Sailwings self-trimming wingsail system

This is a mechanical system for wingsail control. The windthrust to the boat is controlled automatically at all times with the only control for the pilot is a simple lever Forward, Neutral and Reverse no further adjusting system - no ropes no sheets no winches everything is automatic except the control to go stop or reverse. The system gives exactly the same power in reverse setting.
You can stop the boat instantly and reverse out of difficult situations if necessary.
See www.windthrusters.net/simplicity.html Patent: patents.google.com/patent/GB2...

[@lizhikai5587]

Clever design, simple words but profoundly explained. Thanks!

[@rctestflight]

Brilliant!

[@ColinMill1]

Very interesting! I was wondering if there would be some value in increasing the gearing to the control surface (tailplane) so that an angle of attack for the wing of say 10 or 12 degrees is achieved by the time the wind is at 30 degrees to the boat heading but also to introduce some lost motion so that the angle of attack does not go beyond the stall even when the wind is abeam. I guess there is the issue of eventually putting the wing into a fully stalled position for the dead down-wind run. Perhaps a pin running in a profiled track could achieve this.

[@LrrBrr-lb3iw]

Thanks this was very helpfull!

[@lelievre12]

Looks like forward is mixed up with reverse. You boat will go backwards in 'forward' if rigged this way.

[@peterworsley4699]

There are always comments from the less intelligent who cannot understand the simplest of things.

[@ColinMill1]

I thought that initially but he has got it right.

[@peterlelievre]

@@ColinMill1 Yes Peter W is right. I mistunderstood the trim wing as a flap but it's not. Its a 'tailplane' providing decalage to the main wing. ie. the trim wing acts opposite to the wing to set an angle to the wind in the same way a tailplane on an aircraft provides downforce to set the lift angle on a planes main wing. So yes, when the lever is pushed 'forward' indeed the mainsail will rotate to the provide forward lift and the trim wing acts opposite to this lift vector to set the main wing (sail) angle.

[@ColinMill1]

@@peterlelievre Many thanks for the reply. I have been giving this problem a little thought and, I think, as the wind angle moves away from zero one needs to quite quickly establish an angle of attack for the sail close to the best L/D value (perhaps 10 to 15 degrees depending on the aspect ratio of the rig) and that this should increase more gradually so the Clmax is reached for the beam reach situation. At 180 degrees having the tailplane at something approaching 90 degrees is needed to get the sail at about 90 degrees to the wind (though the shift of the centre of effort towards the 50% chord location will shift that requirement somewhat). As for the range of angles from beam reach to dead down wind it obviously depends on Cl & Cd characteristics well beyond the stall and that data is somewhat thin on the ground with Riegels' "Aerofoil Sections" being the only one that gives both for the full 0 to 360 degree range (and then, if I remember correctly, for a FW190 wing!)

[@superkamehameha1744]

So to sum it up, the difference is in the tail configuration

[@johnryan2193]

Great job, I would like to know how to scale it up for an 18 foot bilge Keeler .

[@WindThrusters]

Dear John - You can find most of the information on www.sailwings.net/siteindex.html

[@DaveDaveydo]

Man I love it. Now how do I put one on a small boat?

[@WindThrusters]

Check out my website on www.windthrusters.com/story3.html

[@toroddlnning6806]

@@WindThrusters what about downwind, when the wind is comming from behind. I guess if you have wind blowing in your face you can have a micro controller adjusting the rudder and change the direction. But if you have wind from behind you will need some sort of engine to force the sail in locked sideways possition?

[@WindThrusters]

@@toroddlnning6806 you can constrain it from going more than 180 degrees. Or you can tack downwind

[@WindThrusters]

See windthrusters.com/story.html