Main Landing Gear
The Sabre was originally designed to use
Spring-Air 300 or 700 series main retracts
(89° or 90° retraction angle), but there are
many similar sized units that can be fitted.
The maximum internal depth available in
the wing at the outer end of the retract po-
sition is 34mm.
The main landing gear retract units are
bolted onto milled 6mm composite ply-
wood/fibreglass plates that you must glue
to the fibreglass sleeves that are factory-
installed in the wings. Adjust the milled slots
in the plates to suit your chosen retract
units, if necessary, before gluing them into
the wings. Check that slots for the retracts
are both the same distance from the cen-
treline of the wing, and adjust if necessary.
Sand the back edge of the mounting plates
a little if necessary, so that you can just in-
sert these into the wing. You can fit them in
thru’ the inner end of each retract bay at an
angle, and then straighten them to fit onto
the fibreglass flanges. As the main landing
gear is very close to the Centre of Gravity it
is important to mount the retracts as far
backwards as possible.
Carefully sand and prepare the ply mount-
ing plates, the fibreglass flanges and the
surface of the wing spars where the plates
will be glued. Glue the plates in securely
using a slow epoxy and milled fibre mixture
- making sure of good contact to the fibre-
glass and the wing spars at the front and
back of the retract bays.
Secure the retracts to the plates with small
(M3 or equivalent) bolts and T-nuts each,
as shown. Depending on the thickness of
your retract units you may need to glue
some plywood strips under the retract
flanges. Make sure that there is
at least
a
1mm gap between the top of your retract
units and the fibreglass sleeve that is fac-
tory-bonded to the upper wing skin - so that
you won’t damage the wing surface in the
case of a ‘bouncy’ landing!
Fox Composites Co., Ltd.
16
(above) Prepare the plywood mounts carefully
and glue to the fibreglass flanges and spars with
slow epoxy and milled-fibre mixture.
(below) You may need to pack the retracts up
with scrap plywood. Keep at least 1mm gap to
the wing above the units. Use countersunk bolts
to maximise space available if necessary.
