carbon leg. Redrill the hole in the wheelpant and plywood square only (not the carbon leg) to
4.5mm diameter, and glue an M3 T-nut to the plywood square inside the wheelpant for the M3
bolt. This bolt maintains the correct angle of the wheel pants to the ground. (see photo P3)
Do
not
use a bolt larger than M3, as the larger diameter hole in the leg can weaken it.
The typical order of fitting the wheelcollars, washers and wheel onto the axle, to centre the wheel
in the wheelpant, is shown in the diagram above - but of course it will vary slightly depending on
the size and type of wheel used.
You can use any 4.5” - 5" main wheels. Kavan wheels are
very lightweight, but not very durable on asphalt runways,
and Dubro wheels are a little heavier but much more solid.
Leg Cuffs
The Extra 300SX has fairings at the top of each LG leg
where they enter the fuselage, and these are supplied in
the kit as lightweight fibreglass mouldings. It is a little more
difficult to remove the LG legs for replacement when the
cuffs are in place, and we suggest that they are glued in
place onto the fuselage with clear silicone adhesive (bath
sealant), so they can easily be removed if necessary. Note
that there is a ‘right’ and a ‘left’ leg cuff, but which is which
will be very obvious when you trial fit them to the fuselage!
Mill the slot in each cuff for the carbon legs, leaving about
0.5mm (1/15”) gap all around to allow for the flexing of the
carbon leg during landing, and to make it easier to remove
the carbon legs from the fuselage. Sand border of the cuffs
smooth, and glue to fuselage with a little clear silicone
adhesive.
Tailwheel
The tail wheel setup shown in these photos is an optional
part available from C-ARF (# 801000), and is mounted with
4 sheet metal screws and 2 plastic ‘U’ brackets under the
fuselage, screwed into the plywood reinforcement
that’s installed in the fuselage at the factory.
You don’t need to make the tailwheel steerable if fly-
ing from grass surfaces, a simple castoring action is
fine. However, for hard runways you may prefer to
connect it either to the rudder horn with 2 springs as
shown, or even better to the rudder pull-pull cables
about 250mm in front of the rudder leading edge - as
shown here. It’s easy to make the springs by winding
some 0.8mm Ø piano wire around a 5mm drill bit,
turned slowly in a battery-drill, with a small hook in
each end to connect to the tailwheel steering arms.
(see also photo P21)
Remember - keep it lightweight at the tail end!
Composite-ARF Extra 300SX
(2.6m span)
12
(above) Optional tailwheel assem-
bly from Composite-ARF.
(below) Tailwheel assembly can be
connected to rudder horn OR rud-
der cables with springs for
improved steering.
(above) Fibreglass leg Cuffs are
secured to fuselage with a little
clear silicone adhesive, allowing
easy removal if necessary.