Return-Path: Sender: (Marvin Kaye) To: lml@lancaironline.net Date: Thu, 27 Nov 2003 18:20:53 -0500 Message-ID: X-Original-Return-Path: Received: from imo-r05.mx.aol.com ([152.163.225.101] verified) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2775299 for lml@lancaironline.net; Thu, 27 Nov 2003 17:07:51 -0500 Received: from Sky2high@aol.com by imo-r05.mx.aol.com (mail_out_v36_r1.1.) id q.e6.428cd107 (4410) for ; Thu, 27 Nov 2003 17:07:46 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Thu, 27 Nov 2003 17:07:46 EST Subject: Re: [LML] Re: Vortex generators X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1069970866" X-Mailer: Thailand for Windows sub 220 -------------------------------1069970866 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 11/27/2003 2:07:47 PM Central Standard Time, marv@lancaironline.net writes: A recent issue of Sportplane or Kitplane had an article on an Eracer. The builder placee vortex generators ahead of a NACA cooling inlet which increased the air flow. I have an application for my craft, and I'm trying to find out the construction dimensions and proper attachment angle. If anyone has that info, I would appreciate it. Ridge, Jack is in the hangar behind mine. Because of poor boundary layer characteristics, the vortex generators allowed for the reattachment of the air flow - thus making the NACA duct work a bit better. This is not the only answer as he has added peculiar high ridges to the ducts to force the air to tumble over and into the ducts. Again, this is done because of the early detachment of the air flow - we have no idea how much drag has been added. Also, remember that most of his cooling improvements come from the use of augmenter tubes - thus drawing in cooling air in -- note that the NACA provide very little "pressure" to the incoming air in his application. If you want to improve the air flow to your NACA ducts, you might want to examine the air flow with some oil streaks - this could very well indicate where to place "Vortex" generators to help. You might need to also learn how tall the generators have to be to engage actual flowing air. Generally 30 degrees to the airflow line will create appropriate vortices. Scott Krueger Sky2high@aol.com II-P N92EX IO320 Aurora, IL (KARR) -------------------------------1069970866 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 11/27/2003 2:07:47 PM Central Standard Time,=20 marv@lancaironline.net writes:
<= FONT=20 face=3DArial>A recent issue of Sportplane or Kitplane had an article on an= =20 Eracer.  The
builder placee vortex generators ahead of a NACA coo= ling=20 inlet which increased
the air flow.  I have an application for my= =20 craft, and I'm trying to find out
the construction dimensions and prop= er=20 attachment angle.  If anyone has that
info, I would appreciate=20 it.
 
 
Ridge,
 
Jack is in the hangar behind mine.  Because of poor boundary layer= =20 characteristics, the vortex generators allowed for the reattachment of the a= ir=20 flow - thus making the NACA duct work a bit better.  This is=20= not=20 the only answer as he has added peculiar high ridges to the ducts to force t= he=20 air to tumble over and into the ducts.  Again, this is done because of=20= the=20 early detachment of the air flow - we have no idea how much drag has been=20 added.  Also, remember that most of his cooling improvements come=20= from=20 the use of augmenter tubes - thus drawing in cooling air in -- note tha= t=20 the NACA provide very little "pressure" to the incoming air in his=20 application.  If you want to improve the air flow to your NACA ducts, y= ou=20 might want to examine the air flow with some oil streaks - this could very w= ell=20 indicate where to place "Vortex" generators to help.  You might need to= =20 also learn how tall the generators have to be to engage actual flowing=20 air.  Generally 30 degrees to the airflow line will create appropriate=20 vortices.
 
 
Scott=20 Krueger
Sky2high@aol.com
II-P N92EX IO320 Aurora, IL=20 (KARR)
-------------------------------1069970866--