On Sun, 8 Mar 2009 09:54:53 -0700, "Stuart Fields"
wrote:
"Orval Fairbairn" wrote in message
news
In article ,
wrote:
In uk.rec.motorcycles Morgans wrote:
The anti-auto (or truck) engine crowd will never admit that one of
these
engines would work well, and be reliable in an airplane. I get so
tired of
the "they never run at full output in autos" way of thinking.
I still would rather get in an auto engine conversion airplane that has
had
the bugs worked out, than any airplane with a rotax engine of any size.
There is a fundamental problem, any auto engine is designed to deliver
purely rotational power from the crankshaft to the transmission.
In aero applications the prop is applying the entire power of the engine
trying to pull the crankshaft forward out of the block. That needs some
serious thrust bearings which auto engines simply do not have.
That is where PSRU design takes up the mission. A good PSRU will have
the thrust bearings, etc. required for the mission.
I have a friend who has adapted a V8 engine into his Long Eze. It is direct
drive with no PSRU. He has flown cross country from CA to Oshkosh several
times. As far as I can tell he has not had any engine problems. I believe
a cooling hose once. I also don't believe he did it for cost savings. @
10cents per hour for labor he probably has tens of thousands of dollars in
it. However he can get Vne at less than full throttle and doesn't worry
much about 100LL. He is also a good engineer with a darn good oily thumb.
Of course there are a bunch of Subaru powered aircraft out there with and
without PSRUs. All that said, it is still hard to beat the Lycoming in
every thing but acquisition costs.
Forget the aquisition cost - it's the maintenance/rebuild that kills
you. Certified parts are pricey. An average auto conversion can be
zero timed for the cost of doing one jug on a "real" aircraft engine.