Why does airspeed change when I adjust the prop?

Tony,

Ah, "oversquare" is obvious BS, we can agree on that (said the man coming
from the land of SI units, where the whole idea of oversquare goes away
when you use Pascal to measure MP ;-)).

I cannot think of a cirumstance
when following the commonly taught and used procedure of first reducing
throttle then rpm, or first advancing rpm then throttle, is not the
prudent technique.


Again, I mentioned two examples, one common, one maybe not so:

1. Take-off. Leave throttle at full and reduce RPM to 2500 is better for
the hardware in most cases than reducing to 25/2500.

2. Dogma. If you're reducing RPM by, say, 200 but leaving the MP at the
set value, it makes no sense to reduce MP, then reduce RPM, then increase
MP again. Yet some CFIs will insist you do it that way.

Here's a third: People flying the "full LOP regime" will often leave the
throttle at full for the whole flight, controlling engine power with RPM
and mixture alone. If you really know what you're doing, that's perfectly
safe and good on the equipment.

--
Thomas Borchert (EDDH)