X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [69.171.52.140] (account marv@lancaironline.net) by logan.com (CommuniGate Pro WebUser 5.0.3) with HTTP id 862477 for lml@lancaironline.net; Sat, 03 Dec 2005 23:10:58 -0500 From: "Marvin Kaye" Subject: Re: [LML] Re: Flying in primer question To: lml X-Mailer: CommuniGate Pro WebUser v5.0.3 Date: Sat, 03 Dec 2005 23:10:58 -0500 Message-ID: In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format="flowed" Content-Transfer-Encoding: 8bit Posted for Walter Atkinson : Well, when I used to race Maxi boats offshore, we found that a roughened hull surface held a boundary layer of water which offered less resistance than a very smooth, and shiny surface. When two very close 12 meters were raced, one with a microscopically roughened hull vs one with a polished hull, the rough surface hull was faster. How this would affect a laminar flow vs a non-laminar flow wing could be another matter. There is a boundary layer in both. Air being compressible as opposed to water, changes the equation, I'm sure. But, golf balls have dimples for the same reason, don't they? I would think we are wanting a smooth, non-turbulent, thin boundary layer. There are areas on a 747 wing where the boundary layer is almost a foot thick! ??????? Walter