"If the back of the paddle is left flat, the paddle will exhibit an airfoil effect and generate "lift" when one is sculling or rolling with the flat side down." Follow that. why is it sometimes said that a Greenland padde which is symmetrical in cross section will generate lift. Isn't the flow over each side of the blade the same when sliced sideways? *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Peter Treby wrote: > Why is it sometimes said that a Greenland padde which is > symmetrical in cross section will generate lift. Isn't the flow over > each side of the blade the same when sliced sideways? Only if the angle of attack is zero degrees. Any airfoil will generate lift if it has a positive angle of attack. The issue is usually to get an airfoil that generates optimal lift for minimal drag ... under the conditions of expected use. This is a can of worms, nay, a nest of snakes, nay nay, an ocean of sea serpents, Peter! Theory is very poor in airfoil design, but there is a ginormous body of practical knowledge about airfoils Here are a couple of paragraphs from Wikipedia to when your appetite for the glories of NACA airfoils, high aspect ratio low chord wings, winglets, ailerons, rudders, ad nauseum: http://en.wikipedia.org/wiki/Airfoil -- Dave Kruger Astoria, OR *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Wikipedia refs: Lift: http://en.wikipedia.org/wiki/Lift_%28force%29 Turbulance and laminar flow: http://en.wikipedia.org/wiki/Turbulence Love the image of vortex at wingtip. *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
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