Hello Paul.
This is a mount for a Jabiru 3300 6 cyl engine. What do you think of the
top two engine rubber points?
A company (also called Powersport but not the rotary powersport) is
starting to market them for a Rans S6
Peter

A very common MM design error. The designer assumed the upper
two mounts were rigidly connected to a rigidly mounted engine.
That is not the case as rubber bushings are located at all four
engine mount points. In that case the tail (engine) is
wagging the dog (motor mount). That means the engine end of
two upper links are being moved around as prop torque (about 300
to 400 foot pounds) is attempting to twist the engine. As the
engine twist it moves those two upper links laterally causing bending
loads at their base where they are rigidly connected to the
firewall. The engine twist slightly due to the fact the two lower
mount points on the engine are rubber. The same thing happens when
a lot of G's are pulled or when a hard landing is made. In that case
the engine pitches down pulling forward on the upper two links.

If those upper mount firewall connections and the engine connections
were replaced by four rubber ball joints everything would be fine.
Four rubber bushings would also work. Two on the firewall and
two on the engine. Then the upper links would be in pure tension
or compression.

Paul Lamar ...No rotor no motor.

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