David,
I consider all these excellent comments and I like your reasoning. It would
be nice to see what you could get with even a better fixed pitch prop match.
Something about fuel burn. I have mentioned this repeatedly in several of the
forums on Vansairforce.net too, and that is the higher the output the better the
rotary looks efficiency wise. Mistral's new numbers using their high-end EMS are
competitive, in fact just plain good when using lean of peak operation. This is
all part of using an engine that is an infant compared to the piston engine. We
are still learning a lot. Thanks for your participation, from all of us that
aren't ready yet.
Bill Jepson
In a message dated 4/7/2008 5:02:05 PM Pacific Standard Time,
wdleonard@gmail.com writes:
There is
not doubt that I would have been at least several knots faster with a C/S
prop. I could even pick up a couple knots average time with a little
less pitch in my current prop. A two-bladed prop would have improved
efficiency somewhat as well. But that would have been well offset by
increased fuel burn.
I have gotten several comments from the guys in
the local group commenting on how surprised they were were at how well the
rotary did in terms of fuel burn. I have to admit that I was rather
surprised as well. I think that the major objection to the rotary is
often the excess fuel consumption and not the thought that it can't make
enough power. So in that sense, I think I did more for the reputation by
being modest in both consumption and speed rather than going really fast and
burning a lot of fuel.
Most people also realize that I was also
disadvantaged by the fixed pitch and 3-bladed prop and are impressed that I
still essentially tied for second among the side-by-side aircraft.
The
other important reason for keeping a fixed pitch prop is clearly the
cost. Not just from my pocket book, but to make a statement as
well. If we are using alternative engines to save on the exorbitant
costs of certified engines, then it does not make much sense to spend
thousands on the prop.
My engine/prop package cost at least $15k less
than anyone else in the race and by using MOGAS my fuel costs were less than
anyone who was going for speed. That is what is cool!
Though, I
must admit, it would always be nice to be the "Fastest Mother F'er"
:-)
--
David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net