OK guys, I'm the one who accidentally wrote about tailplanes under the
Splashes subject heading and I am suitably humbled; apologies to all.
But at last I realise that the tailplane tube problem is really serious. We
will have to understand the cause before a proper fix can be worked out. So
far it looks to me that Mark Jackson identified the cause when he said "Is
this true when you consider the mass balance weight? The fact that the
stick doesn't need anyone holding it and the plane stays level, suggests to
me that there must be a force on the pin to counter balance the mass balance
weight. This would then make me think that any slight movement on the
tailplane (due to the air), would put quite a lot of force on the pin,
especially if flutter isn't induced."
Air loads shaking the tailplane against the inertia of the mass balance
weight would not be felt in the stick, the forces fighting against each
other on the TP4! Thus, rough engine starting, or anything else that shakes
the tail up and down quickly and especially rhythmically, would produce a
succession of high loads on the pins and be a very likely candidate for the
cause of our troubles in my view. And this scenario would provide a start to
calculating the forces that will have to be provided for.
Sincerely
JR (Bob) Gowing UK Kit 327 in Oz.
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