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Topic: Direct Down Wind Faster Than The Wind (Read 6022 times) previous topic - next topic

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Re: Direct Down Wind Faster Than The Wind
Reply #50
Also Mythbusters dropped the ball.  I think they feared you would upstage them, and they really hate that.
Don't you see? The H's stopped Mythbusters and all other primetimes from running this stuff.

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Re: Direct Down Wind Faster Than The Wind
Reply #51
Quote
Interestingly, there's some doubt as to whether Bauer's manned cart really achieved DDWFTTW. However, we now know that he too made treadmill models that he demonstrated to the folks at Aerovironment, and that they were definitely successful. What we never have found is the name of the student that wrote the paper that inspired Bauer to build his carts.
http://forums.sailinganarchy.com/index.php?showtopic=82175&page=39
"If you pick up a starving dog and make him prosperous he will not bite you. This is the principal difference between a dog and man."
― Mark Twain 🔭

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Re: Direct Down Wind Faster Than The Wind
Reply #52
50 years from now this is going to happen all over again.
"If you pick up a starving dog and make him prosperous he will not bite you. This is the principal difference between a dog and man."
― Mark Twain 🔭

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Re: Direct Down Wind Faster Than The Wind
Reply #53
 Colin "Dynamic soaring in uniform wind" Taylor has made a video:

https://www.youtube.com/watch?v=CdaoiplgyII

He should have spent his time learning some physics instead.

You might still  remember him from a discussion here on TR and this:
https://www.bou.org.uk/dynamic-soaring/
Debunked here:
https://www.bou.org.uk/birds-and-dynamic-soaring/




  • MikeB
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Re: Direct Down Wind Faster Than The Wind
Reply #54
Colin has himself well convinced that KE tradeoffs with respect to the ground / water are where the bird's energy comes from, if I followed his painfully long video.  The bird doesn't interact with the water, doesn't touch it, so that must be wrong.  It's wind gradient being exploited, apparently, as shown by the 500+ mph record for RC glider dynamic soaring circling between two air masses moving with respect to each other.

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Re: Direct Down Wind Faster Than The Wind
Reply #55
As well as using wind shear, the record R/C glider was also utilising the fact that the general air mass was rising, with the wind blowing up the slope.
Any albatross will travel long distances without the need to circle, using the wind rising up the face of a decent wave, and slope soaring/ridge running.
Interestingly, like the still air/moving ground surface treadmill analogy, you don't need any wind if you have a moving sloping surface like a wave.
 At indoor model flying meetings, you sometimes get the odd nutcase walking around the room with a sheet of card held at an angle. In front of him is a small, very light, glider, usually made from thin Styrofoam, with a flying speed of 3 or 4 mph. As long as you keep walking and moving the slope through the air, the glider will keep flying. 
An easy experiment to try!

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Re: Direct Down Wind Faster Than The Wind
Reply #56
At indoor model flying meetings, you sometimes get the odd nutcase walking around the room with a sheet of card held at an angle. In front of him is a small, very light, glider, usually made from thin Styrofoam, with a flying speed of 3 or 4 mph. As long as you keep walking and moving the slope through the air, the glider will keep flying. 
An easy experiment to try!

Many videos of this online:

https://www.youtube.com/watch?v=LGZN1-diDjU

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Re: Direct Down Wind Faster Than The Wind
Reply #57
I wonder what dear old Humber would have come up with in the way of an explanation!

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Re: Direct Down Wind Faster Than The Wind
Reply #58
I think this indicates the likelihood that tobermoryphil's (that's a mouthful) idea of the moving wave giving enough slope lift to sustain the albatross is valid.  I think, in reality it's more likely that the waves in general are being driven by the wind and moving quite below wind speed so that the lift is on the back side of the wave with respect to the wave movement.

Plus the albatross seems to eke out a bit of energy working the wind gradient in appropriate spots.  With no wind and therefore no wind gradient, plus waves becoming calm, Mr. Albatross will have to flap his wings a bit I expect.

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Re: Direct Down Wind Faster Than The Wind
Reply #59
I think this indicates the likelihood that tobermoryphil's (that's a mouthful) idea of the moving wave giving enough slope lift to sustain the albatross is valid.
Flying along the wave crests definitely helps to save energy, but the main energy input comes from dynamic soaring. Especially when making progress against the wind, or downwind, faster than the wind.


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Re: Direct Down Wind Faster Than The Wind
Reply #60
Bump, just in case some carters drop in and can't find this thread, as just happened to me. Hi guys. Hope you all had a merry Christmyth.

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Re: Direct Down Wind Faster Than The Wind
Reply #61
Thanks arpie and best wishes to you, family and...the TR gang too.  A rough year.

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Re: Direct Down Wind Faster Than The Wind
Reply #62
Anyone notice a disturbance in the Force lately?

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Re: Direct Down Wind Faster Than The Wind
Reply #63
 :reign:
Love is like a magic penny
 if you hold it tight you won't have any
if you give it away you'll have so many
they'll be rolling all over the floor

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Re: Direct Down Wind Faster Than The Wind
Reply #64
We need a death Star smiley
Love is like a magic penny
 if you hold it tight you won't have any
if you give it away you'll have so many
they'll be rolling all over the floor

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Re: Direct Down Wind Faster Than The Wind
Reply #65
Also Mythbusters dropped the ball.  I think they feared you would upstage them, and they really hate that.
Don't you see? The H's stopped Mythbusters and all other primetimes from running this stuff.
I forgot all about the Humbers.  Idiots are not memorable, but the people who actually did cool shit are.
"If you pick up a starving dog and make him prosperous he will not bite you. This is the principal difference between a dog and man."
― Mark Twain 🔭

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Re: Direct Down Wind Faster Than The Wind
Reply #66
The H's really dropped the ball. I received a report that Spork is still freely able to promote the ddwfttw ideas. Must be really raking in the dollars on it by nowhttps://www.youtube.com/watch?v=X6oJpnSJyV8;

https://www.youtube.com/watch?v=X6oJpnSJyV8

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Re: Direct Down Wind Faster Than The Wind
Reply #67
Conversation continued from YouTube:

James McGinn:
Hi Rick. I"m an atmospheric scientist. My specialty is the the aerodynamics that occur naturally in the atmosphere associated with storms, especially severe weather. I think I can improve your explanation of how/why the upper limit of velocity on your DDWFTTW isn't the velocity of wind but, actually, the velocity of air pressure (which is the same as that of the speed of sound). 

Intuitively we assume that the force that is pushing the vehicle is the wind. Actually it isn't.  The force that is pushing the vehicle is air pressure. And the speed limit of air pressure is the speed of sound.

Would you be interested in a really tough question--a question that was designed to put you on the spot?  If not I won't bother. But if you can commit to making an honest attempt at answering it, I will take some time to put together a scenario and some questions that, I assure you, will get to the crux of how/why this vehicle is able to move downwind faster than the speed of the wind.  Are you interested??

Rick Cavallaro:
I think I understand it.  I will take a shot at answering your questions.

Here is my challenge:
Let's consider your DDWFTTW going downwind.  Let's assume it starts with a 14 mph wind.  Within two minutes it is up to 14 mph.  Two minutes later it gets to 32 mph (over 2X).  It stays at that speed for 2 minutes, and then let's say the wind completely dies, dropping to zero. The DDWFTTW gradually slows down and after 2 minutes it stops.

Now lets consider three 10 second snippets in this time series:

1) While it is accelerating, below wind speed:From 1:00 to 1:10. (Wind speed 14 mph)
2) Still accelerating, above wind speed: From 3:00 to 3:10. (Wind speed 14 mph)
3) Maintaining top speed: From 5:00 to 5:10. (Wind speed 14 mph)
4) decelerating, losing speed: From 7:00 to 7:10. (Wind speed 0 mph)

At #2 the DDWFTTW is accelerating.  What is the source of the energy that is causing/producing this acceleration?
 a) The wind?
 b) Air pressure?
 c) Something else?

With respect to the source of the energy involved, how would you differentiate between the acceleration at #1 and the acceleration at #2?

Rick Cavallaro
The source of energy is always the relative motion between the air and the ground.  It slows the air relative to the ground as it passes through it.  I wouldn't differentiate the source of energy in those two cases because the source of energy is in fact the same.

James McGinn
I agree that it slows the air relative to the ground as it passes.  However, I do differentiate.  If wind was the only source of energy the vehicle could never get going faster than the speed of the wind. Aerodynamics underlie an exchange by which air pressure is the source of the energy that allows the higher speeds of the vehicle.  

In explaining how any sail powered vehicle can achieve a velocity that is greater than the velocity of the wind one has to invoke aerodynamics and the fact that the speed limit of the source of the energy that is associated with aerodynamics is not the wind but air pressure.  And the speed limit of air a pressure is very high, literally the speed of sound.

The speed limit of the wind in this scenario is 14 mph.  It cannot push something to go faster. However, it can be the source of the energy that achieves the laminar flow of the aerodynamics that, literally, tap into the abundant energy in air pressure.

The energy that keeps an airplane from falling out of the sky does not come from the thrust of the airplane's engines, it comes from air pressure. The thrust of the airplane's engines provides the energy that allows the airplane overcome drag and achieve a velocity that enables laminar flow over the top of the plane's air-foil wings. Accordingly, the energy from the thrust of the airplane's engines is conserved in the velocity of the airplane.  It being a consequence of velocity,  laminar flow removes the energy of air pressure from the top of the wing.  It does not remove it from the bottom of the wing. Consequently, energy literally flows up into the wing, producing an acceleration force, lift. And so, aerodynamics involves the rules/principles by which the abundant energy in air (air pressure) can be tapped into or channeled.

All in all, aerodynamics involves an exchange, with air pressure being the source of the energy flow that causes lift (an acceleration force).  The same is true for DDWFTTW and any sail powered vehicle.

And so, if we were to model the pathway of the energy that causes the lift on an aircraft it originates in the atmosphere.  It does not originate with the airplane's engine.  It is extracted from the atmosphere by the air foil.   (Nevertheless, the atmosphere does not experience a net loss in energy as a result of the aircraft passing through it but actually experiences a net gain in that the amount of energy associated with thrust/drag more than compensates for the loss of energy associated with lift.)

In a wind powered vehicle the wind is analogous to the motor of the aircraft.  Wind removes the air pressure from the back of the sail or air foil.  Air pressure is what pushes the vehicle. Energy is conserved in the speed of the vehicle and by tacking to maintain laminar flow or, as in the DDWFTTW, the energy is also conserved in the momentum of the spinning propeller/turbine.

In a sail powered vehicle tacking explains how laminar flow is maintained at higher speeds.  With DDWFTTW the spinning motion of the propeller/turbine explains how laminar flow is maintained at higher speeds.  However, explaining how either achieves a speed faster than the wind requires a source of energy that is going faster than the wind, air pressure, which has a speed limit that is the same as the speed of sound.  People are generally unaware that air molecules in still air actually are moving over 700 mph and have a lot of energy.

Lack of awareness of the abundant energy in the atmosphere that is associated with air pressure is one of several conceptual misconceptions that has brought progress in severe weather research to a standstill:
http://www.thunderbolts.info/forum/phpBB3/viewtopic.php?f=10&t=16329

Rick:
You have a number of misconceptions here.

Jim:
Not likely. I'm an expert on this subject. Feel free to delineate these alleged misconceptions. I know you won't be able to.

Rick:
But your basic assumption would suggest that this should be limited to the speed of sound since air pressure moves at the speed of sound.

Jim:
Something can't push something faster than it is going itself without some kind of mechanism, which you have not described here.

Rick:
But that is not the case with this. This can in principle operate faster than the speed of sound.

Jim:
What principle?  I think you are mistakenly assuming that the mechanics of DDWFTTW work like the gear ratios in a car to explain the higher speeds.  That is, definitely, wrong.  Its the speed of air molecules as realized through aerodynamics that explains the high speeds. Your mechanics explains how laminar flow is maintained at higher speeds without tacking. It doesn't explain the higher speeds themselves.  If your mechanics did explain the higher speeds then other sail powered vehicles that lack these mechanics could not go faster than speed of wind.

James McGinn / Solving Tornadoes
Lookout For Bill
http://www.thunderbolts.info/forum/phpBB3/viewtopic.php?f=10&t=16582#p117060?


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Re: Direct Down Wind Faster Than The Wind
Reply #68
>>  I think you are mistakenly assuming that the mechanics of DDWFTTW work like the gear ratios in a car to explain the higher speeds.

I am not making that assumption.

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Re: Direct Down Wind Faster Than The Wind
Reply #69
Truth is out of style

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Re: Direct Down Wind Faster Than The Wind
Reply #70
>>  I think you are mistakenly assuming that the mechanics of DDWFTTW work like the gear ratios in a car to explain the higher speeds.

I am not making that assumption.

That's good.  Maybe instead of trying to explain how DDWDTF goes faster than the wind that is powering it explain how a normal sail powered vehicle can go faster than the wind that is powering it.  I think you will find that you will not be able to do so without invoking aerodynamics and the high speed of air pressure.

Cheers,

James McGinn / Solving Tornadoes

Moist Air Convection Myth
http://www.thunderbolts.info/forum/phpBB3/viewtopic.php?f=10&t=16462

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Re: Direct Down Wind Faster Than The Wind
Reply #71
>>  I think you are mistakenly assuming that the mechanics of DDWFTTW work like the gear ratios in a car to explain the higher speeds.

I am not making that assumption.

That's good.  Maybe instead of trying to explain how DDWDTF goes faster than the wind that is powering it explain how a normal sail powered vehicle can go faster than the wind that is powering it.
It doesn't. The wind that is powering it is the apparent wind. HTH. :)
Truth is out of style

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Re: Direct Down Wind Faster Than The Wind
Reply #72
The experience that spork and his team, as well as many others had online, is a familiar pattern. And I mean it historically, not just online.  One can actually build a working device, demonstrate it, get it certified as breaking the DDWFTTW speed record, and to some people it just doesn't matter.  They are sure they are right, and DDWFTTW is impossible, and nothing is ever going to change their mind.  Certainly not anything like facts.

Unfortunately this is true.  Much of science is tangled up in superstitious notions.
Isaac Newton was a human being
http://www.thunderbolts.info/forum/phpBB3/viewtopic.php?f=8&t=16306

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Re: Direct Down Wind Faster Than The Wind
Reply #73
The wind that is powering it is the apparent wind. HTH. :)

Water currents cause apparent wind for watercraft.  There is no apparent wind on a flat lake bed.

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Re: Direct Down Wind Faster Than The Wind
Reply #74
The wind that is powering it is the apparent wind. HTH. :)

Water currents cause apparent wind for watercraft.  There is no apparent wind on a flat lake bed.
:grin: Ok. You win.  :cheer:
Truth is out of style