Message-ID: <39353506.CE5E66F0@regandesigns.com>
Date: Wed, 31 May 2000 10:51:34 -0500
From: Brent Regan <brent@regandesigns.com>
To: Lancair List <lancair.list@olsusa.com>
Subject: Re: Wing installation, IV-P
Mime-Version: 1.0

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A quick calculation shows that at 10 Gs at max gross each bolt bears about
36,000 pounds in single shear. This is the worst case loading. The loading
case is interesting (read complex) as the there is a leverage induced load
between the wings and a direct load from the fuselage. The bolt diameter is
0.745" for an area of .44 square inches. The theoretical maximum shear force
on the bolt is therefore about 90 KSI. The shear strength of an AN bolt is
76 KSI. Don't panic however, the load calculations assume a rigid system at
the attach points and no friction between the spars and carrier. In the
actual application the loads would be likely 50% to 70% of the theoretical
maximum.

On my plane I machined threads at each end of a 0.75" diameter 6AL4V
Titanium bar (125 KSI shear strength) for -10 J Nuts after cutting the bar
to the right length. The resulting pins weighed over a pound less than the
steel parts with 64% more strength. Machining Titanium is no walk in the
park but if you can work 316 stainless then Ti is only a little tougher;)

Mind the ounces and the pounds will take care of themselves.

Regards
Brent Regan

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