Composite-ARF Extra 300SX
(2.6m span)
lage (factory-installed), using the supplied M6 x 20mm bolts
and washers into the pre-installed T-nuts. See photo P1.
Note that the bend on the underside of each landing gear
leg should be flush with the outside surface of the fuselage
skin, and therefore you may need to chamfer the bottom
edges of the factory-cut slots in the fuselage a little with a
file to make sure that there is no interference.
Sand the inside of the ‘U-shape’ molded in recesses in the
wheelpants, and glue in the milled 3mm plywood U-shaped
part as shown, using 30 min. epoxy. At the same time glue
in a milled 20 x 20mm square plywood plate on the inside
of the wheelpant, against the kevlar reinforcement, with the
centre of the square about 6mm (1/4”) behind the vertical
centre from the axle position, and about 25mm (1”) above
it. This part is reinforcement for the M3 T-nut that will be
installed later. (see photo P2)
Drill a 6mm Ø hole in the bottom of each carbon leg for the
axle, through the small dimple that is molded-in to mark the
correct position. Drill 6mm through the hole in the U-shaped
ply part on each wheel pant. Drill an 9mm diameter hole in
the outside of the both wheelpants, directly opposite the
6mm hole for the axle. This hole is for inserting the M6 x
70mm hardened bolt that is used as the axle.
Insert the bolt into the wheelpant through the 9mm hole,
threading on the washers and wheel collars, used as spac-
ers, as needed to centre the wheel in the pant. The last 2
items to go onto the axle are a plain M6 nut and a washer,
which will be against the inner surface of the wheel pant.
(see typical example below). Secure the axle onto the land-
ing gear with a washer and M6 lock-nut on the inside of the
carbon leg. During final assembly a drop of Loctite on the
M6 lock-nut is good insurance.
Set the fuselage on a level surface with
the tailwheel in place, and adjust the
angle of the wheelpants so that they are
parallel with each other, and will not
touch the ground on takeoff or landing.
Tighten the M6 stop-nut firmly, and tack
glue the carbon leg to the plywood ‘U-
shape’ with 1 small drop of CA to make
sure it cannot move during the next step.
Drill 3mm hole through the middle of the
carbon leg, 25mm above the centre of
the axle, into the small ply square inside
the wheel pant, and fit an M3 x 16mm
bolt and washer in place.
Remove the axle, wheel and spacers and
11
(above & below) Glue the milled
plywood reinforcements to the
inside & outside of the wheelpant
as shown. The inside plate will
have an M3 T-nut glued to it later.
(above) The moulded dimple in
the bottom of the carbon legs. Drill
a central hole of 6mm diameter.
Carbonfibre landing
gear leg
120-125mm
Ø wheel
wheelpant
M6 bolthead
washer
6mm wheel
collar
washer
washer
M6 locknut
M6 nut
milled plywood
WHEELPANT X-Section
