Hi Rolf,
I think there are two problems: The first is the mid-girth rule. If you want to have a furling sail, you have the leading edge more straight and than the rule makes the trailing edge too curved to get enough tension on it to get a good shape. The other "problem" is that a furling sail will have a flatter cut, but I am not sure if this is really a drawback, especially if you save 5 s during hoisting and taking down.
For me, the real development stopper is the mid-girth rule. Remove it and after a couple of years we will see much better down wind sails.
Cheers,
Klaus
On a single hander which is what we're discussing here, I have little doubt a flatter kite would be faster. I'm adding complication here for the sake of internet conversation but could we add short "air batten" parallel to the luff to support the oversize leach?
