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You might notice now that the wheel is sitting a little too far back in the wheel well. That's due to
the fact that most likely the spar in that area is not 100% perpendicular to the 5 degree, which the
axis of rotation has to point outwards. This can be easily adjusted with one or two steps of thin
plywood, used as a spacer on the outside of the gear unit. Tack glue these spacers to the spar,
and slightly re-work the cut out of the horizontal gear mount, if necessary. A dremel with a
sanding drum or a Permagrit sanding block or file will do. Always make sure that the torque rod of
the strut holder is all the way in the gear unit, the rear end should be flush with the gear frame. Do
not try to correct any issues by pulling this out from its original position. Corrections must only be
made by changing the angle of the gear unit.
Once the wheel is aligned in the center of the wheel bay, temporarily fix the gear with 2 small self
tapper screws, make sure that it is flush against the spar, or spare and spacers you installed.
Then cycle the gear so that it is extended. align the strut 100% vertical and the wheel exactly
along the root rib (no toe in or out). Tighten the grab screws slightly so that it won't move by itself.
Now cycle the gear in. Make sure that the motor pulls the brass slider all the way to the end
position. If the gear is retracted, the wheel should not touch the upper skin of the wheel well. If it
does, it will create tension on the gear and it might not unlock reliably in the air, when you try to
put your gear down. This must be avoided. So: The week must turn freely when gear is retracted.
Do this for both gear, right and left.
Now there can be two things: The wheels are not aligned to each other, or the wheels touch the
upper skin of the wheel well.
a) If the wheels are not aligned to each other:
Don't rotate the strut in the strut holder. As long as you have confirmed that the alignment
of the wheel is correct when extended, this should not be adjusted anymore! You should
now adjust the gear unit, using very thin spacers at the top or the bottom of the front
retract frame (the aluminum plate) until the wheels are aligned to each other.
b) If the wheels do not retract all the way, or they hit the top skin of the wheel well:
You need to lift up the gear unit in the mount, there is still some room to the bottom skin of
the wing and gear door, you can most likely add another 3 - 6 mm plywood on that
spacer block. At least try to get close, if you are not 100% successful you should then
extend both gears, loosen the grab screws in the trunnion and move the strut 1-2 degree
outwards. Maybe you did not align them 100% perfectly vertical the first time, in any way,
if the strut is pointe 1-2 degree out, it will not be noticeable when the plane sits on the
ground.
Cycle the gear a few times and make sure it travels smoothly, locks and unlocks without binding.
Now, when your geometry is right, you will have to drill two holes in the spar in the right position,
in order to mount the front frame to the spar. That is a little difficult task, but it is only foam and a
small carbon plate. what works is a 4 mm steel, bent 90 degree and heated with a torch. Burning
the hole through the spar is a little smelly, but the easiest option.
Last but not least, the brass bushing needs to get a support against the spar, and therefore you
mix some 30 min resin with milled fibre and/or microballon. Then you wax the bushing and put the
thickened resin under the bushing. Make sure that the reason doesn't squash over the bushing,
as you will have to be able to remove the gear and bushing for maintenance at any time. This step
is not crucial, the gear unit itself has considerable strength, but if you do it, it helps to carry a hard
bounce better into the center wings structure and takes load away from the two bolts in the front
through the spar.
Then you can permanently mount the gear with the two M5 bolts through the spar and the self
tapping sheet metal screws into the rear horizontal board. The screws have to be long enough
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