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by CapriSun. 11/12/20 09:41 AM
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by Team_Cat_Fever. 11/02/20 09:45 PM
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Faster than the breeze, dead downwind #231748
04/30/11 09:26 PM
04/30/11 09:26 PM
Joined: May 2007
Posts: 127
Rock Hill,SC
KevinRejda Offline OP
member
KevinRejda  Offline OP
member

Joined: May 2007
Posts: 127
Rock Hill,SC


Kevin Rejda
Rock Hill, SC

-- Have You Seen This? --
Re: Faster than the breeze, dead downwind [Re: KevinRejda] #231749
05/01/11 02:43 AM
05/01/11 02:43 AM
Joined: Feb 2005
Posts: 1,382
Essex, UK
Jalani Offline
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Jalani  Offline
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Joined: Feb 2005
Posts: 1,382
Essex, UK
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


John Alani
___________
Stealth F16s GBR527 and GBR538
Re: Faster than the breeze, dead downwind [Re: Jalani] #231761
05/01/11 09:01 PM
05/01/11 09:01 PM
Joined: May 2007
Posts: 127
Rock Hill,SC
KevinRejda Offline OP
member
KevinRejda  Offline OP
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Joined: May 2007
Posts: 127
Rock Hill,SC
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?


Kevin Rejda
Rock Hill, SC

Re: Faster than the breeze, dead downwind [Re: KevinRejda] #231769
05/02/11 04:42 AM
05/02/11 04:42 AM
Joined: Jun 2001
Posts: 12,310
South Carolina
Jake Offline
Carpal Tunnel
Jake  Offline
Carpal Tunnel

Joined: Jun 2001
Posts: 12,310
South Carolina
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.


Jake Kohl
Re: Faster than the breeze, dead downwind [Re: Jake] #231793
05/02/11 02:41 PM
05/02/11 02:41 PM
Joined: Jun 2001
Posts: 733
Home is where the harness is.....
Will_R Offline
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Will_R  Offline
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Joined: Jun 2001
Posts: 733
Home is where the harness is.....
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

Last edited by Will_R; 05/02/11 02:42 PM.
Re: Faster than the breeze, dead downwind [Re: Will_R] #231903
05/04/11 11:16 AM
05/04/11 11:16 AM
Joined: Mar 2002
Posts: 984
2017 F18 Americas Site
Dan_Delave Offline
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Dan_Delave  Offline
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Joined: Mar 2002
Posts: 984
2017 F18 Americas Site
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]

Re: Faster than the breeze, dead downwind [Re: Dan_Delave] #231913
05/04/11 02:01 PM
05/04/11 02:01 PM
Joined: Dec 2001
Posts: 5,590
Naples, FL
waterbug_wpb Offline
Carpal Tunnel
waterbug_wpb  Offline
Carpal Tunnel

Joined: Dec 2001
Posts: 5,590
Naples, FL
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?


Jay


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