On Thu, 28 Jul 2005 16:08:46 -0400, "Gordon Arnaut"
wrote:

Still, compared to a piston engine, the rotary is a pussy cat when it comes
to torsional issues, because it does not have the lever-arm effect of the
crankshaft throws to worry about -- which creates the bulk of the torsional
flex in a piston engine.

This may not be accurate Gordon. There was a company based up in
Washington State that produced a planetary gear box as a PSRU for the
Mazda rotory and they had a HORRENDOUS developmental period with many,
repeat many broken boxes.

They finally got something that was extremely professional looking as
machined aluminum can be, and robust and long lived. They had it on
the front of an RX4 and flew it to various air shows. One of the
developmental partners was killed in an airplane crash and for a while
the psru was still available but I don't know if it still is.

The big issue, the one that was busting props and tearing their boxes
apart was torsional vibration. I remember reading that they claimed
there was something about the rotory engine that gave it a really
powerful torque spike.

I think they eventually solved the problem with some kind of cushion
drive. But for a while it was busting one attempt after another on
the test stand, and a bunch of dead stick landings.

Corky Scott