Spit IIa is now so much more inferior to the 109

[Crumpp]

I don't know why Crumpp came up with "climb rating for cruising" as no would call it "cruising" when you apply "climb rating".

Exactly...think about it.

You have it right here:

Everything setting above that shortens the engine life at a higher rate. Everything below that setting will lengthen the engine life.

It is not a matter of just shortening engine life, it is a matter of reliablity.

It would be more accurate to say:

Everything setting above that is an overload condition which can cause the engine to fail. Everything below that setting is the stress conditions the motor was built to withstand continuously.