Suppose you take a Rogallo wing (like they use on hang gliders) turn it
sideways (nose points forward, plane of the wing vertical instead of
horizontal) and use it for a sail? It would be sort of like a crab claw
rig, I suppose, with rigid leading edges and a loose trailing edge. I
guess the mast would attach where the hang glider pilot would hang to
balance the load on the mast. Does anyone know if anyone has tried
something like this?