Nigel
Thanks for your input. Your diagnosis certainly sounds feasible and I shall
definitely investigate further. In the mean time, for anyone who hasn't yet
assembled the control column fork to the aileron torque tube, it may be
advisable to bond them together with the tube set up vertically not
horizontally. The flange of the bush should then be carefully checked for
squareness with the tube before the adhesive fully cures.
This method hasn't been tried at the factory but whichever method is used
the important point is to check for squareness.
The Redux takes quite a while to fully harden so it'd be wise to recheck
after several hours to see if anything has moved since the first check.
Regards
Andy
At 01:33 PM 1/14/98 GMT, you wrote:
>The problem of stiff roll controls may not have anything to do with the
tufnol
>bearings at all. In my case the apparent stiffness of these bearings was the
>symptom, not the cause.
> For any of you that have bench assembled the yolk, torque tube and free
>spinning tufnol bearings, only to discover an alarming reluctance to rotate
>once the assembly is bonded into the cockpit module, read on..........
> The torque tube is assembled to the yolk using Redux. As explained in the
>manual, a large clearance in purposely left to allow the Redux to self centre
>the torque tube, aligning it concentrically and axially. Nice
theory....but in
>practice this dosen't always happen. In my case (despite careful setting up)
>the tube bonded in at an angle. The result of this is that the far end
will try
>to describe an arc, rather than rotating about it's axis. Bonding the aft
>tufnol bearing in place will hold the end of the tube where the build
>instructions say it SHOULD go....and not where it wants to go!
> The result is a control the may well run freely in some positions, but
>progressively stiffens as it is rotated.
> If this is the case then no amount of lubrication or abrading will do any
>good. The only solution will be to dismantle the system and rebuild it
>correctly.
>The worst thing you can do is to leave it, since the torque tube will
>continually flex until it eventually fatigue fractures, or exert so much
>lateral force on the tufnol bearing that the latter grinds it's way
through the
>tube.....with the same catastrophic results.
> IMHO the design of the tube/yolk is should be changed. Simply by reducing
the
>clearance between these components to a smooth sliding fit, High strength
>Loctite could be used instead if the bulkier Redux. This would force the tube
>to locate concentrically and axially, and the problem would disappear.
> If you see this Andy, I would appreciate your feedback. From a manufacturing
>point of view it would cost no more to produce and from a builders point of
>view, it would eliminate the possibility of a fatal error.
> Nigel (147)
>
>
|