X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao102.cox.net ([68.230.241.44] verified) by logan.com (CommuniGate Pro SMTP 5.2c1) with ESMTP id 2468014 for flyrotary@lancaironline.net; Mon, 12 Nov 2007 13:49:31 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.44; envelope-from=alventures@cox.net Received: from fed1rmimpo03.cox.net ([70.169.32.75]) by fed1rmmtao102.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20071112184852.MFQA18714.fed1rmmtao102.cox.net@fed1rmimpo03.cox.net> for ; Mon, 12 Nov 2007 13:48:52 -0500 Received: from BigAl ([72.192.143.193]) by fed1rmimpo03.cox.net with bizsmtp id Buos1Y0034AaN600000000; Mon, 12 Nov 2007 13:48:52 -0500 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Fuel burn Date: Mon, 12 Nov 2007 10:49:08 -0800 Message-ID: <001001c8255c$b5492db0$6401a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0011_01C82519.A725EDB0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 This is a multi-part message in MIME format. ------=_NextPart_000_0011_01C82519.A725EDB0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Al, =20 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. =20 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. =20 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. =20 Al =20 =20 ------=_NextPart_000_0011_01C82519.A725EDB0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

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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