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Why trim this on Stiffner?

LR60

Active Member
Why trim off the 15 degrees? This is spaced off spar so I don't get it?

(old tail kit)

kmscarb


Trinity-20120123-00012.jpg
 
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As you close the skin, the pivot point is at the trailing edge. If the stiffeners are going to be close to the spar, if not trimmed, the outside edge could contact and scratch the spar while closing.
 
ok got it. Just couldnt get my head wrapped around it.

I spaced mine 1/4 away from spar. The the text says to space 1/4 away from spar, the drawing drawing shows 1/8.

you know which was preferred?
 
Although probably not an issue in this case, tapering a stiffener is also sometimes required to spread the stresses along the length of the piece. If it is not tapered stress concentrates at the end of the stiffener whereas if tapered, the stiffener gets less and less stiff along the taper and so absorbs any stress along its length.
 
I suppose a real weight control fanatic would cut that angle farther back....then add lightening holes too. :p
 
ok got it. Just couldnt get my head wrapped around it.

I spaced mine 1/4 away from spar. The the text says to space 1/4 away from spar, the drawing drawing shows 1/8.

you know which was preferred?

The closer the better. In the older 4/6 kits with the thin .016" skins this is an area prone to cracks (the skin).
 
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