Acro Image

Aerobatics Server

ACRO E-mail Archive Thread: Wing Trailing Edge Damage (drag block tips)

[International Aerobatic Club] [Communications] [Aerobatics Images]

Disclaimer: These aerobatics pages are developed by individual IAC members and do not represent official IAC policy or opinion.

[Usage Statistics]


ACRO E-mail Archive Thread: Wing Trailing Edge Damage (drag block tips)



                


Thread: Wing Trailing Edge Damage (drag block tips)

Message: Wing Trailing Edge Damage (drag block tips)

Follow-Up To: ACRO Email list (for List Members only)

From: Mike Davis <davis at alsc.com>

Date: Mon, 28 Apr 1997 22:08:35 UTC


Message:

  
tension in the drag/anti-drag cause the washers to dish.
When they dish, the load concentrates at the hole, damaging the block.
Some blocks have cracked.  Also, in accidents, I've heard that
the blocks fail, not the wires or jam nuts.  washer and nuts all pull   
through.

I personally don't think 'dimpling' will add to structural integrity.  I   
just fixed all mine.
Most all washers were slightly dished.  I removed the wires, re-finished   
the
block faces and re-installed with new homemade washers....

If memory serves, the std AN3 washer is 0.06".  So I bought 0.09" or .1"   
steel sheet,
cut out in squares to match the block faces.  More bearing area, plus
more strength.  Don't forget zinc chromate on the steel plates.

re: capstrip shearing.  Most have good luck with Al edges.  My guess is   
the
little bend was not taken out at the capstrip and sheared the wood.
make sure you hammer out the Al flat where it goes over the rib.  Also
would check the ply doubler goes up at least that far.  Epoxy/micro fill
to prevent fabric bunching.

davis at alsc.com
S1E rebuild almost done
ps. PLEASE ALL INCLUDE YOUR EMAIL ADDRESSES FOR DIRECT REPLY!!!

 ----------
From:   at [SMTP: at  at mailhost]
Sent:  Monday, April 28, 1997 5:23 PM
To:  iac
Subject:  Re: Wing Trailing Edge Damage (fwd)


Herman,
In your message to Guido, you mentioned the drag wire blocks braking   
loose.
When this does happen, how is it fixed? I was told that the blocks and   
the
spar should be sanded and dimpled with a small nail to allow the glue to
penetrate resulting in more gluing area. Can you comment?

Rgds, Wayne


                


© Dr. Günther Eichhorn
Retired
Email Guenther Eichhorn