: In any case, there are exactly two things "wrong" with aircraft engines. The
: spark timing is fixed and the mixture control is in the hands of the pilot.
: And you can't do anything about the first problem until you fix the second.

The first is a compromise, but generally works really well for aircraft
engines... they *do* run at a constant RPM all the time. The second isn't that big of
a deal if the pilot is properly trained to use the mixture knob. Trouble is most
aren't because of the great degree of OWT and misinformation out there on the subject.

I would argue that the #1 biggest problem with aircraft engines is that they
are still air-cooled. Removing the tremendous thermal stresses of having 450 degree
CHT's make most of the "routine" aircraft engine problems go away. Stuck valves,
cracked exhaust flanges and cylinder heads, ridiculous octane requirements (100 for
8.5:1?) due to the heat and low RPM, galled cylinders/pistons due to overheating,
shock-cooling, and cold-starts, etc.

Liquid cooling stabilizes everything, lets more power be made more efficiently
with greater reliability. It doesn't even have to add too much weight.

-Cory

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* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
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