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Hydrofoil idea's.

Some doodle's, but also some late 70's tests of some concepts, for fast hydrofoil sailing.


#@hanno; june 1976 Home »

Hydrofoil idea's

Hydrofoils some doodle's with some potential.

The figure shows a rough sketch of some idea's I have about increasing the top speed of sailing hydrofoils.

The basic foil design should look something like MONITOR, ladder type, and intersecting at the Centre of effort of the wingsail. The cord of the lower (ie deeper) foils will decrease. The pilot will have limited possibilities to change the angle of attack of the forward foil to assist in decreasing heeling angle.

The "hull" will be left behind after starting, either by towing or lifting of the stating hull. The pilot will be able to point the hull in the direction of the apparent wind, decreasing the windage. Streamlining has up to now been no consideration in sailing hydrofoils. But to beat a craft like yellow pages this will be necessary.

The front foil will take the heeling force. The rear foils are for steering and will have a MONITOR like foil control for pitch.

A wingsail will complement the craft. For speeds in excess of 90km/h and small angles of attack of the apparent wind,a necessity.

The whole design will have to result in a very light craft.

Preliminary idea's

  1. Carbon fibre foils, aluminium carbon structure.
  2. Wing sail..
  3. Hull-less hydrofoil, Tow to speed, and if that is not allowed, dump the hull when at speed. Use inflatable hull.
  4. Craft should be able to tack on foils, to perform consecutive speed runs.
  5. Complete computer assisted, foil control and sailcontrol.
  6. Aerodynamic enclosure for prone pilot.

Some radical thinking.

 The speedsailing record can in my opinion be upped quite a bit. The drawing illustrates two idea's. The one with the sailplane, is already very old, but has always been out of reach. With modern PLC technology it should be possible. (by the way how much computer control is allowed when making record attempts?) The pilot is in the air and only connected to the water by the inverted hydrofoil. Are we still talking about a sailing craft. I think we do, because without the inverted hydrofoil in the water there would be no movement. We have built a model prototype, using a kite and a hydrofoil. The system showed incredible acceleration, but the crude design lacked control.

The other idea of getting the pilot inside the wingsail and high-up, was developed by me and my brother some 15 years ago. We even built a radio-controlled model, of a version with a hull to see if it worked, it did. The system should work beautifully as all is aimed at efficiency. The position of the pilot high up is required to keep the heeling angle to a minimum. Who will dare sail a thing like this.

Some radical experiments.

My brother and I tried balancing a wing mounted on a hull. It worked quite well and it is the basis of this hydrofoil idea seen in the rendering above. All this opens a way to be aerodynamic in the air (wing) and hydrodynamic in the water (hydrofoils)


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