Catsailor.com

Faster than the breeze, dead downwind

Posted By: KevinRejda

Faster than the breeze, dead downwind - 05/01/11 03:26 AM

had to read the whole thing before I started to believe. . . .
http://www.wired.com/autopia/2010/07/its-settled-downwind-faster-than-the-wind-officially-possible/
Posted By: Jalani

Re: Faster than the breeze, dead downwind - 05/01/11 08:43 AM

That's been around for quite a while Kevin - and I think it's also been on here before. Unfortunately, not really applicable to sailboats is it?

Clever use of technology though - and semantics! laugh
Posted By: KevinRejda

Re: Faster than the breeze, dead downwind - 05/02/11 03:01 AM

Applicable?, racing, of course not; cruising, I don't know, maybe. Could it work with a prop instead of wheels? The physics is certainly interesting and fairly well explained though. Jake? Wouter?
Posted By: Jake

Re: Faster than the breeze, dead downwind - 05/02/11 10:42 AM

Originally Posted by KevinRejda
Applicable?, racing, of course not; cruising, I don't know, maybe. Could it work with a prop instead of wheels? The physics is certainly interesting and fairly well explained though. Jake? Wouter?


We did go through this at length and it is a bit of a brain teaser. Bottom line; as long as the drag of the vehicle is less than the energy that can be extracted from the moving air, it can exceed wind speed. We do actually do it on catamarans although it's not DDW because we have to keep some angle on our fixed sails to generate efficient lift.

there is a fella that designed a boat that has a big air driven propeller on the back and a prop in the water - he can drive the boat DDW and you might call it "sailing". It was a jonboat looking thing so I'm not sure if he could exceed windspeed - but he could travel in any direction relative to the wind.
Posted By: Will_R

Re: Faster than the breeze, dead downwind - 05/02/11 08:41 PM

Originally Posted by Jake
We did go through this at length and it is a bit of a brain teaser. Bottom line; as long as the drag of the vehicle is less than the energy that can be extracted from the moving air, it can exceed wind speed. We do actually do it on catamarans although it's not DDW because we have to keep some angle on our fixed sails to generate efficient lift.



+1
Posted By: Dan_Delave

Re: Faster than the breeze, dead downwind - 05/04/11 05:16 PM

I know some people that are involved with this concept but have not finished the plans.


Or if you like something a bit bigger:
[Linked Image]
Posted By: waterbug_wpb

Re: Faster than the breeze, dead downwind - 05/04/11 08:01 PM

nice video on that linked site. I wonder if having a blade pitch control could help increase the top speed by reducing drag on the windmill?
© 2024 Catsailor.com Forums