Ron,
Other than fancy-dancy airpanes, consider these conditions for a single
NA engine aircraft equipped with a non-feathering
and non-electric constant speed prop controlled by engine oil pressure
boosted by a governor:
1 Engine loses power, oil system intact. Slowly rotating prop keeps
governed oil pressure high enough to allow it to remain in coarse pitch if
so selected. OK and a significant reduction in drag (for slick
airplanes). May be able to restart engine.
2. Engine loses oil while still generating power. After a short time
of operating without oil (pilot leaves power in to extend range), the
engine seizes and prop is stopped in flat pitch. OK, but less OK as drag
is significantly less that a windmilling prop but somewhat more than
a coarse pitched rotating prop.
3. Engine loses oil and power allowing the flat pitched prop to
windmill - just like a fixed pitch prop. Not OK. No where to go but
down rapidly....
But during failures, problems 1 or 2 are most likely with 3 a
rarity. Such a CS prop is a reasonable cost vs risk and
weight choice. Everything is a compromise.
Grayhawk
In a message dated 2/14/2013 4:38:21 P.M. Central Standard Time,
cfi@instructor.net writes:
It seems the
discussion on the full feathering prop and non full feathering prop vs drag
has kind of missed the whole point behind the full feathering prop. The
full feathering prop will go to full feather when you lose all oil pressure,
and the standard prop will go to minimum pitch (high drag) configuration with
the lose of oil pressure. The Prop governors work opposite and are not
interchangeable. The best of both worlds is the "counter weighted"
prop. This prop goes to full coarse pitch with the loss of oil pressure
and uses the same gov. at the full feathering prop. I have the 4 blade
MT Prop counter weighted and I know Brent Regan and Bob Pastusek have them as
well as others, but I'd bet most of the folks out there didn't even know they
existed.
I will be very interested to see how the full reversing prop
works that Ronald just ordered. I'm sure you can go full feather as well
as reverse and even if it takes a few seconds to get to reverse, in most cases
this would be enough time say in case there was ice on the runway. It's
always very handy to back up from time to time too. The weight of the
reversing prop will be quite a bit lighter than the full feather metal prop
though, so there might be some W&B issues in a
IVP.
Ron