Message-Id: <5.1.1.5.2.20040405082551.011a6c50@localhost>
Date: Mon, 05 Apr 2004 08:32:54 -0500
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
From: Mark Steitle <msteitle@mail.utexas.edu>
Subject: Re: [FlyRotary] fun  with EGT's
In-Reply-To: <list-3145988@logan.com>
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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.


At 10:10 PM 4/4/2004 -0600, you wrote:
>Hi All,
>
>I've been fighting with a problem getting my EGT's to staying more or less 
>equal but I'm running out of ideas of what might be wrong.
>At idle to about 4600 RPM the EGT's are +/- 20 deg. and go from 1100 to 
>1500 deg.  after that as power is increased rotor 1 will go up to 1820 or 
>more and rotor 2 will max in the mid 1600's (my max static is about 
>5300rpm).  I've tried re-calibrated injectors in all four spots with no 
>change.  I can disable either pair of injectors and run all the way to max 
>static rpm of around 4300 with just one pair enabled and the temps stay in 
>sync so I'm fairly sure the injector flow is reasonably well 
>matched.  I've tried several times in flight to use EC2 modes 4 & 5 to 
>balance the temps and I can get them fairly close  in my cruise settings 
>of 4800-5600 rpm but the engine will then run real rough at lower throttle 
>settings.   One thing I'm wondering about is with my exhaust system the 
>length of the header pipes is about 3" longer on one pipe than the other, 
>is it possible that one rotor  is coming into it's tuned band and causing 
>it to go leaner and hence a 150 deg temp diff?  The tuned exhaust theory 
>almost holds water except it's the rotor with the shorter pipe (rotor 1) 
>that is running hotter and I would be expecting it to be the other pipe 
>that would get to it's tuned length first.  Any one else seen this sort of 
>thing?
>
>
>Perry Casson
>Glastar/13B  - 13 hours
>http://eaa154.dhs.org/perry
>
>
>
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