Posted Sunday, November 23, 2008 @ 09:38 PM
Hi Tim,
I am glad you are progressing. I can't help feeling that if your Fournier was flying fine in the USA, it should fly fine in Australia, but I can also appreciate your inspector's caution.
I regret that I cannot precisely answer your question, but I can provide some supplementary information.
I replaced that forward bolt myself a few weeks back.
I used a proprietary Allen screw.
I read and printed out the correspondence on the 'Metric Hardware' thread, and took this to the fastener supplier.
They said that all their metric Allen screws exceeded the strength requirements mentioned on that thread.
However, when we came to selecting an Allen screw, the only one with a sufficiently long shank had a shank that was a little over-long, plus a very long thread. All I could do was to add washers so that the Allen screw's shank was positioned exactly correctly, so the bearing surfaces of the brackets bore on the shank, and then cut off much of the end of the thread.
Like yours, the friction of the stiff-nut in my nut-plate was not as high as I should have liked, so I used some Loctite on the Allen screw's threads to help it stay in place. I have no idea whether that is the right thing to do, and I have been inspecting that Allen screw carefully on every pre-flight since (perhaps eight aerobatic flights to +6/-3g -- the State competition is next Saturday). There is no sign of it coming undone, and of course it is in shear, rather than pulling out of the fitting, so I would not expect it to come undone.
Having read your post, I now realise that leaving the extra thread in place and adding an additional nut would have been a better idea.
Good luck with getting TKD flying ASAP.
You did tell me where it's based but I have forgotten.
Yours, Bob
[Edit by Bob Grimstead on Sunday, November 23, 2008 @ 09:41 PM]
