Down wind faster than the wind

[humber]

1) I am not representing Mark Drela without his authority. On the contrary, I am leaving him out of it. I will say that those lecture notes, while quite valid, don't have much relevance to this particular discussion.

Good. That is what I meant. So in what way is it not relevant?
I posted it to Hethethet as a source of information. It was something I read. The models indicate that a propeller's output is dependent upon the load. That was my point.

2)
For the purposes of discussion, I'm happy to discuss a vehicle running on a toothed track, with toothed wheels, which would simultaneously enforce the direction of the vehicle and ensure that there's no slipping. Not that I think there's any problem with slipping wheels. If a vehicle travels DDWFTTW with the wheels slipping, it's still going DDWFTTW.

But you do not know that currently they are not slipping? Assuming everything that is unknown will be in your favour, may not be a good idea.
A toothed belt is fine by me.
3)

I didn't say that I would present evidence that it has been achieved. I said that I could explain why it is possible. I guess you're saying that you agree that it is.

Dependent upon the conditions, I agree that you can speculate about that. However, those conditions make the difference between the explanations that are plausible, and those that are not.
Again, this is about the treadmill. The discussion has been about my claims for that and the recent videos. The treadmill does not support ANY model of a windcart, or ANY real windcart.

4)
I'm trying to decide whether your statement is more vague than mine. By "steady state", I mean that it is in a condition where the velocity of the cart, the rotational speeds of all parts, etc. are not changing. In your statement, based on what you have said before, I'm not sure what you would count as an "other source of energy". Given that it will have rotating wheels, there will be some kinetic energy stored in those wheels. Since we can't make massless wheels, would that be a problem?

Do you have a massless cart or propeller? No, so your claim must include that unavoidable situation. Stored momentum must be included in the calculations otherwise the claim may be trivial. Steady state can perhaps be "continuous performance above windspeed", but what if the cart spent say, 20% of the time below that, yet the average was still above windspeed?
Your definition would not allow for any acceleration after that point, or response to changing conditions. It is not my claim, so should be defined by the claimants in precise terms. This is the 21st Century. Simple, obvious claims have long been explained. If it's one of those, but in new clothes, so what?

5)
Read what I wrote again. I am not (at this time, anyway) offering to discuss the operation of the cart on the treadmill. I am offering to discuss the operation of a cart such as this on a flat, smooth piece of ground with the air moving past the ground.

Ok, then we are at crossed purposes.
Claims for the cart's performance rely on the frames idea. Ground energy, the corkscrew propeller and analogies with sailing boats. I say these are false. The logic of the treadmill is flawed, and so discredits that support. I can demonstrate that. Do you see the treadmill as a valid "frame of reference"? Does that fact that the cart stays on the belt, represent in any way windspeed travel?
If you say, no, then we are in agreement.

6)
I've read this several times, and I can't figure out what you're trying to say. Are you saying that Goodman's cart works, the spork/JB cart also works, and that a vehicle like Ventomobile can't work because of something that they're doing pertaining to measurement?

Yes, there are a lot if ideas that need to be teased apart, so you may not quite get the direct answer you expect.
Measurement is critical. If Ventombiile took perhaps the "last instantaneous reading" as their indicator, then they could possibly claim 80% efficiency.
Not a valid result, though. They make no claims for other-world science, just their technical achievement within current science.
In windcart world, I expect the same to apply.

If you are taking the position that DDWFTTW actually does (or at least, actually can) work, then we're in agreement on this point and don't need to discuss it. (If that's the case, then I may address the treadmill issue, but I want to know where we stand on the main issue first.)

Perhaps Goodman's cart does do that, but the evidence does not support it. Very poor science. A cart using the same principles I think could, but steady state might not be assured. Then again, no cart has shown that has been done. Under the same conditions, I could definitely reproduce Goodman's result.

A cart that takes only the energy that is immediately available to it cannot extract enough energy to overcome the forces against its travel, mainly drag. This is denied by ideas supported by the treadmill. The explanation is otherwise. All carts that currently claim windspeed travel use momentum or other forms of storage. Wind measurement is complex, so mistakes can be made. The sock is next to useless.
DDWFTTW is possible if you have enough energy. If that is ignored in the calculations, and faster than wind speed achieved, then that achievement is not worth bothering with. Deploying that energy is a matter of technology, not physics per se.
Notice something about Goodman's and Bauer's carts? Massive energy storage, tiny machines. How many windspeed craft do you see without fairings or other drag reducing elements? These are brute force machines. Odd, considering that energy extraction is the problem at hand, don't you think?
Perhaps the prop/wheel gearing is one way of accumulating and dispensing energy, but by no means the only way.

 

[humber]

I don't think JJ is "attempting" anything. His intellect simply IS superior to yours. It's too bad that embarrasses you.

I don't have the first clue as to what you hope or plan to show us, but I have two predictions that I'm fairly certain of:

1) You will never produce any drawings or descriptions of any kind. You simply don't have the necessary attention span. I suspect you already wonder what we're talking about.

It will be a wonder to you.

2) In the extremely remote case you do provide such plans or description, I'm quite confident your cart won't be capable of doing whatever you claim it can.

A trenchant dismissal that relies upon my failure.
No carts! Good Grief, no!
Just an argument against the treadmill that can't be denied. After that, well, the cart can be explained by conventional means.

 

[jjcote]

DDWFTTW is possible if you have enough energy. If that is ignored in the calculations, and faster than wind speed achieved, then that achievement is not worth bothering with. Deploying that energy is a matter of technology, not physics per se.

Based on this, we would initially seem to be in agreement. But:

A cart that takes only the energy that is immediately available to it cannot extract enough energy to overcome the forces against its travel, mainly drag.

Incorrect. It absolutely can. This is the critical point that I can explain.

Steady state can perhaps be "continuous performance above windspeed", but what if the cart spent say, 20% of the time below that, yet the average was still above windspeed?

Not an issue. The cart can spend 100% of its time comfortably above windspeed. Any real device will show some minor variation in speed, but it will never drop to anywhere near wind speed.

Notice something about Goodman's and Bauer's carts? Massive energy storage, tiny machines. How many windspeed craft do you see without fairings or other drag reducing elements? These are brute force machines. Odd, considering that energy extraction is the problem at hand, don't you think?

Are you suggesting that it's strange that these machines are not streamlined? It's not strange at all. If the windspeed is e.g. 10 mph and the cart is moving at 12 mph, it has an airspeed of only 2 mph. Fairings aren't worth bothering with at such low airspeeds. The one component that is moving fast is the prop, and it does have an efficient shape. Note that the Ventomobile streamlining is because it is going for a different goal (maximum directly upwind speed), and the airspeeds are much higher in that case.

As for energy storage, they have large props not to store energy, but for the same reason that sailplanes have large wings. If it becomes necessary, I'll get the data to caculate how much energy is stored in a spinning prop, and how much forward speed it translates to if it were all dumped into that. It won't be much.

But you do not know that currently they are not slipping? Assuming everything that is unknown will be in your favour, may not be a good idea.

This is such a red herring. First of all, who cares if the wheels are slipping? If it's going DDWFTTW with slipping wheels, then it's still working. Second, loss of traction makes things worse, not better, just like in a car. Slip enough, the prop won't be made to rotate, and the cart fails to work.

Your definition would not allow for any acceleration after that point, or response to changing conditions.

The steady-state case is what I'm proposing to explain. In fact, if conditions change, the result will of course change as well. In a general sense, an increase in wind speed will result in a corresponding increase in cart speed, such that that the cart will settle at a higher speed, though the details of how it gets there can be a bit involved.

The logic of the treadmill is flawed, and so discredits that support. I can demonstrate that.

Well, no, you can't.

Do you see the treadmill as a valid "frame of reference"? Does that fact that the cart stays on the belt, represent in any way windspeed travel?
If you say, no, then we are in agreement.

It doesn't just represent windspeed travel, it is windspeed travel, but that isn't what I'm proposing to discuss. We may have to take a detour into that, unfortunately.

 

[spork]

Well, not that humber has ever been consistent in anything he's said, but on this page he seems to claim DDWFTTW is possible in his nutty and non-committal way:

Perhaps Goodman's cart does do that... A cart using the same principles I think could, but steady state might not be assured... Under the same conditions, I could definitely reproduce Goodman's result.

I checked his earliest posts on this thread and found this on page 1:

I see it this way.
The prevailing wind exchanges momentum with the propeller, driving the vehicle forward. Even if the vehicle reaches wind speed, it can go no further, because at least at that point, it must loose momentum in order to accelerate the air impinging upon the propeller's leading face.
I think the terminal velocity will be determined at the point where the load line of the propellor and resistive forces intersect. I see the gears as a transformer, that will allow for a higher terminal velocity, but one that remains below windspeed.

Now I'm all for people learning and updating their thinking. But I sure as heck never saw any such claim from humber. I eagerly await humber's explanation that these two quotes are consistent with one another.

 

[spork]

Another fun quote from humber:

the cart in that video is nothing more than a flywheel on wheels

 

[H'ethetheth]

With the help of some of Terry's friends, I've made a new video. It's called "Under the ruler 2: the ground moves". I hope you enjoy it.

I was hoping you would make this video, and it's brilliantly executed once again.

Go Carlos!

 

[John Freestone]

SOED:
ingénue /anZeI"nju:; foreign EZeny (pl. same)/ n. Also -gen-.M19. [Fr., fem. of ingénu INGENUOUS.]

An artless innocent young woman, esp. as a stage role; an actress playing such a role.

Ah yes, my mistake, humber. It's that weird 'ingenuous' sounding like it should mean 'disingenuous'. That's one to you.

 

[humber]

Based on this, we would initially seem to be in agreement. But:


Incorrect. It absolutely can. This is the critical point that I can explain.

OK, there we certainly disagree.

Not an issue. The cart can spend 100% of its time comfortably above windspeed. Any real device will show some minor variation in speed, but it will never drop to anywhere near wind speed.

Even with storage, I am not sure that this is possible for any extended time.

Are you suggesting that it's strange that these machines are not streamlined? It's not strange at all. If the windspeed is e.g. 10 mph and the cart is moving at 12 mph, it has an airspeed of only 2 mph. Fairings aren't worth bothering with at such low airspeeds. The one component that is moving fast is the prop, and it does have an efficient shape. Note that the Ventomobile streamlining is because it is going for a different goal (maximum directly upwind speed), and the airspeeds are much higher in that case.

There is drag at windspeed. I say most certainly yes, and you DO have to get there!
Solar craft, even slow ones, want to maximise their efficiency, and so are streamlined. Olympic swimmers are 'slow' but do their best to be low drag. They are all slow, yet streamlined. Bauer's craft indicates that efficiency is not an issue.
A propellor is fast, but not so efficient. If it is the prop, then all prop. craft get the same benefit. Ventomobile is science. That is the critical point.
If the rules are lax, the appearance DDWFTTW is possible, but not under close scrutiny.

As for energy storage, they have large props not to store energy, but for the same reason that sailplanes have large wings. If it becomes necessary, I'll get the data to caculate how much energy is stored in a spinning prop, and how much forward speed it translates to if it were all dumped into that. It won't be much.

I see at the end of this post, you support the treadmill, and in a quite literal way (i.e. is is actually at windspeed), so further discussion is pointless if the treadmill is in anyway relevant to your explanation.

This is such a red herring. First of all, who cares if the wheels are slipping? If it's going DDWFTTW with slipping wheels, then it's still working. Second, loss of traction makes things worse, not better, just like in a car. Slip enough, the prop won't be made to rotate, and the cart fails to work.

I do. IF it has been shown that DDWFTTW has been achieved, (Don't say iceboats) then why do you say that you can show it as a possibility? What would be the point of questioning a proven fact?
The slipping is a detail. It can benefit or hinder. These are details of the cart, and I am discussing them because you asked. The treadmill is my concern.

The steady-state case is what I'm proposing to explain. In fact, if conditions change, the result will of course change as well. In a general sense, an increase in wind speed will result in a corresponding increase in cart speed, such that that the cart will settle at a higher speed, though the details of how it gets there can be a bit involved.

Yes, there is some agreement there, but I am not sure that it is a certainty.

Well, no, you can't.

Yes, I most certainly can.

It doesn't just represent windspeed travel, it is windspeed travel, but that isn't what I'm proposing to discuss. We may have to take a detour into that, unfortunately.

Not even remotely true! If you believe that, then I am sure your proposed windcraft can be "explained". Not a detour, mandatory. There is no point in agreeing with me at the very top of your post, and then denying the laws of physics in a latter explanation. No, treadmill first.

Just out of interest, would you like to name a few of the things that I cannot prove or disprove concerning the treadmill?
I was going to post the explanation to show Christian that I was not toying with words in my friction/floating/hovering" explanation, but if you have some other points, then perhaps I can include them.

 

[humber]

Well, not that humber has ever been consistent in anything he's said, but on this page he seems to claim DDWFTTW is possible in his nutty and non-committal way:

I checked his earliest posts on this thread and found this on page 1:

Now I'm all for people learning and updating their thinking. But I sure as heck never saw any such claim from humber. I eagerly await humber's explanation that these two quotes are consistent with one another.

The first refers to a momentum device. This technique is easy. If you regard your street video as evidence of windspeed travel, then I can do it too. Goodman's also.

The second quote is a denial that a device that uses the wind immediately can succeed in even reaching windspeed.

Page1? Lamentable that it has taken all that time for you to catch on.

 

[spork]

Page1? Lamentable that it has taken all that time for you to catch on.

Lamentable to think you feel you have a leg to stand on, or even a consistent position to defend.

And yes, I'm dying to hear your proof that the treadmill is different from a road beneath the wind.

 

[John Freestone]

It will be a wonder to you.

Let's have it then.

Page1? Lamentable that it has taken all that time for you to catch on.

Your assertions come so thick and fast (and I do mean thick), it's hard to reply to every one. Besides, there's often little point, because your replies to those replies bear little resemblance to the original point. Do you know how many assertions you've made that now have been dropped without further comment or a sideways wriggle?

Falling out a cart at windspeed and being sucked into the prop, for instance - no "Whoops, silly me, of course that won't happen!". Do you still say that their 'model' is wrong because it doesn't predict that sad outcome, or are you going to ignore the question again, or just waffle?

Have you now had time to consider whether a bullet has or has not kinetic energy, and whether it will or will not kill you, if it's fired from a gun on the platform at you as you travel away from it on a train doing bullet-speed? Oh, spork was stupid to fall for that one, wasn't he? Or are you just going to ignore the question again? You know, if you could just once admit that you've been wrong about any single bit of this, you won't dissolve.

An artificial world, where objects accelerate to zero KE and zero V. Momentum rules. The huge mass and gravity of the Earth make it the boss. To change from that, is possible, but pointless.

In the real world, objects do accelerate to zero velocity. If you don't know that, you're just a bad physicist. Decelerating is just negative acceleration. Physicists don't usually deal in a measurement called deceleration. So when you stop your car, it accelerates to zero. The fact that your view of the world is so childishly humbercentric that you don't understand that is irrelevant. Any Chief Scientist will tell you it. (I haven't just caught on, BTW, I'm just bothering to reply to it now, that's all.)

Then, 'zero velocity', is given relative to the particular arbitrary frame of reference we have chosen, an object considered stationary (because, in the real world, we do not know if anything is stationary - really, truly, we have absolutely no idea!).

But maybe you'd like to reply to my request for a definition of 'real wind'. In particular, maybe you'd like to discuss the kinetic energy values of carts sitting 'stationary' at the North Pole and the equator, since you seem to think KE is absolute, and one of them is 'stationary', while the other is travelling at a thousand miles an hour.

 

[humber]

And yes, I'm dying to hear your proof that the treadmill is different from a road beneath the wind.

It will indeed be fatal. It's really simple, but I have no scanner to hand. By tomorrow for sure.

 

[humber]

Let's have it then.

For the child within...

Your assertions come so thick and fast (and I do mean thick), it's hard to reply to every one. Besides, there's often little point, because your replies to those replies bear little resemblance to the original point. Do you know how many assertions you've made that now have been dropped without further comment or a sideways wriggle?

I've read your blog.

Falling out a cart at windspeed and being sucked into the prop, for instance - no "Whoops, silly me, of course that won't happen!". Do you still say that their 'model' is wrong because it doesn't predict that sad outcome, or are you going to ignore the question again, or just waffle?

I said, I've read your blog.

Have you now had time to consider whether a bullet has or has not kinetic energy, and whether it will or will not kill you, if it's fired from a gun on the platform at you as you travel away from it on a train doing bullet-speed? Oh, spork was stupid to fall for that one, wasn't he? Or are you just going to ignore the question again? You know, if you could just once admit that you've been wrong about any single bit of this, you won't dissolve.

No need. Frames concept BS.

In the real world, objects do accelerate to zero velocity. If you don't know that, you're just a bad physicist. Decelerating is just negative acceleration. Physicists don't usually deal in a measurement called deceleration. So when you stop your car, it accelerates to zero. The fact that your view of the world is so childishly humbercentric that you don't understand that is irrelevant. Any Chief Scientist will tell you it. (I haven't just caught on, BTW, I'm just bothering to reply to it now, that's all.)

I am quite sure you are not qualified to speak for physicists. Objects are not said to increase their KE or velocity when moving towards zero velocity.

Then, 'zero velocity', is given relative to the particular arbitrary frame of reference we have chosen, an object considered stationary (because, in the real world, we do not know if anything is stationary - really, truly, we have absolutely no idea!).

No, that is not so. Like a sophomore with a head full of Kafka.

But maybe you'd like to reply to my request for a definition of 'real wind'. In particular, maybe you'd like to discuss the kinetic energy values of carts sitting 'stationary' at the North Pole and the equator, since you seem to think KE is absolute, and one of them is 'stationary', while the other is traveling at a thousand miles an hour.

In your view of physics, you are like a young boy who finds a Playboy magazine. He likes the pictures of the naked ladies, but he doesn't know why.

 

[spacediver]

With the help of some of Terry's friends, I've made a new video. It's called "Under the ruler 2: the ground moves". I hope you enjoy it.

I've been skimming this thread and there's no way I can keep up with it all. But I did watch this video and am I right in surmising the following?

Assuming there is no deceptive trickery going on in this video, it proves, without a single shred of doubt, that DWFTTW is in principle possible.

 

[sol invictus]

I am quite sure you are not qualified to speak for physicists. Objects are not said to increase their KE or velocity when moving towards zero velocity.

Non-zero acceleration can increase, decrease, or leave unchanged KE and velocity. That's the most basic Newtonian dynamics, and you will find thousands of references on the web and in physics texts that confirm that.

No, that is not so. Like a sophomore with a head full of Kafka.

You're wrong. That's basic Newtonian dynamics, and you will find thousands of references on the web and in physics texts that confirm that (I've personally given you links to about four).

 

[ThinAirDesigns]

Objects are not said to increase their KE or velocity when moving towards zero velocity.

Well, your position on this is no surprise -- but it's wrong on such a basic level, and it's certainly understandable how flawed your downstream conclusions are considering this obvious headwater pollution.

JB

 

[Michael C]

I've been skimming this thread and there's no way I can keep up with it all. But I did watch this video and am I right in surmising the following?

Assuming there is no deceptive trickery going on in this video, it proves, without a single shred of doubt, that DWFTTW is in principle possible.

I'd say so.

You have my assurance (and Terry's) that there's no trickery here. Indeed, you could easily make one of these yourself: the hardest thing was finding the two cotton reels. It's best if they're wooden ones (plastic tends to slip); also, the radius at the centre part should be noticeably less than that at the ends. The relation between end radius to centre radius in my cart is about 2 to 1. The size of the third wheel isn't important for the relation between speed of ruler and speed of cart: it's just there to translate the movement at the centres of the cotton reels to the ruler above.

 

[Marcus]

I'm behind on this thread again, perhaps this has been covered.

Couldn't you simply mark equally spaced lines on the treadmill surface and cart wheels? Post a slow motion video and everyone could see with their own eyes that the wheels are not slipping. The speeds are low enough that it shouldn't require a high speed camera.

 

[Modified]

I'm behind on this thread again, perhaps this has been covered.

Couldn't you simply mark equally spaced lines on the treadmill surface and cart wheels? Post a slow motion video and everyone could see with their own eyes that the wheels are not slipping. The speeds are low enough that it shouldn't require a high speed camera.

Nope, tried that. Humber says the wheels are not slipping but the cart is "hovering". At least, when you offer that sort of solution that's what he says.

 

[jjcote]

(I can't believe that I'm going to wade into this particular portion of the quagmire...)

OK, humber, this will have to go through some things that are not explanations of the prop cart itself, but they aren't analogies, they're just some simple mechanical examples so that we can establish the basic rules of motion.

First, let's think about the test area. We can used a toothed rail if need be, but I'll suggest we just go with a nice high-traction rubber surface. To start out, our test area will have limited visibility -- it's dark and foggy, and you can see only as far as your flashlight will shine. We're standing on the rubber surface where our cart is going to run, and there is a steady 10 m/s breeze blowing by, in a uniform direction. Will this be acceptable for a test area, or do you feel that you need to see more of our surroundings?