Any solid object moving through a fluid can generate lift. "Lift" is an unfortunate term that seems to imply vertical force but lift, as Nick pointed out, can operate in any direction (but always normal to the flow) and, while its magnitude varies with shape (plan, camber and profile) and size, it is still "lift". If you have no background in fluid dynamics visit http://www.grc.nasa.gov/WWW/K-12/airplane/short.html where there is a very good site dedicated to fluid dynamics and brought to you by the people who put a man on the moon. It might be useful to go directly to the page defining lift http://www.grc.nasa.gov/WWW/K-12/airplane/lift1.html and then go to the pages that discuss the various erroneous theories of lift that are so common and lead people to erroneous conclusions. All written for school students ands easy to comprehend. There are some great interactive Java Applet simulators that allow you to play with angles of attack etc. If you play long enough you can even optimize the total forces on the foils to see what angle of attack will produce the greatest thrust. For some real fun, go to the kite modeler. The important point to remember with paddles is the thrust coefficient i.e. the amount of thrust produced per unit of area. With paddles, thrust is what drives the boat ahead and thrust is a function of both lift and drag (similar to sails when reaching or running). See Marchaj's "Sailing Theory and Practice" for a good simple discussion of this. Chuck wrote; > The beauty of GP type paddles is that they don't cost more than > the stick of wood, and you are ENTITLED to shape them to suit > yourself. The same applies to low aspect ratio paddles albeit with the additional cost of some glue. (probably not a great problems for some one who can afford a kayak). I have been making low aspect ratio paddles from sticks of wood for over three decades. I once made one out of sticks of wood and dental floss (didn't have a roll of sinew handy) to show that the Inuit could have made low aspect ratio paddles even without glue. It worked but was a pain in the butt to make and probably a good reason why they stuck to high aspect ratio paddles easily made from one piece of wood. Cheers John Winters *************************************************************************** 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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