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Message
Yes, Dave, I did fly with Jim's prop on one
occasion several years ago. As best I recall, I was down a bit on the top
end rpm wise, Only pulling around 5800 rpm at WOT. The static on the other
hand was right at 5100 rpm (down 100 rpm) from my prop. It did seem to add
to my climb rate a bit. I would say you should get 5000 rpm static with
his prop and if you are not then some tuning is indicated. However, you
have a turbo which might cause the static to drop a bit (back pressure on the
exhaust flow) if you are not in a boost situation. But in any case, with that
size prop I think 5000-5200 is a target to shoot for. FWIW
Ed
Ed Anderson
RV-6A N494BW Rotary
Powered
Matthews, NC
----- Original Message -----
Sent: Sunday, May 09, 2004 12:00 PM
Subject: [FlyRotary] Re: What should you
expect was : first flight Tracy's old prop.
Speaking of comparisons, Ed, I am using the 68/74 prop that Jim
Mossur sold me. I know that you had it on your plane at one
time. Do you by chance recall what your static RPM was with my
prop? I am only getting 4600 at 30"MAP which I fear is going to lead me
to needing a fair amount of boost just to match n.a. performance. But
maybe those extra 2" of pitch are slowing it down on the ground and it will be
just right with some boost (yea right :-)
Dave
Leonard
Since Tracy and I had identical props by the same maker 68/72 and the
same model engine 90 Turbo II, both with high compression rotors, we were
about as identical as could get on engine/prop. Oh, yes, our intake
systems were very similar although not identical. We both would get a
nominal 5200 rpm static (on cold mornings due to the EDDIE effect my static
would go as high as 5600-5800 rpm). In my 120 mph (TAS) WOT
climbout I normally would get from 5600-5800 (depending on OAT). So if
you are not getting at least 5000 static, you have some tuning to
do.
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