The impossible machine runs faster than the wind pushing it...

[Externet]

This is neeeat... look at the streamers

 

 

There is many more related videos, just picked one. Filled with controversy, many arguments, they built this one to prove/disprove.

I like the "It may work in practice, but won't work in theory"

[ydoaPs]

Gone one where the track is likely to be level?

[swansont]

Can't view this ATM, but when I saw one of these videos, the controversy stemmed from the makers not doing a decent job of explaining how their device worked. I (and others) had assumed the propellers drove the wheels, in which case it won't go faster than the wind — the driving force vanishes at that point. But when the wheels drive the propeller, that restriction goes away.

[TonyMcC]

I don't know about this video, but it is possible to make a wind driven device that can move faster than the wind pushing it.

A sports sailing dinghy can do this when travelling across the wind.

This is basically because the sail act as an airofoil generating horizontal "lift" in the direction of travel.

travelling down wind with the wind behind you can be a much slower process.

[Mr Skeptic]

As TonyMcC said, we've long had machines that can travel faster than the wind, and they're called sailboats. In the case of sailboats its as simple as traveling at an angle from the wind and having enough sail. The same could be done on land, but if you have a wind turbine as your sail you can also use gears.

[Externet]

Perhaps these links are more accesible ?

 

Add www. in front of ---> youtube.com/watch?v=LjLPPInzSzI

 

same, add www. in front of ---> youtube.com/watch?v=GXtB9N6Oxds

 

[forufes]

 

This is basically because the sail act as an airofoil generating horizontal "lift" in the direction of travel.

i don't get it, how would a sail with negligible uniform thickness,generate lift?

and will it do so based on bernolli's or newton's principles?

 

but as per the op. i thought that it was simply the vehicle riding high wind and gain speed, and not lose it when the wind slows down, and so travelling faster than the wind only temporarily.

 

though i find what swansont said interesting, and wish he elaborates.

[Sisyphus]

i don't get it, how would a sail with negligible uniform thickness,generate lift?

 

The sail is curved like the top surface of a wing.

 

and will it do so based on bernolli's or newton's principles?

 

Both.

 

but as per the op. i thought that it was simply the vehicle riding high wind and gain speed, and not lose it when the wind slows down, and so travelling faster than the wind only temporarily.

 

Nope, it's legitimate. They've managed to go almost 3 times wind speed.

[J.C.MacSwell]

I don't see anything controversial. It has to be fairly efficient to go upwind faster than the wind, but it certainly can be done. At some point the drag increases too fast for the increase in available wind energy, but this does not necessarily happen at the same speed (while opposite direction) as the wind.

 

 

 

"Impossible" would be having it work in no wind, even after pushing it to get started.

 

 

Also, a flat plate can generate lift, though it is not very efficient.

Edited August 13, 2010 by J.C.MacSwell

[Sisyphus]

I don't see anything controversial. It has to be fairly efficient to go upwind faster than the wind, but it certainly can be done. At some point the drag increases too fast for the increase in available wind energy, but this does not necessarily happen at the same speed (while opposite direction) as the wind.

 

This is about going downwind faster than the wind, though. Or are you talking about sailboats?

 

Also, a flat plate can generate lift, though it is not very efficient.

 

That's a good point.

[J.C.MacSwell]

This is about going downwind faster than the wind, though. Or are you talking about sailboats?

 

 

No. I meant upwind. Is there something unique about sailboats? I have an iceboat, fairly common design, that will go faster than the windspeed. In light air it will go upwind much faster than downwind. While it will not go directly upwind, it gets there by tacking, and the speed made good to windward is greater than the true windspeed in many conditions.

 

I can't see how you could maintain downwind faster than the wind though.

Edited August 13, 2010 by J.C.MacSwell

[Sisyphus]

 

No. I meant upwind. Is there something unique about sailboats? I have an iceboat, fairly common design, that will go faster than the windspeed. In light air it will go upwind much faster than downwind. While it will not go directly upwind, it gets there by tacking, and the speed made good to windward is greater than the true windspeed in many conditions.

 

I've sailed on iceboats also. They're lots of fun.

 

I can't see how you could maintain downwind faster than the wind though.

 

And yet it seems you can!

[J.C.MacSwell]

I've sailed on iceboats also. They're lots of fun.

 

 

 

And yet it seems you can!

 

Well, we know we have done it in iceboats...sailed with the downwind velocity vector greater than the wind velocity...and two iceboats on opposite tacks can maintain their combined c.g going straight downwind at greater than windspeed...

 

Are the turbine blades accomplishing essentially the same thing?

 

' Have to think about it...

 

Can't view this ATM, but when I saw one of these videos, the controversy stemmed from the makers not doing a decent job of explaining how their device worked. I (and others) had assumed the propellers drove the wheels, in which case it won't go faster than the wind — the driving force vanishes at that point. But when the wheels drive the propeller, that restriction goes away.

 

Now this makes sense. The propeller must be variable pitch. It must be maintained by dynamic braking on the wheels, which drive the propeller which seemingly gathers energy...even though at windspeed the "relative to vehicle" energy source is the road, not the wind.

 

The blades simply push with more net force than the force of the dynamic braking, using the energy of the wind relative to the road, even when the vehicle speed matches the wind and there is no available wind energy relative to the vehicle.

 

Actually it wouldn't have to be variable pitch either, even at the start, though it would be more effective.

 

Energy is a very relative thing.

Edited August 14, 2010 by J.C.MacSwell

[Newbies_Kid]

 

"The crafts' design achieves staggering efficiency. It enables the land craft to travel at between 3 & 5 times the real wind speed, depending on the surface traction."

 

My link

[forufes]

The sail is curved like the top surface of a wing.

which isn't enough to generate lift. there should be a flat surface as well. since the sail is extremely thin (unlike a wing), it shouldn't be able to generate lift according to bernolli's law, even if it is curved.

Both.

by the newtainian principle, the sail would move but never faster than the wind.

 

as for benolli's, let me get this right.

bernolli states that as the velocity of a fluid increases its pressure decreases.

a fluid will move and "push" from the high pressure area to the low pressure one.

by applying that to a wing to generate "lift", we'd want the air under the wing to push towards the air over the wing to generate "lift".

that'll translate to making the air over the wing go faster than the air under it, hence making the air above it with lower pressure than the one under it, hence lift. [something like this but horizontal: l) ]

that is acheived through curving the upper side of the wing ")" and keeping the lower one straight "l" , while my common sense said that the air travelling at the longer curved surface ")" will be slower than the one travelling by the straight short surface "l" because of friction for the former, our teacher said that no, if point A and B were absolutly next to each other before the wing sliced them apart, and point A went through the "l" route and point B went through the ")" route; it is assumed they will be next to each other after the wing seperates them, and hence one would've travelled faster than the other because one route is longer than the other and we assumed the time they took through them was the same, and so, one side faster than the other, one side with higher presser than the other, sooooo, lift, ta-da.

 

a curved sail with uniform negligiblw thickness wouldn't have that apply to it. i don't see how it can generate lift using bernolli's concept.

 

i never bought it anyway, i think it's simply newtainian. the engine scoops the air from the front to the back, the wing flaps tilt the plane and engine up, and that's it.

 

of course the fact that scientists and engineers are debating the issue of which concept is more relative gave me a hint of how much the design of stuff is mainly chance and luck, with little brushs here and there of intentional calculations or knowldge. it's more trial and error than prediction, more of it happening then speculating why and how, than knowing the why and how and then making it happen.

[insane_alien]

which isn't enough to generate lift. there should be a flat surface as well. since the sail is extremely thin (unlike a wing), it shouldn't be able to generate lift according to bernolli's law, even if it is curved.

 

you should see some high camber aerofoils, they essentially approximate this design. used for applications that need high lift at low airspeeds.

[Sisyphus]

forufes, the sailboat does move faster than windspeed, so obviously your reasoning is wrong.

 

The sail does act like an airfoil, as there is a difference between the convex side and the concave side in terms of air path and pressure.

 

And as a Newtonian description, it is as simple as altering the course of a mass of air more rearwards, and conserving momentum by moving forwards. There is no reason the boat cannot move faster than windspeed, as it's simply a matter of transferring more momentum, and the wind has more relative momentum the faster the boat is traveling upwind.

[J.C.MacSwell]

which isn't enough to generate lift. there should be a flat surface as well. since the sail is extremely thin (unlike a wing), it shouldn't be able to generate lift according to bernolli's law, even if it is curved.

 

by the newtainian principle, the sail would move but never faster than the wind.

 

as for benolli's, let me get this right.

bernolli states that as the velocity of a fluid increases its pressure decreases.

a fluid will move and "push" from the high pressure area to the low pressure one.

by applying that to a wing to generate "lift", we'd want the air under the wing to push towards the air over the wing to generate "lift".

that'll translate to making the air over the wing go faster than the air under it, hence making the air above it with lower pressure than the one under it, hence lift. [something like this but horizontal: l) ]

that is acheived through curving the upper side of the wing ")" and keeping the lower one straight "l" , while my common sense said that the air travelling at the longer curved surface ")" will be slower than the one travelling by the straight short surface "l" because of friction for the former, our teacher said that no, if point A and B were absolutly next to each other before the wing sliced them apart, and point A went through the "l" route and point B went through the ")" route; it is assumed they will be next to each other after the wing seperates them, and hence one would've travelled faster than the other because one route is longer than the other and we assumed the time they took through them was the same, and so, one side faster than the other, one side with higher presser than the other, sooooo, lift, ta-da.

a curved sail with uniform negligiblw thickness wouldn't have that apply to it. i don't see how it can generate lift using bernolli's concept.

 

i never bought it anyway, i think it's simply newtainian. the engine scoops the air from the front to the back, the wing flaps tilt the plane and engine up, and that's it.

 

of course the fact that scientists and engineers are debating the issue of which concept is more relative gave me a hint of how much the design of stuff is mainly chance and luck, with little brushs here and there of intentional calculations or knowldge. it's more trial and error than prediction, more of it happening then speculating why and how, than knowing the why and how and then making it happen.

 

The old "paired molecules splitting and meeting back together after traveling different paths" explanation leads to problems. It has erroneous assumptions leaving it only partially correct. Most sails can be made to work quite well.

 

There really is no debate outside of how best to explain things. Newtonian explanations are correct if the right assumptions are in place. Bernoulli's Principle is based on certain idealized assumptions and is in agreement with and based on Newton's laws.

[TonyMcC]

I don't see anything controversial. It has to be fairly efficient to go upwind faster than the wind, but it certainly can be done. At some point the drag increases too fast for the increase in available wind energy, but this does not necessarily happen at the same speed (while opposite direction) as the wind.

 

 

 

"Impossible" would be having it work in no wind, even after pushing it to get started.

 

 

Also, a flat plate can generate lift, though it is not very efficient.

 

/quote]

 

 

I don't think it is possible to travel against the wind (upwind) faster than the wind.

The proposed device would not differentiate between true wind and air passing over or through it.

Thus, if standing still and headed into the wind, it would start to move and accelerate up to the point where resistance to its movement would stabilise its speed.

If the actual (true ) wind then ceased there would still be air passing over the proposed device.

It would continue to move, indeed it would speed up since the drag component of resistance would be reduced.

We have a perpetual motion machine - or have we?

[Bignose]

Something does not have to have thickness to generate lift. See the excellent book by Batchelor An Introduction to Fluid Dynamics section 6.9, as just one example of the calculation of the lift on a plane presented in many fluid mechanics texts.

Edited August 15, 2010 by Bignose

[J.C.MacSwell]

 

 

I don't think it is possible to travel against the wind (upwind) faster than the wind.

The proposed device would not differentiate between true wind and air passing over or through it.

Thus, if standing still and headed into the wind, it would start to move and accelerate up to the point where resistance to its movement would stabilise its speed.

If the actual (true ) wind then ceased there would still be air passing over the proposed device.

It would continue to move, indeed it would speed up since the drag component of resistance would be reduced.

We have a perpetual motion machine - or have we?

 

If the true wind disappears you have no energy source but your momentum (kinetic energy) relative to the ground.

 

Since you still have drag your device will eventually come to rest.

 

Also, you certainly can go upwind at faster than windspeed. (been there, done that, as has Sisyphus in iceboats...unless his iceboat was a real beater )

 

As for the bolded, the device would "know" it is moving over the ground, as the energy source it uses to maintain it's speed or accelerate is the kinetic energy of the wind relative to the ground, and the energy it expends in traction would be vehicle relative to ground. So it would "know" if it was true or apparent wind.

Edited August 16, 2010 by J.C.MacSwell

[forufes]

you should see some high camber aerofoils, they essentially approximate this design. used for applications that need high lift at low airspeeds.

perhaps you'd elaborate, as google couldn't help much.

 

And as a Newtonian description, it is as simple as altering the course of a mass of air more rearwards, and conserving momentum by moving forwards. There is no reason the boat cannot move faster than windspeed, as it's simply a matter of transferring more momentum, and the wind has more relative momentum the faster the boat is traveling upwind.

EUREKA!

sisyphus you're a GENIUS!

i've thought a lot about this, and reached an analogy, well, kind of..

if you have a vehicle running off a hamster in a wheel, the vehicle can reach a speed faster than the hamster running it.

i always had the problem when trying to imagine a sail boat running faster than the wind pushing it, that the wind particles would actually trying to reach the sail but couldn't, like you won't be able push a speeding car..

.. however, if the boat was going straight up[as a direction] and the sail was tilted at 45 deg for example, and the air came from the right side[90deg], the x component of the relative velocity of the boat to the wind is zero!.. so as long as the wind is faster than zero, it will hit the sail and add momentum to the boat as you said..

 

one problem though, the sail when moving up; its tilted sail will displace the air particles up faster than the ones from the right can replace, no?

 

i think i've grasped the concept but can't quite digest it fully yet..

The old "paired molecules splitting and meeting back together after traveling different paths" explanation leads to problems. It has erroneous assumptions leaving it only partially correct. Most sails can be made to work quite well.There really is no debate outside of how best to explain things. Newtonian explanations are correct if the right assumptions are in place. Bernoulli's Principle is based on certain idealized assumptions and is in agreement with and based on Newton's laws.

hey i didn't buy it either, but was what we were taught in school.

[TonyMcC]

If the true wind disappears you have no energy source but your momentum (kinetic energy) relative to the ground.

 

Since you still have drag your device will eventually come to rest.

 

Also, you certainly can go upwind at faster than windspeed. (been there, done that, as has Sisyphus in iceboats...unless his iceboat was a real beater )

 

As for the bolded, the device would "know" it is moving over the ground, as the energy source it uses to maintain it's speed or accelerate is the kinetic energy of the wind relative to the ground, and the energy it expends in traction would be vehicle relative to ground. So it would "know" if it was true or apparent wind.

 

 

As I don't believe in perpetual motion machines I agree with your first statement - I was being slightly sarcastic when I suggested that was perhaps what we had.

I am going to do what is obviously unwise. I am going to express an opinion about something I have no experience of - iceboats.

I do have experience of racing sailing dinghies and when tacking against the wind the actual speed of the boat can be considerably higher than the wind speed and quite exciting. However when you consider the staight line distance covered into the wind and the time taken and use those figures to calculate speed you always find the speed less than that of the wind. I believe the same must be true for iceboats. My challenge to you is to provide some reliable recorded evidence that iceboats can travel directly into the wind or, when you work your way against the wind by tacking and you calculate speed from straight line distance covered into the wind and time taken, the answer can be greater than wind speed.

 

If the true wind disappears you have no energy source but your momentum (kinetic energy) relative to the ground.

 

Since you still have drag your device will eventually come to rest.

 

Also, you certainly can go upwind at faster than windspeed. (been there, done that, as has Sisyphus in iceboats...unless his iceboat was a real beater )

 

As for the bolded, the device would "know" it is moving over the ground, as the energy source it uses to maintain it's speed or accelerate is the kinetic energy of the wind relative to the ground, and the energy it expends in traction would be vehicle relative to ground. So it would "know" if it was true or apparent wind.

 

 

As I don't believe in perpetual motion machines I agree with your first statement - I was being slightly sarcastic when I suggested that was perhaps what we had.

I am going to do what is obviously unwise. I am going to express an opinion about something I have no experience of - iceboats.

I do have experience of racing sailing dinghies and when tacking against the wind the actual speed of the boat can be considerably higher than the wind speed and quite exciting. However when you consider the staight line distance covered into the wind and the time taken and use those figures to calculate speed you always find the speed less than that of the wind. I believe the same must be true for iceboats. My challenge to you is to provide some reliable recorded evidence that iceboats can travel directly into the wind or, when you work your way against the wind by tacking and you calculate speed from straight line distance covered into the wind and time taken, the answer can be greater than wind speed.

 

As I don't believe in perpetual motion machines I agree with your first statement - I was being slightly sarcastic when I suggested that was perhaps what we had.

I am going to do what is obviously unwise. I am going to express an opinion about something I have no experience of - iceboats.

I do have experience of racing sailing dinghies and when tacking against the wind the actual speed of the boat can be considerably higher than the wind speed and quite exciting. However when you consider the staight line distance covered into the wind and the time taken and use those figures to calculate speed you always find the speed less than that of the wind. I believe the same must be true for iceboats. My challenge to you is to provide some reliable recorded evidence that iceboats can travel directly into the wind or, when you work your way against the wind by tacking and you calculate speed from straight line distance covered into the wind and time taken, the answer can be greater than wind speed.

 

 

 

 

As I don't believe in perpetual motion machines I agree with your first statement - I was being slightly sarcastic when I suggested that was perhaps what we had.

I am going to do what is obviously unwise. I am going to express an opinion about something I have no experience of - iceboats.

I do have experience of racing sailing dinghies and when tacking against the wind the actual speed of the boat can be considerably higher than the wind speed and quite exciting. However when you consider the staight line distance covered into the wind and the time taken and use those figures to calculate speed you always find the speed less than that of the wind. I believe the same must be true for iceboats. My challenge to you is to provide some reliable recorded evidence that iceboats can travel directly into the wind or, when you work your way against the wind by tacking and you calculate speed from straight line distance covered into the wind and time taken, the answer can be greater than wind speed.

 

 

Seems I have to apologise - done some enquiring and it seems iceboats can make distance into the wind faster than the wind if they can sail closer than 20 degrees to the wind - put it down to me not being such a good sailor lol. I didn't think anything could sail that close to the wind!

[Subduction Zone]

The vehicle in the video has no problem sailing directly downwind faster than the wind. This has been debated on the internet for years and is one of my favorites. I was a naysayer at first as well, but I found every preconceived notion I had of aerodynamics and sailing seemed to have been wrong. One of the major claims is that if this device goes faster than the wind that would constitute perpetual motion. I can assure you that it does not break any laws of thermodynamics. The cart gets its energy by lowering the speed of the wind relative to the ground. After the air passes through the rotator disc of the propeller its velocity is slower than it was before. Where did that energy go? Into driving the cart of course.

 

There are also videos of small carts running on treadmills. For anyone who is familiar with the relatively simple concept of a Galilean Transformation it is obvious that if the cart can advance up the treadmill it can go faster than the wind. I am nowhere near as expert as the builders of this cart, but I will try to answer any questions about it.

[Subduction Zone]

Update. The Blackbird, the vehicle that went directly downwind faster than the wind, has been reconfigured. The propeller was replaced with a rotor that works better as a turbine, the gearing has been changed too so that now the turbine drives the wheels instead of the wheels driving a propeller. It has been turned from a downwind cart to an upwind cart. This last weekend they ran it directly into the wind at a speed nearly twice the speed of the wind. You can read more here:

 

Directly upwind blog.