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Al,
I didn't answer your other question. What I suspect is happening is the prop isn't biting until I'm well down the runway. I may want to try a higher rpm (finer pitch) prop setting for takeoff and see how it behaves.
Mark
On Feb 10, 2008 9:14 PM, Greg Ward < gregw@onestopdesign.biz> wrote:
Yeah, I would be interested in this one too, as I am
looking at prop options too.
Greg
(Lancair, on the ground, in the new shop, mating with a
20B as of this weekend....(:-)
----- Original Message -----
Sent: Sunday, February 10, 2008 4:06
PM
Subject: [FlyRotary] Re: Fuel burn
Hi Mark,
Isn't 7000/2.85=2456.14 ??
Is the M/T
optimized (diameter, pitch, twist) for turning only
2150rpm?
Charlie
Mark Steitle wrote:
Al,
Yes, I'm
running one of Tracy's 2.85:1.00 boxes.
Mark
On Feb 10, 2008 12:20 PM, Al Gietzen < ALVentures@cox.net> wrote:
Subject:
[FlyRotary] Re: Fuel burn
Thanks, good data Al. I'm sure that some of the
differences we're seeing are due to altitude. So far, I've stayed
fairly low (3000-5000'). I may try some higher altitude flight soon
just to see how it changes my performance numbers. Another
difference is that I have a M/T electric constant speed prop. I
normally set it to 2150rpm for takeoff. This allows the engine to
turn around 7000 rpm, which will account some for the higher fuel burn I'm
seeing. My airport is at 520' msl, so there's a 1000' difference
there from your 1500' msl airport. Yes, she really accelerates down
the runway. I'm usually airborne in about 900-1000'.
Mark
I'm not sure I
see how these correlate "set it to 2150rpm for
takeoff. This allows the engine to turn around 7000 rpm,";
but the big difference is that
you're putting out more horses than I am. At 7000 you're likely
looking at about 300 hp, so 25-26 gph would be expected. Are you
running a 2.85 ratio redrive; or something
else?
Al
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