> The nice thing about a soft sail is that you can change the shape of it. Both camber and twist. But it takes a lot of knowledge and experience from the sailor and sailmaker to set, and be able to set, a good shape.

I think the answer in part is the materials selected. Theres a lot of experience in the current model for sails, and the sails stiffness represents decades of experiment we couldn't hope to emulate in the short experience with wings. Certainly ease of use sphere is the area people will be attracted to, which is far away from the Americas Cup type of wing. Beneteaus wing and others seem to suggest that all things are possible.

>A rigid wingsail is probably easier to sail due to the wide operating range of angle of attack. But I'm not sure if it is faster, because it will not twist, so the whole sail will never work at the optimum angle if attack.

Ive no doubt rigid is faster. and not by a bit but a lot faster. Greenbird managed 126 mph on land. The thing here is that reefing probably isnt reliably possible so the wing relies upon a zero AoA set. The profile drag at zero lift is better than a reefed standing rig, but I know what concerns Rob is what happens if the wind shifts and the bearing sticks.

Still there is something here worth exploring as a perfect bearing for 50% of sail area might be more achievable than the right soft wing design selection with all its parts.

> Glenn Ashby actively used twist to trim the wingsail on the winning americas cup boat, so I think this is important for performance. The boat had a "semi rigid" wingsail, which is probably optimal for performance, but seem fragile to me.

Durability is yet another issue that will require a materials mix we probably arent using right now. There is a lot of stuff going on in this space with inflatable wings, with RC boats and minimalist aircraft where Im confident that in some way the design selection is already out there, just hidden in the smoke and dust of too much data.

 

• Privacy • Unsubscribe • Terms of Use