Message-Id: <9503200758.AA07171@st.unocal.com>
From: stssram@st.unocal.com (Bob Myers)
Date: Sun, 19 Mar 1995 23:58:53 -0800
In-Reply-To: Guillemot@aol.com
To: baidarka@imagelan.com
Subject: Re: Paddling...
On Mar 19, 20:38, Guillemot@aol.com wrote:
} Subject: Re: Paddling...
> A paddle is typically working like a parachute. A parachute will always pull
> up with an equal and opposite force to that pulling down on it. Its lift is
> parallel to the direction of motion. When used only like a parachute a paddle
> wastes no energy.
>
> A wing generates lift perpendicular to it's direction of motion and
> perpendicular to it's length. For a paddle to work like a wing it must move
> up-and-down and/or in-and-out. Unfortunately when you do that the drag of the
> paddle is not parallel to the direction of the kayak and is therefore wasted
> energy.
Wait a minute - it's not useful to separate lift and drag in this manner.
You don't have to move the paddle in either up-and-down or horizontally
back; you can combine the two motions. If you do so appropriately, there is
no wasted force or energy. Think of it this way: lift and drag are merely
the two perpendicular components of the hydrodynamic force. The part of
that force that is parallel to the direction of motion of the paddle is
called drag, and the part that is perpendicular to the direction of motion
is the lift. If you take that total hydrodynamic force vector, instead of
worrying about whether you're using "lift" or "drag", you should be able to
move the paddle so that the total force vector is horizontal, pulling the
kayak forward - without any wasted force.
-- Bob Myers Unocal Tech. & Ops. I. S. Support Internet: Bob.Myers@st.unocal.com P. O. Box 68076 Phone: [714] 693-6951 Anaheim, California 92817-8076