Would someone in the know please explain to me how one paddle shape produces more forward thrust than another? And dumb it down. I ain't so smart. It seems to me that if the paddle weight, wind resistance, and 'motor' are identical the boat speed would also be identical. I mean X pounds of pressure on your hands should be X pounds of pressure on your hands regardless of what sexy magic is happening under water, right?
(String, this could be the post to fight the winter blahs.)
In a nutshell though, less ‘slip’ allows more efficiency, and the way the blade requires a certain technique to do so, encourages proper form.
There were a couple of other articles I was searching for which delved into the design of individual wings and their twist, blade shape, size, etc. but lo and behold, I cannot locate them.
Different wings have quite different behaviors though, some more efficient than others, some better suited to longer events, etc. I’ve used nothing but a wing for years now. The type of paddling I do doesn’t require duffek, draw, etc. strokes so I’ve never missed my Euro blade. If I did more of this type of paddling, the Euro or Greenland sticks would probably be more suited. The last time I used my Werner Ikelos, though, it felt like a noodle in the water.
Slip vs. grip A 100% efficient paddle would be like planting the blade in a block of concrete. There would be no movement at all of the blade through the water. All of the force that you put in would move the boat.
All real paddles slip through the water to some degree. So you are moving both water and the boat. The water that you move backwards makes the boat move. The water that moves up, or down or sideways to get out of the way of the paddle doesn’t do anything useful for you.
A wing, or other paddle with a good catch or grip moves more water backwards and less water sideways.
Mint has it right I’ve always explained a wing to others like this. Paddling a wing is like paddling in jello. The paddle doesn’t move as far as a euro, which translates to more forward momentum.
one factor has been missed The cross-section of the blade is how the wing gets it’s name. The leading edge of the wing (outside blade edge) moves through the water with much less resistance because of it’s cross-section.
Lift vs. drag Eric has it right - it’s not about minimizing slip it’s about increasing lift. A wing paddle is an airfoil, which can generate lift only by slipping through the water (mostly sideways, not in the direction of the boat motion). For the same wing paddle, if you move it sideways more quickly, it will slip through the water more quickly and should generate more lift force (unless you overpower it and cause separation).
I call it lift, because it’s perpendicular to the path of the airfoil through the water, which is the technical definition of lift. For the paddler, the lift force is actually useful thrust in the direction of boat motion, as the lift vector points mostly forward. Wing paddles also benefit from the drag force on the paddle, as that has a component in the direction of motion as well.
Two different wing paddles will perform differently if they have different cross sections. The lift-to-drag ratio is the governing property that determines how well a wing paddle should function. That’s for two paddles with the same footprint, but different foil profiles.
‘Theory of Wind Sections: Including a Summary of Airfoil Data’ is a nice Dover book that tabulates L-D ratios for a wide range of airfoil shapes. It was done by NACA, before it became NASA. Naval Archs typically use this as a reference for rudder and keel profiles, but is no doubt used by wing paddle designers as well.
slip, grip, lift, etc. If you use a low conventional stroke with a wing, then the wing is acting as a drag device. It will be identical in efficiency to a Euro blade with the same area and drag coefficient. Slip, grip, drag are the same thing, just a measure of area and drag coefficient.
Wing efficiency comes from the wing stroke. The wing makes that stroke easier and more natural by allowing body rotation to produce lift.
If you use the wing in the exact stroke you use for a conventional paddle, the wing is a waste of time, providing no benefit.
Not Lift Since water is not compressible (like air) the lift from a pressure difference that an airfoil produces is IMHO a red herring for the wing paddle in water.
My take is that the high angle wing technique has good ergonomics for rotation and engagement of torso muscles and… (here’s the crux)…
…the sweep of the blade of the wing stroke from catch to release at an angle out from the hull puts the blade constantly into new static water to push against (versus moving and accelerating a block of water counter-productively backwards with a linear straight pull stroke along the hull).
The ability (forced technique) to push against new water throughout the stroke is what makes the wing efficient/productive. This can be replicated with a GP or euro with a similar technique (heresy?). However, I love an ONNO wing!
Sure, there is lots of other stuff that makes a paddler faster, but this is what makes the wing the choice of performance paddlers… forced efficient technique.
This is not correct - lift does NOT depend on compressibility to operate. Lift operates at low speed in air (where compressibility is insignificant, less than about 200 mph e.g. a sailplane, auto lifting surfaces) and at all speeds in water, e.g. propellers, hydrofoils, the list goes on. The large pressure variations that produce lift are due to the varying speed of the fluid in the flow field, rather than compressibility effects (cf. the Bernoulli Equation).
