Composite-ARF kangaroo, Инструкция по эксплуатации

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against the marked lines. Start by cutting the wells for the mechanical part of the main retract units, as shown in
Figs. 1; use the retract unit itself as a template for cutting the opening. Fit the retract unit in the well, then
disengage the retracting leg and fold it down against the underside of the fuselage. Using a permanent felt-tip
pen, carefully mark the wheel axis, i.e. the point which will be the centre of the circle for the wheel well. If you
are using our retract units, Graupner Order No. 175, we recommend that you mark a circle of 43 mm radius. Cut
out the wheel well, then disengage the undercarriage leg and lay it on the fuselage again. You can now easily
mark the outline of the channel in which the undercarriage leg will lie when the undercarriage is retracted. Mark
out the channel with a little excess width, and cut it out using a sharp knife and a steel ruler as a guide.
Install both main retract units, and check by hand that neither the undercarriage leg nor the wheel touches or rubs
at any point on the well and channel when retracted. The main retract units can now be fixed to the mounts using
the type of screw recommended. Fixing screws are supplied with our retract units, Order No. 175. These are self-
tapping screws, and it is important to drill 2.5 mm Ø pilot-holes before fitting them, otherwise there is a danger
of damaging the undercarriage mounts. To be precise, if you fit the retract unit screws without drilling pilot-
holes, the screws may split and destroy the plywood plates into which the screws are driven. The recommended
retract units include pneumatic brakes, and if your undercarriage also has this feature, this is the time to cut the
hole for the pressure hose (see Fig. 4).
Mark the outline of the well for the retractable nosewheel unit based on the dimensions in Fig. 2. Disengage the
noseleg and fit it through the cabin opening on the top of the fuselage and into the retract unit mount designed
for it. Mark round the outline of the retract unit on the inside, as shown in Fig. 2.
The next step is to check that the marked outline on the outside of the fuselage coincides with that on the inside
of the moulding, and this is again done by holding the fuselage against a bright light, so that you can check
alignment. An alternative method of checking the well location is to push stout pins through the GRP laminate at
corner positions. The retract unit well can now be cut out. Work slowly and patiently, with the aim of keeping
the outline as accurate as possible, with just a slight gap all round. When you have established the correct
position and cut out the well as neatly as possible, screw the noseleg retract unit in place as described for the
main retract units (i.e. drill pilot-holes for the screws).
The retract units can now be installed permanently, but before you do this remember to connect the pressure
hoses which control the retracting mechanism and the brakes, because they are much more difficult to fit once
the retracts are installed.
The opening for the airbrake / speed brake, which you have already marked out, can now be cut out (dimensions
in Fig. 3). Check your marked outline by holding the fuselage against a bright light once more - it is important
that the marked flap should not overlap the former which is already installed in the fuselage. There should be at
least 10 mm between the rear edge of the former (Herex foam) and the leading edge of the airbrake flap. When
you are confident about the flap location, start by drilling the holes for the pin hinges; this is much easier to do
before you start cutting. The position of the holes is shown in Fig. 5, but please note that a twist drill does not
work well on the hard surface: instead pierce the GRP skin and the sandwich material with a sharp instrument,
then file out the holes to final size using a suitable round file. The airbrake / speed brake has rounded corners, as
can be seen in Fig. 5. The radius should be approximately that of a small coin. We found it useful to stick four
coins (same value!) in the corners using double-sided adhesive tape, to ensure absolutely constant radii. The
coins themselves then serve as cutting templates. Start by cutting the long straight lines, holding a steel straight
edge against the coins, and finish off by cutting the corner curves. Don’t attempt to penetrate the GRP outer skin
in one cut; it is much better to make repeated light cuts, as this prevents the outer skin and/or the sandwich
material being crushed or distorted. Carefully sand the flap and the opening in the fuselage using coarse
glasspaper on a sanding block, then glue the pin hinges (19) in place using a length of 0.8 mm Ø steel wire (20)
to aid alignment. Note that the pin hinges (19) must be shortened as shown in Fig. 5 before they are glued in
place. Fix the flap in the opening by applying clear Tesa tape on the outside, and check that there is an even gap
all round. Now thread the steel wire (20) through the hinges as shown in Fig. 5, and tape the steel wire to the
outside of the fuselage, applying the tape outside the outline of the flap. This technique ensures that you install
the airbrake hinges with their pivot axes exactly in line, and outside the line of the fuselage, which in turn allows
the airbrake / speed brake to deflect through 90º or more without fouling its surround. The hinges can now be
glued in place using thickened 5-minute epoxy as shown in Fig. 6. Allow the epoxy to cure completely, then
remove the strips of tape. If the flap should foul its surround at any point, sand it back using coarse abrasive
paper. When you are satisfied with the fit, glue the airbrake stop strip (14) (plywood, 350 x 20 x 0.8 mm) to the
fuselage using thick cyano, leaving a support ledge for the airbrake about 5 mm wide.
Now screw the RC components for the steerable nosewheel and the speed brake in the pre-cut openings in the