Hi! Nigel.
Seems good to me( not that I'm purporting to be any authority, simply IMHO!)
as long as the bolt SHANK is to act as the shear in both fore and aft
locations or "double" as you say. If the length isn't sufficient the shear
at the nut end will be taken by the thread which will also be a smaller
diameter resulting in any movement initially being taken on one shank
diameter only should the friction not be enough. The clamping action of the
saddles will deplete as it gets further from the bolt.
Our clamp system, although not having any internal supports to the TP4 Tube
sides of the central assembly and will stiffen the central portion of the
TP4 Tube outboard both sides to encompass about 1/4" of the inboard end of
each TP12 Drive Plate Bush. Our clamps don't change the initial design
(except the slight shortening of the nylon bushes TP10's so unlikely to need
Modification Approval (watch this space!!!!)
Regards
Bob H G-PTAG
-----Original Message-----
From: owner-europa@post.aviators.net
Subject: Re: Tailplanes
Duncan,
I identified this problem some time back.
My solution was to insert into the torque tube, four anodised alloy discs
10mm thick, cross drilled and positioned to align with the torque tube cross
drills at TP's 9 and 12 and secured in position with Loctite. The purpose of
the discs is to prevent the torque tube distorting - the purpose of the
Loctite is to hold the discs in place during assembly - nothing more.
At each station, two alloy "saddle plates" , inside radius machined to match
TP12 & TP9 OD, are bolted in place using AN hardware (replacing the SS
pins).
This provides a positive clamping to prevent movement, drive is provided by
the double shear of the bolts.
Only thing to watch out is the tight clearance between the securing nut and
the bulkhead.
This arrangement can be dismantled and re-assembled at will - unlike your
Loctite solution.
Engineering approval would of course be needed.
Nigel
----- Original Message -----
................. I can't see any proven long term alternative to the
Loctite route and that wouldn't involve potentially protractedPFA approval.
Even then, the Loctite bond might be subject to progressive failure.
Duncan McFadyean
by Aviators Network UK - info@avnet.co.uk
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