Thanks Bud
Will
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Bud Yerly
Sent: 17 January, 2011 21:39
Subject: Re: Europa-List: Main wing bushings
Will, and others,
The play is because the black pins are undersized about .007 I think. The
main pip pin is about .499 so only a tiny amount of play is available.
Normally, the oversized bushes allow what appears to be excessive play when
the wings are not rigged. When the plane is rigged, those sloppy bushes get
hard to align unless you were superman during the cockpit module build up
and got the fuselage and wing bushes just perfect. I only have two
aircraft that align so well, the wing pins slide in easily, but that is only
at 85 degrees and with the tips held just right. Hotter or colder, or with
an untrained assistant, it is tougher to push the pins in. So what to do?
Since none of us is superman, I many times have re-aligned the bushes on
final wing rigging by heating my spare tapered black pin until just too hot
to touch, but not sizzle (180F), and ram it home. Let it set overnight and
the three bushes get aligned. Once in a while, I do have to put my 1/2 inch
reamer into the pilot side hole and knock a thousandth off for a nice hand
fit of the pip pin because of the tighter tolerances.
Note: There is a good reason for using the pip pin when doing spar
alignment, especially on the glider wing retrofit. Unfortunately we don't
have the luxury of setting our own bushes with the short wings. If we
follow the instructions blindly and use just the bolts, you won't quite get
perfect alignment. So just heat the pin and help the bushes align.
Please do not overheat your existing wing pin and destroy the heat treating.
At 6 Gs, you would not believe the shear load on that pin.
So don't rip everything out just yet, try a bit of heat and patience. It's
worth it.
Regards,
Bud Yerly
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