Paul Mather at M-Squared Aircraft was the first to use the AIXRO rotary
on an ultralite. Here is a video.

http://www.youtube.com/watch?v=iMGYx-P4iEY

I spoke with Paul about his gear box. The original Rotax unit shown in
the video apparently had no rubber coupling and it sheared the input shaft.
To be expected with a one rotor driving a huge flywheel like prop.
He then installed a cog belt and it sheared the teeth
on the over run. I don't know how wide the cog belt was.
I mentioned a one way clutch and a rubber
coupling but he felt the belt drive was a better idea and
would result in a lower over all weight. I agree with him.

The good news is he did not give up and ordered a multi V belt.
This is going to work as it will slip when it sees the
big torque pulse. He did not have time to install it for Sun N Fun
but it should be tested by OSH. IMHO this is the hot tip for a one rotor.
The only way to go for a one rotor aircraft engine.

Here are  some pictures of a multi V belt used on some VW engines.
I saw this in Steve Bennet's Great Plains booth.
http://www.greatplainsas.com/
It is made by Gene & Larry Smith Valley Engineering 573 364 6311
http://www.culverprops.com/index.php


BTW You won't find anybody more knowledgeable on aircraft engines than Steve.
His forums in the S-n-F engine work shop tent are the best anywhere.

Paul Lamar