Driven by wind, downwind, faster than the wind...

[onetrack]

Thruster, balloons possibly wouldn't add anything of accuracy to the measurements, as they would be travelling in a different level and speed of airflow.

[Thruster88]

4 minutes ago, onetrack said:

Thruster, balloons possibly wouldn't add anything of accuracy to the measurements, as they would be travelling in a different level and speed of airflow.

Yes I thought about that. If they had neutral bouncy and were released at say 3m height at regular intervals it would be a lot better than a steamer attached to the vehicle, possibly in the wind shadow. 

[Red]

On 24/08/2021 at 3:52 PM, onetrack said:

The wheels are actually driving the propellor via leverage, the wind is not driving the propellor. The propellor is pushing the vehicle forward, against the tailwind. There are multiple factors at work here, propellor efficiency being just one of them.

 

Put simply, the car is leveraging the available energy from the tailwind, to travel faster than the wind speed.

 

https://docs.google.com/document/preview?id=10qzwC8BmR3fr-ezvSveZ1cOJxZ_4gObOk3DHHaPp2GY

Sorry to be blunt, but taken as read that is complete nonsense

 

P.S. Just read the attached file ..good grief does that guy  sell Dihydrogen Monoxide

 

Edited October 16, 2021 by Red

[Red]

On 24/08/2021 at 4:25 AM, facthunter said:

It's not perpetual motion though when you get and use  energy from some thing in an efficient way.. Nev

You can't get more than 100% efficiency in any energy conversion, this device is a joke cleverly explained

[Red]

The short clip of the model on the treadmill at first glance will convince some, look closely and you will notice that she holds the model for a short time so that energy is put into the system and on releasing it drives the model, basicly the treadmill is spinning up the wheels while she inputs a force to keep the model stationary instead of it reacting and moving backwards, the whole description is cleverly tthought out and explained, but its a joke

[facthunter]

Treadmills are not valid for the things they are trying to illustrate. I can't see why it was introduced. A propeller is not a flat plate and like a sail angled to the wind brings is different possibilities. Nev

[IBob]

I don't see why not: in both cases the air is moving relative to the surface. If you think about it, the planet we live on is one enormous treadmill moving under the atmosphere around it?

[facthunter]

The "atmosphere"" generally moves with it, otherwise the prevailing wind would be from the  East. Nev

[IBob]

We just had yet another Americas Cup, with all the contenders sailing faster than the speed of the wind. Granted this was not downwind, and granted the mechanics of what is going on is different and initially counterintuitive, but I can see no reason to reject it out of hand just because we can't initially see how it works.

 

[onetrack]

If substantial free energy is available from the wind, it's not that hard to arrange the energy flow, so that the device can propel itself faster than the wind speed. The power available from the wind is enormous.

 

I guess this means Red believes those big wind turbines are a huge fraud too - producing vast amounts of electrical energy from just a bit of wind, can't be possible!

[facthunter]

There have been wind assisted container ships with vertical axis sails that would go downwind faster than the wind at times. . Nev

[kgwilson]

My reverse cycle air conditioner produces over 8KW of heat for 2KW of input power which is excellent conversion efficiency just as a foiling yacht can exceed 50 knots in a 15 knot wind. That is not directly down wind but is using the kinetic energy of the wind in the most efficient manner.

[onetrack]

Prof Brad Blackford of Novia Scotia has built several boats, utilising a wind-driven propellor to provide energy to drive the boat directly into the wind. The wind-driven propellor drives a propellor under the hull in normal fashion, via a driveshaft.

Blackfords design allows the wind-driven propellor to rotate 360° and face into the wind, regardless of which direction the boat is travelling.

In an interview with Bradford, he explained how he'd perfected the idea over 35 years of tinkering and calculation. He utilises a carbon-fibre propellor with a foam core.

As Bradford states, "You're looking for maximum net force, not maximum net power. There's a subtle difference". 

 

https://www.bluebird-electric.net/wind_powered_ships_marine_renewable_energy_research.htm

 

In 2009, Prof Marc Drela - an MIT professor of aeronautics and astronautics - produced the first equations, demonstrating the feasibility of "Dead-Downwind Faster Than The Wind (DDWFTTW)".

 

http://www.change-climate.com/Transport_Land_Sea_Sustainable/Assisted_Ships_Sails_Solar_Projects_Marine_Pollution/Rotary_Sails_Powered_Sailing_Boats_Ships_Turbines_Wind_Cars.htm

 

Maybe Red needs to study up his physics and Newtonian Laws again.

 

https://www.physicsclassroom.com/class/newtlaws/Lesson-2/Determining-the-Net-Force

[Flightrite]

Looks simple enuf to me but I guess some just see ‘Red’ at such sruff😂😉

[APenNameAndThatA]

On 16/10/2021 at 6:32 PM, Red said:

The short clip of the model on the treadmill at first glance will convince some, look closely and you will notice that she holds the model for a short time so that energy is put into the system and on releasing it drives the model, basicly the treadmill is spinning up the wheels while she inputs a force to keep the model stationary instead of it reacting and moving backwards, the whole description is cleverly tthought out and explained, but its a joke

I’d believe you if you understood the maths. 

[Bruce Tuncks]

I cannot see why the wind was necessary...  why could the vehicle not work in zero wind, given a push start?

This would of course give you a perpetual motion machine, ( eg a circular track ) and solve the world's energy problems.

[IBob]

Bruce. with no wind the only force acting on the thing would be gravity (okay, and equal air pressure all round) and no resulting movement on flat ground.

[Bruce Tuncks]

Ibob, you make a good case why the trolley would not START moving in zero wind... There is no relevant propelling force.

Why is that different from the case where the trolley is going at exactly the same as the speed of the wind?

And remember I said how an initial push would be needed to start the process.

So my question remains...  why is the wind needed? What if the wind dropped away to zero along the way? Why would the trolley stop?

 

[Bruce Tuncks]

I tried to find the mathematics, but only got a woman explaining nothing much. I was more impressed with the story about the boat that could travel UPWIND, but I don't believe that either. (Tacking sailboats with angled sails excepted here, I am referring to a simple setup where a wheel or water driven propeller is doing the driving)

[jackc]

Wind power 🙂 

https://fb.watch/8IkOxXqwva/

[IBob]

Bruce, if the wind dropped to zero, the various frictions of the wheels etc would cause the vehicle to slow and stop. Exactly as it does with any other vehicle.
I can see where this may look like and attempt at a perpetual motion machine, but it's not. It would only be that if the thrust developed by the prop was greater than the rolling energy required to drive the prop. So it can't work in nil wind, but with a constant wind delivering energy to the system (by pushing it along), very careful gearing and avoidance of friction enable the rolling wheels to also turn the prop. I would suggest there is a narrow envelope where this works, or we would indeed have something that accelerates indefinitely!

[onetrack]

Bruce, the wind is needed, because it's the primary and sole energy force. The propellor merely converts the energy available in the wind pressure, to movement - and that movement can be faster than the wind speed.

 

https://www.physicsclassroom.com/Class/newtlaws/u2l1a.cfm#first

[Bruce Tuncks]

I sort of understand the energy argument, which says that the energy in the wind stream wake will be less than otherwise, and this provides the source of the energy needed to run the thing.

It is just so contrary to my intuition that I can't understand what is going on.

Just a bit like the mercury ring prop automatic  balancer, which blokes whose brains I respect say works well, but I just don't understand it.

 

 

 

 

[IBob]

It's certainly a curly one, Bruce, and if we can believe the story, the physics prof lost $10,000 and I would suggest part of his reputation because he couldn't see it.
While some of the principals are different, I found the wheely thing at about 1330 on the YouTube recording quite useful: it shows a free running wheeled object being driven forward by something pushing on it, but travelling forward faster than what is pushing it. In a sense that is what the wind car is doing: being pushed by the wind, which turns the wheels, a certain amount of that turning energy then being used to push back against the wind.

Edited October 18, 2021 by IBob

[Bruce Tuncks]

Thanks Ibob, I finally found  Drela's paper and followed the argument through. While it still seems counter-intuitive, I am forced to accept the logic.

Well I have an electric bike and this can of course be powered by wind energy and go faster than the wind, but this is not counter-intuitive for me.