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> I'm considering a feathering prop but
I've never used one. What happens
> at startup and low RPM's- is there a
control detent to prevent the prop
> from going feathered? -Bill
Wade
Bill, there's no detent in the
control. I am not an expert so I'm posting this so some
prop expert can correct me....
once you set the rpm below some threshold, I've
been told it's going to keep going toward full feathered. I've been
told this happens about 1900 rpm.
There is, however, a detent in the mechanism.
If the govenor setting is above some threshold, the prop is locked in a fine
position as the rpm falls through about 1200 rpm. Therefore you have
to be above that rpm when you command full feather or it won't.
The Hartzell I have, will not unfeather without
power. With a strong battery you can crank it for a long time
( > 20 seconds) to get enough oil pressure to change the pitch back to
fine. This was empiracally tested on one plane I know
of.
So as I see it, the situation relative to full
feathering props is:
pro: automatically goes to feather on engine
out
pro: (or con depending) hub is heavier than stock
so it moves your cg forward
pro: excellent gliding range from high
altitude
con: goes to feather on low oil pressure, even if
the engine is still making power
con: harder to restart in the air if it feathered
because of lo oil passure
con: the hartzell version I have is metal so that
is a rougher ride.
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