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


"platypus" wrote in message
om...

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.


These were not ag vehicles. Passenger car engines were popular back then in
all the class C motor homes, school buses, and light weight dump trucks. My
Chevy was a 350-2v with probably nothing more than the heavy duty 4 bolt
main block. It also had a 4 speed manual transmission, and 2 speed rear. I
would commonly shift the low gears as high a 4000-5000 rpm. The gross weight
on the entire package was around 30,000 lbs.