On Fri, 6 Mar 2009 18:32:24 -0600, "Maxwell" #$$9#@%%%.^^^ wrote:


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


"platypus" wrote in message
. com...

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.

The 2bbl 350 wasn't even a 4 bolt block. Only "select" 4 barrel
engines were 4 bolt.
The small block 400 also was USUALLY not 4 bolt.
396 and 454 were common RV (and truck) engines, along with the 402.
In heavier trucks you were more likely to get "real truck" engines
like the 366 etc.

Chrysler put a LOT of 413 and 440 engines in medium duty trucks (like
dump trucks etc) over the years - and used the same engines in New
Yorkers and Imperials, as well as road runners etc (440).

Ford did the same with the 460. Standard engine in big Lincolns,
optional in pickups and LTDs, and very common in 3-10 ton trucks as
well.