Interesting sail technology which may have implications for clean energy....

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webbie

webbie

Seasoned Moderator
Nov 17, 2005
12,165
Western Mass.
This is the subject of a vast debate among nerds and geeks and physicists....
http://www.youtube.com/watch?v=5CcgmpBGSCI&feature=related

The challenge was to build a machine which could go faster than the wind - directly downwind. This was thought to be impossible. But it has been confirmed by many people who saw it and benchmarked it. This goes 3X as fast as the wind.
For those who don't sail, the basics are this. You can go on a angle to the wind and beat it, but never directly downwind. Think of it this way - release a balloon on a windy day and it can only move as fast as the wind! It can't beat it. Well, now it can!

Amazingly enough, in these days of science and engineering, some (or all) have not quite figured out how or why this can be done. But if it is truly as it seems, this is a breakthrough! One example said that giant sails of this type put on a cargo ship could save 7% in fuel over an ocean crossing!

http://en.wikipedia.org/wiki/Sailing_faster_than_the_wind#Sailing_dead_downwind_faster_than_the_wind
 
That thing is awesome. Can you imagine getting into something with that size prop spinning behind your head? I hope that bowsprit is an instrument and not meant as pitch pole protection.
 
So, if we build a solar sail does this mean we can go faster than the speed of light?
 
I am not good at brainteasers, but if I had to think about how this thing works.... probably wrong!

It is pushed by the wind until the wind is no more - that is when it achieves the speed of the wind, but as it passes through the wind, the sails turn pitch in such a way that they convert the wind coming from the front (the apparent wind is coming from the front once it passes wind speed) ----so it acts like a sail up to wind speed and a propeller or wind turbine once the wind is in front of it.....

Heck if I know. I could not understand their diagrams about it wrapping around a small planet!


What amazes me is that a lot of people still say it does not work! They claim it doesn't because there is no such thing as a perpetual motion machine! But it's not one of those......it's simply an energy converter.

Actually, I am in Miami over the weekend and just sailed a cat today - definitely faster than the wind (but not downwind!).
 
so is this kind of like that "sail boat" that has a giant wind turbine on top and a drive shaft from the turbine to a prop in the water, it "sails" in any given direction you want as the turbine is always facing into the wind and getting power.
http://www.youtube.com/watch?v=NNbNNSDljGI
this isn't the biggest one I have seen video of, there is one that is on a 30 something foot cat, in the video it is moving at a rapid rate, makes you think there is a real motor involved somewhere also.
http://www.youtube.com/watch?v=IzGCYaJbf0A
 
rowerwet said:
there is one that is on a 30 something foot cat, in the video it is moving at a rapid rate, makes you think there is a real motor involved somewhere also.
Click to expand...

7 knots rapid? Two hulls and a mast should plane.
 
Webmaster said:
I am not good at brainteasers, but if I had to think about how this thing works.... probably wrong!

It is pushed by the wind until the wind is no more - that is when it achieves the speed of the wind, but as it passes through the wind, the sails turn pitch in such a way that they convert the wind coming from the front (the apparent wind is coming from the front once it passes wind speed) ----so it acts like a sail up to wind speed and a propeller or wind turbine once the wind is in front of it.....

Heck if I know. I could not understand their diagrams about it wrapping around a small planet!


What amazes me is that a lot of people still say it does not work! They claim it doesn't because there is no such thing as a perpetual motion machine! But it's not one of those......it's simply an energy converter.

Actually, I am in Miami over the weekend and just sailed a cat today - definitely faster than the wind (but not downwind!).
Click to expand...

Certainly over my head on physics & engineering here and I didn't find an explanation on a quick look through the website, but I don't get how that would work exactly. Watching how it slowly accelerates, then builds speed quickly as forward speed increases I'd GUESS that it is geared more simply than that:
The wheels may simply drive the propeller as, well, a propeller. So from a standstill, the wind just pushes on the prop blades & body like a sail and then the wheels convert groundspeed to prop power, pushing the prop to spin against the (true) wind. It can get above windspeed by trading greater torque (at the wheels) for greater velocity (at outer ends of the prop blades) just like a transmission.
I dunno if that explanation maks sense, bit it sounds good in my own head %-P
 
btuser said:
This video helped me try to understand. I'm looking at it and I don't think its going to work. I'm like Coco.

http://www.youtube.com/watch?v=k-trDF8Yldc&feature=related
Click to expand...

Wow, very interesting demos !! I became first acquainted with FTTW sailing on the various sailing and cruising websites I used to hang out on in my ocean sailing days.

In fact, I always thought I had a pretty good idea how FTTW works. Until I saw these demos, that is.

Lots of food for thought......

Henk[del][/del]
 
btuser said:
This video helped me try to understand. I'm looking at it and I don't think its going to work. I'm like Coco.

http://www.youtube.com/watch?v=k-trDF8Yldc&feature=related
Click to expand...

I sit there listening to this Mr. Rogers guy & watching him play with some lego, thread spools and a ruler, talking with stuffed animals and he slowly & methodically blows my mind! :wow:
In the end I see the thing works in the way I thought it did, ...or possibly I still don't see at all. I also see that I should stop thinking about it while my reality is still mostly intact.

It's very cool, but I'm not seeing practical applications... Not to say there isn't cool wind tech in development for power generation (piezo-electric rods, flying turbines tethered with cables, wind concentration...) I just don't see how this prinicple would apply for anything other than locomotion direct downwind.
 
Very cool technology.
 
This is fantastic news!

Now that the 100% efficiency barrier has not only been broken, but indeed shattered, it's only a matter of time before economies of scale will make wind energy limitless and virtually free for all.

I'm just afraid that the Republican House will put the kibosh on this somehow.

--ewd
 
midwestcoast said:
It's very cool, but I'm not seeing practical applications... Not to say there isn't cool wind tech in development for power generation (piezo-electric rods, flying turbines tethered with cables, wind concentration...) I just don't see how this principle would apply for anything other than locomotion direct downwind.
Click to expand...

I also am not optimistic that there will be a whole slew of practical applications. After all, none of the component technologies constitute a real breakthrough. Basically, they just have been put together in a very clever way to try and overcome/break old sailing or wind-carting limitations and records.

Interestingly, the real holy grail here is not to go faster than the wind while sailing/riding DOWNwind, but rather to sail/ride directly UPwind at a speed over the ground faster than the true wind speed. In a way, they have been using the downwind start as a means to get up to speed but as soon as their speed over the grou8nd surpasses the true wind speed they are effectively going UPwind again.

Since they achieved speeds (over the ground) in the 2.6 -2.8 x true wind speed range, they have already demonstrated that it is possible to drive against the wind at an apparent speed of 1.6 -1.8 X the true wind speed. Some, however, might call this cheating because they used the initial downwind part of the run to slingshot themselves into the upwind part of the run.

Therefore, they say they are now working to achieve a speed over the ground greater than the true windspeed while going directly UPwind from a standing start . There seems little doubt that they will be able to achieve that goal soon since miniature carts have already been able to do so on a treadmill.

Henk
 
Its a neat math problem but I don't see it as a revolutionary energy source. Its a feedback loop, but instead of being plugged into the wall their plugged into the wind. Better to keep the windmill charging a car and leave the extra weight at home.
 
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