Re: Ever Heard Of This??!!
Just thought of this: Since you are actually flying a wing through the water:
Google or look up NACA in the reference area of your library. NACA was the predecessor of NASA. They had a whole book for aeronautical engineers showing thousands of wing chords (cross section through a wing) AND the expected lift per square foot of area. So instead of going in blind, you can figure the expected weight of your boat and gear, figure out the approximate area of the wing(s) in the water, and just find a suitable profile to yeild the lift required. ---Figuring the difference in speeds, and the density of water and air. Need Help? Find the local math whiz at the high school or college, and contact the local model airplane club. Explain clearly what you want to do.--I was once one of those geeks--They will be exuberant--out of their minds with glee--to help you.
Just for a little background so you know why it works: Air is a fluid just like water. An airplane wing or hydrofoil wing functions because of Bernoulli's principle. Fluid traveling over the top of the wing MUST travel farther. Because it travels farther, it must travel faster. The faster fluid generates a lower pressure than the slower fluid on the bottom of the wing , and this lower pressure (actually the differential pressure between surfaces) lifts up the wing. A wing is simply a flattened venturi--same principle, same pressure drop. A wing lifts something, a venturi sucks out fuel from the carb bowl.
Be aware of a phenominon known as "induced drag." The thicker the wing profile, the higher the lift (generally) and the greater the induced drag. --DRAG = Anchor = slower
You may want to consider using a symmetrical Chord, and vary the lift by changing the angle of attack. This tends to reduce induced drag.
Doing all this work on paper is easily accomplished during the bad weather and greatly improves your chance of success on the first try with the prototype.
Go for it! Good luck with your project. It's not really as difficult as I may have made it seem-you can do it. You should have a great time with it, and after doing the research and building, you should be proud of yourself.
By the way:Your attachment points will be supporting the weight of the whole boat, engine, gear, and foil assembly. You need to be sure the fastener size and reinforcements will have a safety factor of 3. That is, since you will have three points of attachment, each point should be capable of supporting the entire weight of the rig. Remember: even though you are flying the foils through the water, the ride is smoother, and the hull is above any roughness, there still will be impact loads (high wakes, for example) to contend with.
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