Peter Treby wrote: >Still can't see that the paddle / horizontal >rudder acts as a foil. G'Day Peter, I believe you are correct and the crossection of the blade doesn't play much of a role in lift when the blade is set at an angle in the water. If the paddler were applying a horizontal push or pull to an angled blade the lift could be understood in terms of the blade being forced to move in the direction of least resistance to water pressure and therefore least work. If you had the blade angled up and facing forward the line of least resistance will either be forward and up (lift) or backwards and down (time to practice that roll) but would always have to be in the direction the paddle is moving. All the best, PeterO *************************************************************************** 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: - >A symmetric blade at an angle of attack produces lift >away from the back side of the blade due to relative low >pressure on that side of the blade, because of >turbulance. G'day, That isn't necessarily the case. For a blade held at an angle of attack and being pushed through the water the line of least resistance is the minimum energy path and therefore likely to be preferred. It might be taken in the presence of either laminar flow or turbulent flow. The forces acting on the blade can be broken down into horizontal and vertical components and balanced without invoking turbulence. A car coming to a hill might plow into it, which takes a lot of energy, or go up it at the same angle as the hill, which takes the least energy. Mostly cars go up the hill. All the best, PeterO *************************************************************************** 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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