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Author Topic: Directorly Downwind Faster than the Wind  (Read 148415 times)

Rapadura

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Re: Directorly Downwind Faster than the Wind
« Reply #75 on: April 03, 2010, 05:56:46 PM »
Thrust Calculator:

http://personal.osi.hu/fuzesisz/strc_eng/index.htm

How can this help us?

Cloxxki

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Re: Directorly Downwind Faster than the Wind
« Reply #76 on: April 04, 2010, 04:42:50 PM »
Well
Very Cool that it was scaleable!
It seems to be an old school prop design , but there "must" be something special there!

Gotta be something special to over come all that drag and still make power to move?

@Clo
A Tiny replication?
I'll play![gotta be cheap]

Chet

Hi Chet, check this out for a build plan! http://www.youtube.com/watch?v=T-ArigMKhi4
Cheaper than a Mylow replication, I suppose.

Easiest to appreciate result (involving less running after the thing) would be to gear it to fight an upwind.

ramset

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Re: Directorly Downwind Faster than the Wind
« Reply #77 on: April 05, 2010, 01:19:25 PM »
Clo
Sweet!

But I think where missing something ?

what kind of claims are these fellas making?
I can't find any claims as to where they are going with this?

Perhaps Greg [gmeast] has a point, or is this the best thing since canned beer?

Chet


Cloxxki

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Re: Directorly Downwind Faster than the Wind
« Reply #78 on: April 05, 2010, 07:14:42 PM »
It's the best I've seen for sure, just it's not OU. It's the afterburner button we'd not found before.

Claims? A vehicle can take the wind's energy, and attain fast-than-the-wind speeds, I suppose?

The positive feedback loop seems able to extract more energy from the wind than it would be willing to give to a simple sailing cart. In stead of settling for equal-to-wind-speed, the feedback loop boosts cart speed, to a much higher equilibrium wind speed than 100%, limited only by the no-prop drag of the vehicle, and the size and efficiency of the prop used.

We'd not be surprised to learn that a 500ft tall wind turbine could extract sufficient energy to let a toy car on a race track reach 100mph, while the turbine is seeing only 10mph winds. We'd be more surprised to see the same fan, stuck on a relatively vehicle, in the same 10mph winds, hitting 30mph. Still, it's not all that different from an input-output point of view.

I asked Spork whether the world would need to re-think current technology because of his team's findings, and his answer was quite modest, but possibly true.
Wind turbine are not going to extract 3x more energy for the same diameter, I think.
Wind however, IMO does become a more viable (main) power source for a personal vehicle, in everyday traffic. We're learning a lot about storing on the fly (re)generated energy into batteries, and now wind power will need to be reconsidered for our high-speed traveling in low-speed winds. Wind is not just a drag factor that keeps changing, it's a power cource that keeps coming from different directions, every time you take a turn. The way I see it, we now have efficient wind propulsion systems for wind acting on a vehicle from any angle. The +/- 20 degress DDW and upwind, have been little exploited, expecially not on vehicles confined to narrow, straight roads.

ramset

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Re: Directorly Downwind Faster than the Wind
« Reply #79 on: April 06, 2010, 02:36:26 AM »
Cloxxi

SO...........

If we can go faster than the wind,we should be able to go in "no wind"?

Why not?
I'm not being a wise guy, I can't understand this.

Once you exceed wind speed down wind the tell tales go slack!
I have NEVER seen this EVER!
and I sail past wind speed ALL THE TIME![never down wind].

Do you understand whats going on here?
Can you make "apparent wind" in no wind?
That would be a "miracle" No?

Chet

BEP

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Re: Directorly Downwind Faster than the Wind
« Reply #80 on: April 06, 2010, 01:11:38 PM »
I'm with Chet on this.

I can't say I'm much of a sailor. I had a 21' sloop and spent a lot of summers alone on it. If the tell-tales are slack there is no wind seen by the vehicle.
This thing's function seems natural but I still can't explain it.

At least, the armchair debunkers will stay busy.

Cloxxki

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Re: Directorly Downwind Faster than the Wind
« Reply #81 on: April 06, 2010, 01:14:00 PM »
It's all about the positive feedback loop. No energy is being created. It's sucked out of the wind better.
If 5m² of sail can extract x amount of energy from the wind at wind=ground speed V, it can power a 1m² car by more than V.
The propellor, in contrast to a sail, had no negative drag. It's (geared to be) scooping up air faster than it hits the prop at. So, it only offers positive thrust, on top of the speed of the cart.
Only when the losses of the cart (cockpit air drag, rolling resistance) equal the maximum energy input of the wind multiplied by prop efficiency, is equilibrium speed reached. I am not engineer, but that's how I understand it at this point.

Another thought expirent, before testing it in reality:
We have a sloping road, and no wind.
We mark a start and finish line.
We let the cart go at start line, from standstill
We let a cart with freely spinning prop go down it, and time it.
We let the cart, less prop, but with compensating ballast do the same. We likely find a quicker descend time.

Next, we gear the prop to always spin faster than the cart is rolling.

Does the latter cart beat the propless cart? This time there is no difference in cart speed and apparent wind speed to exploit.

It's not meant as a trick question, I haven't thought about it long enough to come to a hypothesis yet.

In stead of the wind (which is proven to work DDW) we'd be trying to exploit the pull of gravity. Gravity has a pulling potential related only to mass and angle, but it doesn't push back when you decide to move "down" quicker than 9.8m/s².

BEP

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Re: Directorly Downwind Faster than the Wind
« Reply #82 on: April 06, 2010, 02:09:31 PM »
Except for the need of drag on the wheels and atmospheric pressure, I doubt gravity has much to do with it.

It seems to just be a difference of potential. The driving wheels create a greater difference of potential between the air in front and behind of the prop. This difference creates more acceleration. More acceleration creates more difference in potential, etc.

This seems more like the air pressure equivalent to a static charge, except a static charge can't continuously increase its own charge.

Maybe reverse of common logic? Perhaps it is a motionless object tends to stay motionless. Maybe they can only travel from East to West?

Enough. Off to work....




Cloxxki

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Re: Directorly Downwind Faster than the Wind
« Reply #83 on: April 06, 2010, 06:07:15 PM »
Except for the need of drag on the wheels and atmospheric pressure, I doubt gravity has much to do with it.
Perhaps the term "traction" fits better than "drag". A perfect cog/rail system will create zero drag for unlimited traction. Actually, a large bicycle wheel offer greater traction for the total load on it, while at the same time reducing rolling resistance compared to the smaller wheel.

It can't be overstated, in case of the DDWFTTW cart, it's all about the speed difference between the ground and the wind. One could also see the prop driven by the wheels as a the cart creating a smaller surface area at its front, compared to its big butt being pushed by the wind. A solid shape can't do that to the same effect. And with DDW, the wind from head is always weaker and slower than from behind. This strength difference is being exploited to get teh wind to push a "second, and third time", if you will.

Any takers for the wind still downhill rolling prop cart's performance vs. a textbook V=1/2 G*T²?
Eternal respect is to be won! I have not asked Spork or other prop cart owners to test this, but it would be equally controversial, if anomolies were to be found...

AlanA

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Re: Directorly Downwind Faster than the Wind
« Reply #84 on: April 06, 2010, 06:35:27 PM »
Hi folks,

for all out there who think that this is a joke see the work in progress:
http://www.fasterthanthewind.org/2009_10_01_archive.html


the idea bases on the project of Dr. Andrew Bauer:
http://projects.m-qp-m.us/donkeypuss/
scoll down to:
DWFTTW Update, Saturday, May 2, 2009
there you can download the paper from Andrew Bauer

You will see that this is not only an idea, it is a reality


Rapadura

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Re: Directorly Downwind Faster than the Wind
« Reply #85 on: April 07, 2010, 03:00:50 AM »
If the wheels of the cart were bigger than the propeller, couldn't the rotation of the propeller be so fast that would give a very high speed to the cart?

Just make the wheels of a very light plastic material and don't put a pilot in the cart, because humans are very heavy.

And make the best possible propeller, a very optmized propeller, that gives maximum thrust.

To test the device, there is no need for a truck pushing it, just suspend the cart in the air, and use a motor to accelerate only the wheels. The rotation of the wheels will make the propeller rotate too. When the propeller is rotating very fast, producing a lot of wind, put the cart in the ground and let it run.

If everything is OK, the cart will never stop again!

ramset

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Re: Directorly Downwind Faster than the Wind
« Reply #86 on: April 07, 2010, 03:27:48 AM »
Alan
Thankyou for the links.
You seem to be a student of this work?

Where do you think this will take us?

I am not being facetious ,I am genuinely interested
In where this could be applied.
Chet 

sparks

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Re: Directorly Downwind Faster than the Wind
« Reply #87 on: April 07, 2010, 04:22:44 AM »
To hell with a propellor put a big old spinning frisby up there and wheels once she lifts off that turn into backward inclined turbine blades.  Adjust the angle of the Frisby to the direction of travel intended.  The low pressure created on the lift surface of the frisby gives it's ability to fly.  You dont throw a frisby to get distance without spinning it.

AlanA

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Re: Directorly Downwind Faster than the Wind
« Reply #88 on: April 07, 2010, 08:57:09 AM »
@ ramset

I am not a student of this work.
I haven' t any relation to this project. I only set down yesterday and did some simple research. So I have found this information. I thought it could be helpful for someone.

You ask where could it be applied? I don't know. But it is very impressive to see the little cart driving so fast.

Cloxxki

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Re: Directorly Downwind Faster than the Wind
« Reply #89 on: April 07, 2010, 09:08:31 AM »
Do you guys actually think that the wind is not needed to go fast down level ground? Free energy everywhere, you just need to want to tap it? Right?
If there is any free energy to be had, it's going to have tpo be in conjuction with gravity. Wind turbines are proven to work, just not without wind. All we see is a cart that can reverse the prop to get more speed from the wind.

If gravity's pull could be exploited extra by the prop cart (I can see it, but not believe it), then that might be real OU. Gently push the cart off a 5m tall ramp. If it goes faster than 9.8m/s at the bottom, you have OU, cart should be able to reset itself, ride up another 5m tall ramp.
In this little fairytale, the force of gravity is used twice : once to get the cart rolling, and once to make the wheel turn the prop to a higher speed than the cart's speed, beating the apparent head wind. <zero wind resistance, if you will. If it sounds too good to be true...