Hi Michael
"I am not sure yet how I will be able to measure it but definitely will
try once the plane is loaded"
A good way to measure is put a straight edge against the front or back of
both tires, and measure the angle of rims to that. You need to make or
borrow a set of greased plates to accurate measure though. Lets say you
had a bit of toe in, and rolled the plane forward, the wheels will want to
come together and will twist and give you a bit more toe in, roll
backwards and the reverse will happen. Setting wheels on greased plates,
just unweight, then weight plane a little a few times and you can see that
the tires are happy not stressing the gear legs. Just use a little TRIG to
figure out angles.
As a matter of fact, why don't you bring stuff to next Europa meet, and
measure tri gears with no one in plane, then load 2 people inside plane
and 1 person on each wing root and see where those planes come in at. An
added bonus for those who insist on flying an "unconventional gear"
aircraft, would be to not only measure light and heavy toe in/out and
camber, but once the "sweet" aircraft are discovered that don't eat up
tires and wear them even, measure those aircraft with wheels off the
ground so future "unconventional gear" builders or retrofitters can tweak
things in their favor.
I changed out welded steel axles on my 1948 Cessna 170 ragwing for solid
aluminium ski axles. I could not obtain any old part number shims, so I
just TRIGed what I needed, then wandered through the FBOs wheel shim stock
and picked what was close to what was needed, and hand lapped to exact
what I needed. Worked perfect first time. This was after 3 tries, 1 by IA
who changed axles, and 2 by FBO who was not too swift at TRIG. Handling of
a traditional taildragger with toe in is a real challenge!
BTW has nothing to do with toe in or out, but I used the same straight
edge I used to TRIG my C-170 wheel alignment to make sure my undercarriage
mounting frame had my main monowheel tracking straight. I just offered it
up to brake rotor and made sure the offset was the same at the wheel as it
was at the aft fuse.
A straight ladder and carpenters square should work, I used 4 old saw
blades for grease plates I had laying around, just set the teeth to 1 side
so as not to bind.
Ron Parigoris
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