How long we windsurfers need to wait to have to proper airfoil sails instead of simple sheets?
When the properly build sail will be invented and what difference it could make to the ride?
As you look at airplanes and wind turbine blades nobody longer use plain sheets for that sort of aerodynamics (beside maybe poor para gliders and ancient dutch wind mills.
Soon to be invented proper windsurfing sail consist of two sheets of standard sails , sealed at at edges and pumped with air inside like the kiter's do.
Two sheets are separated at strategically important distance, hold by bridges together to create proper 3Dimensional airfoil sail not twisted and banded 2D surface.
Sort or sailing with air-materace attached to your mast.
There some advantages:
-improved aerodynamics
-extra buoyancy
but also drawbacks since such area could be very easy to punch a hole.
That could be mitigated with permanent structure similar to the board but lighter -ie filled with airgel. Or two sheets separated and resting on the skeleton -rigid 3D sails ?
Can't wait to see my sails on the water :)
At low airspeeds such as the speeds windsurfers go, the single sided aerofoil is nearly as efficient as a double sided one, and very much lighter, so the benefit of the double side is outweighed by the disadvantage of the extra weight and expense.
If we start sailing at 50 knots and above then it will be worth it, but that won't be me.
These things (see link below), and many others before them (eg Little America's Cup) have very successfully used solid aerofoils. The aerofoils tack quite successfully, with a canterlever system to "reshape" the aerofoil for the port ans starboard tacks. As previously noted there'd be an awful weight disadvantage, especially with a rig which must be lifted and held aloft by hand. The expense would be horrendous too I'd reckon.