Jay Honeck wrote:

Just one nit: Running at "redline" in a light aircraft isn't the same as in
your car. Aircraft engines turn very slowly, by comparison, and "red line"
is set conservatively low.

No, it's not set "conservatively" low. Because aircraft engines turn slowly, the
valve springs are much lighter than those used in auto engines. This allows the
manufacturers to also build the rest of the valve train much lighter. Because the
entire system is lighter, the valves will begin to float at a much lower rpm than is
typical for cars. Both aircraft and auto tachometer redlines are set low enough to
allow proper fucntioning and avoid damage to the valve train. There's about the same
amount of safety factor in both cases.

George Patterson
None of us is as dumb as all of us.