Composite-ARF kangaroo Instruction Manual page 10

RC installation plate (8). At the same time install the RC system switch (in our case the Power switch harness.
The servo which operates the speed brake has to be installed inverted as shown. In the example in the pictures
we are using two electronic control valves, Order, to operate the pneumatically operated and braked retractable
undercarriage. If you prefer to use mechanically operated pneumatic valves to control the undercarriage
functions, there is plenty of space on the RC installation plate (8) for the servos and associated components. The
installation plate (8) is designed to be removable, to make it easier to install the various components. Fix the RC
installation plate (8) to the machined plywood front support (9) and the two 35 x 19 x 9 mm plywood support
blocks (10) using the 2.9 x 13 mm self-tapping screws (24). The position and layout are shown in Fig. 7. As with
the retract unit mounts, don't forget to drill 1.5 mm Ø pilot-holes for the fixing screws, otherwise the plywood
may split. Now place the RC installation plate assembly (complete with RC components) in the fuselage, and
position it with the centreline of the nosewheel steering servo central in the fuselage. Assemble the linkage to
operate the speed brake and connect it to the inverted servo. This pushrod is made up from a length of M3
studding (threaded rod) (21), an M3 clevis (22) and an M3 nut (23). Cut an opening in the factory-fitted Herex
foam former large enough to clear the airbrake / speed brake pushrod; this is shown in Fig. 7. Now slide the RC
installation plate, complete with all its fittings, into final position and glue the plywood support components (9)
and (10) to the Herex foam former and the fuselage floor using 5-minute epoxy. Take care not to glue the plate
itself in place. At this stage the Novotex horn (17) for the airbrake / speed brake can be placed in position (Fig.
6) and tacked in place using thick cyano. When the glue has hardened, reinforce the joint with a generous fillet
of thickened 5-minute epoxy as shown. Now cut the airbrake / speed brake pushrod to length and adjust it
carefully: when the servo is moved from end-point to end-point, the flap should close completely without stalling
the servo, and then extend to max. 90°. Pushrod parts: M3 studding (21), M3 clevis (22), M3 nut (23).
Cut part (12) (turbine electronics support plate) to length, so that it fits exactly between the two factory-fitted
Herex foam formers. Measure the actual dimensions from your fuselage, as manufacturing tolerances may cause
slight differences (Fig. 8).
Now glue two plywood blocks (13) in place in such a way that the plywood plate (12) (on which the turbine
electronics components will be installed) fits snugly between them: glue one part (13) to the bottom of the
fuselage using thick cyano or 5-minute epoxy, and the other to the rear Herex former, parallel to the first and 3
mm above it (to allow for the thickness of the support plate (12)); use thick CA for this joint. Please note that the
position of the fueltank (2-litre disposable Pepsi bottle) is fixed by the manufacturer; check that it still fits when
parts (12) and (13) are installed.
Now fit the trimmed support plate (12) between the two plywood blocks (13) to establish the position of the third
block (13), to which the plywood plate for the turbine electronics is screwed. Screw part (13) to the plate (12)
using two 2.9 x 13 mm self-tapping screws (24), then glue part 13 to the former securely using 5-minute epoxy.
When the epoxy has set hard, unscrew the two self-tapping screws (24), and it should be possible to lift out the
support plate (12) (Fig. 8). The third part (13), to which the plate (12) is screwed, should now be attached
securely to the front Herex former and the fuselage floor.
Epoxy the retaining plate (16) to the fuselage at the rear end of the canopy opening (Fig. 8).
Now tape the canopy (2) to the fuselage, taking care to position it accurately. You will find marked lines on both
sides of the canopy, indicating the correct position of the canopy latches. Extend these lines onto the fuselage.
Locate the marked point in the rear end of the canopy and drill a 6 mm Ø hole in that position, drilling right
through the plywood plate (16) which you have just fitted to the fuselage. Enlarge the hole in the GRP canopy
moulding to accept the head of the M6 x 20 socket-head cap screw (25); the screw head should pass through it
without binding.
Remove the tape holding the canopy to the fuselage, taking care not to wipe off the marked points for the canopy
attachment, then cut out the openings in the GRP fuselage and canopy as shown in Fig. 9; study the picture
carefully! Installing the retainer lugs as shown in the picture may look difficult and excessively complicated, but
the system works well and the canopy does not fall off!
On our model we use two retainer lugs (7), but you may wish to install up to four of them for extra security. This
does involve extra work, and if you find our suggested latch system too complex you are welcome to invent your
own alternative system. Just remember that it must be strong enough to ensure that the canopy cannot possibly
come loose in flight!
The method of canopy retention described in these instructions may appear difficult and excessive, but in
practice it is a simple, reliable system which has already proved its worth in the large number of "conventional"
KANGAROOs of the same design which have already been produced and sold.