"G.R. Patterson III" wrote in message
...


Russell Kent wrote:

It may be slower, but it doesn't "ring true" to me that the cause is
higher
cooling drag. Diesel engines are more efficient than gasoline engines
because they extract more of the chemical energy as useful work, and
less
chemical energy is converted to waste heat. With less waste heat, their
cooling drag should be *less* than a gasoline engine's.

Well, they don't. They have a higher compression ratio, and that produces
heat. The
SMA diesel is air-cooled, it produces more waste heat than an IO-540, and
there's
more cooling drag than with an IO-540.

Aren't they also heavier, i.e., pound of engine weight per HP generated?