Differences between automotive & airplane engines

On Fri, 10 Feb 2006 13:34:18 +0100, Philippe Vessaire
wrote:

Chris Wells wrote:


How are "normal" airplane engines tuned to run at a lower rpm? What
changes would have to be made to an automotive engine to shift the
power band down accordingly?

the airplane enemy is weight.

Any engine may fit, the lighter is the better.

An automotive engine, with PSRU is always heavier than an airplane one.
An automotive engine burn the same amount of gas than an airplane one

Is automotive engines cheaper than a 2000h core of airplane engine? (with
the PSRU).

By
Not ALWAYS heavier, but usually. How much depends on a lot of
factors. An automotive engine without a psru can be very close. It can
also burn less fuel, under some circumstances.

An O200 and a Corvair weigh virtually the same (within 30 lbs), with
electrical systems, and provide virtually the same hp and thrust.

Cheaper? most definitely can be - and certainly is cheaper to overhaul
when the time comes. And the automotive engine MAY run longer between
major overhauls.
I can build a zero timed Corvair for not much more than the cost of
rebuilding one cyl on a Lycoming.