IMM wrote:

Do a find on helicopter. US and Russian come up. The US heli is not a one
off, being a production model. Rotaries are popular with light aircraft for
obvious reasons.


Rotaries are not popular for light aircarft, because they are probably
not certified, the spares will be ahrd to come by, and the service
issues not widely known.

In light aoirfcarft what counts above everythinglese is total
reliability. Typically these engines are run at low RPM, and have
extremely stringent service requirements.

Wankel Roraries are an interesting oddity: No way are they mainstream,.
or popular.