taildragger to trike

Be careful designing landing gear mount structure. Taxiing over rough
ground is really hard on gear, harder than bumpy landings. I've seen
some gear on ultralights that looks scary. Watched one collapse on
landing several years ago. And have heard of other gear failures on
homebuilts. We had a gear failure on a Glastar about five years ago,
when the single AN5 bolt sheared during braking after touchdown. The
gear is a round, tapered steel rod mounted in a steel tube socket
welded to the fuselage cage structure, and that AN5 bolt passed
through the tube and leg. Braking forces try to turn the rod in the
socket and landing/turning/taxiing loads try to push it inward, and
that bolt couldn't take it. (additional info snipped)

I've never looked closely at the Glastar undercarriage, but the RV-8A uses a
similar system with good success. In the case of the RV that I looked at,
there would be no torsion applied to the mounting of the gear leg with the
tire correctly inflated. However, some torsional force would exist in the
event that the tire is either over-inflated or under-inflated.

Another point that I feel compelled to make, even though I really do not
like to say it, it that the gear leg and socket should NOT be lubricated. I
am not saying that the gear on the Glastar was, but just making the point
that the bolt is mainly to align the under carriage when not in use and that
friction should greatly exceed any capacity of the bolt when the airplane's
weight is on the wheels.

Peter
(Not a mechanic, but I've seen some strange things!)