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Luff Lines

Posted: Mon Aug 16, 2010 3:46 pm
by gertcoetzee
Whilst fitting a safety cable I looked at the middle luff line attachment (if this is also called a luff line). On the picture below I get the impression that the loop (A) cut into the attachment (B). It could be that the spacer (C) in the loop creates this impression. It is difficult to see what is going on.

Is this normal? (Windlass Aquilla I wing)
What will happen if this centre luff line goes?

Re: Luff Lines

Posted: Tue Aug 17, 2010 8:12 pm
by kloot piloot
loop (A) cut into the attachment (B). It could be that the spacer (C) in the loop creates this impression.
Photo did not display A, B or C, but I got the gist.

Spacer C is a plastic/nylon innovation to keep the cable from twisting and kinking when not under tension. I.e. a handy "tool" when rigging and de-rigging.

Remove the safety cable and twist the upper rigging cable through 90 degrees to expose the front of the hole in the attachment to see whether it has cut or elongated the hole and judge your corrective actions accordingly. But to do this you will have to de-rigg partially. In order to slack the upper rigging your kingpost needs to come out.

It is not a normal wear and tear point though.

Upper rigging cables are not realy under tension in flight (unless when going negative G). However if it does come out in flight, the kingpost could get dislodged with a lot of "draadwerk" heading for the prop.

Re: Luff Lines

Posted: Tue Aug 17, 2010 9:37 pm
by Africa
remember you need an AP to do this or watch you and sign this off.. :twisted: :twisted:

Re: Luff Lines

Posted: Wed Aug 18, 2010 10:02 am
by skybound®
Hehhehe Jamie - the thread killer ;-)

The (c) spacer does have a slot in it - so don't mistake the slot for wear.

Re: Luff Lines

Posted: Wed Aug 18, 2010 6:28 pm
by Biggles
gertcoetzee wrote: What will happen if this centre luff line goes?
Interesting question. If you ignore the fact that if it does go you will get a lot of loose wires and the kingpost blowing around near the prop theoretically you will still be flying as it supports the wing when its negatively loaded (and on the ground). Of course when you land it will go pear shaped quickly. At that point you had better leave it too an AP. ##

Re: Luff Lines

Posted: Wed Aug 18, 2010 6:33 pm
by Biggles
And IIRC the luffline's (at the trailing edge) function is again only during pitching forward as they allow the trailing edge to flex up but not down.