On Fri, 6 Mar 2009 13:11:32 -0600, "Maxwell" #$$9#@%%%.^^^ wrote:


"platypus" wrote in message
m...

The thing that everyone seems to forget when promoting automotive engines
for aircraft is that most piston aero engines have a very hard life.
Take-off and climb is full power or very nearly, then they throttle back
to cruise at 75% or thereabouts. The only roadgoing vehicles that
approach that sort of use are in motorsports, and how long do they last?


Not true at all.

I drove a 6500
series Chevy dump truck years ago, always pulling a Case 580C back hoe. It
was 100% power almost all the time, and always at lease 75% on the highway.

But that;s true of nearly all agricultural vehicles, which is why they
tend to use understressed, low-revving, low-tech motors. And just
because you can drive them on the road doesn't make the road-going
vehicles.