"Ben Jackson" wrote in message
news:yLqec.18880$rg5.39150@attbi_s52...
A typical power chart for a constant speed prop will limit the RPM to
2400 at all altitudes and power settings. The 75% power table will
just end when it is no longer possible to make enough manifold pressure
to get 75% HP out of the engine at 2400 RPM.

I don't think that is by any means universal. The Mooney 201 POH has (IIRC)
settings for 2600 and 2700 (red line).

Is the answer that the constant speed prop is slowed down because we
*can* and the fixed pitch prop is just suffering all the ill effects
you'd expect, like higher wear, more noise and frictional losses?

It is, but you should still get more power with the CS prop at higher RPM.
It just won't necessarily deliver that power efficiently.

Julian Scarfe