Mailing List flyrotary@lancaironline.net Message #40311
From: Al Gietzen <ALVentures@cox.net>
Subject: RE: [FlyRotary] Re: Fuel burn
Date: Mon, 12 Nov 2007 10:49:08 -0800
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>

Al,

 

What rpm do you normally see in cruise?  I'm curious as Tracy pointed out that the most economical rpm for the rotary engine is 5200.  When I dial my prop speed down to 1700 and lean the mixture, I see about 5100-5200 rpm and  11.2 - 11.5 gph, but this is only at about 3000 msl.  I would expect lower fuel burn at higher altitudes, but that will have to wait for later. 

 Mark

Sorry; meant to include that, the data I took was at about 5300 RPM.  I don’t have enough experience with it to say that is optimum, but it does seem that 5200-5300 is a good place for moderate cruise.

 

Also, I haven't calibrated my fuel burn either (not sure how to do that).

See instructions for the FFCAL parameter in Tracy’s EM2 writeup.  I think the default was set at 156. I’ve had to increase that quite a bit – I think mine is now at about 240; which just happens to be the ratio of 3:2 (rotors).  Over the last 20 gallons, the measured fuel and the EM2 fuel burn agree within a few percent.

 

Al


 

 

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