Return-Path: Received: from wb2-a.mail.utexas.edu ([128.83.126.136] verified) by logan.com (CommuniGate Pro SMTP 4.2b2) with ESMTP-TLS id 3184955 for flyrotary@lancaironline.net; Thu, 22 Apr 2004 14:50:14 -0400 Received: (qmail 65824 invoked from network); 22 Apr 2004 18:50:12 -0000 Received: from dhcp-191-101.per.utexas.edu (HELO benefits3.mail.utexas.edu) (146.6.191.101) by wb2.mail.utexas.edu with RC4-SHA encrypted SMTP; 22 Apr 2004 18:50:12 -0000 Message-Id: <5.1.1.5.2.20040422134756.029e75d0@localhost> X-Sender: msteitle@mail.utexas.edu@localhost X-Mailer: QUALCOMM Windows Eudora Version 5.1.1 Date: Thu, 22 Apr 2004 13:49:33 -0500 To: "Rotary motors in aircraft" From: Mark Steitle Subject: Re: [FlyRotary] Re: intake ideas? In-Reply-To: Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="=====================_76916640==.ALT" --=====================_76916640==.ALT Content-Type: text/plain; charset="iso-8859-1"; format=flowed Content-Transfer-Encoding: quoted-printable At 11:52 AM 4/21/2004 -0400, you wrote: > > >One more comment on intake manifolds & race results. Do not ignore the=20 >benefits of a really clean air inlet with ram air recovery BEFORE the=20 >manifold. At 1125 ft msl, 220 IAS, I saw manifold pressures around=20 >31.8" Hg. Ignore this factor and you throw away about 6% "free"= horsepower. > > >Al, I forgot to comment on your last note about your MAP tap in=20 >manifold. I think it is highly possible you were seeing errors induced by= =20 >air stream eddies or some other unpredictable factors caused by that=20 >location. It is a challenge to get MAP measurements when you have no=20 >real plenum, only runners with high velocity air. >Tracy > > >I use the stock ports in the TWM throttle body. I assumed they would know= =20 >where to place the port to get a good measurement. >Where do you measure MAP on your system? I can=E2=80=99t believe that you= could=20 >see that kind of pressure at the engine end of a long intake tube. But I= =20 >remember once before when I was wrongJ. >Al >I measure it at the dynamic/plenum chamber, just under the throttle body. >Tracy >Hum-m-m. That=E2=80=99s about equivalent to me measuring it in the air= plenum=20 >before the TB. It would be very interesting to know what it is on yours=20 >about 4=E2=80=9D from the intake port. Then there is the whole question of= =20 >=E2=80=98which=E2=80=99 MAP pressure the EC-2 should be interpreting =96 or= maybe it=20 >doesn=E2=80=99t matter. . . >Al > > >Before the TB? I don't follow you. Ideally, that would be true at WOT=20 >only, but it would be a fairly useless figure. And it would definitely=20 >matter to the EC2 if you tried to measure MAP there (i.e., Would Not Work= ). > > >At one time I did measure the MAP at the far end of the small (primary)=20 >runners and found a .8" Hg drop at WOT compared to dynamic chamber=20 >reading. I expected this drop. For reasons of not wanting to enter a=20 >prolonged and fruitless discussion on rotary engine manifold design, I=20 >will not explain why this drop is desirable : ) > > >But my main point was that you can get about 2" of MAP increase from ram=20 >air recovery (at ~200 mph), REGARDLESS OF WHERE you measure it. > > >Tracy Tracy, So, where's the correct location for the MAP port? Mark S.=20 --=====================_76916640==.ALT Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable At 11:52 AM 4/21/2004 -0400, you wrote:

One more comment on intake manifolds & race results.   Do not ignore the benefits of a really clean air inlet with ram air recovery BEFORE the manifold.   At 1125 ft msl, 220 IAS, I saw manifold pressures around 31.8" Hg. Ignore this factor and you throw away about 6% "free" horsepower.

Al, I forgot to comment on your last note about your MAP tap in manifold. I think it is highly possible you were seeing errors induced by air stream eddies or some other unpredictable factors caused by that location.   It is a challenge to get MAP measurements when you have no real plenum, only runners with high velocity air.
Tracy

I use the stock ports in the TWM throttle body. I assumed they would know where to place the port to get a good measurement.
Where do you measure MAP on your system? I can=E2=80=99t believe t= hat you could see that kind of pressure at the engine end of a long intake tube. But I remember once before when I was wrongJ.
Al
I measure it at the dynamic/plenum chamber, just under the throttle body.
Tracy
Hum-m-m.   That=E2=80=99s about equivalent to me measuring it = in the air plenum before the TB. It would be very interesting to know what it is on yours about 4=E2=80=9D from the intake port. Then there = is the whole question of =E2=80=98which=E2=80=99 MAP pressure the EC-2 should b= e interpreting =96 or maybe it doesn=E2=80=99t matter. . .=20
Al

Before the TB?   I don't follow you. Ideally, that would be true at WOT only, but it would be a fairly useless figure. And it would definitely matter to the EC2 if you tried to measure MAP there (i.e., Would Not Work ).

At one time I did measure the MAP at the far end of the small (primary) runners and found a .8" Hg drop at WOT compared to dynamic chamber reading. I expected this drop. For reasons of not wanting to enter a prolonged and fruitless discussion on rotary engine manifold design, I will not explain why this drop is desirable : )

But my main point was that you can get about 2" of MAP increase from ram air recovery (at ~200 mph), REGARDLESS OF WHERE you measure it.

Tracy

Tracy,
So, where's the correct location for the MAP port?

Mark S. --=====================_76916640==.ALT--