Return-Path: Received: from relay01.roc.ny.frontiernet.net ([66.133.131.34] verified) by logan.com (CommuniGate Pro SMTP 4.1.3) with ESMTP id 2576141 for flyrotary@lancaironline.net; Thu, 11 Sep 2003 12:54:47 -0400 Received: (qmail 2415 invoked from network); 11 Sep 2003 16:54:46 -0000 Received: from unknown (HELO frontiernet.net) ([65.73.33.245]) (envelope-sender ) by relay01.roc.ny.frontiernet.net (FrontierMTA 2.3.6) with SMTP for ; 11 Sep 2003 16:54:46 -0000 Message-ID: <3F609B32.F019A91A@frontiernet.net> Date: Thu, 11 Sep 2003 11:56:34 -0400 From: Jim Sower X-Mailer: Mozilla 4.77 [en] (Win98; U) X-Accept-Language: en MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Intake temps References: Content-Type: multipart/alternative; boundary="------------4EBA0FB42A82F98304AD1AC1" --------------4EBA0FB42A82F98304AD1AC1 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit <... pressure drop, and temp change will be on the engine side of the throttle body ...> True. But that's at idle, on the ground. In the air, at or near WOT, the temp drop across the throttle body would be much less. <... Where are you guys putting your air temp sensors ...> I'm not even remotely there yet, but I would feed my EFI the temperature in the intake runners since that's what the engine sees. I would put TIT and compressor outlet temps on the panel if I had enough parameters and display space. -- Jim Sower Crossville, TN; Chapter 5 Long-EZ N83RT, Velocity N4095T Russell Duffy wrote: > Idle at 2000 rpm can generate around 15" of manifold vacuum > and that converts to 45 deg F temperature drop. That is > waaaaaaay more than the dew point spread in most places. A > lot of the heat (and therefore temp drop) gets absorbed by the > warm environment, but not all. It is the same phenomenon that > causes carb ice. Just a theory .... Jim S. I've seen the same > condensation on my intake when running at low power on the > ground. Now that you mention it, I realize that my air temp > sensor is not in the best location. I have it in the > pressurized air box on the outside of the throttle body. As I > understand it, the pressure drop, and temp change will be on > the engine side of the throttle body. Since this can change > the temp quite a bit, I bet that's why I have such a > difference between the A and B controller (B doesn't use the > air temp sensor) at low power on the ground. Where are you > guys putting your air temp sensors? Cheers,Rusty (new oil > cooler arriving today) > > --------------4EBA0FB42A82F98304AD1AC1 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit <... pressure drop, and temp change will be on the engine side of the throttle body ...>
True. But that's at idle, on the ground. In the air, at or near WOT, the temp drop across the throttle body would be much less.

<... Where are you guys putting your air temp sensors ...>
I'm not even remotely there yet, but I would feed my EFI the temperature in the intake runners since that's what the engine sees. I would put TIT and compressor outlet temps on the panel if I had enough parameters and display space.
--
Jim Sower
Crossville, TN; Chapter 5
Long-EZ N83RT, Velocity N4095T

Russell Duffy wrote:

Idle at 2000 rpm can generate around 15" of manifold vacuum and that converts to 45 deg F temperature drop. That is waaaaaaay more than the dew point spread in most places. A lot of the heat (and therefore temp drop) gets absorbed by the warm environment, but not all. It is the same phenomenon that causes carb ice. Just a theory ..... Jim S. I've seen the same condensation on my intake when running at low power on the ground. Now that you mention it, I realize that my air temp sensor is not in the best location. I have it in the pressurized air box on the outside of the throttle body. As I understand it, the pressure drop, and temp change will be on the engine side of the throttle body. Since this can change the temp quite a bit, I bet that's why I have such a difference between the A and B controller (B doesn't use the air temp sensor) at low power on the ground. Where are you guys putting your air temp sensors? Cheers,Rusty (new oil cooler arriving today)

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