Red Star RC Yak-3 User manual

Yak-3

Instruction Manual

Wingspan: 55 in. (1397mm.)

Wing Area: 680 sq. in. (43.87dm2)

Weight: 5 – 5 1/2 lbs (2268g – 2495g)

Length: 50 in. (1270mm.)

Wing Loading: 17-18.6 oz per sq ft

(51.7-56.9g per dm2) 308 Belltown Road, Owings Mills, MD 21117-3239

www.redstarrc.com

red_star_rc@yahoo.com

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Thank you for purchasing Red Star RC YAK-3 sport scale model Kit. This kit has been designed using

3D computer engineering and interlocking construction design help you to build straight lightweight

model. Low wing loading and built in washout make this model a good flying plane. Please keep in mind

that this kit is intended for intermediate builder and intermediate pilot. If you do not meet these criteria, it

is recommended to seek help from a more experienced builder / pilot.

Good luck!

George & Mike

Red Star RC, BALTIMORE, MARYLAND, USA

redstarrc@yahoo.com

WARRANTY…..Red Star RC 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 Red Star RC’s liability exceed the original cost of the purchased kit.

Further, Red Star RC reserves the right to change or modify this warranty without notice.

In that Red Star RC 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.

NOTES BEFORE BEGINNING CONSTRUCTION

• Read the instructions and the plan sheet prior to start any work.

• Do not remove the parts from sheets until required.

• Prior to gluing, test fit and match parts over the plan.

Kit Contents:

• Computer Drawn Plan Sheet 1

• Illustrated Instruction Manual 1

• Laser Cut Balsa and Plywood Parts Sheet

• Clear Canopy 1

• 1/16x4x24 Balsa Sheet 16

• 3/32x4x24 Balsa Sheet 2

• 3/4x3x36 Balsa Block 1

• 1 1/2x2x12 Balsa Strip 1

• 1/8x1/4x24 Balsa Strip 2

• 1/4x1/4x24 Balsa Strip 3

• 1/2x1/2x12 Balsa Strip 1

• 1/16x1/4x36 Balsa Strip 3

• 1/16x1/2x36 Balsa Strip 2

• 1/2x1x36 Balsa Block 2

• 1x1x9 3/4 Balsa Block 1

• 1/8x1/4x24 Bass strip 10

• 1/2x1/2x24 Bass block 1

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Additional Hardware (Required for completing kit):

6-32 Bolt-nut Set (4 bolts, 4 Flat Washers, 4 Lock Washers, 4 Blind Nuts) 1

Control horns (Du-Bro #107) 3

Push rod (Du-Bro #230) Ailerons 1

E/Z Links (Du-Bro #855) Ailerons 1

E/Z Connectors (Du-Bro #121) 1

Push Rods Sullivan Gold-n-Rod 1

Retracts Hobbico 1

Dubro Nylon Large Straps 5/32"(4) Landing Gear Covers 1

Wheel Axels (Du-Bro #615) 1

Wheel Collars (Du-Bro #140) 1

Wheels (Du-Bro super light #300sl) 1

Tailwheel (Ohio OHI100) 1

Fuel Tank Sullivan 8 oz (s427) 1

Spinner (Du-Bro 2.75" #293) 1

Engine OS-.40FX (OS-.46FX) 1

Muffler Jtec JT-601 1

Prop Master Airscrew 11x6 1

Recommended Finishing Items:

Monokote (Sky Blue 20206) 1

Monokote (Gray/Green 20211/20214) 1

LustreKote Spray Paint 1

LustreKote Spray Flat Clear 1

CA Hinges

Radio Gear:

5-channels receiver (7-channels recommended) 1

6” Servo Extension 2

6” Y-servo Extensions 1

Futaba Standard Servo 5

Items You May Need:

Thin and Medium CA

30-min Epoxy

Wax Paper or Plastic Wrap

Razor Blades

Different Grid Sand Paper

Balsa Wood Filler

Windex

Isopropyl Alcohol

4

Laser Cut Patterns

5

6

Build the Stab & Elevator

1. Locate and carefully remove Horizontal Stab and

Elevator parts from balsa sheets. Test fit and sand

them if necessary. Assemble using this figure as a

reference. Fill the gaps with thick CA if needed.

2. Bent 4.5” long piece of 2-56 pushrod according

to picture. Drill holes and join two elevator halves.

Build the Fin & Rudder

Unroll the plan sheets. Put them on your building

board and cover with wax paper so glue will not

adhere.

1. Locate and carefully remove Fin and Rudder

parts from balsa sheets. Test fit and sand if

necessary. Assemble using this figure as a

reference. Fill the gaps with thick CA if needed

Sand LE of Horizontal Stab and Fin round. Sand LE

of Elevator and Rudder triangle and TE round.

Hinge them according to the hinge locations.

1

”

2.5

”

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Build the fuselage

1. Locate one 1/8”x 6”x 24” ply sheet and two

1/8x4x24 balsa sheets with fuse formers. Carefully

remove needed parts from the sheets.

2. Cover your working area with wax paper. Locate

and glue two rear halves of main fuse horizontal

former F-B and F-D together.

3. Glue two front halves F-A and F-C together.

4. Glue front and rear horizontal fuse former parts

together.

5. Glue bottom formers according to the plan. Using

building square make sure they are 90° to horizontal

former.

6. Splice two pieces 1/8” x 1/4” x 24” bass stringers

together with an overlap as shown. Make two of

them.

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7. Glue side bass stringers extending forward as

shown. They will be attached to the firewall later.

8. Cut into shape at the rear and glue together.

9. Locate two wing bolt support WB-A and WB-B

and glue them together.

10. Locate two fuse side formers S1. Insert WB

block into one side of the former, and then put

another former in place and glue.

11. Install bottom 1/4”x 1/4” balsa stringer.

12. Locate TB-A and TB-B fuselage tail block

halves. Glue them together and install in place.

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13. Sand tail block into shape.

14. Locate tail wheel support plate TW. Test fit it

and glue in place.

15. Using 30-min epoxy, glue together firewall

FW-A and FW-B formers, motor mount ML-A and

ML-B, MR-A and MR-B.

16. Test fit and glue firewall into side formers using

30-min epoxy. Glue bass stringers to firewall and side

formers. Cut flush with firewall. Test fit motor mounts.

Pay special attention to their position. You should get

3° right and 3° down thrust! Then test fit your motor!

Make sure motor sits tight in the motor mount. When

satisfied with the result glue them permanently using

30-min epoxy. Also pay attention that fuselage stays

true and straight after this step!

17. Glue top formers according to the plan. Using

building square make sure they are 90° to horizontal

former.

18. Glue cockpit doublers f2 and f3 to the formers

F2 and F3. Glue 1/8”x 1/4” top fuse spar.

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19. Install two sheeting support doublers using

1/8x1/4 leftover balsa strip.

20. Install wing pin doubler in place.

21. Align 1/16”x 4”x 24” balsa sheeting using

T-pins alongside center of the fuselage side stringer.

Connect two sheets on sheeting support doubler.

22. Glue it to formers and stringers, and then trim

alongside the bottom stringer and wing saddle.

23. Sheet the other side of the fuselage same way.

Do not sheet the bottom of the fuse yet. You need

free access to it when you mount pushrods.

24. Cut two 15” long 1/16” balsa sheet. Glue to the

top stringer. Spray with Windex to make it more

flexible. Bend it over formers and fix in bent

position using masking tape. Let it dry. Trim and

glue it on fuselage.

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25. Repeat for the other side.

26. Sand side sheeting flash with formers.

27. Here is closer look.

28. Glue four sheeting support formers F into place.

29. Glue two 1/16” balsa sheets together alongside.

Cut 10” long sheet. Using the same technique, sheet

the middle part of the fuselage. You will cut the

opening for the cockpit later.

30. Here is the result.

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31. Using the same technique, sheet front of the

fuselage.

32. Here is finished fuselage

33. Glue 1/2”x1/2” balsa stringers at the bottom

front of the fuse. Fill the gap between stringer and

sheeting with 1/8” leftover balsa.

34. Glue FS-1 and two FS-2’s together to create an

air outlet for easy engine cooling.

35. Glue air outlet in place.

36. Cover bottom front of the fuselage with 1/4"

balsa and cut an opening for an air outlet.

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37. Clamp your engine to the motor mount with

front ring FFR and spinner. Align and glue ring in

place. Mark mounting holes.

38. Drill mounting holes. Install blind nuts and

secure them with thick CA. Be careful! Do not let

glue go on the thread.

39. Using 3/4”x 3” balsa block provided, build top

engine cowl and glue it in place.

40. Glue bottom sides from 3/4”x 3” balsa block

provided.

41. Shape it according to the 3-view drawing at the

end of this manual.

42. Glue small pieces of balsa leftovers in the

middle of bottom cowl and shape them round.

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43. Shape top cowl according to the 3-view drawing

at the end of this manual.

44. Locate and glue together tail fixture making

sure that they are squared.

45. Install the fixture. Using 1”x1” balsa block

provided cut it by half and glue in place making

sure you don’t glue them to the tail fixture which

will be removed later. Shape tail according to

fixture shape.

Build the Wing

1. Unroll the wing plan sheet. Put it on your

building board and cover with wax paper so glue

will not adhere. Locate all balsa ribs, plywood rib

doublers and wing joiner. Do not remove special rib

tabs at the end of the ribs. They designed to help

building wing true and straight.

2. Glue wing joiners together. Locate 1/8”x 1/4”x

24” bass strips. Cut 11.5” and glue to 24” bass

strips. Make 4 of them.

3. Glue ply rib doublers to the balsa ribs. Refer to

the drawing for doubler position.

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4. Cut 1/2” x 1/2”x 24” maple block on 4 equal 6”

parts. Insert landing blocks into ribs.

5. Place bass stringer over the plan and pin it down.

Put all ribs according to the plan and pin them

down.

6. Glue leading and trailing edge parts together.

7. Put top bass spar, leading and trailing edge and

glue them making sure ribs 90° to the building

board.

8. Locate and glue precut hinge blocks HB-A, B, C,

D according to the plan.

9. Glue two 1/16x4x24 sheets of balsa provided.

Make two of them and then cut them across like on

the picture.

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10. Sheet the top of the wing. We are using White

glue method. Mark sheeting in the place it’s going

to contact frame, apply thin bead of glue on the

frame and sheeting and let them dry for approx

30min.

11. Put sheeting in place, align and using sealing

iron on the maximum temperature iron down

sheeting to adhere it to the wing structure.

Note: Leave wing pinned down to the building

board to insure that it is straight and true.

12. Install top trailing edge sheeting using 1/16”x

1/2” balsa strip provided and remove wing from

building board.

13. Using template that came with retracts

removed material from landing gear mounting

blocks to let retract fit in.

14. Install shear webs. The first three shear webs

go from both sides of the main spar to create a

box for the wing joiner. Remember that shear

web grains oriented vertically relative to the main

spar.

15. Glue shear web before sheeting the bottom of

the wing. Remove rib tabs.

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16. Build the right wing the same way the left one

was built.

17. Join two wing halves using wing joiner prepared

in step 2 and SLC and STC parts. Make sure wing is

straight and not warped

18. Reinforce trailing joints using leftover balsa.

19. Do the same for the front one.

20. Assemble two aileron servo trays using ST-A

and two ST-B parts. Assemble retract servo tray

using RST-A and two RST-B parts. You can

reinforce spots where servo screws go in using

precut pieces (has been located inside F3 fuse

former).

21. Glue retract servo tray in place.

22. Test fit your retracts. Run pushrods. Connect

radio and check retracts for smooth operation.

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23. Sheet bottom of the wing and bottom trailing

edge. Cut wheel well template from the plan. Put it

on the wing. Mark wheel well location.

24. Cut wheel well according to the template.

25. Glue central ribs in place. Glue a piece of

1/4"x1/4” balsa stick in the top of wing joiner for

sheeting support.

26. Using piece of 1/16” leftover balsa sheeting 4”

wide and 5 1/2“ long, spray it wet with Windex and

put around bottle 3 1/2” dia. Put rubber band over

and let it dry. Then cut it by half lengthwise.

27. Glue halves to the wing. Sand them to the wing

shape. Sheet forward bottom part. Cut wheel well

opening. Flip the wing over.

28. Sheet forward top.

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29. Locate precut pairs of wing trailing blocks TC,

TS-A, TS-B. Glue them together and to the wing.

30. Sand them into shape.

31. Sheet center top of the wing.

32. Sheet center bottom of the wing.

33. Install capstrips using 1/16” x 1/4” x 36” balsa

strips provided.

34. Cut 1 1/2 x 2 balsa block provided on two

pieces 5” and 6” long. On each end of 6” block

measure 1” from edges. Draw a line and cut across

this line.

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35. Mark them according to the plans.

36. Glue them to the wing.

37. Locate two 1/2” x 1” x 36” balsa strips. Cut 20”

and glue leading edge to the wing.

38. Carve and shape wing leading edge.

39. Shape front central section of the wing.

40. Glue wing front plate WFP in place. Drill 1/4”

hole and install wing pin provided. Glue two pieces

of 1/8” leftover balsa sheet and sand them in shape.

41. Carve wing air scoops in shape for better scale

appearance.

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Red Star RC Yak-3 User manual

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