4 ms·
Two reasons: First, solid wings are dramatically better in lift drag ratio. They start out around 3x better per square meter than conventional sails on a berm
by jasonwatkinspdx 3y ago
Two reasons:
First, solid wings are dramatically better in lift drag ratio.
They start out around 3x better per square meter than conventional sails on a bermuda rig, and can get up to 7x better with careful design. This is why the America's Cup boats with wings are dramatically faster than conventional rigs (the other reason being foils).
Second, the simplicity of the rig.
These designs are self trimming, which means there's a control flap you set, and that causes the wing to have a consistent angle of attack vs the wind. As the wind vector shifts around the sail just tracks it without needing any active control or electronics. You only have to change the control flap when the bow or stern crosses the wind during a turn.
If you get into severe weather you just put the control flap in neutral and the wing just acts like a weather vane. Surprisingly enough a feathered wing like this has less drag than a bare cylindrical mast with no sail lifted. Aerodynamics can be counterintuitive.
That's what's so cool about this technology. It really is just a bolt on.
- wolverine876 3y ago> solid wings are dramatically better in lift drag ratio Why has anyone used fabric sails? If they could build a wooden boat, they could have made wooden sails. Too heavy, and thus modern strength/weight materials were needed?
- mrcartmeneses 3y agoWeight and the fact that wings are a modern invention that requires an understanding of aerodynamics
- jasonwatkinspdx 3y agoYes, people 200 years ago did not possess the material science knowledge to build a solid wing that would not be insanely heavy, vs... canvas.
- pbronez 3y agoMy thought exactly. Some university should build a wing sail ship using exclusively materials and tools available during the Golden age of sail.
- jasonwatkinspdx 3y agoThat's a tall ask but I think something is possible. The best approach imo would be a "soft wingsail" made from two fabric sails that sandwich a central mast with ability to pivot widely if not freespin. There's some companies today chasing this as a middle ground. It's not as efficient as a solid wing, but sailors are understandably conservative and like something fabric they can take down in high winds vs let weathervane, even if the physics of the latter work out.
- wolverine876 3y agoHow would that differ from a lateen sail?
- jasonwatkinspdx 3y agoIt would have battens to create an airfoil. Lateen vs burmuda is beside the point. Here's an example of what I'm talking about: https://www.omerwingsail.com/ https://www.omerwingsail.com/
- wolverine876 3y ago> Lateen vs burmuda is beside the point. I was thinking of fore-and-aft (which I should have said instead of lateen specifically) compared with square, but my knowledge is pretty limited.
- paholg 3y agoIn addition to what others are saying, look at the sails of giant ships of the past. They're just big rectangles that block the wind, they don't work anything like a wing.
- wolverine876 3y agoLook up fore-and-aft sails and lateen sails, which seem winglike (but I'm not sure of the actual aerodynamics).