten full

turns and install a silicone retainer.

10. Mount the rudder servo in the servo tray in the fuselage.

Rudder lines cross one time.

S3171SV

❏ 11. Arrange the rudder pull-pull lines so they will cross as

illustrated. Also be sure the lines are below the cross brace

at the cockpit former as illustrated in the image at step 13.

❏ 12. With the servo arm and one of the clevises connected

to the servo and the servo powered and centered with the

radio on, attach the other end of one of the lines to the

threaded coupler as shown with another swage – use

hemostats or pliers to lightly tension the line while positioning

and squeezing the swage with pliers.

❏ 13. Attach the other rudder pull-pull line the same way.

14. Remove the tape that was holding the rudder centered.

Adjust the clevises on the couplers to add or remove

tension from the lines to center the rudder—the lines should

be tensioned just enough to keep the rudder from  opping

around when the servo is powered.

❏ 15. Attach a 12" [305mm] servo extension to the elevator

servo, then mount the servo in the fuselage and guide the

wire down through into the cabin. Hook up the elevator

servo with the same hardware used for the ailerons with

one exception; if 3D throws are to be used, instead of

using a 90° pushrod connector on the servo, a Z-bend will

be required. If 3D throws are not going to be used a 90°

pushrod connector is  ne.

Mount the Motor and ESC

❏ 1. Push a pin or a small nail into the four “+” marks in

the  rewall, noting the location of the holes for the motor

mounting screws. If using a motor different than the

recommended RimFire .32, use the cross marks and the

circle on the  rewall to align your motor and mark new holes.

❏ 2. Drill 1/16" [1.6mm] pilot holes through the punch

marks, then enlarge the holes with a 5/32" [4mm] drill.

❏ 3. Assemble, then mount the motor with four M3 x 10

Phillips screws, M3 lock washers and  at washers and M3

blind nuts in the back of the  rewall.

❏ 4. Prepare the ESC with any bullet connectors and

battery connectors needed. Then, mount the ESC to the

bottom of the motor mount box as shown with 1/8" [3.2mm]

double-side adhesive-backed foam mounting tape (or other

cushioning) and a nylon zip tie (not included).

❏ 5. Apply a full strip of the rougher, “hook” side of

adhesive-back hook-and-loop material to the battery tray

and a smaller, partial strip of the softer, “loop” side to your

battery. (The “loop” on the battery grips the “hook” on the

battery tray well, potentially making battery removal dif cult,

so only a small strip is needed on the battery. And it’s the

hook-and-loop strap that does most of the work securing

the battery anyway.)

❏ 6.

Make a battery strap from the non-adhesive-back hook-

and-loop strip.

Final Radio Installation

Refer to this image while mounting the receiver.

1. Connect the ESC and elevator and rudder servos to the

receiver and 6" [150mm] servo extensions for the aileron

servos. Mount the receiver with adhesive-back hook-and-

loop strips or other preferred method. Guide the servo wires

over and around the internal structure as needed so nothing

interferes with the rudder pull/pull lines.

Position and secure the receiver antennas according to the

receiver manufacturer’s speci cations. For the Futaba receiver

shown (and Tactic), the antennas are to be positioned 90° to

each other. Small pieces of plastic tubing (as from an aerosol

spray can or similar) were glued to the fuselage in the desired

location and the antennas were inserted into the tubes.

3. Without the propeller, make a quick test-run of the motor

to make sure it is turning in the correct direction. If necessary,

swap any two of the three motor wires that connect to the

ESC, or reverse the motor direction in your ESC.

FINAL ASSEMBLY

Mount the Landing Gear

1/8"

[3mm]

3/16"

[5mm]

Wheel Axle

Flat spot

❏ 1. File a 3/16" [5mm]  at spot on the wheel axle 1/8"

[3mm] from the end.

Axle

Washer

Nut

Wheel

Collar

Wheel pant

❏ 2. Assemble the wheel and wheel pant to the landing

gear as shown—hold the nut with hemostats or needle-nose

pliers while tightening the axle with a  at-blade screwdriver.

Tighten the set screw with a 1/16" hex driver wrench.

3. Assemble the other gear/wheel/pant assembly the same

way.

❏ 4. Mount the main landing gear to the fuselage with four

M3 x 10 SHCS and lock washers and  at washers.

Now let’s do the tail gear…

❏ 5. Glue the nylon tail gear bushing into the bottom of the

fuselage.

❏ 6. Slide the tail gear clip and a small wheel collar over the

tail gear wire, then insert the assembly down into the

bushing. Align the clip, swing the tail gear out of the way,

then drill 1/16" [1.6mm] holes through the bottom of the

fuselage for the mounting screws.

❏ 7.

Use medium-

grit sandpaper to

roughen the end of

the axle portion of the

tail gear wire so glue

will adhere. Install the

tail wheel, add a small

drop of medium CA to

the very end of the wire,

and then press a nylon

retainer onto the wire to

retain the wheel. Add

another drop of thin CA

to the retainer around

the wire.

❏ 8. Mount the tail gear wire with the clip, two M2 x 10

Phillips wood screws and a wheel collar with the set screw.

Use a .050" hex driver wrench to tighten the set screw to

lock-in the tail gear wire, then slip the nylon tiller peg over

the tiller wire on the end of the tail gear and  t, then glue the

peg into the bottom of the rudder.

Mount the Cowl

❏ 1. Cut four approximately 4" [100mm] long “ ngers” from

paper or thin cardstock. Use a 3/32" [2.4mm] brass tube

sharpened on the end or a hobby knife to cut a small hole in

the end of each  nger.

❏ 2. Align the hole in each  nger with the hole in each tab

for the cowl mounting screws and securely tape the  ngers

to the fuselage.

❏ 3. Install the cowl, the spinner back plate, propeller and

prop nut to the motor. Position the cowl so it accurately

aligns with the spinner back plate with the desired spinner

gap (approximately 3/32" [2.5mm]). If necessary, use tape or

an assistant to hold the cowl in alignment while marking the

holes in the  ngers onto the cowl. (Once aligned, the cowl

on our model stayed in place on its own.)

❏ 4. Remove the prop, spinner and cowl. Support the

inside of the cowl with a piece of wood while drilling 1/16"

[1.6mm] pilot holes through the cowl at the marks you made.

❏ 5.

Enlarge the pilot holes with a 1/8" [3.2mm] drill. Then,

test-mount the cowl with the spinner and prop using M3 x 10

Phillips screws and lock washers and  at washers. The 1/8"

holes in the cowl should be just large enough to  t the screws,

so if the cowl requires slight adjusting to perfectly align with

the spinner, the screw holes may be enlarged or elongated to

slightly reposition the cowl.

6. Remove the propeller and spinner for checking the

control throws next.

PREPARE THE MODEL FOR FLIGHT

Set the Control Throws

CAUTION: The propeller should not be installed. If

you have not yet done so, remove the propeller before

checking the control throws on the workbench.

❏ 1. It is easiest to check and set the aileron throws with the

wing mounted to the fuselage. Install the wing and connect

the aileron servos to the receiver.

❏ 2.

Support the fuselage so the model will sit level, or nearly

level. Use a ruler (or a tool that measures angular degrees)

to measure and set the control throws according to the

measurements below. NOTE: The control throws are measured

at the widest part of each surface and the dimensions

provided are for each direction of travel. (Example: low-rate

aileron throw is 1/4" [6mm] 6° up and 1/4" [6mm] 6° down.)

CONTROL SURFACE THROWS (each direction)

AILERONS

LOW RATE

7/8"

[22mm]

13°

Up & Down

1-1/2"

[38mm]

15°

Up & Down

5/8"

[16 mm]

9°

Right & Left

ELEVATORSRUDDER

HIGH RATE

1-1/2"

[38mm]

23°

Up & Down

[51mm]

20°

Up & Down

1-1/4"

[32mm]

17°

Right & Left

2-1/2"

[64mm]

40°

Up & Down

2-1/2"

[64mm]

25°

Up & Down

2-1/2"

[64mm]

37°

Right & Left

❏ 2. Use the programming in your transmitter and/or move

the pushrods to holes farther out or in on your servo arms

and/or the control horns to adjust the control throws as

necessary.

❏ 3. If using the 3D throws, a high volume of negative

exponential is desirable on 3D rates – approximately -60%

is a good place to start for each surface.

❏ 4. While working with radio setup and programming

(and before installing the propeller), now would be a

good time to set and check the Failsafe function so

that, in the event the receiver ever loses signal (such

as if you inadvertently turn off the transmitter before

disconnecting the battery) the throttle will go to a pre-set

position. The recommended pre-set throttle position is

“off”, so the motor will not turn. Follow the instructions

that came with your radio control system to check and

set the failsafe.

Check the C.G.

❏ 1. If you haven’t yet done so, get the model in completely

ready-to- y condition. First install the propeller and spinner

with a sandpaper disc on both sides of the spinner back

plate. The sandpaper discs allow the back plate to grip the

motor and propeller so it will not rotate while tightening the

propeller nut.

❏ 2. Install the battery. Attach the wings with the M3 x 10

SHCS screws, lock washers and  at washers used before,

then install the canopy hatch.

3-1/4"

83mm

The recommended C.G. is 3-1/4" [83mm] back from

the leading edge of the wing where it meets the

fuselage. The recommended C.G. range is from

2-3/4" – 3-3/4" [70mm - 95mm].

❏ 2. Use a Great Planes C.G. Machine with the rulers set to

the recommended C.G. and place the model upside-down

on the stand, or mark the recommended C.G. on top of the

wing and lift the model upside-down with your  ngertips.

3. Shift the battery forward or aft or add nose or tail ballast

as necessary to get the model to balance.

Balance the Model Laterally

❏ 1. Support the bottom of the rudder (a servo case was

used for the model in the image) and lift the Sbach several

times by the propeller shaft to see if one wing drops. Do this

several times to get a consistent reading.

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

opposite tip by sticking it to the outside or strategically

concealing it inside the balsa tip. An airplane that has been

laterally balanced will track better in  ight and maintain its

heading better during maneuvers when the plane is climbing.

❏ 3. This static lateral balance check will be a good starting

point, but performance in the air will be the  nal determining

factor whether or not the model is laterally balanced.

Performing high-G pulls will reveal if further lateral balance

is required. Adjust the weight as necessary.

PREFLIGHT

Motor Safety Precautions

Failure to follow these safety precautions may result

in severe injury to yourself and others.

● Use safety glasses when running motors.

● Do not run the motor 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 when the motor

is running.

● 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.

WARNING: Never have the motor battery connected

to the ESC without the transmitter turned on – after

each  ight (or any time after running the motor) always

disconnect the battery before turning off the transmitter.

And when ready to  y (or whenever running the motor

for any reason), always turn on the transmitter  rst

before connecting the motor battery.

Also make certain your failsafe is activated and programmed

correctly according to your radio manufacturer’s instructions.

Motor/Propeller Discussion

The recommended Rim re .32 is rated for 50A constant

current and 80A surge current. Powered by a 4S LiPo on

an APC 13 x 8E it draws about 58A static and momentary,

maximum peaks of about 50 – 55A in the air, but averages

a little less than 20A through a “normal”  ight. This is a

suitable propeller choice and  ies the Sbach well. Another

suitable propeller choice is the APC or Xoar 14 x 7 which

provides slightly more thrust at the expense of a little speed

which is okay for this type of plane. You can experiment

with different propeller choices in this range as long as

they do not exceed the current speci cations of the motor

and ESC.

Typical  ight time may be as low as 4 minutes or over 8

minutes depending on how aggressive and active you are

with the throttle – more throttle means shorter  ight times.

Use a  ight timer initially set to a conservative time (4

minutes for example). When the timer sounds, land. Use

a LiPo checker (shown above) to measure the resting

(unloaded) voltage when you land. The voltage should not

be below 3.75V/cell. When you charge the battery also

note how much capacity it took to recharge (indicating how

much was used for the  ight). Aim to use no more than 80%

of the battery’s capacity. Adjust your timer according to the

voltage and capacity used for the  ight.

You can also use the worksheet on page 22 to determine

optimum  ight times based on your  ying style and

battery capacity.

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

Charge and store LiPo batteries in a safe place!

Never leave charging LiPo batteries unattended!

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  ying the model:

Battery Precautions:

There are two ways to connect multiple battery packs:

In Series and in Parallel.

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Tower Hobbies Sbach User manual

Brand: Tower Hobbies

Model: Sbach

Category: Remote controlled toys

Type: User manual

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Tower Hobbies Sbach User manual

Tower Hobbies Sbach User manual

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