Merged DDWFTTW in a “Real” Wind

[Llyricist]

@ Myriad

A slick way of doing that would be to mount the rotor on a pivot that rotated through 180 degrees from 90 left to 90 right. And figured out how to do a pitch adjustment that also changed the twist of the blades (yeah right?). So you could adjust the pitch straight through from turbine to prop. And somehow managed to keep the drive train efficient enough.

It would have an elliptical speed profile with the long axis in line with the wind direction and offset a good bit away from the wind.

 

[Myriad]

That is simply rhetoric. And none if it excuses you from not asking Spork to explain, or are you biased, rather than objective?

I understand the matter sufficiently. There is nothing at present that I require Spork to explain, so why should I ask him for any explanation?

Those 4 videos are not mine. Yet, the upwind cart, which uses a rotor that will function as a prop, works, but Spork's doesn't. He use and internet programme and toyed with the numbers, but does not know what he is doing.
He's a sales manager working in sports promotion.

I can prove the 3W claim for the BB's prop, and have done so. The response form the cart brigade had been silence. That is because it is correct, but belief does not provide a reply.

The "TM" of those other videos is a belt sander; a means of driving the wheel, and not a "Galilean Equivalent", yet it does what Spork's does.

I take it that you know nothing of meteorology, or you would be able to respond in an appropriate manner. Dynamic systems of that sort, are first year engineering. General theory, which applies to many disciplines, but applied in this case, to a vane.

The real world trail is a farce. In the Jenkins' video, the camera pans to the vane, and he says uneasily "significant headwind". That's right. There is a headwind coming about 30 degrees off ddw.

Yes, those are some of the arguments that I find unconvincing, and in some cases, not even relevant. If anyone else finds them relevant and convincing, I invite them to explain to me why.

Respectfully,
Myriad

 

[humber]

I've given you the finger, and you failed to comprehend it. Will repetition help?

Well Prof, here is part of the reviewer's response to Andy Ruina's paper on ddwftw, presented to the Am J physics. in 1980

That is the paper is from where Spork ripped off the tacking prop, tethered ice-boat analogies and wheel and ruler idea.

The first objection concerns the fact that steady state has not been shown
because of acceleration. You lack the perspicacity notice that applies to the cart and ruler. Only by manipulation, can the speed be maintained as constant.

But, regarding your "counter-intuition"

"The second and more serious flaw in the manuscript, is the wordy way in which the author deals with the problem at hand. His attempts to demonstrate intuitively, by means of discussions and analogies, that the boat can sail both into the wind at any speed, is simply not the way to
solve a problem on mechanics. It is unsatisfactory as far as good science is concerned, and is disastrous with regard to the teaching of physics to students, for upon reading a paper such as this, students will come away with the mistaken notion that mechanics deals withe qualitative verbal
"explanations" for observed motions of dynamical systems, rather than quantitative predictions of these motions.

The author would surmount both of the above mentioned deficiencies in his paper, by formulating a first order ordinary differential equation of motion governing u (neglecting gyroscopic effects of the propellers) and producing plots of u versus t for a series of the values of the wind speed W.

....and eliminate the need to resort to "explanations" of any kind."

Your explanations are entirely verbal or simple but flawed kitchen physics.
The trial is visual, and no calculus is used in any math. But analysis of the data and instruments, say the claim is BS.

However, Harold Bricer, did that calculus, and the conclusion of his calculations is way less than WS. That can be seen, when the cart plods along or stalls until the wind changes.

The upwind cart will be another cheat, and exploit the wind variation and gradients. If any of the builders of the current upwind carts object, no doubt Spork will call them idiots.

 

[humber]

I understand the matter sufficiently. There is nothing at present that I require Spork to explain, so why should I ask him for any explanation?

And you can explain the differences between NALSA's data and Spork's chart?
Go ahead. Right now.

 

[humber]

My comments in red.

All answered. Attempts to regain ground by repetition, and add confounding factors pulled out of the air, when Newton says it in one line.

To paraphrase you, if you can't understand a stick, then it is no wonder that instrument dynamics are way above your head.

 

[humber]

You lack even the courage to call Spork on the massive rotor he intends to use, to steal a prize.

 

[GlennB]

That's not correct. You do not understand. The prop does not turn the wheels. The wheels turn the prop.

Humber, after all this time, do you really still not understand this basic fact?

Seconded. My first real "ahah!" moment trying to understand the cart was when I finally took in this basic fact (at which exact point, spookily, Pink Floyd sing '...just the basic facts...' through my headphones. Hopefully recounting this small coincidence might prove more entertaining than humber's bulloney)

 

[sol invictus]

Well Prof, here is part of the reviewer's response to Andy Ruina's paper on ddwftw, presented to the Am J physics. in 1980

The American Journal of Physics is intended as a pedagogical resource for physics students. Apparently that paper was badly written. What relevance you think that has to my posts in this thread only you can know.

Your explanations are entirely verbal or simple but flawed kitchen physics.

The arithmetic involved is utterly trivial.

However, Harold Bricer, did that calculus, and the conclusion of his calculations is way less than WS. That can be seen, when the cart plods along or stalls until the wind changes.

Nonsense.

 

[Myriad]

A slick way of doing that would be to mount the rotor on a pivot that rotated through 180 degrees from 90 left to 90 right. And figured out how to do a pitch adjustment that also changed the twist of the blades (yeah right?). So you could adjust the pitch straight through from turbine to prop. And somehow managed to keep the drive train efficient enough.

It would have an elliptical speed profile with the long axis in line with the wind direction and offset a good bit away from the wind.

Yeah, sounds like an engineering nightmare, in some respects. The most interesting question, to me, is whether the overall performance on an open course could possibly exceed a conventional sail cart with the ability to reach and tack. (Of course, enforcing directly upwind or directly downwind legs by means of e.g. narrow course boundaries would favor or require a propeller/turbine design.)

Respectfully,
Myriad

 

[humber]

Seconded. My first real "ahah!" moment trying to understand the cart was when I finally took in this basic fact (at which exact point, spookily, Pink Floyd sing '...just the basic facts...' through my headphones. Hopefully recounting this small coincidence might prove more entertaining than humber's bulloney)

Umma Gumma, careful with that axe, Eugine.

There can only be one source of power applied to a series device. You need a load at one end. If both drive the system, they oppose, such that
the sum remains the same. One is reduced, by the amount that the other increases.

Turn the wheel clockwise by hand. That represents the generator that Spork has attached to the wheel ( see his submission to NALSA)
The prop will turn CW. That is the prop mode.
At the same time, use a finger to turn the prop CW, to represent the added wind power.

What happens to the force applied at the wheel?

 

[Myriad]

And you can explain the differences between NALSA's data and Spork's chart?
Go ahead. Right now.

The most fundamental difference is, NALSA's data is a set of time series of numerical values, while Spork's chart is an array of differently colored pixels.

Respectfully,
Myriad

 

[humber]

The American Journal of Physics is intended as a pedagogical resource for physics students. Apparently that paper was badly written. What relevance you think that has to my posts in this thread only you can know.

Nothing but hand-waving, and the Am J Physics, is not for students, but for
the dissemination of research. Don't bluff me, crank.
And that's right. It was rejected. The cart is based on ideas stolen from a rejected paper.

The arithmetic involved is utterly trivial.
Nonsense.

Produce it.

 

[Jack by the hedge]

All answered. Attempts to regain ground by repetition, and add confounding factors pulled out of the air, when Newton says it in one line.

All answered wrongly, but I haven't given up hope of the lightbulb turning on some day. Despite your appeal to Newtonian authority, your diagram does not describe the operation of the cart, so is not useful.

 

[Llyricist]

The most fundamental difference is, NALSA's data is a set of time series of numerical values, while Spork's chart is an array of differently colored pixels.

Respectfully,
Myriad

Not to mention that what he call's "spork's chart" is actually Bob Dill's chart (NALSA BOD), that happened to be prepared using "Rick's anagraph software".

 

[humber]

All answered wrongly, but I haven't given up hope of the lightbulb turning on some day. Despite your appeal to Newtonian authority, your diagram does not describe the operation of the cart, so is not useful.

Try it. To speed up the prop using either the finger at the prop or the hand at the wheel, one must "give"
Newton does not yield to a salesman's notions.

 

[humber]

Not to mention that what he call's "spork's chart" is actually Bob Dill's chart (NALSA BOD), that happened to be prepared using "Rick's anagraph software".

No, Spork produced that chart. He told me so, and the difference is crystal clear.
NALSA gave Spork the data from the CV

 

[sol invictus]

Nothing but hand-waving, and the Am J Physics, is not for students, but for
the dissemination of research. Don't bluff me, crank.

Wrong (as always). Their editorial guidelines expressly prohibit papers that contain new research.

"Welcome to the American Journal of Physics (AJP). AJP publishes papers that meet the needs and intellectual interests of college and university physics teachers and students." http://ajp.aapt.org/about/about_the_journal

"Manuscripts announcing new theoretical or experimental results, or manuscripts questioning well-established and successful theories, are not acceptable and should be submitted to an archival research journal for evaluation by specialists."
http://www.kzoo.edu/ajp/docs/edpolicy.html

Produce it.

Problem: A wine bottle with main radius R, neck radius r, rolls on a flat table. A finger pushes forward under the neck with velocity vf. What is the velocity v of the bottle relative to the table?

Solution: v=Rw and v-vf=rw, where w is the angular velocity of the rolling bottle. Solving for v gives v=vf/(1-r/R)>vf.

 

[humber]

This upwind cart, is going to get knocked down before Spork has the chance to foist more crap as science. He will whine at every restriction imposed.
So there you go Spork. I predict you will do that.

 

[Llyricist]

No, Spork produced that chart. He told me so,

Forgive me if I don't automatically believe that. But even if true, It is still Bob DIll's chart by dint of it being found in his report.

and the difference is crystal clear.

There is no difference, as I explained to you no less than 3 times before you ran away and hid.

 

[humber]

Wrong (as always). Their editorial guidelines expressly prohibit papers that contain new research.

"Welcome to the American Journal of Physics (AJP). AJP publishes papers that meet the needs and intellectual interests of college and university physics teachers and students." http://ajp.aapt.org/about/about_the_journal

"Manuscripts announcing new theoretical or experimental results, or manuscripts questioning well-established and successful theories, are not acceptable and should be submitted to an archival research journal for evaluation by specialists."
http://www.kzoo.edu/ajp/docs/edpolicy.html


Oh, I see. You are suggesting that that same body has double standards?
Firstly, they allow any old crap, in the expectation that will result in good feedstock for the research journal?
That the intellectual interests of Professors are not science, nor worthy?
Interestingly, your intellectual pursuit and the one you champion, was rejected, even by the journal you hope to slight.
Cranky unpublished prof ahoy!

Problem: A wine bottle with main radius R, neck radius r, rolls on a flat table. A finger pushes forward under the neck with velocity vf. What is the velocity v of the bottle relative to the table?

Solution: v=Rw and v-vf=rw, where w is the angular velocity of the rolling bottle. Solving for v gives v=vf/(1-r/R)>vf.

Hilarious. My Little Physics.
Replace the finger with a thread. Using only friction at the surface, and the moment of the reel, show which way it will turn.