Moving faster than the wind using only wind power

I'm guessing most people have seen this by now considering how viral the original video went but for those who haven't this is a really interesting machine which can move faster than the wind using only wind power. Even after watching all these explanations my mind still has a hard time understanding how it works. One physicists was so convinced it didn't work he bet $10,000 that Derek was wrong.

a reply to: ChaoticOrder

Sailboat have always gone faster than the wind pushing them.
Why is doing this on land any different than a sailboat?

I see the problem. The string is at ground level. The propeller is up in the air. The air is always slower at ground level because of the drag on the ground. The propeller never gets to the speed of the wind because the wind is faster up there.

I am underwhelmed by this fail. Go fly a kite, you will get the proof from that.

a reply to: Bluntone22

I believe it is based on a similar principle, the last video explains it with the help of sailboats. But I do find it interesting how all these videos provide a sort of different explanation for how it works. The pulley/gearing explanation is what made the most sense to me.

a reply to: Bluntone22

Sailboats that go faster than the wind do not use direct downwind. And need to travel in a zig zag pattern.

The bet was can you go faster than the wind using only direct downwind as the 'power source'.

a reply to: beyondknowledge

The propeller is attached to the wheels with a chain so that it acts as a fan, if I understand it correctly. The way it works has nothing to do with different wind speeds at different heights. The physicist who made the bet with Derek used a similar argument to "debunk" this machine. Spoiler, he lost 10K.

a reply to: strongfp

There is nothing direct downwind in the propeller. It is traveling at an angle exactly like a sailboat would in the zig zag to go faster than the wind. Also the wind is faster at the propeller than at the indicator.

a reply to: ChaoticOrder

The propeller is not directly down wind. It is at an angle to the wind.

To prove this you would need pitot tubes placed at different heights actually neasuring the wind on the vehicle, one above the propeller, one centered at the propeller, one below and one at the body of the vehicle. There would be a difference in speed between them. The string is only proof of the vehicle going faster than the ground wind.

I would not have paid the bet because there is no proof that the entire vehicle went faster than the wind.

a reply to: beyondknowledge

That's the whole point... to prove that a vessel or cart, or whatever you want to call it can use downwind only and go faster than the downwind speed itself, in the direction of the wind. The propellers are the means of how that is achieved coupled with certain gearing configurations.

It's a very specific experiment...

a reply to: beyondknowledge

To prove this you would need pitot tubes placed at different heights actually neasuring the wind on the vehicicle, one above the propeller, one centered at the propeller, one below and one at the body of the vehicle. There would be a difference in speed between them. The string is only proof of the vehicle going faster than the ground wind.

I would highly suggest you watch the second video. That has already been done, and like I said it has nothing to do with how this works. The 3rd video I embedded from Xyla shows a small scale device which actually blows my mind even more than the large scale version because it doesn't need wind, yet moves forward on the treadmill, demonstrating how this really does come down to gearing ratios.

a reply to: strongfp

Gotcha

a reply to: ChaoticOrder

If it works the way he says in the second video, the wind is irrelevant. With no wind, the vehicle should be able to be pushed to a slow speed and then it will accelerate continuously on its own until it is stopped or crashes. Now that would be impressive.

While this explanation could be correct, the bet is lost and the videos are incorrect because it is not wind powered.

originally posted by: beyondknowledge
I see the problem. The string is at ground level. The propeller is up in the air. The air is always slower at ground level because of the drag on the ground. The propeller never gets to the speed of the wind because the wind is faster up there.

I am underwhelmed by this fail. Go fly a kite, you will get the proof from that.

Good objection, one of the same objections made by the physics professor who bet $10000 that and other things explained it. Watch the second video, he admitted he lost the bet.

originally posted by: beyondknowledge
a reply to: ChaoticOrder

If it works the way he says in the second video, the wind is irrelevant. With no wind, the vehicle should be able to be pushed to a slow speed and then it will accelerate continuously on its own until it is stopped or crashes. Now that would be impressive.

The second video doesn't say that, you're misinterpreting the video.

While this explanation could be correct, the bet is lost and the videos are incorrect because it is not wind powered.

If it's not powered by the wind, what powers it?

a reply to: Arbitrageur

You did not watch the second video? The wheels power the propeller to push the vehicle forward as the wheels roll. At least that is what is said in that video and also on all the treadmill models that seem to work.

a reply to: beyondknowledge

The large version is definitely powered by the wind, where else is the energy coming from? The small version seems to work because the wheels turn the fan, which provides thrust, so it is also wind powered in a sense, but the energy must really be coming from the treadmill. The large version seems to work a similar way because the propeller is connected to the wheels. The vehicle wont keep accelerating forever, there is a limit we can calculate.

originally posted by: beyondknowledge
a reply to: ChaoticOrder

If it works the way he says in the second video, the wind is irrelevant. With no wind, the vehicle should be able to be pushed to a slow speed and then it will accelerate continuously on its own until it is stopped or crashes. Now that would be impressive.

While this explanation could be correct, the bet is lost and the videos are incorrect because it is not wind powered.

Thats exactly what happens in a treadmill. Your lack of understanding makes me think you might ve a UCLA physics professor.

originally posted by: beyondknowledge
a reply to: Arbitrageur

You did not watch the second video? The wheels power the propeller to push the vehicle forward as the wheels roll. At least that is what is said in that video and also on all the treadmill models that seem to work.

And what powers the wheels? The wind pushing on the cart, so it's wind powered. Yes I watched the second video but I interpreted it correctly, nothing in the second video implies "the vehicle should be able to be pushed to a slow speed and then it will accelerate continuously on its own until it is stopped or crashes", it will begin slowing down as soon as you stop pushing it if there's no wind.

You are all still thinking the wind pushed the propeller around. I thought so to at first.

The wheels drive the propeller to push the vehicle like the fan on an air boat would. Only the power for this fan is provided by the wheels and not the wind. The wind just starts it rolling then the wheel powered fan pushes it forward accelerating it.

As I have stated, this vehicle is not wind powered and the wind is totally irrevelant to its operation. Push it to a cartain speed and it will accellerate on its own if it works as explained in the second video and all the treadmill models that work.

Yes, there would be a limit to its speed as air resistance increases with speed. The main limit is how long a flat, smooth, track you can run it on.

Why not take it to an oval race track on a calm day and run it for hours non stop? That would be really impressive but he would have to pay the bet off to the physicist because the wind is not powering it.

a reply to: beyondknowledge

You are all still thinking the wind pushed the propeller around. I thought so to at first.

No, we aren't. I've said multiple times the propeller acts like a fan.

Only the power for this fan is provided by the wheels and not the wind. The wind just starts it rolling then the wheel powered fan pushes it forward accelerating it.

And what powers the wheels? The wind. If the wind speed dropped to zero after the vehicle was above wind speed, I believe it would slowly decelerate without the extra wind to push the craft the turn the fan. It can only accelerate if there is energy coming into the system, and without the external wind power that isn't the case, so friction will cause the vehicle to lose energy and slow down.

a reply to: ChaoticOrder

And what powers the wheels? The wind. If the wind speed dropped to zero after the vehicle was above wind speed, I believe it would slowly decelerate without the extra wind to push the craft the turn the fan. It can only accelerate if there is energy coming into the system, and without the external wind power that isn't the case, so friction will cause the vehicle to lose energy and slow down.

Then how do you explain the treadmill models? They had no wind, only the spinning wheels.

To accuratly simulate the full size one on the treadmill, you would have to put a fan blowing opposite the treadmill direction and the same speed wind. That was not the case. They still went forward without the wind.