Merged DDWFTTW in a “Real” Wind

[Llyricist]

It is simply a toy on a belt. Not proof of ddw. Not something that you seem to think can't be done by several means, and without a prop. It's trivial.
Like the small cart and the BB. Nothing except for hyperbolic promotion.

You would not want to contradict Dr Drela, would you?

"P = sqrt[ T^3 / (2 rho pi) ] / (eta_h R)
T = thrust
rho = air density
pi = 3.14159
eta_h = hover figure of merit = hover efficiency ( = 0.8 typically)
R = rotor radius

F = P / V

V = 5 m/s = 11 mph (looks like the speed of the cart)
T = 1 N (102 grams)
R = 0.4 m
eta_h = 0.5 (assume crummy prop to be conservative)
rho = 1.2 kg/m^3

This gives the following prop shaft power P = 1.8W

The power-generating force on the wheels is:

F = P/V = 1.8 W / 5 m/s = 0.36 N

T_net = T - F = 1.0N - 0.36N = 0.64 N = 65 gram = 2.3 oz"

Change the belt to 10m/s. To keep the same prop AV, and so the same power, the wheel radius must be doubled. The force at the belt is then
1.8W/10ms = 0.18N
Net = 1N - 0.18N = 0.82N

Change that to 20m/s, and again double the wheel radius
1.8W/20ms = 0.09N
Net = 1N - 0.09N = 0.91N

All will work on the belt. So "proving" that the same 1.8W cart can travel at 5, 10, 20....m/s.

Wherein humber fails to notice that we all have been saying that the higher the difference between ground speed and airspeed, the better the cart works.

 

[humber]

That's a good suggestion, humber, and that already seems to be the norm; people are quite willing to attribute your ignorance to you. But thanks for agreeing with that policy.

Having a TM, means that you have no excuse at all, offered to do a test that would contradict the Harold Bricer test, and failed to show the cart working in the wind, so I why do you think you have any credibility?

 

[humber]

Wherein humber fails to notice that we all have been saying that the higher the difference between ground speed and airspeed, the better the cart works.

Sure it does

Belt = 5m/s
Net = 1N - 0.36N = 0.64N

Belt = 10m/s
Net = 1N - 0.18N = 0.82N

Belt = 20m/s
Net = 1N - 0.09N = 0.91N

All capable of 5, 10 and 20m/s WS travel with a total change of 0.27N in net force.
You would not want to contradict Dr Drela.

 

[Subduction Zone]

humber still has an incredible problem with relative velocity. The cart worked exactly as predicted by spork and JB and exactly the opposite of how it was predicted by Harold and humber in the Harold Bricer test.

Only in the humberverse when a test goes exactly the way that your opponents claimed it would can be declared a victory for humber and company.

And yes Windgrins is right about the vibration theory being dead. The deniers cannot explain why the cart will go up the ramp either forward or backward.

 

[windgrins]

What I think!

You do think it's magic.

What I think is that you can't back up any of your rhetoric for the past three years. I think you can't show a device that doesn't store energy that operates only on the belt (and not on the sides of the TM) that climbs the belt like you allege.

I think you can't show a cart that climbs the regular TM belt due to its vibrations. (not a vibratory conveyer which happens not to translate under the material in the ground reference frame).

I think the theory of operation as the carteers have proposed is consistent with all experiments and complies completely with everything we have seen and explains very well how everything works, while not only not violating the laws of physics, but completely adhering to them.

I think that when you think you know "what I think", that you should refer back to this post as its clearly stated here.

I think you can't show a cart the moves up the TM with any of your theoretical modes.

If so, do it.

Now you know what I think.

WindGrins

 

[Subduction Zone]

Sure it does

Belt = 5m/s
Net = 1N - 0.36N = 0.64N

Belt = 10m/s
Net = 1N - 0.18N = 0.82N

Belt = 20m/s
Net = 1N - 0.09N = 0.91N

All capable of 5, 10 and 20m/s WS travel with a total change of 0.27N in net force.
You would not want to contradict Dr Drela.

And humber continues to shoot himself in the foot.


humber all of your force calculations show that the cart will accelerate even faster when going at wind speed at ever increasing wind speeds. Exactly what spork and JB predicted and what was observed.

 

[windgrins]

And humber continues to shoot himself in the foot.


humber all of your force calculations show that the cart will accelerate even faster when going at wind speed at ever increasing wind speeds. Exactly what spork and JB predicted and what was observed.

Reading his post looked that way to me also but I assumed I must be misreading it since he showed exactly what we expect-the faster the wind, the more force on the cart.

Is he trying to explain something else?

WindGrins

 

[humber]

Reading his post looked that way to me also but I assumed I must be misreading it since he showed exactly what we expect-the faster the wind, the more force on the cart.

Is he trying to explain something else?

WindGrins

Hilarious. The denial at being shown how bare the cupboard is.
"It still works, coz it does 'n' all!"

If there is an increase of net force with speed, no matter how small, and even though 20 other parameters fall or remain constant, proves the cart works." That's why you fell for the scam.
Fooled by algebra.

 

[Myriad]

It is simply a toy on a belt. Not proof of ddw.

I never understood this claim. Are we to assume that "toys" are somehow exempt from the laws of physics?

In engineering, characterizing a small-scale prototype as a mere toy is shorthand for claiming that it works using methods that will not easily scale up for any practical use. For example, a potato-battery clock or a rubber-band powered model airplane.

However, a working toy still represents a proof of concept. If anyone could have shown Benjamin Franklin a working potato-battery device, or the Wright Brothers a working rubber band powered model airplane, they would have been impressed and would have studied them intently, because those "toys" demonstrate basic principles that at the time were not yet well established.

Similarly, if I could manage to land a homemade "toy" spacecraft on the moon, I bet NASA (and every aerospace agency in the world) would be impressed regardless of how small it was or what it was made of. It might be difficult to scale up, but there's no doubt they'd pay me millions of dollars to try.

Humber and PPG have not claimed that the DDWFTTW principle can't scale up, but that it can't work at all. A working "toy" refutes that claim every bit as much as the full scale Blackbird.

Respectfully,
Myriad

 

[Llyricist]

Sure it does

Belt = 5m/s
Net = 1N - 0.36N = 0.64N

Belt = 10m/s
Net = 1N - 0.18N = 0.82N

Belt = 20m/s
Net = 1N - 0.09N = 0.91N

All capable of 5, 10 and 20m/s WS travel with a total change of 0.27N in net force.
You would not want to contradict Dr Drela.

I'm not. I already know that the higher the difference between ground speed and airspeed, the better the cart works. As long as ground speed > airspeed

 

[windgrins]

I never understood this claim. Are we to assume that "toys" are somehow exempt from the laws of physics?

In engineering, characterizing a small-scale prototype as a mere toy is shorthand for claiming that it works using methods that will not easily scale up for any practical use. For example, a potato-battery clock or a rubber-band powered model airplane.

However, a working toy still represents a proof of concept. If anyone could have shown Benjamin Franklin a working potato-battery device, or the Wright Brothers a working rubber band powered model airplane, they would have been impressed and would have studied them intently, because those "toys" demonstrate basic principles that at the time were not yet well established.

Similarly, if I could manage to land a homemade "toy" spacecraft on the moon, I bet NASA (and every aerospace agency in the world) would be impressed regardless of how small it was or what it was made of. It might be difficult to scale up, but there's no doubt they'd pay me millions of dollars to try.

Humber and PPG have not claimed that the DDWFTTW principle can't scale up, but that it can't work at all. A working "toy" refutes that claim every bit as much as the full scale Blackbird.

Respectfully,
Myriad

A good point and furthermore:

In this case, there really is no such thing as a "toy"! The original claim was can a vehicle be built that travels DDWFTTW powered only by the wind.

A small vehicle that does it is not a scale model, it is the vehicle itself.

It is obvious that by using the deprecatory "toy" moniker that Humber intends to demean the small carts value. Hopefully no one still reading is stupid enough to fall for this so we just ignore Humber's negative inferences as they have no merit. He has a very long track record as evidenced by his posts of "demeaning to diminish" when he has no valid point to make.

Regards,

WindGrins

 

[profpangloss]

No, it is not wrong and the numbers are correct. You don’t even need to read the entire paper, here is the relevant part again:



In the given example, 70 N is approximately 10% of a subject’s body weight which is mg. So a person with a mass of 70 kg has a weight (force) on the treadmill of approximately 700 N and 10% of that is 70 N. That is the same magnitude as the “noise” forces recorded on the treadmill with no subject on the treadmill. In fact, in the vertical direction the noise was 80 N. The readings of 60 N in the horizontal and lateral directions degraded the signal/noise ratio during physiological testing with subjects on the treadmill.

We don’t need to get into the physiology here, only the kinematics of the treadmill itself. What matters in this discussion is that even with a custom-made treadmill with specially machined rollers, significant forces were measured in all three spatial directions.

It is not difficult to imagine that a 60 N force concentrated in the frequency spectrum between 46 to 86 Hertz can have some effects on a 200 gram cart that is loosely coupled to the treadmill belt. In fact, it is nonsensical to think that it would have no effect!

I do not need to prove what the effect is to discount the Galilean transform of the cart on a treadmill to a cart on a road in a wind. I only need to show that these forces are present on the treadmill and they have not been transformed to the situation of the cart on the road. That is more than enough to say that such a transform is incorrect, incomplete and invalid!

No response to this? I think I know why!

Let’s start at the beginning and return to the issue of inertial reference frames.

Quoting from Wikipedia: http://en.wikipedia.org/wiki/Inertial_frame_of_reference

The weakness of the principle of inertia lies in this, that it involves an argument in a circle: a mass moves without acceleration if it is sufficiently far from other bodies; we know that it is sufficiently far from other bodies only by the fact that it moves without acceleration.
There are several approaches to this issue. One approach is to argue that all real forces drop off with distance from their sources in a known manner, so we have only to be sure that we are far enough away from all sources to ensure that no force is present. A possible issue with this approach is the historically long-lived view that the distant universe might affect matters (Mach's principle). Another approach is to identify all real sources for real forces and account for them. A possible issue with this approach is that we might miss something, or account inappropriately for their influence.

Indeed, that is exactly what is happening when the carteers attempt a Galilean transformation of the cart on a treadmill to a cart on a road in the wind.

As noted and quoted above, there are forces acting on the treadmill belt on the order of 60 N. Considering the cart on the belt has a mass of about 0.2 Kg, exerting a downward force on the belt of about 2 N, and considering the propeller thrust of said cart is on the order of only 1 N, these forces on the belt are roughly 60 times greater than the propeller thrust, and 30 times greater than the weight of the cart on the belt.

Now consider what that implies for a 200 Kg cart on a road in the wind that has a propeller thrust of approximately 100 N. The downward force of the cart on the ground is about 2000 N or 20 times greater than the propeller thrust, while the small cart on the treadmill had a weight to thrust ratio of 2:1. That is a huge difference and in itself must invalidate any conclusions drawn from the cart on the treadmill being applied to the big cart in the wind.

But that is not all that is wrong with the carteer’s “transformation”. They have completely neglected to transform the belt forces on the treadmill to the situation with the cart on the road.

Those forces of 60 x the propeller thrust, and 30 x the cart weight, would correspond to seismic forces of the ground motion on the order of 60,000 N !

As I stated earlier, the only correct transform for a cart on a treadmill, that accounts for all of the real forces present, would be a velocity transform only, that results in a cart that remains on a treadmill, and nothing to do with a cart on a road in the wind.

This is not a matter of opinion. It is a matter of scientific fact. The transform the carteers are attempting to push off on the unwary is completely wrong and deserves no further consideration.

 

[Subduction Zone]

Hilarious. The denial at being shown how bare the cupboard is.
"It still works, coz it does 'n' all!"

If there is an increase of net force with speed, no matter how small, and even though 20 other parameters fall or remain constant, proves the cart works." That's why you fell for the scam.
Fooled by algebra.

Yes, all carteers are terribly fooled by algebra. For example when we analyze the trajectory of an object we are fooled by the algebra that says the acceleration of the object at the top of its arc is not zero, but not humber He knows that if the vertical velocity is zero then the vertical acceleration is zero.

 

[phunk]

No response to this? I think I know why!

No, unless you happened to be at my doctor's office this morning, I don't think you do know why. Some of us are employed. I just got to my office, when I have time I'll respond more fully.

But for now, how is 10% the same magnitude? It's not, it's 10%. And that's 10% of a person's weight standing still, when running they are impacting the treadmill at around 2.5 times that. So more like 4%.

 

[Subduction Zone]

ppg, you are sorely mistaken about how to do a Galilean Transformation. You posted such a sorry example it is hard to explain through my laughter. According to your extremely poor understanding wind tunnels would not work either since they did not transform how much force it takes to accelerate the whole Earth. You are grasping at straws.

We are not transforming the belt, we are transforming the forces on the cart, and it does not care why its wheels are spinning. The forces on the cart would be the same whether someone held it still over a treadmill or held it in place while accelerating the whole Earth relative to it. Granted the forces on the Earth would be incredibly high, but that is not what is being analyzed.

 

[profpangloss]

ppg, you are sorely mistaken about how to do a Galilean Transformation. You posted such a sorry example it is hard to explain through my laughter. According to your extremely poor understanding wind tunnels would not work either since they did not transform how much force it takes to accelerate the whole Earth. You are grasping at straws.

We are not transforming the belt, we are transforming the forces on the cart, and it does not care why its wheels are spinning. The forces on the cart would be the same whether someone held it still over a treadmill or held it in place while accelerating the whole Earth relative to it. Granted the forces on the Earth would be incredibly high, but that is not what is being analyzed.

Nothing but empty words. For a correct transform you must identify all real sources for real forces and account for them. If you fail to do this you might miss something, or account inappropriately for their influence.

The transform that you carteers are attempting to pass off does not account for all of the forces acting in the FOR. Therefore, the transform is wrong. That is not my opinion, it is a fact and I have presented the sources to back that up.

You cannot transform only the forces you wish to show to prove your point and ignore the rest. That is ignorant and unscientific.

Forget about using the treadmill to prove anything about a cart going DDWFTTW. Now that is settled, what else do you have? There is no evidence of a small cart ever exceeding wind speed, but several videos showing things like popcorn and leaves blowing past these carts. The NALSA trials are a farce, because the wind is acting at on angle on the cart. The mathematical analyses show that the cart can never reach wind speed, and if towed there the cart will slow down as soon as the tow rope is removed.

In short, you have nothing to support your claim.

 

[profpangloss]

No, unless you happened to be at my doctor's office this morning, I don't think you do know why. Some of us are employed. I just got to my office, when I have time I'll respond more fully.

But for now, how is 10% the same magnitude? It's not, it's 10%. And that's 10% of a person's weight standing still, when running they are impacting the treadmill at around 2.5 times that. So more like 4%.

You still do not understand that 10% of 700 is 70? And that is the same magnitude as the forces on the belt? Wow! I guess that explains why you accept the claim of DDWFTTW!

 

[Dr. Keith]

Having a TM, means that you have no excuse at all, offered to do a test that would contradict the Harold Bricer test, and failed to show the cart working in the wind, so I why do you think you have any credibility?

Mender, humber has thrown down the gauntlet. I suggest you respond with a video of the requested tests "soon" or you will lose all credibility.

Of course, in the humberverse "soon" means you have at least 3 years . . . so don't cancel your dinner plans.

ETA: I have no idea what "credibility" means in the humberverse.

 

[CORed]

I never understood this claim. Are we to assume that "toys" are somehow exempt from the laws of physics?

In engineering, characterizing a small-scale prototype as a mere toy is shorthand for claiming that it works using methods that will not easily scale up for any practical use. For example, a potato-battery clock or a rubber-band powered model airplane.

However, a working toy still represents a proof of concept. If anyone could have shown Benjamin Franklin a working potato-battery device, or the Wright Brothers a working rubber band powered model airplane, they would have been impressed and would have studied them intently, because those "toys" demonstrate basic principles that at the time were not yet well established.

Similarly, if I could manage to land a homemade "toy" spacecraft on the moon, I bet NASA (and every aerospace agency in the world) would be impressed regardless of how small it was or what it was made of. It might be difficult to scale up, but there's no doubt they'd pay me millions of dollars to try.

Humber and PPG have not claimed that the DDWFTTW principle can't scale up, but that it can't work at all. A working "toy" refutes that claim every bit as much as the full scale Blackbird.

Respectfully,
Myriad

It's one of humber's standard tactics: Proof by insult. If he calls the small cart a toy, or the BB a "rolling junkyard", he doesn't have to account for the fact that both work exactly as claimed.

 

[Dr. Keith]

In short, you have nothing to support your claim.

Typing that sentence after 10K posts in this thread alone detailing the evidence of the claim and completely destroying every half-assed theory to the contrary is really the height of performance art.

Well done, profpang/oss. RCP should be proud.


ETA: See, I'm finally putting that art history Phd to work! Thanks humber.