There is truth in all of these statements. Had the designers a free hand in
all areas the engines would look much the same as now. The outcome is a
result of all of the constraints and pressures applied over the years. They
have a concept that works, and they are making money in a closed loop. You
have to use their parts, so, there is no competition, (or very little). What
is alarming is the number of certified engines that don't make it to
overhaul. 

If you bought a new car and it had a spare engine in the trunk, you
would wonder about the reliability of the one up front (or in the rear where
God intended). New airplanes should come with a spare engine for the hanger,
in case you make it back from your engine failure. The types of failures are
alarming also because it is engineering ground that has been covered a
thousand times. Broken pistons. Did you know they use cast pistons?

Connecting rods the size of your wrist breaking? Any after market rod
manufacturer could make you a set so you could turn up 9,500 RPMs, and at
least the rods wouldn't break. Plus you could buy a set of them for less than
the price of two automobiles. Better yet, whittle them from 4340 or whatever.

Make your own. Lycomings beat out the center bearing web.
The get rust in the crank snout. Continentals drop counter weights off the
crank.

The weight is held on with two pins pressed through plastic bushings.
Lycomings wipe cams and lifters. they all snatch the bottom half of pistons
out, and Lycomings start it with a broken wrist pin. They make few of the
engines parts and farm out all of the common looking parts. Continentals
crack cases and break rockers. The list goes on as though a series of 16 year
olds were building their first small block Chevy. The difference is they sell
it to you for $20,000.00 and you put it in your plane. I don't regard putting
a car engine in an airplane, as taking a chance on anything, but rather,
improved reliability over the certified engine. Your supplier  used the wrong
metal in the crank on my new airplane engine and I have to pay take it out
and buy another one off of you (not at a reduced price or free if I used the
old one too long) and pay to have it put back together? No thank you. Trade a
manufacturer who has made thousands of engines for one that has made millions
of engines. I run on....... Lynn E Hanover

A wee bit of exaggeration here and there Lynn :-) Never the less aircraft engines
have a remarkable power to weight ratio given their duty cycle.

Those truck engines I just mentioned usually weigh three to four times as much
from 2000 to 2500 pounds with comparable HP ratings.

Paul Lamar

 
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