Merged DDWFTTW in a “Real” Wind

[Jack by the hedge]

What about a cart on the table? It has zero velocity relative to the air, but I don't think you would say it was at wind speed.

Why not? It is moving at the same velocity as the air. It may be unconventional to declare the existence of wind when air is not moving relative to your surroundings, but windspeed is just the local speed of motion of the air and that's what the cart is matching. So yes, it is going at windspeed.

Rest the chassis on some books or whatever, and spin the wheels using an electric drill. Now it is at windspeed? All the TM does is to spin the wheels and prop.

Yes again. The cart is still at windspeed.

<Galileo digression snipped>
It is not possible to actually construct a new reality, the TM is a model, not the "same thing".

Right. It's a model. That's what I said.

No. The belt is the road. That is; the planet's surface.

I rather thought I said that, too.

Imagine that from outer space. The claim becomes that the spinning Earth is driving the cart. That is, it is "dragging it backwards" through the air to create a "virtual tailwind". Nonsense.

Nonsense indeed. The claim is that relative to the air, the land is moving backwards and the cart is moving forwards, driven against the air by its propeller which is powered by the motion of the land under it, and the energy to drive the system comes from the relative motion of the air and the land. Which doesn't sound very much like what you said.

<irrelevant digression on the nature of wind snipped>

The TM is a simple machine.
Imagine that a simple wheeled cart is put on the belt. There is good friction, so a drag force of 1N, and the belt drags the cart down the belt. Perhaps over 1/10 second it moves 10mm, and gains KE in the direction of the belt.

But, if the wheel turns, all of the work is done on the wheel, and none on the cart. All of the KE is stored angularly in the rotating components.
It has no KE down the belt.
That is largely how it works. The prop provides a stabilising force. The rest is rather complex detail over short time scales, but the overall effect is that the cart gains no linear KE, and operates at a very low power level, resulting in low friction to the belt. It essentially slides on the belt.

I was with you right up to the highlighted non sequiturs. The cart has no need to slide at all. (Is essential sliding different to actual sliding, I wonder.) The cart's wheels roll on the belt. No slip is required to make the design operate.

 

[Jack by the hedge]

The trees work for me.

This may be the most surreal moment in the entire thread.

 

[jduffy77]

What about a cart on the table? It has zero velocity relative to the air, but I don't think you would say it was at wind speed. Rest the chassis on some books or whatever, and spin the wheels using an electric drill. Now it is at windspeed? All the TM does is to spin the wheels and prop.

This is one of Humber funniest misconceptions lately. Ok, its in the top hundred. Or so. The TM cannot spin the wheels.

 

[I Ratant]

You are correct, of course. I was parodying an earlier thread in which humber took me to task for daring to assert that a Ph.D physicist that he claimed supported him was wrong.

ETA: The demonstrations have been done. The DDFTW cart works. One crank refuses to accept the results.

.
Yeah, but the "how" is what's being discussed/argued...
3 cups of coffee later, this morning....

 

[CORed]

Oh...there's trouble in the village.... a troll.
He bringeth knowledge from afar.

He carries the knowledge directly from the feedlot.

 

[CORed]

Because he keeps coming up with hilariously absurd statements.

Agreed. He is the most entertaining troll (or crank, I'm not really sure which) I've ever encountered.

 

[CORed]

.
Yeah, but the "how" is what's being discussed/argued...
3 cups of coffee later, this morning....

There's really no mystery as to the "how", either.

 

[humber]

Just stick around. Humber regularly makes idiotic claims like the reel-stuff, that people then disprove with simple experiments.

You can also make some experiments to check this humberthesis:
http://talkrational.org/showthread.php?p=1189476#post1189476

And that is quite possible if you know something about material science.
And the sail. You always post that, but don't have the math to back up your assertions,
but somehow, you are right about a cart you have never seen, nor conducted any experiments, nor done any math. You do hide your talents very well indeed.
ETA:
Perhaps you would like to stick to the topic, rather than gossiping, and rummaging through the back catalogue?

 

[humber]

Now that's just funny. So if you stack to bathroom scales, they will each tell you half your weight?

Again possible, but you need to know how load cells work.
In a cartoon world of simplified Wiki, all is either novelty, or absurd.

 

[humber]

Why not? It is moving at the same velocity as the air. It may be unconventional to declare the existence of wind when air is not moving relative to your surroundings, but windspeed is just the local speed of motion of the air and that's what the cart is matching. So yes, it is going at windspeed.

But not when the cart is stationary.

Yes again. The cart is still at windspeed.

All speeds are windspeed.

Right. It's a model. That's what I said.
I rather thought I said that, too.
Nonsense indeed. The claim is that relative to the air, the land is moving backwards and the cart is moving forwards, driven against the air by its propeller which is powered by the motion of the land under it, and the energy to drive the system comes from the relative motion of the air and the land. Which doesn't sound very much like what you said.

Find one text book that says the ground drives a wheel.
Find one text book that says props tack.
etc.

I was with you right up to the highlighted non sequiturs. The cart has no need to slide at all. (Is essential sliding different to actual sliding, I wonder.) The cart's wheels roll on the belt. No slip is required to make the design operate.

It has no KE, and is not moving. The videos show that it is marginally stable.
A student built one for a science fair. There is a video. It slides all over the place.

You might do better if you could show that my idea could not work. That I would find interesting.
Simple denial is available in bulk quantities.

 

[jduffy77]

You might do better if you could show that my idea could not work. That I would find interesting.

Humber, everyone knows you are lying about your toy cart. You don't even seem like you're trying very hard at the moment.

 

[CORed]

Let's see 'em.

Well, he's lying a teensy bit. He know how to make carts that climb the belt without a prop, and the ones he's made almost work and he'll show us how just as soon as he's made a couple tweaks to get them to actually work, which should happen about ........



































Never.

 

[temporalillusion]

Actually humbers super spring theory opens even greater possibilities:

Lol nice!

Don't anyone ask him if a compressed spring weighs more than an uncompressed one.

 

[spork]

Lol nice!

Don't anyone ask him if a compressed spring weighs more than an uncompressed one.

hyev will tell you the compressed one has to weigh more - because it won't stay compressed on its own - it needs some sort of clamp. And you sure as heck can't find weightless clamps.

humber is likely to come up with some different offering of wrong.

 

[Jack by the hedge]

But not when the cart is stationary.

But not when you move the goalposts. What are you talking about now? When the air is stationary and the cart is stationary they are both travelling at the same speed, and that speed is zero. What part of that confuses you?

All speeds are windspeed.

Find one textbook that says so.

Find one text book that says the ground drives a wheel.
Find one text book that says props tack.
etc.

It's not my job to find textbooks for you. As I and others have already explained to you, you will find that the propeller is acting as a propeller and textbooks will describe that behaviour as the normal behaviour of a propeller. I frankly neither know nor care whether any textbook exists which describes the similarity between the blade of a propeller and the sail of a yacht. It wouldn't surprise me at all, but I simply don't know if any do. That similarity exists nevertheless.

It has no KE, and is not moving. The videos show that it is marginally stable.

So what, exactly?

You might do better if you could show that my idea could not work. That I would find interesting.

Which idea? Can I get to pick one? How about the one about stacking 2 sets of bathroom scales and seeing if they each register half your weight - was that one of yours?

 

[D'rok]

Well, he's lying a teensy bit. He know how to make carts that climb the belt without a prop, and the ones he's made almost work and he'll show us how just as soon as he's made a couple tweaks to get them to actually work, which should happen about ........



































Never.

Maybe he just needs to bang out 7 million more words in The Great Downwind Cart Flame Wars first.

Priorities, priorities.

 

[recursive prophet]

@I Ratant: Could you post a link where I could get more info on the plastic carts? Thanx.

It is intriguing that despite so many having fun with this topic, some seem motivated to make comments which are clearly brinking the-attack ideas not posters-civility rules here. The subject has been put on mod-stat 3 times already. A record? Wonder why anyone would want to unequivocally tinkle on the parade and terminate all discussion?

 

[spork]

some seem motivated to make comments which are clearly brinking the-attack ideas not posters-civility rules here.

I assume RCP is referring to humber's insisting on defaming me with continuous lies. But there's nothing to worry about. The mods are cool with that.

 

[D'rok]

@I Ratant: Could you post a link where I could get more info on the plastic carts? Thanx.

It is intriguing that despite so many having fun with this topic, some seem motivated to make comments which are clearly brinking the-attack ideas not posters-civility rules here. The subject has been put on mod-stat 3 times already. A record? Wonder why anyone would want to unequivocally tinkle on the parade and terminate all discussion?

There is no discussion. All the issues have been resolved to the complete satisfaction of anyone with a modicum of sanity long ago. It's just all about the ****-storm now.

 

[I Ratant]

Oh, I didn't realize that.
OK.