Graham,
Taper pins only cause distortion of the tube if they are over-tightened,
Apparently Europa decided that the risk of builders over-tightening
taper pins was greater than the inconvenience of having to replace the
torque tube periodically. Having spent the whole summer trying to do
that (be aware that Europa have changed the diameter of the torque tube
at various stages of the kit development and that they don't carry
spares of the older tubes), I have a different opinion. Let me quote
---From my engineering text "/Plain and threaded taper pins (AN385 and
AN386) are used in joints which carry shear loads and where absence of
play is essential".
/ The problem with parallel pins is that, even if they start off "as
tight as a camel's a**e in a sandstorm!" (as mine originally did), it
only takes a knock or a shock (eg letting the counter weight thump down
on the stop when removing the tailplanes, over enthusiastic full and
free movement of controls check or struggling with mod 70) to introduce
some play, and your torque tube is toast! Play begets play!
As Rowland Carson says, a number of builders have already made this
change and I think there should be an approved PFA mod for it , as
judging by the number of replies I have had to my query it's
something that affects a lot of builders
Graeme
Graham Singleton wrote:
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>>Graeme,
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>>I am going to have to replace the pins in my torque tube before long.
>>The factory will supply oversize pins and Bob Harrison has an approved
>>mod which clamps the TP12 and TP9 to the tube. I haven't come across
>>any taper pins as an alternative but, if this is an option I would be
>>grateful if you would let me have any info you find out.
>>
>>Richard Iddon G-RIXS
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>You can't use taper pins, they will distort the tube and that will cause
>friction in the bearings.
>Only alternative I can think of is expandinhg pins. You will have to make
>your own. I made a set from the soft 1/4"stainless the factory use, taper
>hole in the ends and taper bushes to expand the tube by tightening AN3
>bolts.Worked beautifully. Don't think PFA have approved this soloution but
>I did write to Francis years ago.
>Graham
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