X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 2 [X] Return-Path: Received: from ms-smtp-05.southeast.rr.com ([24.25.9.104] verified) by logan.com (CommuniGate Pro SMTP 5.1.8) with ESMTP id 2027894 for flyrotary@lancaironline.net; Sat, 05 May 2007 20:27:03 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.104; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-103-061.carolina.res.rr.com [24.74.103.61]) by ms-smtp-05.southeast.rr.com (8.13.6/8.13.6) with SMTP id l460Q1Hj009818 for ; Sat, 5 May 2007 20:26:01 -0400 (EDT) Message-ID: <000701c78f75$50b60440$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Ed's Pinched Ducts Date: Sat, 5 May 2007 20:27:22 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0004_01C78F53.C949C120" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3028 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0004_01C78F53.C949C120 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi TJ First, yes there are general coordinates for a Streamline Duct in K&W - = some manipulation required to size them for your core size and opening, = but not hard.=20 Yes, to the best of my ability and patience, I really did not have much = space (3" on one side and about 5" on the other) to made a transition. = So I started with the bell against the core and the opening had to be an = average of 4" in front of the core - so as you can imagine there was not = much room left between inlet and core to place the "pinch". =20 The only advantage (if I may) that I see for the pinched duct is that = simply truncating the streamline duct (especially if you are talking = leaving only 3 -4") leaves a lot of the core exposed to a higher = velocity airstream and I believe results in more cooling drag. By = making the intake smaller but squeezing it to cause higher velocity = boundary layer my "theory" is that it delays separation, slows the = airstream down and results in a better "constrained" space duct. =20 Don't know if the theory holds water but it appear to do at least OK = with air {:>) Ed ----- Original Message -----=20 From: Thomas Jakits=20 To: Rotary motors in aircraft=20 Sent: Saturday, May 05, 2007 8:14 PM Subject: [FlyRotary] Ed's Pinched Ducts Hi Ed, question: Are your ducts lofted (built from coordinates?) for the diffuser part = of the duct? If you look at it from the radiator towards the intake - is the = diffuser a "true" streamline until it becomes necessary to fair into = your "pinches" or is the diffuser "eyeball"-engineered?=20 I believe there are general coordinates available from the K&W = publication for a complete streamline.... TJ All, OFF-Topic: Can't find a 3A, 125VAC 4-position switch, 2 wires IN, 4 wires OUT, = rotary-type, Fan on/off and 3-speed control,=20 any ideas for mail-order? Thanx! ------=_NextPart_000_0004_01C78F53.C949C120 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi TJ
 
First, yes there are general coordinates for a = Streamline=20 Duct in K&W - some manipulation required to size them for your core = size and=20 opening, but not hard. 
 
 Yes, to the best of my ability and = patience, I=20 really did not have much space (3" on one side and about 5" on the = other) to=20 made a transition.  So I started with the bell against the core and = the=20 opening had to be an average of 4" in front of the core - so as you can = imagine=20 there was not much room left between inlet and core  to = place the=20 "pinch". 
 
The only advantage (if I may) that I see for the = pinched=20 duct is that simply truncating the streamline duct (especially if you = are=20 talking leaving only 3 -4") leaves a lot of the core exposed to a = higher=20 velocity airstream and I believe results in more cooling drag.  By = making=20 the intake smaller but squeezing it to cause higher velocity boundary = layer my=20 "theory" is that it delays separation, slows the airstream down and = results in a=20 better "constrained" space duct. 
 
Don't know if the theory holds water but it = appear to do=20 at least OK with air {:>)
 
 
 
Ed
----- Original Message -----
From:=20 Thomas Jakits
Sent: Saturday, May 05, 2007 = 8:14=20 PM
Subject: [FlyRotary] Ed's = Pinched=20 Ducts

Hi Ed,
 
question:
 
Are your ducts lofted (built from coordinates?) for the = diffuser=20 part of the duct?
If you look at it from the radiator towards the intake - is the = diffuser=20 a "true" streamline until it becomes necessary to fair into your = "pinches" or=20 is the diffuser "eyeball"-engineered?
I believe there are general coordinates available from the = K&W=20 publication for a complete streamline....
 
TJ
 
 
All,
OFF-Topic:
 
Can't find a 3A, 125VAC 4-position switch, 2 wires IN, 4 wires = OUT,=20 rotary-type, Fan on/off and 3-speed control,
any ideas for mail-order?
 
Thanx!
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