Skyshark Stuka User Manual

Universally known as perhaps the most effective
dive bomber ever flown, the Stuka (a contraction
of the word “Sturzkampfflugzeug” or diving battle
aircraft) was born of a generation of aircraft ren­dered obsolete before the advent of WWII.
Design work began in 1933, and the prototype
first flew in 1935. Tested in combat first in the
Spanish Civil War, the Stuka proved its worth.
The -B model grew out of shortcomings defined
in this conflict, and cemented the profile of the
Stuka that would terrorize a continent only a few
years later. The Stuka flew in all theaters in
WWII, enjoying great success in the early battles
in Poland Scandinavia, and Russia. Only the
Battle of Britain would humble the mighty Stuka,
showing that it couldn’t succeed against deter­mined fighter opposition.

The Stuka has a wingspan of 45 feet 3 inches, a
length of 36 feet 3 inches, a maximum weight of
almost 9,500 pounds, and could carry a variety
of bombs to a maximum of 2,200 pounds. The
Stuka is powered by a water-cooled, 12 cylinder
iverted-vee Junkers Jumo 211engine producing

1,200 horsepower. Crew consisted of the pilot
and a gunner firing a 7.92 mm MG 15 machine
gun. Forward firepower included two 7.92 mm
MG 17 machine guns mounted in the wings.
Later models were outfitted as tank destroyers,
firing 40 mm cannons mounted in pods under
the wings.

Skyshark R/C Corporation

75 Mid Cape Terrace, Ste 7
Cape Coral, FL 33991, U.S.A.

Website: www.skysharkrc.com
email: [e-mail]

Thank you for purchasing the JU-87 Stuka from Skyshark
R/C Corporation. For the first time, R/C enthusiasts have a
choice in scale aircraft designs. Our goal, through comput­er technology and state-of-the-art production techniques, is
to offer aircraft which in the past have not been modeled
simply because they weren’t popular enough to justify mass
production. Our production techniques allow us to produce
aircraft which, though not as popular and well known as P­51s and P-47s, still offer historical significance (good or
bad!), Good looks and flying characteristics, and a unique­ness that is sure to turn heads wherever you take your air­plane!

Your airplane has many unique features
in its design:

parts on each sheet of wood, reducing the waste, and low­ering the cost to you. Since laser cutting does not have the
same limitations that mechanical cutters do, small and
hard-to-produce parts are simply a computer file away, so

you get a more accurate airplane.

Plastic and Fiberglass

The cowl is accurately reproduced in high quality fiberglass.
The canopy is accurately reproduced in clear plastic, and
the wheel pants are reproduced in heavy duty styrene plas­tic.

A Word About the Building Options

Engine Options

Many parts of the country (and the world) sit at higher ele­vations. At 7200 feet, a .40 size airplane will barely fly with
a .40 engine. The engine size range of .45 to .61 for this kit
is designed to compensate for engine performance loss
due to elevation. Below 3500 feet in elevation, a good .45
will fly the Stuka with authority. Above 3500 feet, a larger
engine will help return the airplane to sea level perform­ance.

Electric Options

CAD Design

CAD design allows strength to be built into the airplane
without sacrificing weight. Accurate parts design and place­ment ensures a perfect fit.

CAD Drawn Plans

The plans in this kit are not copied from a master set! They
are originals drawn directly from the CAD program where
the airplane was designed. We do this because it allows us
to use color, which helps you better visualize the various
components of the airplane, and we can use better quality
paper, which greatly reduces the possibility of shrinkage.
Since you’re going to build directly on the plans, they ought
to be the proper size! Also, parts placement is guaranteed
to be accurate, so you can build a better, straighter model.

Laser Cut Parts

The same program that generates the design and plans
also drives the laser, so every part is reproduced exactly as
it was designed. Laser cutting also allows us to fit more

Electric conversion on a kit this size is very easy and
straightforward. You will simply need to plan for a battery
hatch in order to save having to remove the wing for bat-

tery changes.

Retract Options

Right!

Flaps

The flaps can be made functional. A linkage arrangement
is shown on the plans, explained in this manual, and some
required parts are provided. The scale offset hinging system
makes functional flaps as easy as adding a servo! Some
adjustment of the flaps will be required whether the flaps
are functional or not; remember, the surfaces are airfoils,
and need to be set for optimum flight performance.

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General Building Information

Accessories needed to finish the Stuka:

The Stuka can be built by a person with average building
skills. It is designed for someone who has built a trainer or
low wing sport plane. No unusual building techniques are
required, although more difficult areas are explained in
detail where necessary. Certain steps in the building
process must be followed as depicted, or you might find
yourself digging back into the structure to redo something.
These areas are outlined when necessary.

Occasionally hints will be included at certain building steps.
These are not required for completion, rather they are tips
intended to ease a particular process.

The laser does not cut through the wood, it burns its way
through. As a result of this, occasionally there will be
scorching on the surface of the wood. This is normal, and is
only a surface discoloration, and does not affect the wood
in any other way. Similarly, the laser settings are optimized
for wood density averages, so occasionally, due to varia­tions even in individual sheets, some areas might not cut
through completely. This is apparent mainly with the ply­wood. Simply use care in removing the parts from the
sheets; most of the time, the parts will literally fall out of the
sheets!

Hardware and a motor mount are not included in the kit.
There are so many choices for quality hardware that these
choices are left to the individual preferences of the builder,
rather than include something in the kit that you’ll probably
throw away anyway. A vibration-dampening motor mount is
recommended for use regardless of engine choice, so
select a mount suited to your particular engine.

Sullivan Gold-N-Rods, 48" (Part no. 504) or other appro­priate pushrods

Sullivan RST-10 or -12 Fuel Tank or other 10 - 12 ounce
fuel tank

Motor mount for appropriate engine

2-3/4” Stuka Spinner

3-1/2" Main Wheels (Robart #135)

1-1/2" Tailwheel (Dubro 150TW)

Hinges - We normally use CA hinges for ease.

Control Horns, Clevises, Bolts, Nuts, Screws, etc. (consult
our website)

1/9th Scale Pilot Bust Figures (2)

Engine, Muffler, Radio, Covering, Paint, etc.

Electric Conversion:

Brushless Outrunner Motor 400-600Kv
Cobra 4120-16 or E-flite Power 52

ESC: OS70, Cobra 80 or E-flite 80

Battery: Ulti-Power 5 cell 3300 - 5200mAh

This aircraft is not a toy. It must be flown in a responsible
manner according to the rules set forth by the Academy of
Model Aeronautics. The builder assumes the responsibility
for the proper assembly and operation of this product.
Skyshark R/C Corporation shall have no liability whatsoev­er, implied or expressed, arising out of the intentional or
unintentional neglect, misuse, abuse, or abnormal usage of
this product. Skyshark R/C Corporation shall have no liabil­ity whatsoever arising from the improper or wrongful
assembly of the product nor shall it have any liability due to
the improper or wrongful use of the assembled product.
Skyshark R/C Corporation shall have no liability for any and
all additions, alterations, and modifications of this product.

Having said that mouthful, turn the page and start building
the best airplane on the market!

Rare Earth Magnets for battery hatch.

Notes:

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Horizontal Stabilizer Assembly

1. Pin S1 to the board. Cut the stab leading edge from
3/8 x ¼ balsa stock and pin in place. Cut the stab
trailing edge from ¼ x ¼ balsa stock and pin in place.
Glue all the pieces.

3. Sheet both sides of the vertical stab. So not sheet
the tab on S2.

4. Sand the leading edge to shape. Sand all the edges
smooth.

2. Cut the stab stringers from ¼ x ¼ balsa stock and
glue in place.

3. Sheet the top of the horizontal stabilizer using a
piece cut from 1/16 x 4 x 36 balsa sheet.

4. Cut a slot in the sheeting to match the slot in S1. This
will align the vertical stab during assembly.

5. Sheet the bottom of the horizontal stab.

6. Sand the leading edge to shape and sand all the
edges smooth.

Elevator Assembly

1. Glue E2 into the slot in E1. Guides for the rib are
etched into E1 for reference.

2. Repeat for E3, E4, E5, E6 and E7. See Figure 5.

3. Bevel the trailing edge of E1 to match the taper of
the ribs.

4. Fill the inboard space between ribs E2 and E3 with
scrap balsa and sand even with the ribs. This will
provide strength for the elevator joiner wire and con­trol horn mount.

Vertical Stabilizer Assembly

1. Pin S2 and S3 to the board. Cut the stab trailing
edge from ¼ x ¼ balsa stock and pin in place. Glue
all the pieces.

2. Cut the stringer and top support from ¼ x ¼ balsa

stock, pin in place, and glue.

5. Note that all E1s are marked for location. Glue the
respective E1 to the previous assembly, aligning all
the ribs into the slots.

6. Cut the elevator leading edge from ¼ x ¼ balsa
stock and glue into the channel in the elevator
assembly. Make sure the edges of E1 attach firmly to
the leading edge. Sand all edge smooth.

7. Glue the elevator horn to the end of the elevator
assembly.

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8. Repeat for the remaining elevator.

Rudder Assembly

1. Glue R2 into the slot in R1. Repeat for R3, R4, R5,
and R6.

2. Bevel the edge of R1 to match the contour of the
ribs.

3. Fill the open bay between R2 and R3 with scrap
balsa. Sand to match the ribs.

Center Wing Section

1. Epoxy W2A to W2. Make a right and left side (be
careful here; it’s easy to make two left sides!)

2. Epoxy W4B to W4. Make a right and left side.
Repeat the “be careful” part.

4. Glue the remaining R1 to the assembly.

5. Glue two R8s together, then glue to the bottom of the
rudder assembly.

6. Cut the rudder leading edge from 3/8 x ¼ balsa
stock, and glue in place. Note that the leading edge
extends to the bottom of R8s and the upper edge of
the built-up portion of the rudder assembly.

Note: The first part of assembling the center wing
section should be accomplished by interlocking
the pieces only. Do not glue them until the instruc­tions say.

3. Slide W1 into the slot in W14. (There is an extra W1
in the pre-cut sheets; discard this piece.)

4. Slide W2 (with W2A facing outward) into its slot in
W14. Slide W13 under W14 and insert the tab into
the slot in W2.

7. Glue two R7s together, and glue to the top of the rud­der assembly. The rudder horn may be re-inforced
by soaking it with thin CA. Sand R7 and R8 to match
the taper of the rudder.

5. Slide the other W2 into the slot in W13 and insert the
tab on W14 into W2. Align this assembly to the board
and pin in place.

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6. Slide W22 Ply Servo Tray into the slots in W1 and
W2. Slide W3s in place and pin to the board.

7. Slide W4s (with W4Bs facing inward) in place and
pin to the board.

13. Unpin the assembly from the board and turn it over.
Cut the bottom balsa spars from ¼ x ¼ stock and
glue in place.

8. Glue all the pieces at this time. Add tri-stock to the
corners of W13 and W14 and W2 and W4.

9. Glue W15 to the trailing edges of W1 and W2.

10. Glue W16 to the trailing edges of W3 and W4,

11. Cut the balsa spars from ¼ x ¼ stock, and

glue in place. Add ¼ x ¼ spacers to W22
for the servos to mount to. Add the mounts
for the flaps on top of W22, and the
mounts for the ailerons on the bottom of
W22.

14. Cut the Maple Gear Blocks to size and epoxy into
the slots in W2, W3 and W4. Relieve the slots as
necessary to allow the gear block to fit flush.

15. Epoxy the Maple Gear Block Anchors to the gear
blocks and W2A.

16. Add tri-stock to the sides of the gear blocks for sup­port.

Note: The spar in this case is not for structural strength, it’s
for attachment of other pieces.

12. Cut the leading edge pieces from 3/8 x 1
x 18 balsa stock, and glue in place. Glue
the center piece first, followed by the
outer pieces. Leave at least 1/16” overlap
of the leading edge with the ribs for the
sheeting to but against.

17. If you plan to add functional flaps, drill a hole in
W19 at the “+” and slide W19 into the slots in W3
and W4. Align flush with the edge of W4.

18. Install bellcranks to W19 (on the bottom), with the
“L” facing outward. Add the pushrods for the servo

5

linkage.

19. Glue W21 Dowel Guides to the top and bottom
spars as indicated on the plans. Install so that the
arrow faces up and inward. This will properly align
the hole for the dowel.

20. Slide F23 onto W1. This will provide a guide for
drilling the holes in the leading edge for the dowels.
Mark the holes, and drill or bore ¼” holes in the
leading edge. Remove F23.

25. Trim and sand the sheeting, and carefully trim the
sheeting flush with the inside edge of W2.

26. Cut three 3 1/2” pieces from 1/16 x 4 x 36 balsa
sheet, and one 3 1/2” piece from 1/16 x 3 x 36 balsa
sheet. Edge glue these sheets. Sand the edges
until the sheet lays in the slot between the other
sheets.

27. Cut short pieces from 1/8 x ¼ balsa stock. Glue
these pieces to W2, aligning them with the edge of
the rib. These pieces will form an edge for the
sheeting to lay on.

21. Cut the dowels to size (approximately 5/8 to ¾”
should extend from the leading edge) and slide
them into the wing. Slide F23 onto the ends of the
dowels to align them. Epoxy the dowels in place
(DO NOT epoxy F23 in place! You’ll need it later)
Remove F23 and set it aside.

22. Sand the top of the center section smooth. Bevel
W2A to match the angle of the ribs.

28. Sheet the center of the wing section.

29. Remove the wing from the board. Remove the tabs
on the ribs.

30. The trailing edge extends ½” past W15 and W16.
Mark this location and trim the trailing edge sheet­ing. Bevel the sheeting to match the lower rib cam­ber.

23. Cut three 5” section from sheets of 1/16 x 4 x 36
balsa, and cut one 5” section from 1/16 x 3 x 36
balsa. Edge glue these sheets.

24. Trim the sheet to fit the outer panel of the center
section. Trim the leading edge to fit, but allow a
slight overlap on the edges; this will be trimmed
later. Allow for at least 1/2” overlap of the trailing
edge. Sheet the angled section. Repeat for the
other side.

31. If you are building the fixed flap option, add a 3/8”
maple block to W4 in the location shown on the
plans. Glue it flush with the bottom of W4, and sand
to the angle of the ribs.

32. Mark the locations of the flap pushrod exits.

6

33. Cut slots in W1 and W2s for locating W23 Ply
Holddown Plate. The location for W23 is shown on
the plans. Glue W23 in place. Drill a small pilot hole
through W23, W1 and the top sheeting to locate the
holddown bolt postion.

37. Add 1/8 x ¼ spacers to W2 to support the bottom
center sheeting, just as you did with the top.

34. If you use the Gold-N-Rod pushrod option, do the
following: Cut the red 48” housing into two 17”
lengths. Cut the yellow pushrod into two 19”
lengths. Assemble the pushrods and the Dubro
Aileron Ball-Link Connector into one continuous
pushrod. Slide the pushrod through the holes in the
ribs and center in the wing. Slide the housings over
the pushrod until 1/8” extends past W2. Glue the
housings to the ribs, but leave the housings at W2
free to “float”.

38. Cut three 3 ½” sections from 1/16 x 4 x 36 balsa
sheet, and a 3 1/2” section 1” long from spare 1/16”
sheeting. Edge glue these pieces.

39. Sand the edges of this sheet to fit snugly in the cen­ter section. Glue the sheet in place.

40. Trim and sand the sheets at the trailing edge, W4,
and the joined edges.

41. Cut both the top and bottom sheets as shown to
allow for servo fit.

42. Cut out the slots for the flap linkage.

43. Cut out the slots for the wire gear legs.

Right Wing Panel Assembly

35. Using the same technique as the top sheeting, cut
5” sections of 1/16 x 4 x 36 balsa sheets and 5”
sections of 1/16 x 3 x 36 balsa sheets and edge
glue. Sheet the outer sections of the center section.

36. Trim the sheeting flush with W2, and trim and sand
the trailing edge even with the top sheeting.

1. Slide W4A into the slot in the Ply Spar and align with
W4 (they’re the same size). Glue in place. For the
fixed flap option, glue a maple block to W4A as
shown on the plans.

2. Cut two 24” lengths from 1/4” x 1/4” balsa sticks.
Glue one of these spars to the Ply spar, aligning it
with the bottom edge, and fitting it into the slot in

7

W4A.

3. Thin the outer 4” of the balsa spar to allow the fit of
the last two ribs. Thin to 1/8”.

4. Slide W5, W6, W7, and W8 onto the Ply Spar, align,
and glue.

5. Glue W17 to the trailing edges of the ribs.

6. Drill a hole in W20 and assemble the bellcrank to it.

7. Slide W20 into the slot in W8 (the bellcrank will be on
the bottom of W20) and cut the pushrod housing and
pushrod to size. Attach a clevis to the pushrod and
the bellcrank and align the assembly.

12. Select two 1/16” x 4” x 24” sheets. Cut a 1/16 x 3 x
36 balsa sheet in half. Edge glue the two 4” sheets
and one 3” sheet to form the top sheeting.

13. Trim the leading edge to fit, and sand the inner
edge to match the center section sheeting. Sheet
the top surface of the right wing panel.

14. Mark a point 9/16” perpendicular to W17 at W8.
Mark another point 11/16” perpendicular to W18 at
W12. Connect these points and the trailing edge of
the center section. Trim the top sheeting to match
these lines.

8. Slide W9 in place, slide W20 into the slot in W9, and
glue all the pieces.

9. Glue W10, W11, and W12 in place.

10. Glue W18 against W17 and to the trailing edges of

W9 thru W12. Glue the remaining ¼ x ¼ x 24 balsa
spar in place. Thin the outer 4” to 1/8” to fit in W11
and W12.

11. Cut the 3/8 x 1 x 36 balsa leading edge to length,

and glue in place. Cut scrap 1/16” balsa for shear
webs and glue in place (see plans for location).

15. Remove the tabs on the rib bottoms, and bevel the
top sheeting trailing edge to match the bottom rib
camber.

16. Mark the location of the exit point of the aileron link­age so the slot can be cut after sheeting.

17. Select two 1/16” x 4” x 24” balsa sheets. Edge glue
these two pieces and the remaining 3 x 18 sheet to
form the bottom sheeting.

18. Trim the sheeting to fit the leading edge, and sand
the inner edge to match the center section sheet-

8

ing. Sheet the bottom of the wing panel.

19. Trim the trailing edge to match the top sheeting
and the center section sheeting.

20. Glue on the wingtip. Sand to shape.

Note: the slots in the trailing edge in the picture will be cut
later.

6. Drill a hole in W20 and assemble the bellcrank to it.

Left Wing Panel Assembly

1. Slide W4A into the slot in the Ply Spar and align with
W4 (they’re the same size). Glue in place. For the
fixed flap option, glue a maple block to W4A as
shown on the plans.

2. Cut two 24” lengths from 1/4” x 1/4” balsa sticks.
Glue one of these spars to the Ply spar, aligning it
with the bottom edge, and fitting it into the slot in
W4A.

7. Slide W20 into the slot in W8 (the bellcrank will be
on the bottom of W20) and cut the pushrod housing
and pushrod to size. Attach a clevis to the pushrod
and the bellcrank and align the assembly.

8. Slide W9 in place, slide W20 into the slot in W9, and
glue all the pieces.

9. Glue W10, W11, and W12 in place.

10. Glue W18 against W17 and to the trailing edges of

W9 thru W12. Glue the remaining ¼ x ¼ x 24 balsa
spar in place. Thin the outer 4” to 1/8” to fit in W11
and W12.

3. Thin the outer 4” of the balsa spar to allow the fit of
the last two ribs. Thin to 1/8”.

4. Slide W5, W6, W7, and W8 onto the Ply Spar, align,
and glue.

5. Glue W17 to the trailing edges of the ribs.

11. Cut the 3/8 x 1 x 36 balsa leading edge to length,
and glue in place. Cut scrap 1/16” balsa for shear
webs and glue in place (see plans for location).

12. Select two 1/16” x 4” x 24” balsa sheets. Cut a 1/16

x 3 x 36 balsa sheet in half. Edge glue the two 4”
sheets and one 3” sheet to form the top sheeting.

13. Trim the leading edge to fit, and sand the inner

edge to match the center section sheeting. Sheet

9

the top surface of the right wing panel.

14. Mark a point 9/16” perpendicular to W17 at W8.
Mark another point 11/16” perpendicular to W18 at
W12. Connect these points and the trailing edge of
the center section. Trim the top sheeting to match
these lines.

15. Remove the tabs on the rib bottoms, and bevel the
top sheeting trailing edge to match the bottom rib
camber.

Fuselage Assembly

1. Pin two ¼ x ¼ x 36 balsa spars to the fuselage top
view as shown. Cut a ¼ x ¼ balsa stock for a fin post.
Glue in place. Bevel the ends of the spars to fit at the
fin post.

2. Bevel the top edge of F2A to match the angle of
F1A. Glue F2A in place.

16. Mark the location of the exit point of the aileron link­age so the slot can be cut after sheeting.

17. Select two 1/16” x 4” x 24” balsa sheets. Edge

glue these two pieces and the remaining 3 x 18 sheet
to form the bottom sheeting.

18. Trim the sheeting to fit the leading edge, and sand

the inner edge to match the center section sheeting.
Sheet the bottom of the wing panel.

3. Using the fuselage angle gauge provided, set F1A
in place and set the angle. F1A will rest against F2A.
Glue in place.

4. Glue the bulkheads F3A through F10 in place.

5. Add ¼ x ¼ balsa keels between F1A and F3A, and
between F5A and F8A.

6. Glue F12 in the slots in F8A and F9A.

7. Align F11 with F9A and the fin post, resting on F10.
The top edge of F11 will align with the bottom of the
notch in F9A. Glue in place.

19. Trim the trailing edge to match the top sheeting

and the center section sheeting.

20. Glue on the wingtip. Sand to shape.

Note: the slots in the trailing edge in the picture will be
cut later.

The remainder of wing construction will be accom­plished after fuselage assembly.

10

8. Add 1/8 x ¼ balsa stringers to the fuselage, starting
with the bottom row first. Add the stringers simulta­neously to each side; this will help keep the fuse
straight. Bevel the stringers that attach to the fin
post.

9. After the bottom row is in, add F21 and F22 Cockpit
Floors. Note that F22 buts against F5A.

10. Continue adding stringers, noting that the third row

stops at F10. This row will also twist as you lay it in
the grooves. Also note that this row does not extend
between F3A and F5A.

11. Add a stringer between F3A and F5A, fitting in the
slot in F4A. This stringer is for locating the sheeting
only. Attach it level with the other stringers, butting
against F3A and F5A.

12. Sand F11 to match the contours of F9A and F10

and the fin post. Sand any high spots from the fuse­lage structure.

13. Pin short pieces of 1/8” balsa scrap to the edges of

the fuse at the ¼ x ¼ spars. This will elevate the
sheeting by 1/8” to allow the bottom sheeting to
attach.

14. Using 1/16 x 4 x 36 balsa sheets, sheet the fuse-

lage. Pick matched density sheets to prevent warp­ing, and sheet both sides of the fuse at the same
time.

16. Add the pushrods by feeding the housings through
the holes in the bulkheads. A slight amount of the
stringer near F9A will have to be relieved to allow
the housing to pass through. Cut a hole in the
sheeting between F9A and F10 to allow the
pushrod to pass through.

17. Glue the housings in place. The pushrods may be
added later during control surface installation.

This will keep the fuse from warping. Work slowly, starting
at the center, moving fore and aft, side to side. Glue the
sheeting one stringer section at a time, working up. After
gluing to the second row of stringers, cut the balsa away
from the cockpit area (you don’t have to be precise, this just
relieves the stress in the sheets). Wetting the sheets with
water or a water/ammonia mix will help the sheeting con­form to the fuse. Trim the sheeting as you get to the top, to
butt the sheets together. Trim away the sheeting at the aft
end as you finish sheeting around the fin post, F10, F9A,
and F8A. This area is difficult, and the sheeting may crack
as it tries to conform to this area. Glue the cracked areas
and continue. This area will be smoothed with lightweight
filler later.

15. Trim the sheeting at the cockpit area by placing the
canopy in position and marking its edges. Try to
leave at least 1/8” of the sheeting overlapping. Trim
and sand the sheeting flush with F1A and the fin
post/F11 area.

11

18. Slide F14 into the fuselage and locate the tab into
the slot in F3A.

19. Slide F2B onto F14; concurrently, slide F1B onto
F14. Lock the tabs and slots into each other and
glue all the pieces.

20. Glue F3B, F4B, F5B, F8B, F7B, and F8B in place.

21. Glue F13 into place against F5B, F2B, and the
balsa spar.

22. Add ¼ x ¼ balsa keel pieces to the slots in F1B and
F2B, and the slots in F5B though F8B.

23. Add 1/8 x ¼ balsa stringers to the lower fuse half.
Add short segments to F1B and F2B. Add the
stringers from the spar to the keel, simultaneously
to prevent fuse twisting. The stringers but against
F9B.

24. Trim and sand the stringers even with F9B, F5B,
F2B, and F1B.

30. Align the trailing edge of the wing with the fuselage
and mark it’s location. Drill a hole through the wing
center section (corresponding with the pilot hole
you drilled earlier) and through F24. Tap the hole in
F24 for your wing holddown bolt. Remove the wing
from the fuselage.

31. Slide F15 into position, inserting the tabs on F1A
and F2A into the slots. Epoxy in place.

32. Trim F16 to clear F23 and the dowels and epoxy to
F2B and F1B.

33. Bevel the edges of F17 to fit into the slots in F14
and F15. Epoxy both pieces in place.

34. Bevel the edges of F18 to fit into the slots in F14
and F16. Epoxy both pieces in place.

25. Slide F24 Ply Holddown Plate into the slots in F13
and epoxy in place.

26. Using 1/16 x 4 x 36 balsa sheets, and using the
same techniques as with the top sheeting, sheet
the bottom half of the fuselage.

27. Trim and sand the sheeting at F9B and F1B. Trim
and sand the wing saddle area flush with F13, F5B,
and F2B.

28. Place the wing in the wing saddle and center and
align the leading edge with the fuselage (the dowel
holes in F2B are cut oversize to allow adjustment).
When centered, mark the location.

29. Working through the open area in the front of the
fuse, slide F23 onto the dowels and epoxy to F2B
(NOT the dowels!). Hold the wing in it’s aligned
position while the glue sets.

12

35. Epoxy the firewall in place.

36. Slide the tabs on F19 into the slots in F15 and F1A
and glue in place.

37. Slide the tabs on F20s into the slots in F16 and F1B
and glue in place.

38. Center and align the horizontal stab onto F11. Align
the stab with the fuselage, check for level, and
epoxy in place.

39. Slide the tab on the vertical stab into the slot in the
horizontal stab and epoxy in place.

40. Using the elevator assemblies as a guide, glue the
stab horns onto the ends of the horizontal stabiliz­er.

41. Fill the aft fuselage area with lightweight filler to fill
any gaps and smooth the surfaces.

42. Glue the balsa tail block to the aft lower fuselage
and sand to shape. Fill any gaps with lightweight
filler and sand smooth.

48. Cut an access hole in the belly pan for servo
access. Cut a hatch cover (plastic cover provided;
cut to size) for the hole.

49. Locate the screw holes for the cover. Glue hard­wood screw supports behind the skin and mount
the hatch cover.

43. Mount the wing to the fuselage. Glue F2C to the
leading edge, aligning it with F2B.

44. Glue F5C to the trailing edge, aligning it with F5B.

45. Cut a ¼ x ¼ balsa keel to size and glue to F2C and
F5C.

46. Slide F3C and F4C under the keel until they’re snug
with the wing and the keel. Do not bow the keel, it
should be straight.

47. Glue the pre-cut 1/16” belly pan panels in place,
one side at a time, and work the panel along the
stringers and glue to the wing sheeting. Trim and
sand the ends. Cut a hole to allow access to the
wing holddown bolt.

Flaps & Ailerons

The flaps and ailerons are built up with a hinging system
that closely approximates the full-size airplane’s offsett con­trol surfaces. Building these assemblies is not difficult; how­ever, care should be used to prevent getting the parts
mixed up, crossed, or backward during assembly. Once an
assembly is glued together, it’s permanent. A method that
works is to work only with the parts needed for a particular
control surface at one time; that way, you won’t have 50
pieces laying on your work bench at once.

1. Remove two AH-1 hinges from the parts tree.
Carefully sand the edges smooth and scuff the sides
with sandpaper. Epoxy the hinges together, making
sure they’re aligned. Repeat this procedure with two
AH-2s, and again with two AH-3s.

3. Note that the aileron halves are marked top and bot­tom and side to side. Start with the left bottom
aileron half. Cut a piece from the 1/16” wire provid­ed to fit in the channel in the aileron.

13

4. Slide the hinges onto the wire with the slots facing
up.

4. The hinges will set at an angle, so carefully, using a
1/16” drill bit, drill the hole in the hinges to an angle
(it helps to hand drill this). Work until the angle
matches the slots in the aileron.

5. Center the hinges with the slots in the aileron (AH-3
at the tip, AH-2 in the center, AH-1 at the base)and
with the slots in the hinges facing up (it helps to have
the wing handy for reference).

13. Same hinge assembly techniques, glue two FHs
together, and make two hinges. Cut the 1/16” wire
to fit, and slide the hinges onto the wire.

14. Epoxy the “top left” half to the bottom, trapping the
wire/hinge assembly.

15. Repeat for the right side flap section.

6. Lay the hinge/wire assembly into the channel in the
aileron, and epoxy the “top left” aileron half to the
bottom, trapping the wire. Clean the epoxy from the
hinge slots, and place the aileron on a flat surface (it
helps to add weight for pressure to the assembly)
and let the epoxy cure.

7. Repeat the procedure for the right aileron, starting
with the bottom right half. If you always start with the
bottom half, the slot in the hinges always faces up.

8. Build the outer flap section the same as the ailerons,
starting with the bottom left half.

9. Epoxy two FHs (flap hinge) together. All the flap
hinges are the same, and use the same assembly
techniques as with the aileron hinges. Make two
hinges.

10. Angle drill the hinges to match the slots in the flap,

and cut the 1/16” wire to fit. Slide the hinges onto
the wire, and epoxy the “top left” half to the bottom.
Remember, start with the bottom half and the hinge
slots face up!

16. Trim and sand the edges of the control surfaces to
remove excess epoxy. Carefully remove any
excess epoxy buildup in the hinge slots.

17. Sand the aileron and flap sections to an airfoil
shape (shown on the plans). You don’t have to be
exact here, we even tested an airplane with square
control surfaces, but I don’t recommend that; it’s a
scale airplane, after all!

11. Repeat the procedure for the right side flap section.

12. Same techniques again for the inner flap section,
start with the bottom left half.

14

18. Since mounting the control surfaces can be consid­ered a final assembly item, I recommend covering
the wing and control surfaces before attaching
them to the wing. Here we go:

19. Locate and cut slots through the wing sheeting
(CAREFULLY! That’s my favorite word!) Flush with
the respective ribs. See plans for hinge/rib relation­ships. Trim the slots and test fit the aileron/hinge
until the hinges slide into the slots and lock into
W18 (for the ailerons, W17/W16 for the flaps). Trim
the slots in the hinges to allow for the angle. Note
that the ailerons and flap sections cannot be
reversed; each is specific.

Test fit each control surface, and trim until, with the hinges
locked in place, the control surface pivots freely and does­n’t interfere with the wing.

20. Starting with the ailerons, epoxy the hinges in
place. Don’t go overboard, but don’t skimp with the
glue.

25. Locate the position of the maple blocks either side
of W4. Mount the control horns on each flap section
and gauge the angle to the block. Drill the block at
that angle, and install pushrods into the blocks.
Connect with clevises to the control horns. We will
adjust them in a moment.

Functional flaps:

Mount the control horn for the inner flap section. Connect
the bellcrank and control horn for the inner flap section with
a pushrod and clevis. Mount a control horn to the outer flap
section at an angle pointing slightly aft of the bellcrank link­age. Attach a clevis and pushrod to the control horn and
bend the pushrod until it is parallel to the inner flap pushrod.
Mark this location, remove both pushrods, and solder them
together. (Scuff the puhsrods with sandpaper; find a piece
of old automotive wire, and peel off the insulation and save
a few strands of the wire. Wrap the pushrods with the wire
and then solder; the joint will outlast the airplane!)

Now let’s adjust everything: using the W4 (flap) and W8
(aileron & flap) incidence gauges provided, start with the
ailerons. Connect the pushrod and servo and center the
servo. Mount the W8 Incidence Gauge to the wing (top) at
the inner end of the aileron and adjust the aileron to match
the guage (if your aileron doesn’t quite match the contours
of the gauge, that’s OK. Eyeball it, because this is prelimi­nary) repeat for the other aileron. Connect and center the
flap servo. Use the W4 Incidence Gauge to set the outer
flap section. The flap and aileron should be even with both
centered. Adjust the inner flap section to match the outer.

21. Bevel the edges of the outer and inner flap sections
to allow a flush seam, and epoxy the outer flap sec­tion in place. Verify that the flap and aileron ends
are even.

22. The inner flap section hinges do not attach to ribs.
Locate the slots by test fitting and comparing with
the outer flap. Maintain the same distance with the
wing trailing edge, and epoxy in place.

23. Mount the control horn for the aileron directly aft of
the linkage, and mount the horn on the aileron so
that the screws do not interfere with the wire
trapped inside. Connect the aileron linkages and
adjust.

24. Each flap section uses it’s own control horn. Do the
following for fixed flaps:

15

Final Assembly

1. Glue F25 Cockpit Bulkhead to the top of F4A and
angle it to match the rear of the forward sliding
canopy.

2. Finish the interior as you wish. An instrument panel
is provided on the 3-view drawings; cut it out, and
glue it to the back of the pre-cut balsa panel, and
glue in place. Add pilot figures, etc., to suit. A rear
machine gun may be added. Note that a portion of
the rear cockpit floor is relieved to allow the servos
to fit. You may build up this area with scrap balsa if
you desire.

3. Glue the canopy in place.

4. The wheel pants may be mounted either as a perma­nent installation or removable for flight. To mount
them permanently, do the following:

5. Mount the gear leg into the slot in the wing. Slide F27
onto the wire. Slide the wheel onto the wire and posi­tion the inside half of the wheel pant to the wire.
Mark the position where the wire meets the plastic.
Check for wheel clearance. Bolt the wheel pant to
the gear leg using a gear strap. Epoxy F27 to the
wheel pant. Place the outside half against the inner
half and check for clearance. When satisfied, perma­nently mount the wheel, and glue the wheel pant
halves together. Paint to match your color scheme.
The down side to permanently mounting the wheel
pants is that access to the wheels is impossible.

Removable wheel pants can be accomplished by adding
blocks to the inside edges of the wheel pants. Drill through
the blocks and screw the wheel pants together. Add the
gear strap to mount one half to the gear leg, and cut F27 in
half and glue to each wheel pant half to locate to the gear
leg. Paint to match your color scheme, and remove for
flight.

Servo and Receiver installation

3/8” maple blocks are provided for servo rails. Mount
these as shown on the plans and mount the servos.
Mount the receiver and connect the components. The bat­tery may be mounted in a location that will aid in balanc­ing the airplane.

Covering

Cover the airplane with the covering of your choice. The
covering choices are too numerous to mention, but the
airplane shown in the photos was covered with film, paint­ed, and clear-coated. It is recommended that the airplane
and control surfaces be covered separately.

Control Surfaces

Locate the control arm positions, and install the control
arms. Final sand the control surfaces. Locate the hinge
points (hinges and other hardware are not provided int he
kit because everyone has his own preferences. Rather
than put in stuff that most of you will throw away, we left it
out to keep the kit price down) and install the hinges and
control surfaces. Use at least three hinges per control sur­face for best results. Connect and adjust the pushrods.

Fuel Tank and Throttle Cable

After deciding which direction the engine will point (up,
down, or sideways) drill holes for and install the throttle
cable. Mount the fuel tank of your choice, and connect the
lines.

Center of Gravity:

The CG is measured with the aircraft UPSIDE DOWN 3­7/16” back for the wing leading edge, where the wing
meets the fuselage.

6. Locate the cowl to the fuse and mark the screw loca­tions. Gluing a piece of carbon fiber or aluminum to
the cowl at the screw hole will add strength to this
area and will prevent cracking.

The remainder of the construction consists of attaching
the rest of the components to the airplane. Most of this is
builder’s choice, and individual tastes, styles, and compo­nent selection, so any detailed descriptions would be
impossible. The remainder of assembly is described in
general terms only.

Engine installation

Measure and mark the center horizontally and vertically of
the firewall; this will be the centerpoint for motor mount
installation. Install the motor mount and engine of your
choice. The photos of the airplane are shown with a .61
installed inverted, completely enclosed. Inverted engine
installation causes it’s own set of problems, so the flat fire­wall allows the engine to be installed pointing any direc­tion that suits you (side mounted with a Pitts-style muffler
will hide most of the engine/muffler and exhaust system).

Control Throws:

Ailerons: 7/16” up & down
Elevator: 7/16” up & 3/8” down
Flaps: 1” down
Rudder: 3/4” left & right

Flying

The Stuka is a very stable flyer, but approach the first few
flights with caution; it will take several flights to “dial in” the
flap and aileron incidences, so as you make changes,
make them gradual and incremental. Large adjustments
may create the opposite effect you were intending!

The rest is up to you! Fly and enjoy!

16

1. After painting the laser-cut cockpit parts, cut
the clear plastic gauge inserts to size. Be sure
to cut away any areas where stringers will
attach or notches where levers will be inserted.

2. Using a small amount of medium CA, attach
the clear gauge insert to the back of the panel
so the protruding lenses fit into the laser cut
holes.

3. Color any necessary parts of the paper gauge
panel and apply glue to the front of the paper.
DO NOT USE CA for this step (the fumes from
the CA will cloud the gauges). We use a
Scotch glue stick for our prototypes.

4. Apply the paper to the back of the panel so the
gauges line up with the laser-cut holes and
allow to dry.

Skyshark R/C

Gauge Face Assembly Instructions

Paper gauge faces are located on the 3-view drawing that are included with the instruction manual.