"Jim Logajan" wrote in message
.. .
Ron Wanttaja wrote:
On Tue, 26 Aug 2008 21:07:46 -0700 (PDT), "
wrote:

everyone says "ooh -- auto...dangerous" but no
one can explain exactly why.

1. Ignition systems with insufficient redundancy.
2. PSRU failures.
3. Difficulty in implementing efficient liquid cooling systems.

But doesn't the Rotax 912 have reduction gearing and liquid cooling? It is
getting put into an awful lot of aircraft models - particularly LSAs.

That's true, and the biggest annoyance (of which I am aware) is that they
have increased the recommended "idle" speed to increase the service life of
the PSRU--which is of the spur gear type. I don't know whether any of the
belt or chain type PSRU installations have a similar requirement.

As to cooling: there were a lot of liquid cooled aircraft engines in WWII,
but the the aircraft they in which they were installed looked a lot
different from their air cooled counterparts.

Peter