X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [201.225.225.168] (HELO cwpanama.net) by logan.com (CommuniGate Pro SMTP 5.0c5) with ESMTP id 775322 for flyrotary@lancaironline.net; Thu, 20 Oct 2005 20:24:47 -0400 Received-SPF: none receiver=logan.com; client-ip=201.225.225.168; envelope-from=rijakits@cwpanama.net Received: from [201.224.93.110] (HELO usuarioq3efog0) by frontend2.cwpanama.net (CommuniGate Pro SMTP 4.2.10) with SMTP id 50832856 for flyrotary@lancaironline.net; Thu, 20 Oct 2005 20:10:39 -0500 Message-ID: <009001c5d5d5$77359dc0$6e5de0c9@usuarioq3efog0> From: "rijakits" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] flyrotary NACA scoops Date: Thu, 20 Oct 2005 19:22:03 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_008C_01C5D5AB.8D5BBA50" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1437 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 This is a multi-part message in MIME format. ------=_NextPart_000_008C_01C5D5AB.8D5BBA50 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Okay, here is the site with the modified NACA-ducts: http://4dw.net/marcborom/ Check: "Oil Flow Test on NACA inlet" and "Cylinderhead Cooling Trials" Keep in mind, this is a aircooled engine - less pressure delta, but higher flow. Reading superficially through the mentioned NACA-report: http://naca.larc.nasa.gov/reports/1951/naca-tn-2323/ (not taking any formulas...) it is iteresting that the report also mentions the flow-fences you see on the marcborom site - they cost efficiency. No mention of the corner-guides..... What I read out of the report is that NACA works - for a specific situation, if specifically developed for it. As soon as there developes some backpressure you will get some costly drag. It seems this is not a solution for big speed-spread. The report seems (maybe not....) to give some indication on how to use the formulas to develope a proper duct for specific situations, but it looks like a lot of maths. Thomas J. ------=_NextPart_000_008C_01C5D5AB.8D5BBA50 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Okay,

here is the site with the modified=20 NACA-ducts:

http://4dw.net/marcborom/

Check: "Oil Flow Test on NACA inlet" and=20 "Cylinderhead Cooling Trials"

Keep in mind, this is a aircooled engine - less = pressure=20 delta, but higher flow.

Reading superficially through the mentioned = NACA-report:=20 http://naca= .larc.nasa.gov/reports/1951/naca-tn-2323/
(not=20 taking any formulas...) it is iteresting that the report also mentions = the=20 flow-fences you see on the marcborom site - they cost = efficiency.

No mention of the = corner-guides.....

What I read out of the report is that NACA works = - for a=20 specific situation, if specifically developed for it. As soon as there = developes=20 some backpressure you will get some costly drag. It seems this is not a = solution=20 for big speed-spread.

The report seems (maybe not....) to give = some=20 indication on how to use the formulas to develope a proper duct for = specific=20 situations, but it looks like a lot of maths.

Thomas J.

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