Merged DDWFTTW in a “Real” Wind

[humber]

No thanks, I'm done for now.

I just think it's important that anyone casually reading the thread realises that you have absolutely no idea what you're talking about. After my succinct post they can then read all of yours to confirm that this is the case.

Might be back later.

Miss you already.

 

[Dr. Keith]

So it's just a rounding error .....

Yes. The position is measured to more significant figures than you are showing and is rounded appropriately. The actual measured data will be in a random scatter around the true position in accordance with the accuracy of the unit.

Have you ever taken a course in measurement? Have you ever taken measurements in a lab or field environment? This is very basic stuff.

That produces a >200 degree change in the direction calculated from that?

More than that would be possible. Think of darts hitting a dart board and then taking the heading from one dart to the next. It would be all over the place. That is what your data shows.

It is not swinging around like a wind vane, it is taking headings from the darts as they hit the board in succession. The gps unit takes a reading every second whether the cart has moved or not.

So how useful would that be, do you think?

It is not useful at all in the case shown, but then the heading of a stationary object isn't useful anyway, is it? Heading only has usefulness upon movement, but the long lat data clearly show that the gps unit is stationary. Therefore, you are being mesmerized by noise in the gps data while the unit is at rest.

I don't need your white flag.

Then just tell me what is capturing the energy from the change in direction?

According to PPG it can be any shape, but I don't see any other carts out there taking advantage of his assertion . . .

 

[ThinAirDesigns]

Good on them for trying to come clean. We will have to wait and see the final result.

No we won't have to wait -- the current result (the record) is the final result.

In the interest of fair and balanced, and perticularly in the interest of good science, both Google and Joby should grant the same sponsorship to Humber that they gave to Spork. I am calling on them to do so.

Good luck with that. It makes a lot of sense to sponsor the guy who says it can't be done after all. He can spend their money, not do it and then say "see -- I told you it was impossible". Fortunately they are smarter than a third grader.

JB

 

[humber]

Yes. The position is measured to more significant figures than you are showing and is rounded appropriately. The actual measured data will be in a random scatter around the true position in accordance with the accuracy of the unit.

Have you ever taken a course in measurement? Have you ever taken measurements in a lab or field environment? This is very basic stuff.

The rhetorical question means that you have not.

More than that would be possible. Think of darts hitting a dart board and then taking the heading from one dart to the next. It would be all over the place. That is what your data shows.
It is not swinging around like a wind vane, it is taking headings from the darts as they hit the board in succession. The gps unit takes a reading every second whether the cart has moved or not.

And it's the CV, and no matter what YOU say, the calculated direction changes 200 degrees in 0.2 seconds. That's a problem for this reason:
NALSA Report
" The true wind speed and direction were calculated from the vector sum of the speed, heading and apparent wind of the chase vehicle and the
speed and heading of the craft."

And for another, that has flown over your head.

It is not useful at all in the case shown, but then the heading of a stationary object isn't useful anyway, is it? Heading only has usefulness upon movement, but the long lat data clearly show that the gps unit is stationary. Therefore, you are being mesmerized by noise in the gps data while the unit is at rest.

And that error disappears when in the more difficult case of motion? That did take a long time for you to grasp.

The rest, I really don't care to answer, because your opinion is only that.

This says more about your perspicacity, than you fail to do.

 

[humber]

No we won't have to wait -- the current result (the record) is the final result.

OJ got away with the first trial.
If you think that you can pressure NALSA, maybe, but when the collated results are posted where I please, you will be unable to defend it.
Add to that, the propless TM cart, and your record will be face value only.

 

[Subduction Zone]

Oh my, ppg is just mailing it in. Harold, if you make incorrect assumptions about how much the wind will accelerate the cart you will get incorrect results. Your conservation of energy analysis was fatally flawed since you tried to take all of the energy gain of the cart and turn it into acceleration. The cart will not accelerate at that rate. And before I forget it the conservation of momentum claim was wrong too. In both analyses you forgot about the Earth. The Earth will take up some of the momentum change. You are arguing like a creationist, you are incorrectly applying physics.

So one more time, Harold wrong, try again.

 

[tobermoryphil]

OJ got away with the first trial.
If you think that you can pressure NALSA, maybe, but when the collated results are posted where I please, you will be unable to defend it.
Add to that, the propless TM cart, and your record will be face value only.

Humber: the £1000 award is still waiting for you to demonstrate your propless cart advancing on a treadmill.

Either have the guts to show it, or the guts to admit it is non-existent.

You will, I confidently predict, do neither, so just STOP flannelling on about it.

 

[windgrins]

Dr. K-have a cool drink and enjoy!

Yes. The position is measured to more significant figures than you are showing and is rounded appropriately. The actual measured data will be in a random scatter around the true position in accordance with the accuracy of the unit.

Have you ever taken a course in measurement? Have you ever taken measurements in a lab or field environment? This is very basic stuff.



More than that would be possible. Think of darts hitting a dart board and then taking the heading from one dart to the next. It would be all over the place. That is what your data shows.

It is not swinging around like a wind vane, it is taking headings from the darts as they hit the board in succession. The gps unit takes a reading every second whether the cart has moved or not.



It is not useful at all in the case shown, but then the heading of a stationary object isn't useful anyway, is it? Heading only has usefulness upon movement, but the long lat data clearly show that the gps unit is stationary. Therefore, you are being mesmerized by noise in the gps data while the unit is at rest.




Then just tell me what is capturing the energy from the change in direction?

According to PPG it can be any shape, but I don't see any other carts out there taking advantage of his assertion . . .

Dr. Keith,

You've fallen into the pit again. It seems you have somehow been led to believe that information, facts, logic, or reason has anything at all to do with combating the insane/lame assertions here from our Anti-Carteerian team.

If you find yourself tempted to persuade these posters of anything at all, go to any random 10 pages and just read it. It will tend to cure you of this ill!

I'm delighted to hear from Spork in his earlier posts that we have a feedback path from NALSA. I doubt very seriously that H & H will ever actually lodge a protest given their wonderful arguments over the last 15 pages. But we'll know this if they do or don't.

Think of this as lowbrow comedy of the "Three Stooges" variety and enjoy!

WindGrins

 

[69dodge]

Yes indeed, and if you followed my calculations you will see where I have done that. I added the 350 Watts at the propeller to the MAX amount of power that can be extracted from the wind (given the parameters of the problem) and the total was about 1,350 Watts , rounded UP, and it was well short of the 1,440 Watts needed.

Yes. I can't find any errors in those calculations, except that you considered the frictional losses to be greater than is reasonable. (But I could be wrong, of course. I am far from being any sort of expert in these matters.)

I think that instead of choosing the frictional losses at the beginning, more or less arbitrarily, then doing a calculation based on them and using its result to state categorically that the cart can't work, it might be more useful to do a calculation assuming zero frictional losses (except perhaps for inefficiencies in the propeller, which are unavoidable), and see what the numbers look like in that case. That way, if the numbers still show that the cart can't work, it certainly can't, and otherwise, the numbers will show exactly how much frictional losses are allowable for the cart still to work.

In fact, the calculation can be made even simpler, and the result for the cart is much worse!

All we need to do in order to prove or disprove this claim, is examine the two fundamental laws of conservation, The Law of conservation of Momentum, and the Law of conservation of Energy.

We can do that quite easily with the example we have been examining, with the 295 Kg cart moving at 9 m/s directly down wind in a wind of 7 m/s. We already calculated the air mass to be 72 kg, and the amount of acceleration given to the air by the propeller to be 2.2 m/s.

Now it is a simple matter to calculate the initial and final velocities, momentum and energies to see if it all agrees with the two great conservation laws:

Initially, the cart is moving at 295 kg cart is moving at 9 m/s and has a momentum of 2,655 kg x m/s

Initially, the 72 kg block of wind is moving at 7 m/s and has a momentum of 504 kg x m/s.

The Total momentum of this system is 3,160 kg x m/s and this must be conserved.

After being worked on by the propeller, the air mass is slowed by 2.2 m/s to a velocity of 4.8 m/s

Finally, the 72 kg block of wind, moving at 4.8 m/s has a momentum of 346 kg x m/s.

To conserve momentum, the cart must have a final momentum of 3,160 – 346 = 2,814 kg x m/s.

The 295 kg cart’s final velocity must be 9.54 m/s having a momentum of 2,814 kg x m/s.

So far, the law of conservation of momentum has been observed, but in order for this to be valid, the law of conservation of energy must also be shown to be conserved:

Initially, the 295 kg cart, moving at 9 m/s has kinetic energy of 11,950 Joules

Initially, the 72 kg block of wind, moving at 7 m/s, has kinetic energy of 1,765 Joules.

The total energy of the system is 13,715 Joules, and this too must be conserved.

After being worked on by the propeller, the air mass is slowed by 2.2 m/s to a velocity of 4.8 m/s.

Finally, the 72 kg block of wind, moving at 4.8 m/s, has a kinetic energy of 830 Joules.

Finally, the 295 kg cart, moving at 9.54 m/s, has a kinetic energy of 13,425 Joules.

The Total kinetic energy of the system is 14,255 Joules, and that is 540 Joules more than the system started out with.

There has been no input of energy from any other source, as all calculations are done in the frame where the ground is at rest and has no energy. The cart has gained more energy than the wind lost, based on the relative velocities and conservation of momentum. Conservation of energy has been violated, and that is not possible.

The momentum of the air decreases by 158 kg m/s. You claim that, therefore, in order for momentum to be conserved, the momentum of the cart must increase by 158 kg m/s, which yields a velocity increase of 0.54 m/s. But the cart exerts a forward force on the earth, increasing its momentum as well. Some of the 158 kg m/s increase in momentum is thus taken up by the earth, so the increase in the cart's velocity is less than what you calculated. The increase in the cart's energy is therefore also less than what you calculated, and so energy may be conserved after all.

(Because energy depends on the square of the velocity, and the earth, due to its huge mass, undergoes such a small change in velocity, the change in energy of the earth is negligible, so when treating energy, it's ok to focus solely on the cart and air, and to ignore the earth. But momentum depends on the first power of velocity, and therefore the change in momentum of the earth is of the same order of magnitude as the change in momentum of the cart and of the air, and so cannot be ignored.)

 

[jadebox]

It is a perfectly closed system, consisting of the kinetic energy of the wind that is processed by the propeller (72 kg moving at 7 m/s) and the 295 kg cart moving at 9 m/s. The ground is the reference frame and contributes no energy as it has none. If you say this is not a closed system then you must show another source of energy other than what I have shown. Hop to it!

You keep forgetting, or conveniently omitting, that the wind keeps blowing. It's not a closed system.

In a closed system, the total energy would remain constant. In this case, the wind keeps blowing or, from the, IMHO, easier to visualize reference point of the cart, the wheels keep turning.

Your calculations and descriptions seem to assume that the propeller must keep the cart moving at wind speed. That's not true. All the propeller has to do is to accelerate the cart.

Look at it this way. If the cart was travelling 9 m/s and that was the same as the wind speed (and assuming no friction between the wheels and the road), then propeller would not have to supply any energy to keep the cart moving. Inertia will keep it moving at the speed of the wind (in the real universe).

Any thrust provided by the propeller would accelerate the cart. Now, if we allow the wheels to be turned by the road, they provide energy to turn the propeller which will accelerate the cart. If the thrust of the propeller is greater than the drag (and friction) as the cart exceeds the speed of the wind, the cart will accelerate.

-- Roger

 

[CORed]

OJ got away with the first trial.
If you think that you can pressure NALSA, maybe, but when the collated results are posted where I please, you will be unable to defend it stop laughing for a week.

Fixed.

Add to that, the propless TM cart, and your record will be face value only.

Humber, you do realize that the wheels on the floor or other stationary surface on you propless cart, geared to the wheels on the treadmill, will actually validate the concept of the ddwfttw cart, don't you?

Of course not.

 

[temporalillusion]

I've worked creating location enabled applications before and worked with a geomatics engineer for a number of years.. back before the iPhone and pervasive location APIs you often wrote your own or implemented others' algorithms for determining heading, dealing with bad locations, eliminating the jitter to show a stable location, etc etc.

Dr. Keith has the right of it and as usual humber's objections fall close to "not even wrong" territory.

 

[Dr. Keith]

Dr. Keith,

You've fallen into the pit again. It seems you have somehow been led to believe that information, facts, logic, or reason has anything at all to do with combating the insane/lame assertions here from our Anti-Carteerian team.

If you find yourself tempted to persuade these posters of anything at all, go to any random 10 pages and just read it. It will tend to cure you of this ill!

I'm delighted to hear from Spork in his earlier posts that we have a feedback path from NALSA. I doubt very seriously that H & H will ever actually lodge a protest given their wonderful arguments over the last 15 pages. But we'll know this if they do or don't.

Think of this as lowbrow comedy of the "Three Stooges" variety and enjoy!

WindGrins

Yep. I'm done. This was an eye opening experience.

If humber can't understand that the calculated heading of a stationary object will include the noise of the lat long measurement errors, then I really can't be bothered. He would have never made it through a basic surveying course, much less anything serious.

 

[Dr. Keith]

I've worked creating location enabled applications before and worked with a geomatics engineer for a number of years.. back before the iPhone and pervasive location APIs you often wrote your own or implemented others' algorithms for determining heading, dealing with bad locations, eliminating the jitter to show a stable location, etc etc.

Dr. Keith has the right of it and as usual humber's objections fall close to "not even wrong" territory.

Thanks. I used to work with GIS and some GPS back in the mid nineties, but it has been some time so I'm glad I'm not too far off the current tech.

This seems like such an obvious thing that I just can't understand how wrong humber can be on this. I guess when you look at this stuff with the pre-conceived notion that something is fishy then everything is fishy.

 

[humber]

Fixed.

Humber, you do realize that the wheels on the floor or other stationary surface on you propless cart, geared to the wheels on the treadmill, will actually validate the concept of the ddwfttw cart, don't you?

Of course not.

Keep the rose water handy.

 

[humber]

Yep. I'm done. This was an eye opening experience.

If humber can't understand that the calculated heading of a stationary object will include the noise of the lat long measurement errors, then I really can't be bothered. He would have never made it through a basic surveying course, much less anything serious.

You got whipped. Fancy thinking that the stationary GPS will be less accurate than one in motion.
And the there are vast differences between the number of decimal places, resolution and accuracy.

 

[Dr. Keith]

You got whipped.

No doubt I am completely exhausted by your willful ignorance. Whipped is an apt description.

 

[profpangloss]

Yes. I can't find any errors in those calculations, except that you considered the frictional losses to be greater than is reasonable. (But I could be wrong, of course. I am far from being any sort of expert in these matters.)

I think that instead of choosing the frictional losses at the beginning, more or less arbitrarily, then doing a calculation based on them and using its result to state categorically that the cart can't work, it might be more useful to do a calculation assuming zero frictional losses (except perhaps for inefficiencies in the propeller, which are unavoidable), and see what the numbers look like in that case. That way, if the numbers still show that the cart can't work, it certainly can't, and otherwise, the numbers will show exactly how much frictional losses are allowable for the cart still to work.

All I did there was use the parameters provided by lyricist, it was his problem set, not mine, and he admitted it was crap. I can work up a new problem with more ideal parameters, and I plan on doing that. I'm quite sure the cart will still not work, however.

The momentum of the air decreases by 158 kg m/s. You claim that, therefore, in order for momentum to be conserved, the momentum of the cart must increase by 158 kg m/s, which yields a velocity increase of 0.54 m/s. But the cart exerts a forward force on the earth, increasing its momentum as well. Some of the 158 kg m/s increase in momentum is thus taken up by the earth, so the increase in the cart's velocity is less than what you calculated. The increase in the cart's energy is therefore also less than what you calculated, and so energy may be conserved after all.

(Because energy depends on the square of the velocity, and the earth, due to its huge mass, undergoes such a small change in velocity, the change in energy of the earth is negligible, so when treating energy, it's ok to focus solely on the cart and air, and to ignore the earth. But momentum depends on the first power of velocity, and therefore the change in momentum of the earth is of the same order of magnitude as the change in momentum of the cart and of the air, and so cannot be ignored.)

I don't think the momentum of the planet is changed in any significant way by the cart passing by! I'm not ridiculing you for bringing it up, as I have actually seen calculations in basic physics texts, placed there to impress the newcomers, but the numbers are incredibly tiny and can be ignored. In fact, the planet itself is not really affected, as some loose dirt is shoved backwards by the wheels. It would make more sense to calculate the momentum of the dirt that is kicked up, but it still is not significant enough to affect the calculation when we are looking for about 500 Joules/sec.
But thanks for your input, it is nice to work with someone who shows a genuine interest in getting at the truth and not just a closed mind. For my part, if the math were to show it works, then it works, and that is all there is to it. But the math shows me quite the opposite, and the treadmill is a ridiculous misrepresentation. I will have more on the treadmill later, but the key point is that the cart, in never being allowed to go back with the tread, never develops the momentum or inertia (depending on your reference frame) that the tread would impart to it. Being free of that inertia, the tread is a source of energy for the cart. A cart on the road is never free of the inertia given to it, by this big planet of ours and the road, being firmly attached to the planet, can never be a source of energy to the cart. The treadmill can not be compared to the cart on the road at all.

 

[windgrins]

Humber,You are truly oblivious to any subtlety whatsoever!

You got whipped. Fancy thinking that the stationary GPS will be less accurate than one in motion.
And the there are vast differences between the number of decimal places, resolution and accuracy.

Humber,

You didn't kick Dr. Keith. You have no idea what he even told you!

It's very sad to realize you don't even have a clue what both Dr. K and I were telling you about GPS heading data. You are running true to form like you were with reference frames and PE of NB balloons.

I never expect you to awaken!

Windgrins

 

[profpangloss]

You keep forgetting, or conveniently omitting, that the wind keeps blowing. It's not a closed system.

In a closed system, the total energy would remain constant. In this case, the wind keeps blowing or, from the, IMHO, easier to visualize reference point of the cart, the wheels keep turning.

Your calculations and descriptions seem to assume that the propeller must keep the cart moving at wind speed. That's not true. All the propeller has to do is to accelerate the cart.

Look at it this way. If the cart was travelling 9 m/s and that was the same as the wind speed (and assuming no friction between the wheels and the road), then propeller would not have to supply any energy to keep the cart moving. Inertia will keep it moving at the speed of the wind (in the real universe).

Any thrust provided by the propeller would accelerate the cart. Now, if we allow the wheels to be turned by the road, they provide energy to turn the propeller which will accelerate the cart. If the thrust of the propeller is greater than the drag (and friction) as the cart exceeds the speed of the wind, the cart will accelerate.

-- Roger

There are two many points here that I totally disagree with. If you want to consider no friction, then every pmm ever conceived of will work. I don't see any point at all in such an approach when we have the means to calculate frictional losses, or at least estimate them to a reasonable level of accuracy.
I also disagree the road is a source of energy to the cart. The cart has inertia and momentum from the planet earth that it can never be free of. As long as that is the case, the planet does not move under the cart and power it. It is the wind that must blow against the cart and move it over the planet. The wind is the energy source. YES YES I know all about Galilean transforms but there is no need at all to get into all that if we just use the FOR where the ground is stationary as our reference frame. If I can show the cart does not work in that frame, then it does not work in any frame, and that means all the voodoo you have been fed is a load of guff.