X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao06.cox.net ([68.230.241.33] verified) by logan.com (CommuniGate Pro SMTP 5.0) with ESMTP id 813331 for flyrotary@lancaironline.net; Thu, 03 Nov 2005 10:29:31 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.33; envelope-from=ALVentures@cox.net Received: from BigAl ([68.7.14.39]) by fed1rmmtao06.cox.net (InterMail vM.6.01.05.02 201-2131-123-102-20050715) with ESMTP id <20051103152748.TABU24014.fed1rmmtao06.cox.net@BigAl> for ; Thu, 3 Nov 2005 10:27:48 -0500 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Another Run - with Questions Date: Thu, 3 Nov 2005 07:28:42 -0800 Message-ID: <000001c5e08b$46119300$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C5E048.37EE5300" 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 V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C5E048.37EE5300 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable 1. EGT's are 2000-2050F. Seems a tad high to me!! My EGT probes = are located about 2.5" from the rotor housing. When I shut it down my = exhaust manifold/muffler was a very nice glowing red. It's made out of Inconel = and is .06 thick so it seems to hold up pretty well. But if it's like this = at 1600RPM what's it going to be at 5800RPM?? =20 As others have noted; something definitely amiss with the EGTs. My EGT probe placement is the same as yours. I looked for recorded data points = at idle conditions in my data, but since this is not an area of interest = could only find a couple, and conditions probably different than yours. No = load at 1600 showed EGT of 950-1000. With a prop I'd guess something more in = the 1100-1200F range as normal. =20 On my 20B from Atkins the timing marks on the pulley were not correct; probably because of a change to a 12A front cover with different pointer position. With some effort, we learned that the timing was about 23 = degrees too late. Looking back at the data it seems that caused an increase in = the EGT by maybe 200-300 degrees. So I'm going to guess that even a serious timing error would not explain your results. =20 The deep red glow would suggest something too high; maybe 1500-1700F or = so; 2000 would be getting quite bright. Of course how it appeared depends = on how light it was in your shop. =20 Also guessing; the mixture so far off as to cause that high a temp would result in rough running of the engine. It suggests you need to look at mixture (you have O2 sensor?), timing, and EGT calibration. Call Dave = and get his input on trouble shooting. =20 MAP reading seems low. Probably 11-12" Hg would be more typical. =20 FWIW, =20 Al ------=_NextPart_000_0001_01C5E048.37EE5300 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

1.      EGT’s are 2000-2050F.  Seems a tad = high to me!!  My EGT probes are located about 2.5” from the rotor housing.  When I shut it down my exhaust manifold/muffler was a = very nice glowing red.  It’s made out of Inconel and is .06 thick so it = seems to hold up pretty well.  But if it’s like this at 1600RPM what’s it going to be at 5800RPM??

 

As others have noted; something definitely amiss with the EGTs.  My EGT probe placement is the same = as yours.  I looked for recorded data points at idle conditions in my = data, but since this is not an area of interest could only find a couple, and conditions probably different than yours.  No load at 1600 showed = EGT of 950-1000.  With a prop I’d guess something more in the = 1100-1200F range as normal.

 

On my 20B from Atkins the timing = marks on the pulley were not correct; probably because of a change to a 12A = front cover with different pointer position.  With some effort, we = learned that the timing was about 23 degrees too late.  Looking back at the data = it seems that caused an increase in the EGT by maybe 200-300 degrees.  = So I’m going to guess that even a serious timing error would not explain your = results.

 

The deep red glow would suggest something too high; maybe 1500-1700F or so; 2000 would be getting quite = bright.  Of course how it appeared depends on how light it was in your = shop.

 

Also guessing; the mixture so far = off as to cause that high a temp would result in rough running of the engine. =  It suggests you need to look at mixture (you have O2 sensor?), timing, and = EGT calibration.  Call Dave and get his input on trouble = shooting.

 

MAP reading seems low.  = Probably 11-12” Hg would be more typical.

 

FWIW,

 

Al

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