Maintaining washout.pdf

nience of the barbecue spit and the luxury of precise dial in of the twist. Some simple brackets were welded together which support a 2.5" aluminum tube I had ...
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MAINTAINING WASHOUT By PAUL J. YARNALL

My submission to the Snap-on's Hints For Homebuilders column is a solution for covering wings while maintaining the recommended washout.

Some simple brackets were welded together which support a 2.5" aluminum tube I had laying around. Water pipe or EMT would work just as well. At one end the pipe is bolted through the bracket. At the other the pipe passes through the bracket and is free to rotate in it. An arm is fastened to that end and a turnbuckle installed back to the bracket holding

The problem was that our wing

the wing. Tightening up the turn-

structure came out pretty stiff in torsion with the continuous D cell leading edge in our extended Tri-

buckle tries to torque the long pipe which, in turn, reacts against the

wing. The wing has very high lateral stiffness due to the internal drag wires and struts and will only twist. The resulting offset of the pipe bracket centers is small but is handled by the loose fit of the pipe in its brackets and the ability of the pipe to take a slight "s" bend if necessary. Everyone who has seen this set up is

wing structure causing it to twist. A

pretty impressed.

EAA 116895 2440 Brickyard Rd. Canandaigua, NY 14425

pacer wings.

Holding the wing

twisted during covering so that the

finished covering would not wrinkle when installed on the plane was the challenge. Usually the wing is strapped down to horses and a block of the appropriate height inserted under the outboard trailing edge. I

decided this would be quite awkward, especially when it was time to

flip the wing. I wanted to use the "rotisserie" stands I made because it

would greatly facilitate rib stitching and painting. The photos show my solution which allowed the convenience of the barbecue spit and the luxury of precise dial in of the twist.

74 JUNE 1992

straight edge across the wing bottom surface and a level or precision angle finder is used to measure the relative twist between the root and tip of the