Return-Path: Received: from fed1rmmtao11.cox.net ([68.230.241.28] verified) by logan.com (CommuniGate Pro SMTP 4.2b2) with ESMTP id 3161943 for flyrotary@lancaironline.net; Sun, 11 Apr 2004 21:24:57 -0400 Received: from BigAl ([68.107.116.221]) by fed1rmmtao11.cox.net (InterMail vM.6.01.03.02 201-2131-111-104-20040324) with ESMTP id <20040412012457.BXUV15011.fed1rmmtao11.cox.net@BigAl> for ; Sun, 11 Apr 2004 21:24:57 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: EGTs Date: Sun, 11 Apr 2004 18:25:21 -0700 Message-ID: <003e01c4202d$05d57970$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_003F_01C41FF2.5976A170" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 Importance: Normal This is a multi-part message in MIME format. ------=_NextPart_000_003F_01C41FF2.5976A170 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable =20 I'm running along at normal mixture, and settle into a cruise = configuration. When I start to lean the mixture, EGT's go immediately up to 1800 plus degrees (about 10 inches from the port). This trips the alarm that = Tracy had pre-set in the EM-2, and I richened it back up. What should I shoot = for on leaning the rotary? Is there a rule of thumb such as X number of = degrees on the rich side of peak EGT? =20 =20 Thanks for any comments. =20 =20 Rusty; =20 One question is at what percent power are these temps. Clearly they are = on the high side. I found on dyno runs with my 20B, WOT max power = enrichment was somewhere around 100-150 degrees rich of peak in the 5000 -6500 RPM range; that being about 1600F. Peak was about 1700 - 1750. 5000 RPM, = 90% power EGTs at 1520. My TCs are about 2.5 inches from the port. =20 =20 Normally you'd want to lean to about 100 - 150 F lean of peak. I did a lean-of-peak run at 60% power with EGTs of 1500 and a BSFC of 0.49. Did = you ever get it over to lean of peak? =20 I'm running 9.0 : 1 rotors, so that keeps things a bit cooler. What are yours? Going to 9.7 shouldn't make that much difference. And I = wouldn't think that a bit of fractionating in the runners would more than 25 F difference in EGT. I would get quite nervous when running EGTs over = 1700. I'd be very nervous at 1800. Could it be unburned fuel burning out into = the pipe? Timing? Plugs? Are you producing lots of power? =20 Al ------=_NextPart_000_003F_01C41FF2.5976A170 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message

 

I'm running along at normal = mixture, and settle into a cruise configuration.  When I start to lean = the mixture, EGT's go immediately up to 1800 plus degrees (about 10 = inches from the port).  This trips the alarm that = Tracy had pre-set in the EM-2, = and I richened it back up.  What should I shoot for on leaning the rotary?  Is there a rule of thumb such as X number of degrees on = the rich side of peak EGT?  

 

Thanks for any = comments.  

 

Rusty;

 

One question is at what percent = power are these temps.  Clearly they are on the high side.  I found on = dyno runs with my 20B, WOT max power enrichment was somewhere around 100-150 = degrees rich of peak in the 5000 -6500 RPM range; that being about 1600F. =  Peak was about 1700 – 1750.  5000 RPM, 90% power EGTs at = 1520.  My TCs are about 2.5 inches from the port. 

 

Normally you’d want to lean = to about 100 – 150 F lean of peak.  I did a lean-of-peak run at = 60% power with EGTs of 1500 and a BSFC of 0.49.  Did you ever get it = over to lean of peak?

 

I’m running 9.0 : 1 rotors, = so that keeps things a bit cooler. What are yours?  Going to 9.7 = shouldn’t make that much difference.  And I wouldn’t think that a bit = of fractionating in the runners would more than 25 F difference in = EGT.  I would get quite nervous when running EGTs over 1700.  I’d be = very nervous at 1800.  Could it be unburned fuel burning out into the = pipe?  Timing?  Plugs?  Are you producing lots of = power?

 

Al

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