Return-Path: Received: from fed1rmmtao06.cox.net ([68.230.241.33] verified) by logan.com (CommuniGate Pro SMTP 4.2b1) with ESMTP id 3146812 for flyrotary@lancaironline.net; Mon, 05 Apr 2004 11:29:19 -0400 Received: from BigAl ([68.107.116.221]) by fed1rmmtao06.cox.net (InterMail vM.6.01.03.01 201-2131-111-101-20040311) with ESMTP id <20040405152915.VJRE25766.fed1rmmtao06.cox.net@BigAl> for ; Mon, 5 Apr 2004 11:29:15 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: fun with EGT's Date: Mon, 5 Apr 2004 08:29:24 -0700 Message-ID: <001501c41b22$c6372fc0$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0016_01C41AE8.19D857C0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 In-Reply-To: Importance: Normal This is a multi-part message in MIME format. ------=_NextPart_000_0016_01C41AE8.19D857C0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Subject: [FlyRotary] Re: fun with EGT's =20 Perry, I'm experiencing the same thing on my 3-rotor, the center rotor runs=20 cooler than the other two. (Keep in mind that this is w/o a prop, so = most=20 of this is meaningless per Tracy's EM-2 calibration instructions.) I've = tried changing Mode 5 rich and lean to no avail. Last weekend, I = switched=20 EGT sensors around, hoping that it was a sensor problem. Not! Then I=20 swapped injectors around, which didn't help. I'm thinking that it might = be=20 a result of my intake plenum design. I have decided to wait until I = have a=20 prop installed to do any further trouble-shooting. =20 Mark S. =20 One thing to be careful of in balancing the EGTs is to know which side = of peak you are. You may have two rotors giving the same EGT at some condition, but one is lean of peak and the other rich of peak. I had = this on my 20B on the dyno. I don't remember now exactly how it went, but I think rotor 2 was higher at max power mixture than rotor 3. I was = puzzled why, as I leaned out, rotors #1 and #3 would swap - #1 would go down, #3 would go up. Until I realized they were on different sides of peak. =20 And intake plenum is also a factor. The spread would vary with RPM; and although they remained within 75 F spread, the #1 rotor would depart = from the other two as rpm increased - which correlated with the plenum being least restrictive for #1. More air flow, same amount of fuel, leaner mixture. =20 I guess best bet is to set for the minimum spread at cruise condition = (all on same side of peak). =20 Al ------=_NextPart_000_0016_01C41AE8.19D857C0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Subject: [FlyRotary] Re: fun with EGT's

 

Perry,

I'm experiencing the same thing on my 3-rotor,  the center rotor runs =

cooler than the other two.  (Keep in mind that this is w/o a prop, so most =

of this is meaningless per Tracy's EM-2 calibration instructions.)  I've

tried changing Mode 5 rich and lean to no avail.  Last weekend, I = switched

EGT sensors around, hoping that it was a sensor problem. Not! Then I =

swapped injectors around, which didn't help.  I'm thinking that it might be =

a result of my intake plenum design.  I have decided to wait until I = have a

prop installed to do any further trouble-shooting.

 

Mark S.

 

One thing to be careful of in balancing the EGTs is = to know which side of peak you are.  You may have two rotors giving = the same EGT at some condition, but one is lean of peak and the other rich of = peak.  I had this on my 20B on the dyno.  I don’t remember now exactly = how it went, but I think rotor 2 was higher at max power mixture than rotor = 3.  I was puzzled why, as I leaned out, rotors #1 and #3 would swap - #1 would = go down, #3 would go up.  Until I realized they were on different = sides of peak.

 <= /font>

And intake = plenum is also a factor.  The spread would vary with RPM; and although they = remained within 75 F spread, the #1 rotor would depart from the other two as rpm increased – which correlated with the plenum being least = restrictive for #1.  More air flow, same amount of fuel, leaner mixture.

 <= /font>

I guess best = bet is to set for the minimum spread at cruise condition (all on same side of = peak).

 <= /font>

Al

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