Actually its double single-shear, with the shear being in the same
tangential direction rather than opposed.
Your solution relies on friction generated (from the tension in the bolt)
over only the small area under the saddle washer. It would reduce the edge
loading on the TP tubes. Given the size of the washer and tension in the
bolt, it would be easy to calculate the % contribution. I suspect not very
great in relation to the bearing strength of the pin/tube interface.
Duncan McFadyean
On Thursday, January 17, 2002 9:17 AM, nigel_graham
[SMTP:nigel_graham@intercept.com] wrote:
> 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
>
|