At the risk of being shot down in flames (yet again), this is a subject which is
quite dear to my heart. I've asked a few people over the years the same question
and never been given a definitive answer. I doubt very much that there's
anyone at Europa who could either. What I do know is that the late Nev Eyre
replaced
the bronze bushes for at least one of his customers, but seemingly only
because they wanted it done and not because he thought it was really necessary.
That's the impression he gave me anyway.
Either you belong to the school of opinion that even slight play is
unacceptable,
or you take the pragmatic view of considering whether the play is likely to
cause a problem. I fall in with the latter and have no reason to believe that
even a mm of play in the bush would cause flutter or any other undesirable
effect.
One of my bushes has about .015" of movement and the other is probably double
that. The airframe has around 1200 hours and I've been aware of play for
several years.
In order to keep those bushes lubricated, I have a plastic syringe drilled out
to accept a very thin plastic tube of the type which inserts into the nozzle of
an ACF 50 spray can. I load the syringe with a little clean engine oil and using
a torch, I insert the tube through the narrow gap at the root of each tail
plane. The oil flows around and down the metal sleeve which passes through each
bush and then wicks sideways into the gap.
This I do every few flying hours and it avoids the need to unpin and slide each
tail plane sideways. For the past couple of years there has been no discernible
increase in wear of the bushes.
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