"Anthony W" wrote in message
news:Bldqj.4239$f73.3718@trndny08...
Bill Daniels wrote:

Well, I'm not going to build a Hyabusa flat 8 but if I were, I'd be
thinking about a planetary gear PSRU. Planetarys have a lot of gear
tooth engagement and are happy with high RPM sun gears. A fairly small
planetary can get 4:1 reduction which would reduce 9000RPM to a very
usable 2250.

The propeller thrust bearings would be on the ring gear - the engine
crankshaft would see only torque loads. This little screamer would
produce about 280HP in stock trim from an engine about the size of an
O-200.

Bill D

I think we would be back to the same problem, the engine can't dissipate
that much heat. Motorcycles don't run at peak output any more than car
engines do and the sustainable power level would be considerably lower.
Not that a Suzuki V8 wouldn't be fun, I don't think it has what it takes
to be a good aircraft engine.

The more I think about it, the less I think any auto engine conversion is
going to do the job well. I'm looking for an old but rebuildable airplane
engine that I can rebuild rather than spend all my money on an engine I
can't trust. I don't mind it not having the certificate and I don't think
that's all that important on an home built anyway.

Tony

These are liquid cooled engines so with a large enough radiator, you could
keep it cool. I think motorcycles do run at higher percentage power than
automobiles - they have a far worse Cd.

Bill Daniels