>
>During my preflight check I discovered that I had some play on the left
>outside aileron hinge.
I posted a letter about 3 months ago about the use of a teflon tubing around
a reduced diameter stainless steel replacement hinge pin. I didnt get one
expression of interest, even though it is a commonplace fix for hinge wear
on Longeze and Vari-eze a/c in the States! The practice is so widespread on
these aircraft that it is incorporated in one of the Rutan building
publications, and all builders seem to abide by it. Since everyone already
knew about this mod, or wasn't interested I didn't bother talking about it
anymore. Might I summise that most of the people on this list are beyond
this stage and would prefer not to know! There is however a large, or I hope
large, group of would be/will be builders, and if they are like me they will
be happily archiving the info for that appropriate day in the future. It
does beg the question as to why Ivan didn't include this build method when I
feel confident it would have been known about since he built one of Burts
Birds. My source of my information has flown hundreds of hours on the same
hinge pin without servicing/lubrication etc. He is supplying me with the
text from the applicable Rutan manual, as well as the tube supplier in the
US and the best type of replacement hinge pin to use. I'm getting his left
overs very kindly at a proportionate cost to what it cost him 12 years ago (
bit of a win!). I think this topic is quite an issue as our hinges are not
readily removeable.
Whilst I discuss hinges I would like to expound on my theory of the poor
safetying method of bending pins. Firstly, they don't bend easily as some of
you already know. Secondly, I guarantee that the last lug you would have
been applying lateral pressure on, to bend the hinge pin, is distorted. Now
I am not a metallurgist but I guarantee that the molecules of aluminium have
not been stretched, but torn. I'll bet London to a Brick there are small
tears or should I use the more shocking term "cracks" now in this lugs, not
fatigue induced but incurred by us. What my Engineer friend did on his
Vari-eze I would like to offer as an alternativefor Europa to comment on
and for us to discuss. I probably need to validate his credentials so that
others value his judgement. He was the one of the youngest flight engineers
in Qantas after holding every engine/airframe/electrical ticket he could at
the time. The company retrained him as a pilot and he now sits in the RHS of
our 767s, and will soon be doing his Command Training. Not a bad building
mentor don't you think! He entrapped the hinge pin within the hinge and
secured it from working out with 2 small split pins through the outboard
lugs. This is the teflon encased hinge pin remember! Obviously the hinge
becomes nominally longer, and if anyone is going to use this method Europa
will need to verify that the additional length of reinforcing plies in the
applicable flanges doesnt transfer loads to the wrong places. I doubt this
is going to be a problem. I would also like to know if the reinforcing plies
must extend beyond the lateral edges of the hinges, especially if they are
longer than originally planned and therefore have a bigger bearing area to
transfer their "twisting off" forces ( what is that called again??). I
suspect that they might have to.
So if anyone is interested in more goss about hinges drop me a line directly.
Could I also please ask that someone in Technical at Europa address the
technical questions above at your earliest convenience.
Reg
Tony Renshaw
>The play is in the vertical plane and I discovered it by pushing the
>aileron upwards at a point close to the hinge. I can then move the aileron
>at the tip end up and down for almost 1,0 mm !!
>I have the feeling that due to vibration the aileron hinge pin has somewhat
>enlarged the hinge hole - my guess would be that the hinge has enlarged
>holes of 0.5 mm. There is almost no play on the hinges at the root.
>On the right aileron hinge there is also some play at the wing tip hinge,
>but I would say only half as much as on the left side.
>
>I do have now 75,5 total houres flown with 123 landings. About half of it
>flown alone.
>
>Could it be that during taxying and on each landing, the aileron hinge has
>to support some up and downwards forces and/or vibrations especialy on its
>tip ? (high weight of aieron with balance weight!)
>
>Does any one had similar experiences ?
>
>In any case I will take the ailerons off the wings and will try to get the
>hinges out for inspection next week...I hope this can be done without too
>much destruction of the aileron... (one side of the hinge is riveted and
>epoxied in....)
>
>Any suggestions are welcomed.
>
>
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