Mailing List flyrotary@lancaironline.net Message #63358
From: Steven W. Boese <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] F/A and EGT data
Date: Wed, 10 May 2017 05:04:36 +0000
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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Bobby,
I have noticed significant changes in EGT indications depending on how cooling air passes over the exhaust headers even with the thermocouples a few inches from the exhaust ports.  I'm not suggesting that this explains your observations, but it may be an additional variable.

Steve Boese

On May 9, 2017, at 8:13 AM, Bobby J. Hughes <flyrotary@lancaironline.net> wrote:

I recently purchased a two channel  portable wideband O2 system and installed bungs and plugs on each exhaust runner. I also have a downstream wideband that I have been using for several years. I was able to spend a very productive hour ground tuning and adjusting Mode 4 injector balance prior to my flight yesterday from Austin to Akron OH. I’m not sure what to make of the F/A EGT spread data I collect during yesterday’s flight.

 

During the ground tuning session I balanced rotor 1 to match rotor 2 using F/A ratios for takeoff condition. This produced very close EGT readings. However at my preferred cruise settings I’m seeing a large EGT spread. I would expect a consistent EGT ratio change when adjusting the mixture knob at a steady rpm / MP.  This appears not to be the case. What am I missing?

 

 

Bobby Hughes

 

 

 

<EGT and Fuel Air data.pdf>
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