Correct me if I am wrong but with Butch's LAEV prop the motor uses juice
only when the position is changed right? I am interested in the new
AeroComposites' C/S prop. Pricey but light and extremely well made. They
only make electric drives for their military contracts unfortunately. I
would have to modify their hub to adapt a electric motor and worm drive
gear.
Doug in Japan
The big advantage to the metal CS prop is the high efficiency. I have
yet to see a composite prop equal it.
Paul Lamar
RE> You should look at the whirlwind props.
RE>
http://www.whirlwindpropellers.com/
RE> Marc Wiese
RE> Some of the guys racing tried them. Still not as good as metal.
RE> Hard to beat the big bucks that Hartzel and McCauley put into R & D.
RE> It would be best if some of the carbon fiber guys
RE> copied exactly the the metal prop plan form, airfoil and twist.
RE> Paul Lamar
What have you-all heard about the AeroComposite Props? See:
http://www.aerocomposites.com
They claim significant anecdotal improvements over standard metal
props across the board.
--
Best regards,
Steve Thomas
mailto:steve@stevet.net
SteveT.Net
805-569-0336 office & fax
# RV-8 takes second place in Sun 'N Fun Air Race (IO-360, 220 hp, Sam James Cowl, 220
mph speed) with a 2-bladed constant speed AeroComposites propeller!
# Lancair IVP takes first place in Air Venture Oshkosh race. Kitty Hawk to Dayton
with max TAS of 360 mph @ 22,000 ft.. Average ground speed was 298 mph (flying west,
includes the time for climb to altitude).
First time I have heard decent race results.
I will have to take a closer look at one when I get to Sun & Fun this year.
Tracy Crook went 217 MPH with a fixed pitch wood prop in the Sun 100
in his RV4. Of course an RV8 is bigger. Tracy Saylor has gone 238 MPH
in the Sun 100 with a metal constant speed prop in his O-360 powered RV6.
When the checkered flag drops the BS stops:)
I am not that impressed yet. :)
Paul Lamar
To Paul,
- Paul i'm an agricultural engineer, we deal with centrifugal type pumps and positive
displacement pumps every day. Before making a selection on a specific pump for a
specific duty, we compare different pumps and manufacturers for the most effeceint
pump for that duty.
The manufacturer will publish his duty curve of that specific impeller with its
efficiency.
The question i ask is why do aircraft propeller manufacturers not publish similar
figures for there products? They seem to keep these figures extremely secret.
Surely having access to these numbers would make choosing a propeller and making
comparisons a lot easier between different manufacturers.
Regards Craig SA
It is a matter of proving your claims. That is why the big prop
makers are so involved with Reno air racing. If I were a manufacturer
I would hesitate to make any claims for my prop because someone
else could easily claim higher performance and no way to prove
or disprove the claims. As I said with racing "When the checkered
flag drops the BS stops". On the other hand it is unfortunate
because racing is very expensive so it is hard for the little guy
to make a big impression.
Paul Lamar
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