diverting wind

Isn't that what sailboasts do on a close-haul?

Brian Whatcott

well, i was hoping to find some smaller arrangement. sailboats don't sail directly against the wind right?

There *is* one device that 'sails' directly upwind.

It consists of a diagonal shaft. On the top end is mounted an airscrew [windmill] , and on the bottom end is mounted a water screw. There is a float to keep the thing top side of course.

It causes endless debate on its putative impossibility from physicists, engineers, etc. It does indeed work!

Brian Whatcott Altus, OK

< There *is* one device that 'sails' directly upwind. < It consists of a diagonal shaft. On the top < end is mounted an airscrew [windmill] , < and on the bottom end is mounted a water < screw. There is a float to keep the thing top < side of course.

< It causes endless debate on its putative

< impossibility from physicists, engineers, < etc. It does indeed work!

Conservation of energy can easily be satisfied for a vehicle version if it creeps forward slowly enough relative to wind speed.

A vessel or boat, however, would make better headway by tacking back and forth with a conventional sail.

Bret Cahill

"ajay" wrote ..

About sailboats, I suppose it doesn't sail straight into the wind, but at an acute angle. Sometime this is good enough. But if it zig zags left and right, it can effectively sail straight against the wind.

Lion

Jaques Cousteu and company built a boat that sailed any direction at all, if I remember it correctly. They called it "Alcyone", and it used a kind of tube sail. See:

The sail was a tall tube, like the main mast on a sailboat; but fatter. It's cross-section shape was sorta like a teardrop, or like an airplain wing and it's mirror image, joined together. I think there were vertical slots, and some kind of internal airfoils, too. The tube had a fan (wind-driven, probably) that drew air into the tube, which created lift in a direction that was determined by the rotation of the tube with respect to the wind, and not with respect to the boat's axis.

A thorough web search, or a look at Cousteau Society literature in a good library, might provide more details.

KG

-- I'm sick of spam. The 2 in my address doesn't belong there.

The idea sounds interesting for a sailing boat, and it is not difficult to built. Is there information that this has been tried out?

I have seen pix and descriptions of the concept at the model size. I haven't searched, but I don't recall anything at the full-size scale. However, a vessel that can only sail close to the wind is almost as useful as a vessel that can only sail downwind.

Brian Whatcott Altus OK

To reduce wind drag, the windmill cannot have too many blades. True enough, I did a search and found this sailboat powered by a 3-blade wind turbine,

It is not a model, but a full scale 36 ft twin hull catamaran with 20 ft blades. I think the blade angles can be changed.

< To reduce wind drag, the windmill cannot < have too many blades.

Depends on if the increase in power recovered by the full recovery turbine exceeds the increase in drag at that speed.

A de lavel wind turbine gets 80% efficiency -- much more than the 2 or

3 blade wind mills.

Does the drag on an impulse turbine increase accordingly?

Bret Cahill