From: "Marvin Kaye" <marv@lancaironline.net>
Subject: Re: Fuel consumption data
To: flyrotary
Date: Sat, 31 May 2003 11:57:04 -0400
Message-ID: <web-2369710@logan.com>
In-Reply-To: <000001c3277f$de35bf20$6400a8c0@BigAl>
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Posted for "Al Gietzen" <alventures@email.msn.com>:

FUEL CONSUMPTION

The fuel consumption data was very limited because of a high degree of
scatter caused by poor flow meter performance.  The computer logged data for
this parameter was essentially unusable.  Some good data was measured by
doing timed runs, i.e.; set up a steady state engine operation and take
weight readings of a fuel supply container at one minute intervals for five
or more minutes.  The number of these runs was limited to 4 as these were
the last tests we were doing and ran out of time.  The results are as
follows:

RPM	Mixture	MAP ("Hg)  	Avg EGT (F)	HP	BSFC	mpg	
5,100 WOT	Max pow	26.6	1,570	220	0.52	12.5	
5,100	Leaned	23.8	1,556	155	0.49	16.9	
5,000	Max pow	24.8	1,544	200	0.54	12.9	
4,550	Max pow	21.8	1,488	150	0.55	15.6	

The max power mixture setting was approximate, and was typically with a
lambda of about 0.94, and maybe 100 - 150 degrees rich of peak EGT.  The
"leaned" run was done at about the same amount lean of peak.  The leaned run
may have no relevance in actual operation with a prop because rpm was held
as mixture was reduced by varying load while trying to maintain about 24"
MAP. Power dropped significantly, but estimated fuel economy is clearly
improved.

The BSFC values seem good; pretty much in line with expectations for a
rotary engine.  The miles/gal values were computed using the Velocity
factory values of airspeed as a reference and adjusting it by the cube root
of HP.