So far, the prop has been the least of my trouble.  At 7300rpm, my prop
turns 2560~ and Launie Prince, Prince Props, says I can go to

8800/3100rpm

before the tip breaks supersonic.  I climb out at 7000, at 120kts,
+1600 fpm rate.RV6A.  I had originally thought I would get 7500, but not
yet. At 7300 I get 164kts (190mph)at 3000 ft alt.  Temperatures start to
climb after 6500, however, 85F OAT. Perhaps, this fall, I can push the

upper

limit.

Jerry Bass      you can send this to Paul Lamar.

Ian & Irene Beadle wrote:
Full blast tests at 3500 feet in my 2.85 RV6A got 180MPH at 6400RPM (prop

2250), no increase in temperatures and very smooth. As I am not up to full
engine power yet, VNE in level flight is a distinct possibility. Before I
get the 72" X 81" prop. shaved I have a question for the Gurus. At full
throttle manifold pressure reads 7" Hg. Should I be seeing 0 Hg. ? I have a
short inlet manifold and an oil impregnated filter with NACA inlet. Jerry,
what is your manifold pressure at 190 MPH ?

Here comes the best part. Fuel consumption over three runs, all of which

were two hours or more and included several landings and high speed tests,
was around 27 litres an hour. 7.1 US gallons.

Cruise speed 130MPH Fuel air ratio 14.7.
Ian. Down under.
beadles@webace.com.au

I think what you mean is you are seeing 22 or 23 inches of Hg and what you

want to

see is 29 to 30 inches of Hg. 29 to 30 inches is atmospheric pressure or
15 psi absolute. A bit confusing. Is that they way they express MAP Down Under?

You are definitely losing a lot of MAP and power with that filter Ian.
Perhaps a bit with your induction air intake duct although I have not seen

a picture

of it yet :-)

Thanks for the data Ian.

Paul Lamar

OK, 7.1 gph x 6 lb/gal = 42.6 lb/hr;   assuming a BSFC of 0.55 lb/HP-hr, we
get 77.45 hp.  If we assume 0.45 (lower limit) we have 94.66 hp , if we assume
0.65 we get 65.5 hp.  Looks like you are cruising on about 75 hp, since I'd bet
your actual BSFC is about 0.57 lb/HP-hr.

Bill Freeman
Long EZ builder & pilot
BSME, MSME
EAA Technical Counselor

 
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