In a static situation the tailplanes are counterbalanced by the
counterbalance weight, the moments for which are transmitted through the TP
pins.Any g loading increases these loads proportionately.Any shock loads
(counterbalance weight coming up against the upper stop) have a similar
magnifying affect.
Interesting thread this! No concrete solutions yet though.
Duncan McFadyean
On Wednesday, January 16, 2002 5:56 PM, Fred Fillinger
[SMTP:fillinger@ameritech.net] wrote:
> Bob Harrison wrote:
> >
> > Hi! Barry.
> > I also tried the ring of loctite on the outside (carefully because you
will
> > have a "bad hair day" if it gets in the main bush,) and only one side
> > ,however keep it/them checked because it could still come loose without
the
> > bulb, mine did ,been there done that...... also remember that the
phosphor
> > bronze bush is a very effecient heat conductor through to the Redux
holding
> > them in place.
> > So ever slowly the numbers of people that have this problem is
creeping up,
> > I was begining to think it applied to only a few!
> >
>
> Is it more than a few? The original inquiry, and my response, were
> from builders with zero hours yet, and at least mine are fine!
>
> I wonder, though, if both pins have been Loctited, how does one
> introduce heat through the torque tube on the first tailplane to be
> removed?
>
> Is there a consensus as to the cause of eventual looseness?
> Rotational force against the pin in cruise should be zero, without any
> pressure on the stick. Maybe some turbulent air and helical prop wash
> on the stabs, but is that enough to distort the steel to make the hole
> larger? Aerobatics then? Or is it in starting the engine, or turf
> bouncing on the monowheel, or engine runup in high winds from a
> certain direction on the tri-gear? I have peeked back at the latter
> effect on my AA-5, and it ain't pretty. Maybe just in how the holes
> were drilled? The manual method was not approved by the Director of
> Acceptable Methods in my one-man shop. I hand-enlarged them to a snug
> 1/4" with hobby tools, and I question the manual in stating it doesn't
> matter that they're drilled off- center.
>
> Regards,
> Fred F.
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