Main Landing Gear - Composite-ARF SPARK Instruction Manual

Composite-ARF SPARK
then tighten the 4 bolts that secure the servo.
Because of the curved shape of the upper wing
skin in this area you need to glue a couple of 5
x 5mm balsa strips to the bottom of the ply plate
and sand them to fit the wing skin, as shown in
the photos. Fit a heavy duty JR servo arm to the
servo and centre it using your R/C. Make up the
linkage as shown, using the M3 x 40mm all-
thread, steel clevises and M3 nuts. Loctite the
clevise that will be clipped onto to the servo arm
now. The clevise on the linkage at the servo end
usually needs to go on the outer hole of the
servo arm, 20mm out from the servo centre.
Adjust the linkage carefully so that the servo arm
does not go 'over-centre' when the speedbrake
is closed, and make it difficult to open it by hand
to make the Rx antenna connection when
assembling the plane.
You can make small semi-circular 'finger-hole'
cut-out in the wing skin behind the speedbrake
to make it easy to open it when assembling the
model at the airfield. (see photo below/right )

Main Landing Gear

The Spark was designed to use low-cost, light-
weight and reliable retractable landing gear, and
the Spring Air 301's fit this specification perfect-
ly. They were used in both prototypes without
any problems at all; one set was fitted with light-
weight plastic wheels, and the other with the
optional 60mm Behotec 'slim' aluminum wheels
and brakes especially designed for the Spark.
It is your choice what to fit, but of course the
plastic wheels (without brakes) are more than
adequate for grass airfields - whereas the
Behotec wheels and brakes will be more suit-
able and durable for hard runways. Both wheel
types were fitted to the standard Ø 4mm wire
legs supplied with the Spring Air set. The Spring
Air 301 'Firewall set' and the Behotec wheels &
brake set are both available from Composite-
ARF as options.
techsupport@composite-arf.com
(above) A small hole allows access to rear
servo bolts with a long ball-driver if necessary.
(below) Wing is fixed to fuselage by a pair of
6mm carbon pins at the front. Wrap the servo
extension leads & air tubes together to make
it easier to insert them into the fuselage cable
duct when fitting the wing for flying.
(below) View of Landing gear installed.
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