Dear Paul.

Re ff.  statement.   Does it mean no dynofocal mount is necessary ?
What about helicopters ?

"Perry Mick's rotary is bolted solidly in his Long Ez airframe for
the last 16 years or so. No rubber bushings. One can hardly
feel the engine running.".

Best regards.
Benjamin.

The dynafocal mount was designed to deal with piston engines
vibration. The rotary just doesn't have certain piston
engine modes so the dynafocal is unneeded.

What it does have is a torsional mode. Not as severe as a four cylinder
but it is still there. So the rubber mounts are placed to deal
with that. Here are some graphs that illustrate that.

It is best to separate the mount as far apart laterally as possible.
That way they can be made softer. The best place to put
them is around the CG so Jeff's PSRU Adapter plate does
the job well.

This applies to helicopters as far as just the engine is concerned.
As I under stand it there are a lot of vibrations in a helicopter
that have nothing to do with the engine.

Paul Lamar