Merged DDWFTTW in a “Real” Wind

[jduffy77]

An ideal proof (that it can't work) is one with no friction and 100% efficiency, where the only rolling drag comes from the power needed to drive the propeller.

Otherwise it's really only a proof that the bearings/tyres/propeller design won't support ddwftw, not a proof that the concept is unphysical.

I understand the nay-sayers to believe that the entire concept is unphysical, not simply impractcal.

Right, but as Spork and TAD showed (and I think were surprised by) 3 years ago when they first started doing calculations on this there is so much extra thrust that it is amazing. Without fudging drag and efficiency gloss's mission would be untenable. He is not Humber in the sense that at least at first glance it needs to make some sense.

 

[spork]

An ideal proof (that it can't work) is one with no friction and 100% efficiency, where the only rolling drag comes from the power needed to drive the propeller.

Otherwise it's really only a proof that the bearings/tyres/propeller design won't support ddwftw, not a proof that the concept is unphysical.

I understand the nay-sayers to believe that the entire concept is unphysical, not simply impractcal.

We've presented trivial analyses that show it has huge reserves of energy to spare when no losses are assumed. We then introduce easily achievable real-world losses and show that the analysis still works just fine.

For people that aren't so keen on mathematical analysis, we built a working model and demonstrated it on a treadmill. And for people that can't understand the equivalency of inertial reference frames, we built a manned cart and set a world record.

We think the real world evidence pretty much trumps any theory.

 

[jduffy77]

They were granted 85% overall efficiency ( including the prop), aero drag was ignored and the rolling losses were minimal. It failed.

By failed do you mean granted a world record of 2.8x ws ddw by the worlds leading authority on land sailing which you yourself said would be the perfect judging body?

Spork posted an electrical model that fails in principle, so there is another black mark, and that will withstand attack, no problem.

By failed do you mean works exactly as stated?

 

[Llyricist]

Bluff.

No, I don't do what you do.

Try again. The same time frame as I posted. Warts and all.
Do you have a problem with that? Are the others not worthy of display?

Why should I? My graph looks a lot like yours, except that it's less cluttered and easier to read.

 

[fttw]

We've presented trivial analyses that show it has huge reserves of energy to spare when no losses are assumed. We then introduce easily achievable real-world losses and show that the analysis still works just fine

I do understand that.

Profpangloss said earlier that he had a simple analysis, in the earth-at-rest frame, that showed the cart can't work. I'd really like to see it.

 

[humber]

We've presented trivial analyses that show it has huge reserves of energy to spare when no losses are assumed. We then introduce easily achievable real-world losses and show that the analysis still works just fine.

The recorded data shows a constant net force of 32N. Not one of your
calculations supports that.
In fact, you claimed in print "the torque of a Corvette" at 650ft-lb.
That is 811N.m at the shaft and 2300N at the ground.
The electrical model fails in principle, and shows a rising net force with speed. The Javaprop data used by Steve Morris to design the prop, contradicts all models, and the trial results.

For people that aren't so keen on mathematical analysis, we built a working model and demonstrated it on a treadmill. And for people that can't understand the equivalency of inertial reference frames, we built a manned cart and set a world record.

Whether you like it or not, the TM is dead, awaiting a public burial.
The record is an obvious fraud. It casts doubt on NALSA, when it was not noted that the wind has a periodic shift from +50 to -50 degrees. It is accelerating as the incoming wind is forced into the confines of the lake floor. A huge mass of accelerating air.

We think the real world evidence pretty much trumps any theory.

Well, we can see you shoehorn that 32N net force into your calculations can't we? you should produce a chart from Javaprop, covering the rev. range of the trial.

 

[humber]

No, I don't do what you do.





Why should I? My graph looks a lot like yours, except that it's less cluttered and easier to read.

Really don't care if you do. What you don't present will gain you nothing.

 

[humber]

By failed do you mean granted a world record of 2.8x ws ddw by the worlds leading authority on land sailing which you yourself said would be the perfect judging body?

Like Hell I did. You keep your words in your mouth.

 

[jduffy77]

The recorded data shows a constant net force of 32N. Not one of your
calculations supports that.
In fact, you claimed in print "the torque of a Corvette" at 650ft-lb.
That is 811N.m at the shaft and 2300N at the ground.

As I mentioned gloss is not quite Humber. I think he at least understands the difference between force and net force.

 

[drewid]

Really don't care if you do. What you don't present will gain you nothing.

*cough* propless cart

 

[CORed]

I'm still (just) looking for a simple re-statement of the argument that it can't work so I can judge for myself!

As far as I'm concerned, the concept has been proven experimentally to work, so the only interest I would have in arguments about why it can't work is to find the mistakes.

 

[Michael C]

No.

Momentum is conserved only in a closed system. Closed systems are finite; if the earth has infinite mass it cannot be part of a closed system.

Example: I sit on the cart and push myself along with a stick. I impart momentum to the cart. Where does that come from? Two answers, either of which are acceptable (but you can't mix-and-match)

EITHER: The earth is finite and the momentum that the cart-and-I gain is cancelled by an equal and opposite change of momentum of the earth.

OR: The earth has infinite mass, cannot accelerate when pushed against, and remains an inertial frame (all three exactly equivalent conditions) and functions as infinite source/sink for momentum which I transfer to the cart by pushing with the stick. Momentum is not conserved in this view but there is no violation of the "Law of Conservation of Momentum" because this system is not closed.

Either viewpoint is fine; either leads to good physics when used consistently. Switching between the two "at will" will lead to incorrect conclusions.

Very well put. It's very important to distinguish between conservation of momentum and conservation of energy:

- When we use the Earth as an almost inertial frame, we can apply the law of conservation of energy because the change in the kinetic energy of the Earth will be so small that it can be neglected in comparison to the change in energy of the air or the cart.

- In the same situation, we cannot apply the law of conservation of momentum, for the reasons fttw gives above.

 

[humber]

As I mentioned gloss is not quite Humber. I think he at least understands the difference between force and net force.

But JB doesn't, and the chart say unequivocally, 32N.

 

[ThinAirDesigns]

And you moved the start position as the day passed, to ensure that wind was always there.

Oh the shame.

JB

 

[ThinAirDesigns]

An ideal proof (that it can't work) is one with no friction and 100% efficiency, where the only rolling drag comes from the power needed to drive the propeller.

Otherwise it's really only a proof that the bearings/tyres/propeller design won't support ddwftw, not a proof that the concept is unphysical.

We completely agree. Once you prove that input exceeds output (at zero losses), then it's an engineering problem rather than a physics problem.

In this case, one can pick whatever efficiency numbers one wants to use (even 99% losses) and it can still be shown to work given a high enough wind speed and a low enough multiple (for instance, 1,000.001mph in a 1,000 mph wind).

JB

 

[humber]

Oh the shame.

JB

Yes, it will be.

 

[humber]

We completely agree. Once you prove that input exceeds output (at zero losses), then it's an engineering problem rather than a physics problem.

In this case, one can pick whatever efficiency numbers one wants to use (even 99% losses) and it can still be shown to work given a high enough wind speed and a low enough multiple (for instance, 1,000.001mph in a 1,000 mph wind).

JB

32N. The force of gravity on a bag of groceries. "The power of a supermarket trolley"

 

[jduffy77]

By failed do you mean granted a world record of 2.8x ws ddw by the worlds leading authority on land sailing which you yourself said would be the perfect judging body?

Like Hell I did. You keep your words in your mouth.

What are you saying? Are you saying you did not say the exact words "the perfect judging body" or are you saying that you did not state over and over again things like "Nalsa will never test the cart", "Nalsa will not be taken in by this hoax", "Nalsa will not ratify the record", etc, etc, etc?

Don't forget I have millions of your words in a full text database from when I created the Humbersim.

 

[A.T.]

Did you mean '>' ?

Yes, sorry.

Oh no, not the dreaded ground power!

In the instantaneous inertial rest frame of the ground, the ground doesn't provide any power.

 

[humber]

Oh the shame.

JB

You should learn derivatives. That, and this from llyricist, says why.

When the wind direction is compensated for cart speed and plotted over that image, your claim of ddw looks laughable. A picture paints a thousand words.