----- Original Message -----
From: "Cliff Shaw" <flyinggpa@attbi.com>
Subject: Re: Wing angle of incidence
>
> We had a problem like that too. The easiest fix was sent to us from
"Europa
> Bob" .
>
> It was to get a 1/2 " reammer.Rig the wings with one 1/2 pin in place, and
> run the reamer through the other hole. Then insert a pin it that hole and
> ream the first hole. Absolutely genius. It gives you a exactly tight
> fitting hole that the pins slide into using one hand.
>
I would urge extreme caution with this procedure. Be sure you know exactly
how much material you will remove from each bushing, and from which surface,
before proceeding. We used this same fix, and discovered afterwards that we
had removed .027" of material from one bushing. Reamers can chew up
aluminum fast! Worse still, the surface that was removed was not the one
that transfers the static load of the airplane into the wing spars under
positive G loading, so a large deflection somewhere would have been required
before the pin began to carry its intended load. Had we first run a
succession of undersize pins through the hole to see just how much material
would be removed, we would certainly not have continued. As I recall, the
nominal clearance between the pin and sockets was about .007", so it would
be prudent to check with the factory, if the proposed enlargement approaches
this amount.
Having damaged the spar bushings, we removed them and bonded in new ones.
We removed the mating bushing in the cockpit module, enlarged the mounting
hole as required, and bonded the bushing in place, shimming it with aluminum
to keep it properly aligned. Not something I would care to repeat, but not
terribly difficult either, after the precise measurements have been made to
show exactly what is needed.
If the pins are merely tight, the fit may ease up after an extended period
of being rigged. I would recommend delaying any adjustments as long as
possible. We found that the fit changed substantially when the fuselage was
removed from the building frame and set on its gear, and then again when the
engine was hung.
Dave DeFord
N135TD
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