X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from ispmxmta05-srv.alltel.net ([166.102.165.166] verified) by logan.com (CommuniGate Pro SMTP 5.0.8) with ESMTP id 1033056 for flyrotary@lancaironline.net; Mon, 13 Mar 2006 19:42:58 -0500 Received-SPF: pass receiver=logan.com; client-ip=166.102.165.166; envelope-from=montyr2157@alltel.net Received: from Thorstwin ([166.102.185.184]) by ispmxmta05-srv.alltel.net with SMTP id <20060314004210.IYSG18974.ispmxmta05-srv.alltel.net@Thorstwin> for ; Mon, 13 Mar 2006 18:42:10 -0600 Message-ID: <000501c64700$2549e650$01fea8c0@Thorstwin> From: "M Roberts" To: Subject: Cooling Dyke Delta Date: Mon, 13 Mar 2006 18:42:17 -0600 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0002_01C646CD.DA8950B0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0002_01C646CD.DA8950B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Ernest, FWIW If I were you I would go with the pitot inlet in the leading edge of the = wing. The place you have the flush inlet is not really a high pressure = area. The air is being accelerated there and the pressure is actually = lower than ambient. You do not have a laminar flow situation so don't = worry about a little external diffusion.=20 I would also move your exit to just aft of the thickest point on the top = of the airfoil. And you need to have a nice smooth exit ramp that merges = the air back in with the flow. Not at 90 degrees. If you get too far aft = of the thickest point you will actually be in a pressure recovery area = and that is not good. The lowest pressure happens at the thickest point = on the top where the velocity is the highest. Just aft of that is an aft = facing area with low pressure-DRAG. Dump the exit air there and you kill = the drag and get good pressure differential. I would also keep the internal ducting length to a minimum so that you = minimize internal flow losses.=20 Isn't it nice how all of this probably conflicts with structural members = and other considerations! Welcome to compromise. I have no Idea on sizing without really digging into the power = requirements of your airframe and I am way too busy to do a thorough = analysis right now. Copy Tracy's inlet sizing or make it bigger = proportional to the power difference and speeds. Probably closer than a = bunch of number crunching anyway. Just taking an break for an afternoon. It rained a lot last week and I = have to wait for it to dry out so I can get back to work on the shop. = Which of course provides the perfect opportunity to do TAXES.....YUCK.=20 Of course I am using every excuse in the book to do something else.=20 Monty ------=_NextPart_000_0002_01C646CD.DA8950B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Ernest,
 
FWIW
 
If I were you I would go with the pitot = inlet in=20 the leading edge of the wing. The place you have the flush inlet is not = really a=20 high pressure area. The air is being accelerated there and the pressure = is=20 actually lower than ambient. You do not have a laminar flow situation so = don't=20 worry about a little external diffusion.
 
I would also move your exit to just aft = of the=20 thickest point on the top of the airfoil. And you need to have a nice = smooth=20 exit ramp that merges the air back in with the flow. Not at 90 degrees. = If you=20 get too far aft of the thickest point you will actually be in a pressure = recovery area and that is not good. The lowest pressure happens at the = thickest=20 point on the top where the velocity is the highest. Just aft of that is = an aft=20 facing area with low pressure-DRAG. Dump the exit air there and you kill = the=20 drag and get good pressure differential.
 
I would also keep the internal ducting = length to a=20 minimum so that you minimize internal flow losses.
 
Isn't it nice how all of this probably = conflicts=20 with structural members and other considerations!
 
Welcome to compromise.
 
I have no Idea on sizing without really = digging=20 into the power requirements of your airframe and I am way too busy to do = a=20 thorough analysis right now. Copy Tracy's inlet sizing or make it bigger = proportional to the power difference and speeds. Probably closer than a = bunch of=20 number crunching anyway.
 
Just taking an break for an afternoon. = It rained a=20 lot last week and I have to wait for it to dry out so I can get back to = work on=20 the shop. Which of course provides the perfect opportunity to do = TAXES.....YUCK.=20
 
Of course I am using every excuse in = the book to do=20 something else.
 
Monty
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