----- Original Message -----
Sent: Sunday, May 23, 2004 5:08 PM
Subject: [FlyRotary] Re: Beam Motor Mount
(semi-long)
Good points Bill and I fully agree that the Shertz Beam is infinitely
preferable to the 'Mount on the adapter plate' scheme.
The only point which truly affects safety is the point about stress on
the bolts. In the original configuration, the six bolts are all in a row
and going on 'gut feel' stress analysis, this will result in >=
90% of the force in tension being placed on a single 6mm bolt (the one
on the end). If this bolt fails, the rest of them would break in quick
succession. The geometry is such that the force will increase as the next bolt
in line will see an ever increasing load as the one outboard of it
fails.
The fix that you proposed (tying the beam to more bolts along the side of
the engine) should work well and this removes any concern I had
about its safety as long as the rear mount is properly handled. This is
much easier on composite structures than on 'beer can' designs.
Tracy Crook