Mailing List flyrotary@lancaironline.net Message #66755
From: Finn Lassen finn.lassen@verizon.net <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: EGT probes location
Date: Wed, 28 Apr 2021 20:43:41 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Thanks Neil, Steve, Matt and Charlie.

I did try to get tip of probes centered in the openings, but now I remember that a very slight difference made a significant difference in readings during initial engine runs.

So I think I'll ignore it for now (and set the alarm higher). Then later on I can try to adjust the front/rear rotor fuel ratio. Perhaps watching fuel flow vs RPM will be a better way to optimize this?

Definitely a disadvantage to using the stock exhaust manifold. The ideal setup would probably be separate (outer) runners, perhaps with an O2 sensor in each runner.

Finn

On 4/28/2021 7:21 PM, Matt Boiteau mattboiteau@gmail.com wrote:
Cyl 1 will be hotter since it gets the coolant the last. I can be anywhere from 50-100f difference sometimes.

I think too, with our high temperatures, the accuracy of the probes probably have a good amount of +/- in there.

- Matt Boiteau


On Wed, Apr 28, 2021 at 7:15 PM Stephen Izett stephen.izett@gmail.com <flyrotary@lancaironline.net> wrote:
Hi Finn

Yes.
An example of our EGT’s at WOT take off - Lambda ~0.9 / AFR 13.3
1598 & 1679 - So 81 higher.
I’m not sure our EGT probes are inserted exactly the same distance into the header.
Not sure the variation in temp this might cause.
One of our probes is burnt out now.

Cheers

Steve Izett


> On 29 Apr 2021, at 5:30 am, Finn Lassen finn.lassen@verizon.net <flyrotary@lancaironline.net> wrote:
>
> So, I'm using the Renesis stock exhaust manifold.
>
> Tried to mount the EGT probes as close as possible and same distance from the ports.
>
> However, at high power I'm seeing as much as 120F higher on rotor 2.
>
> Exhaust gas from rotor 1 passes by rotor 2 exhaust port so I'm wondering if that somehow increases rotor 2 EGT readings.
>
> Caught my attention today when EGT2 got above 1,800F at 6,200 RPM and 161 mph TAS @ 3,300' density altitude.
>
> Any of you that's using the stock exhaust manifold run into this?
>
> Finn
>
>
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