Return-Path: Received: from [65.54.169.142] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2904334 for flyrotary@lancaironline.net; Wed, 24 Dec 2003 16:57:51 -0500 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Wed, 24 Dec 2003 13:57:50 -0800 Received: from 67.24.244.200 by bay3-dav112.bay3.hotmail.com with DAV; Wed, 24 Dec 2003 21:57:50 +0000 X-Originating-IP: [67.24.244.200] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] Re: Streamline Vs Parabolic Ducts/Diffusers Date: Wed, 24 Dec 2003 16:57:50 -0500 MIME-Version: 1.0 X-Mailer: MSN Explorer 7.02.0011.2700 Content-Type: multipart/alternative; boundary="----=_NextPart_001_0004_01C3CA3F.1058A0A0" Message-ID: X-OriginalArrivalTime: 24 Dec 2003 21:57:50.0509 (UTC) FILETIME=[F9562DD0:01C3CA68] ------=_NextPart_001_0004_01C3CA3F.1058A0A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Reply #2.. =20 Ed, Are you sure the labels are not backwards on the two duct pressure= recovery charts? Tracy Labels are correct, however, I used two different Y scales for the dynam= ic pressure on the two charts. The dynamic pressure values are correct b= ut the unequal scales appear to give the parabolic curve the greater dyna= mic pressure recovery, when in reality it is the streamline duct. The Y axis on the right is for dynamic pressure. I just posted the two charts with their dynamic pressure scales equal and= I think it is clearer now. Ed Anderson Ahh! that explains it. The only thing missing (for me) is that I don't = have a mental picture of the streamline duct shape. In fact, I may have = it wrong for the parabolic as well. I picture the duct area for the par= abolic going up like the chart for the streamline shows it. I also thought a 7 degree duct was a simple straight sided duct with side= s that diverge at a 7 degree angle from the centerline. Maybe I'm more c= onfused than I though : -) BTW, this is great stuff Ed, keep it coming! Tracy ------=_NextPart_001_0004_01C3CA3F.1058A0A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Reply #2.. = ;

Ed, Are you sure the labels are not backwards = on the two duct pressure recovery charts?

Tr= acy

Labels are correct, how= ever, I used two different Y scales for the dynamic pressure on the two c= harts. The dynamic pressure values are correct but the unequal scal= es appear to give the parabolic curve the greater dynamic pressure recove= ry, when in reality it is the streamline duct.

The Y axis on the right is for dynamic pressure.

&n= bsp;

I just posted the two charts w= ith their dynamic pressure scales equal and I think it is clearer now.

Ed Anderson

Ahh! that explains it. The only= thing missing (for me) is that I don't have a mental picture of the stre= amline duct shape. In fact, I may have it wrong for the parabolic a= s well. I picture the duct area for the parabolic going up li= ke the chart for the streamline shows it.

I also thought a 7 de= gree duct was a simple straight sided duct with sides that diverge at a 7= degree angle from the centerline. Maybe I'm more confused than I t= hough : -)

BTW, this is great stuff Ed, keep it coming!
Tracy
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