....What' the diff. between the "Hanno" RF, and the
regular RF in my post #6 ?

I might have kept my hat out of the ring on this
one ....APC's are a horse of a different
color, for sure. Their thrust seems to come more
from the hub...to about 2/3 out towards the tips.
From that point on....the tips taper almost to a
point, as well as the pitch diminishing to almost
nothing at the tips.

When I talk about props, I generalize....and refer
to "regular" props. The engines see the the APC"s
as smaller props, and will allow more RPM, or allow
more pitch, that wouldn't work with a "regular" prop.

Example : see props below, both 12/8's....say you
were running an O.S., or a T.T. motor with the APC,
( .61's ) and life is good....it's pulling about 12,000
just like is should....plane flies just fine.
Now put the the 12-8 wood prop on.
PRESTO !!! You just turned it into a 10,000 RPM
DOG....

Dave.