Vance Jaqua wrote:

I am very much in favor of rubber in contact with
composite structure in local high load points, BUT I
do not think this should be the primaray engine
cushioning. The resulting low cantilever frequency,
and relatively high deflection would probably grind
out the cowl in the spinner area. I think a very stiff
rubber interface at the f/wall plus the classic rubber
engine mount - for the rotary probably a bed mount.
The attached sketch describes the approach I would
have in mind at the f/wall. Firm rubber sheet - about
like die rubber - about 60 Schore and roughly 1/4 in
thick. At least 2 square inches with an over length
core so it will be expanded by the compressive load.
Heavy preload on the bolt (significantly greater than
twice the static load) , and castellated locking.
Cheaper and firmer than the Barry units. Vance

That is a valid point Vance I had not thought about. Why can't we
just open a larger hole in the spinner area of the cowl?

Paul Lamar
 
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