Return-Path: Received: from [65.54.169.61] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2904131 for flyrotary@lancaironline.net; Wed, 24 Dec 2003 13:23:30 -0500 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Wed, 24 Dec 2003 10:23:30 -0800 Received: from 67.24.244.200 by bay3-dav31.bay3.hotmail.com with DAV; Wed, 24 Dec 2003 18:23:29 +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] Streamline Vs Parabolic Ducts/Diffusers Date: Wed, 24 Dec 2003 13:23:28 -0500 MIME-Version: 1.0 X-Mailer: MSN Explorer 7.02.0011.2700 Content-Type: multipart/alternative; boundary="----=_NextPart_001_0002_01C3CA21.1E4DC2D0" Message-ID: X-OriginalArrivalTime: 24 Dec 2003 18:23:30.0153 (UTC) FILETIME=[07F79590:01C3CA4B] ------=_NextPart_001_0002_01C3CA21.1E4DC2D0 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 ----- Original Message ----- From: Ed Anderson Sent: Wednesday, December 24, 2003 12:39 PM To: Rotary motors in aircraft Subject: [FlyRotary] Streamline Vs Parabolic Ducts/Diffusers For those of you interested in such stuff. Attached is a gif of how different ducts affect the conversion of kinetic energy in the airflow t= o dynamic pressure. It appears that the streamline duct's unique curve controls th= e growth in diffuser area such that the non-linear growth in area (blue cur= ve) causes the dynamic pressure recovery to follow a linear curve (yellow li= ne) and that is the key to the more effective pressure recovery of dynamic pressure . The parabolic duct curve on the other hand results in an apparent linear growth in diffuser area which apparently forces the press= ure recovery to under go a non-linear development which possibly accounts for more loss. Not certain I understand exactly why, but it appears to h= ave to do with the difference in changing velocity of the air molecules near = the duct wall, boundary layers, separation and wall friction between the two type diffusers. Any aerodynamic types out there with a different interpretation? Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_001_0002_01C3CA21.1E4DC2D0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Reply #2..&nbs= p;

Ed, Are you sur= e the labels are not backwards on the two duct pressure recovery charts?<= /DIV>

Tracy

----- Original Message -----
=
Fro= m: Ed Anderson

Sent: Wed= nesday, December 24, 2003 12:39 PM

= To: Rotary motors in aircraft