Front Wheel Modifications
November 23, 25 & 29
December 6, 7, 9 & 13
The original front wheel
assembly and method of operation is far too harsh for the Australian conditions with most of our
strips, apart from the bitumen surfaces, hard gravel and dirt with tufts of
grass. After sourcing assemblies from many suppliers, I decided of
purchasing an assembly manufactured by Hughes Group of Companies
who manufacturer the Lightwing Aircraft
as well as boats. The weight of both wheel assemblies is
approximately the same, however the 13" front wheel is larger and
||The fork has a collar enabling steering through
the front wheel. Attached to the collar is two sleeves enabling two
welded chrome molley tubes to be attached to the frame of the
undercarriage thus giving support to the front wheel assembly to prevent
shimming or flutter during taxi, take-off and landing regardless of the
surface. A grease nipple provides a lubrication point to allow the fork
to move freely inside the collar.
||Each leg of the fork has a cylinder with suspension
provided by compressing a 1" diameter piece of high density (Sure 80)
Polyeurethane. As the swivel arm moves, the piston pushes on the
retaining collar compressing the polyeurethane.
||The polyeurethane has been compressed to enable an
AN4 bolt with spares to be inserted into the holes at the bottom of each
fork. The spacer prevents the arms from being squashed too far,
restricting the movement of the swivel arm.
||Using the original front wheel support tube, another
bracket has been constructed to slide into the tube and bolt into place
with two AN4 bolts. The bracket provides the 17 degree angle, has a
thrust bearing to take the shock and provide the turning moment, and the
two push rods will be attached to the turning arm to provide the front
wheel steering. The steering assembly is held in place with an AN5 bolt,
castle nut and split pin tightened sufficiently to allow free movement.
||These two images show the front wheel assembly in
its temporary position at an angle of 17 degrees to the vertical. The
stem of the wheel will bolt to the mounting bracket that will insert
into the engine mount frame. Two AN4 bolts will be used to hold the
assembly in position after the correct height has been established by
releasing the full weight onto the wheel once support brackets have been
welded to the collar and fixed to the cabin frame next to the wing
||With the full weight of the engine resting on the
front fork bracket, the tube is cut and all bolt holes drill so the
horizontal stabilizer is parallel with the ground. The two braces have been
shaped and welded into position to prevent the front fork from skimming,
as well as providing an anchor point for the steering push rods to be
||With the two support tubes keep the wheel at the
correct angle while preventing flutter. A 1" X 1" aluminum
frame has been constructed to bolt onto the swivel bracket assembly
providing a solid mounting point for the landing light rather than on
the engine cowl.
||The linkage rods connect the brackets under the
pedals to the steering arm on the front wheel. The new landing gear
configuration which works extremely well without any shimmy or flutter
yet provides enough spring for our hard Australian runways.
December 27, 28 & 30
|After the front wheel collapse and the damage to the
engine mount frame, a new front wheel support structure has been
constructed from 2 sections of 1 1/2" x 1" x 1/8" T6 aluminum angle with
6 lengths of 3/4" x 3/4" x 1/8" T6 aluminum angle stiffeners. Solid
rivets have been used throughout its construction and securing to the
cabin frame and the base plate. 1/8" round head solid rivets are spaced
every 32mm apart to the base plate and 40mm apart to the cabin frame.
In addition, 2 round head 3/16" solid rivets have been used to secure
the new support to the corners of the cabin structure and 2 only 3/16"
round head rivets either side of centre.
1/8" counter sunk rivets have been used on the front of the front wheel
structure so that the firewall will fit flush to the frame and
While this modification will add additional weight, it will provide
strength and support for the front wheel which can now be removed
without interfering with the engine mounting frame.
A .040" stainless steel plate has been cut and shaped to fit the
section cut out of the floor pan that was damaged as the wheel collapsed
under the aircraft. The two slots are for the steering linkages and
holes predrilled for the foot pedals, the pattern taken before the
section was removed.
1/8" round head solid rivets spaced every 32mm are used to secure the
stainless steel plate to the aluminum angle, while 1/8" pop rivets every
32mm are used to secure the stainless steel plate to the floor pan.
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