"Richard Lamb" wrote in message
ink.net...
RapidRonnie wrote:

Bottom line is that if you use an auto engine made in the millions you
can research the failure rate, particularly if you pick an engine used
in motorsports run to destruction you can see where they fail first. I
would pay a premium, a big premium, to be able to fly a small block
Chevy in terms of a bigger airframe than you otherwise would, just for
that huge knowledge base.


Gently disagree, Ron.

The reason is that the prop loads are far different from anything you'll
see on the race track.

Apples and oranges again...

Richard

Perhaps, but it is entirely possible to use a Geschwender chain drive or one
of several belt drives that have all been around for 30 years themselves.
Their job is to match the prop to the crank. The loads on the crank can be
reduced to nothing but torque, and the torsional vibration issues dealt
with. The engineering has been done, and it works.

The NorthWest Aero belt drive http://www.northwest-aero.com/ as an example,
was derived (I think) from the Blanton PSRU that has been around since the
1960's. Many Ford 3.8 and GM 4.3l V6's and 350 V8's have been run many
thousands of hours. Improvements have been made over the years (better
belts, different bearings, easier adjustments.

If there has been a failure of a properly maintained one in the last few
years, I'd love to hear about it.

Failures of auto conversions tend to be stupid stuff anyway. This guy
http://www.epi-eng.com/Prop-SudnStop.htm somehow left one of those blue
paper towels inside his cowling. It got sucked through the turbocharger,
shredded, and completely clogged the air filter. Bad...but not the fault of
the fact that it was an auto engine.