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BK 117
The BK 117 helicopter fuselage kit is designed to accept FUTURA fuselage mechanics in conjunction with the 1:10 conversion set [S2931] and the
petrol engine. For the ZG 23 you will need the silencer [S0906] and the exhaust extension for the BK 117 [S2946], and these parts are not included in the kit.
The parts in square brackets [ ] are not included in the kit.
If you are converting the tail rotor gearbox [S2919] (for 2 mm Ø steel rod drive shaft) to take the tail rotor 24 mm Ø [S2977] you will also need:
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tail rotor gearbox housing R + L [S4624]
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spacer sleeve [S4833]
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tail rotor input shaft [S4747]
For the two-blade rotor head we recommend CG-corrected GRP main rotor blades [S2939 - right-hand rotation] or [S2940 - left-hand rotation].
The four-blade rotor head [S2914] should only be flown with the matching CG-corrected GRP rotor blades. To use this head you will also need the swashplate
driver [S2802], the M2.5 x 6 ball-end bolt [S4442], four M2.5 x 60 mm pushrods [S3589] and eight 2.5 mm ball-links [S3083].
Long tail rotor blades (wood, 140 mm long) are available under Order No. 3855.
We recommend the following adhesives: UHU-plus endfest 300 and Robbe Ropoxi [5066].
Completing the fuselage
Cut the openings (a - j) in the fuselage using the marked lines as a guide. You can either use a small electric disc-cutter for this, or use a saw and file.
View A shows a typical door glazing panel as an example of the method of fixing the glazing. Cut out the glazing panels (b, c, e and f) leaving a flange about 6
mm wide all round, and trim them to fit in the fuselage. Adjust the window openings if necessary. Trim the front screen (d) to fit in the recess. Both fuselage open-
ings (a) should be left open for better air throughflow and for easy access to the engine for starting.
Note: the glazing panels (b, c, e and f) should be fitted on the inside of the fuselage openings and glued in place with Pattex transparent (clear contact cement)
once the model has been painted. If you install scale cockpit fittings (optional) you may prefer to secure the front screen with 2.2 x 6.5 mm self-tapping screws
(S0042).
The fuselage formers are supplied pre-cut. Assemble the parts „dry" (without glue) and trim them as necessary until they can be aligned as shown in views B
and C. Carefully glue the parts together using white glue or high-viscosity (thick) cyano. Note that the lateral supports (19) are not glued to the other parts at this
stage; they are fitted when the assembly has been installed and glued in the fuselage. Place the mechanics on the assembly and fit the retaining screws in the
rear holes as shown in view C, detail k. Mark the position of the front attachment point (l), remove the mechanics and drill a 4 mm Ø hole at that point.
View C: epoxy the plastic parts (S3352) to the inside of the openings designed for them. Press M3 captive nuts (S2466) into the outside of the front and rear
formers, force them tightly into the wood and apply epoxy round them for additional security.
Roughen up the rear face of the carrier plate (S1682) and the joint surface inside the fuselage.
View K: adjust the locating holes in the fuselage if necessary, then glue the carrier plate in position using UHU-plus endfest 300.
The following components of the main mechanics have to be replaced:
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Main rotor shaft 186 mm by main rotor shaft 196 mm(S4775)
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Swashplate pushrods [S3203 + S0497] by (S0436 + S0528)
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If necessary tail rotor shaft connector S3300] (for 2 mm Ø steel rod drive shaft) by front coupling (S4742)
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If necessary tail rotor shaft [S3380] (for 2 mm Ø steel rod drive shaft) by tail rotor input shaft (S3705)
Remove the tail boom support [S4325] / [S4606] from the trainer mechanics and fit the spacer [S4136] in its place.
View L: attach the brackets (S1425) to the rear fixing holes of the spacer (S4136 or S4191) using M3 x 45 socket-head cap screws (S1722) and M3 self-lock-
ing nuts (S0012). Press the mechanics holder (S4047) into the spacer .
Drawing D: convert the tail rotor gearbox [S2919] (for 2 mm Ø steel rod drive shaft) to the 24 mm Ø specification [S2977] by fitting the gearbox shells [S4624],
the spacer sleeve [S4833], the self-tapping screws [S4283, S1005] and the tail rotor input shaft [S4747].
Place the prepared wooden former assembly in the fuselage, swivelling it to get it through the top opening. Fit the mechanics and screw the assembly to the for-
mer structure using M4 x 25 and M3 x 25 socket-head cap screws.
Set the assembly central in the fuselage. Tack the wooden parts to the fuselage, check alignment again, then epoxy them in place securely.
Make up the top mechanics attachment as shown in view L . The distance from the mechanics to the fuselage sides may vary slightly depending on the exact
position of the wooden formers. Trim the length of the support (7) in conjunction with the holder (20) and the plywood support, then drill the second mounting
hole. Glue the plywood part to the fuselage in the correct position. Drill 2 mm Ø holes for the holder (20) and screw the holder in place.
Views F + G: slide the skid bars (S1738) into the fuselage, set them central and fix them to the former structure using the plastic parts (S3352) and M3 x 25
socket-head cap screws (S0037). Fit the skid mounting (S1737) onto the skid tubes. Press an M3 self-locking nut (S0012) into each of the skid connectors (8),
with the plastic insert facing out. To fit the skid mountings press a strip of 2 mm plywood 11 x 500 mm into the channel in the skid connectors, and use this as a
tool to slide the connector into the tube until the thread is visible in the hole in the skid mounting. Fit an M3 x 16 socket-head cap screw (S0031) to secure it.
Views G + H: slip the retaining clip (9) on the skid bars (S1738). Press the skid mountings (S1737) onto the skid bars (S1738) and secure them from the rear
with a 2.2 x 6.5 mm self-tapping screw (S0042) after drilling a 1.5 mm Ø pilot hole.
Attach the connecting bracket (10) to the mounting clip using an M3 x 25 socket-head cap screw (S0037) and M3 self-locking nut (S0012), and fix it to the step
with an M3 x 10 countersunk screw (11) and M3 self-locking nut (S0012). Align the parts carefully - note the correct installed height - before tightening the screws.
View K: Fit the 20 mm Ø tube (S1684) through the fuselage opening (g) and into the fuselage, then push it into the mechanics holder (S4047) as far as it will
go. Draw a mark on the tube (S1684) 2 mm from the half-clip on the carrier plate (S1682).
View M: remove the tube (S1684) from the fuselage, saw it off at the marked point and file or sand the end flat and square. Use the drilling jig (S2963) as a
clamp for this job.
View L: Remove the mechanics holder (S4047) from the mechanics and glue it to the 20 mm Ø tube (S1684). Drill a 1.5 mm Ø pilot hole and fit a 2.5 x 6.5 mm
self-tapping screw (S1005).
Slide the 6 mm Ø drive tube (S1685) into the drilling jig until one end is flush with it. At this end drill the 2 mm Ø holes A and B in the drive tube using the drilling
jig as a template. Turn the drive tube round in the drilling jig. Open up the outer hole with a file to form a slot and remove all rough edges - C.
Push one coupling claw (S4633) onto the drive tube and secure it with an M2 x 10 screw (S0020). Note the different hole diameters in the coupling claw before
you fit the screw.
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ZG 23
View K: slide the drive tube into the fuselage and press the coupling claw (S4633) into the front coupling (S4742) as far as it will go. Draw a mark "MK"
on the drive tube (S1685) 5 mm forward of the carrier plate (S1682).
Remove the drive tube from the fuselage, saw it off at the marked point and file or sand the end flat and square, using the drilling jig (S2963) as a clamp.
Remove the coupling claw.
Drill the 2 mm Ø holes A and B, and file out the outer hole to form a slot - C.
View N: measure the length of the drive tube (S1685) and mark the positions for the bearing bracket sleeves (S4750). The spacing should be se same.
Apply a little epoxy to the bracket sleeves (S4750) and glue them to the tubular drive shaft (S1685) with the flanges facing each other. Slide the O-rings
(S3544) onto the brackets (S47482) according to the drawing. Fix the ballraces (S01311) attached to the brackets (S47482) to the bracket sleeves
(S4750), again using a little epoxy. Caution: take care to avoid adhesive getting into the ballraces (S01311). Apply Loctite to the coupling claws (S4633),
fit them on the tubular drive shaft (S1685) and secure them with the M2 x 10 cheesehead screws (S0020).
Views P + Q: assemble the 45° gearbox, and trim the bellcrank. Mount the gearbox on the carrier plate using socket-head cap screws and washers,
and fit the bolt and crank.
Slide the 6 mm Ø drive tube (70-1686) into the drilling jig until one end is flush with it. At this end drill the 2 mm Ø holes A and B in the drive tube using
the drilling jig as a template. Turn the drive tube round in the drilling jig. Open up the outer hole with a file to form a slot and remove all rough edges -
C.
Apply Loctite to one coupling claw (S4633), push it onto the drive tube and secure it with an M2 x 10 screw (S0020). Note the different hole diameters
in the coupling claw before you fit the screw.
Fit the drive tube in the integral vertical stabiliser and engage the coupling claw in the 45° gearbox.
View Q: glue the tail rotor bulkhead (S4046) in the fuselage at a distance of 44 mm from the front edge of the vertical stabiliser.
View R: fit the 2.2 x 6.5 mm self-tapping screws (S0042) and the washers (S0000) for additional security.
Fit the second coupling claw on the plain end of the drive tube (70-1686) and engage the tail rotor gearbox. Measure dimension „Y" from the tail rotor
bulkhead to the mounting surface of the tail rotor gearbox.
View M1: please note the when cutting the tube to length:
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24 mm Ø tail rotor [S2977]: use the drilling jig, and shorten the drive tube by dimension „Y" + 1 mm.
Drill the 2 mm Ø holes A and B, and file out the outer hole to form a slot - C.
Fit the second coupling claw (not forgetting the Loctite) and secure it with an M2 x 10 screw (S0020).
Remove the 45° gearbox from the fuselage.
View A: glue the horizontal stabiliser (12) in slot H, checking that it is exactly central. Glue the vertical stabilisers (13) to it.
Trim the fuselage hatch (16) to fit in the top fuselage opening and drill 1.5 mm Ø holes through both parts. Cut out the gearbox cover (17) following the
marked lines, tape it in place centrally and drill through the cover and fuselage as before. Strips of plywood are used to reinforce the fuselage cover;
glue them under the edge of the fuselage and continue the holes through the ply. Open up the holes in the fuselage cover and the gearbox cover to 2
mm Ø.
Fix the fuselage cover (16) and the gearbox cover (17) to the fuselage using 2.2 x 6.5 mm self-tapping screws (S0042) and washers (S0000), but not
until the mechanics assembly has been installed permanently.
Drill holes for the door handles, aerials, screen wipers and hand-holds at the points shown. Install the detail fittings, ventilation grilles and steps before
or after painting the model, depending on your choice of colour scheme.
View S: cut an opening in the side support (19) and the underside of the fuselage to clear the exhaust extension. Glue the support to the former struc-
ture.
Examine the fuselage joint seams and sand them lightly where necessary. Apply several coats of primer to the wooden parts, sanding smooth between
coats. Apply fuel-proofer to prevent the parts absorbing oil and fuel. The fuselage can now be painted. We recommend only synthetic enamel paints for
this model. Important: be sparing with the paint, as pigment is heavy and you need to keep an eye on the model's all-up weight. It is very easy to add
several hundred grammes of weight in this way!
Installing the mechanics
Lightly grease the coupling claws (S4633), then oil the mating surfaces and slide the complete rigid drive system and jig tube into the tail boom (S1684).
Complete the 20 mm Ø tube (S1684) by fitting the servo mounts (S0940) and servo, the pushrod guides (S1241), and the two-part pushrod (S0375,
S3477) complete with pushrod connector (S1242) and clevises (S0059).
View L: place this assembly in the fuselage. Press the mechanics holder (S4047) in the mechanics spacer and screw it to the bracket (5) together with
the top mechanics attachment.
Connect the tail rotor servo to the receiver or gyro.
Views P + Q: fix the rear end of the 20 mm Ø tube (S1684) to the carrier plate (S1682) using the clip (S4371) and M3 x 14 socket-head cap screws
(S3198).
Install the 45° gearbox, engaging the coupling claws on the drive tube (S1685) in the mechanics and the 45° gearbox as you do so. Connect the clevis
to the lever on the angle gearbox.
Grease the claws of the coupling attached to the drive tube (S1686) and fit it in the vertical stabiliser together with the tail rotor gearbox. Engage the
coupling claws in the 45° angle gearbox and the tail rotor gearbox at the same time.
Tighten the tail rotor gearbox retaining screws.
Fit clevises to both ends of the pushrod (S3452), fit the pushrod in the vertical stabiliser and connect it to the lever on the 45° angle gearbox and the
bellcrank on the tail rotor gearbox.
When fitting the tail rotor [S2977] you will need to drill four 6 mm Ø holes in the vertical stabiliser to allow access to the tail rotor bulkhead.
If you are using the two-blade rotor head it is essential to fit the longer flybar (S4516) supplied in the kit. We also recommend installing a set of iner-
tia weights [S0755].
We reserve the right to alter technical specifications.
BK 117
S 2918
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