The sockets in the fuse are steel and don't have a bushing. The
thickness of the receptical (and thus the width of the contact area for
the pins) is only about 1/4". This was probably underengineered.

The wear on the top surface of the pins is therefor localized to the
1/4" wide area where the pin was in contact with the fuse. I measured
the wear at one point, but don't have those numbers handy. I'm guessing
it was on the order of 1/32" With something like 0.015 to 0.020
elongation in the hole. In smooth air, it was no biggie. On a final
glide it rattled and bumped, but didn't affect flight stability, etc.



Bob Kuykendall wrote:
Earlier, Gary Emerson wrote:

The pins that transfer the load from the wings to the fuse are installed
in the wing. There are holes on the fuselage side. It's an older
glider and as such doesn't have the replaceable swivel bearings on the
fuse. In this case, the holes are elongated vertically from wear and
the pins have wear on their top surface. The result is play in the wing
to fuse connection...


If this is a composite glider, I'd bet that the holes in the fuselage
side are actually bronze or similarly soft bushings installed in steel
sleeves. The most common such installation is such that the sleeves are
steel tubes that go all the way across the fuselage to the opposite
side so as to transfer compression loads from drag or thrust to the
opposite root rib.

Wandering off topic, my experience with newsgroups is that you will get
the most useful responses for stuff like this when you explicitly
specify the glider make and model, and state the nature of the issue in
the Subject line. For example "Lift pin socket wear: how to address?"

Thanks, and best regards to all

Bob K.
http://www.hpaircraft.com