Merged DDWFTTW in a “Real” Wind

[humber]

It's this level of clarity of language which makes this thread so concise and easy to follow.

I think what humber's attempting to say is that the cart will run off the end of the treadmill.

I have already stated it several times JBTH, so it becomes redundant to make every detail each time.

I
But if you speed up the treadmill that would be equivalent to increasing the windspeed, and would be futile as the cart will just accelerate and run off the end of the treadmill anyway.

(a) The belt is the road. If the cart is moving at 4m/s AND the road is seen to move the other way, the difference is 8m/s between cart and road.
So 4.1m/s becomes 8.2m/s etc
But...the belt (road) remains at a constant speed as the cart moves faster the other way. And where would the observer be that can see (a)? It was a mistake to claim faster than the belt. If only WS, they would have got away with that error.

The cart exploits changing wind direction and height gradient. It's a sail cart that is inhibited by having the rotor oppose the wheel. At low cart speeds the pylons function as simple sails, while the rotor is too slow to do its thing. Nobody cares about how well it does that...A.T.

Recall what Steve Smith of NASA said about the albatross, and then this description.

Dynamic Soaring.
The ocean desert surface moves slower than the wind above it does. So, the wind moving just above the ocean desert surface is slowed quite a bit by friction.
The higher you get from the surface, the less the wind is slowed by the ground.
So, if an albatross wanted to fly into the wind, it should fly close to the ocean surface, where the wind against the bird would be the slowest. That is what they do, and they also do something else, and this is the interesting part.

(Put the cart body low to the ground, and measure the wind as close to the ground as you can get away with)

Picture an albatross that wants to fly to the west, but the wind is blowing from south to north. The albatross is five meters in the air (a bit taller than your ceiling probably is). It points itself to the north and glides quickly downwind. It gains speed rapidly because it has the wind pushing it and because it is gliding gradually from a high position to a low position. After a long downhill glide with the wind pushing it, the albatross turns west, which is the direction it wants to go.

( Keep the same approximately downwind course, and let the wind change direction for you.)

It is moving very fast, just as you would be on a bike after a long downhill with the wind at your back. Conveniently for the albatross, the wind moving from south to north is slowed so much by friction with the ocean that the bird's flight is not affected much by wind (like we said earlier). Compared with the bird's speed, the wind is not blowing much at the surface. So, the bird can fly a long distance, maybe a hundred meters (the length of a football field) on the energy it got from the long downhill glide. It has not been flapping its wings during this time. Finally it slows down enough that it needs more energy to keep going. It could flap its wings to increase its speed, OR...
It could change the angle of its wings so that it rises up above the ocean surface where the wind is blowing more strongly, and grab itself some more wind energy by flying downwind again. During the downwind glide they pick up enough energy to fly some to the west and also to rise up into the wind again at the end of their progress to the west.

(...or turn a rotor that moves between the higher speed wind, and the lower speed wind. The gradient is always there.)

I said before the BB was even conceived that a momentum cart could work this way if "built to the max". Seems I was right.

The little cart is just a rag in the wind, and not at all like the BB. The TM is something else again, and the theory is not of this planet.

 

[Jack by the hedge]

I have already stated it several times JBTH, so it becomes redundant to make every detail each time.

So did you mean the cart will run off the end of the treadmill, or shall we never know?

(a) The belt is the road.

(a) OK.

If the cart is moving at 4m/s...

4ms^-1 relative to the treadmill or relative to the ground?

... AND the road is seen to move the other way, the difference is 8m/s between cart and road.

Seems like you meant wrt the ground. And that the belt is moving at the same speed in the opposite direction.

So 4.1m/s becomes 8.2m/s etc

So you have some way of making the treadmill match the cart's groundspeed? OK.

But...the belt (road) remains at a constant speed as the cart moves faster the other way.

Oh. So you don't have a way to make the treadmill match the cart's groundspeed. So we should ignore that bit? OK.

And where would the observer be that can see (a)?

Somewhere in the same room would be good, I suppose. Really not sure what you're implying.

It was a mistake to claim faster than the belt.

It was a mistake for whom to claim what was faster than the belt?

If only WS, they would have got away with that error.

If (something) was moving at windspeed, or perhaps was claimed to be moving at windspeed, than the claimant would have got away with an erroneous claim for something to be faster than the belt. What?

The cart exploits changing wind direction and height gradient.

We're going off at a tangent now, and I'm afraid the thread is much less efficient at that angle. I'd only remark that you already suggested what you regarded as a possible figure for the wind gradient and it was immediately clear that there was only a few percent difference between the wind at the prop's hub and it's uppermost reach, so it could in no way account for the cart reaching 2.8x windspeed.

 

[humber]

So did you mean the cart will run off the end of the treadmill, or shall we never know?

And you think the one that you have seen, won't? It does.
Allowing that motion to be seen, is like proverbial Lemmings, producing a conveyor belt to hasten their demise over the cliff

It says in one stroke that the TM is false. The road never goes backwards, and to emulate that illusion as physics is, well....dare I say it....obviously funny.

It's done: you have all been had by a pair of wannabe cranks.

 

[Jack by the hedge]

And you think the one that you have seen, won't? It does.
Allowing that motion to be seen, is like proverbial Lemmings, producing a conveyor belt to hasten their demise over the cliff

It says in one stroke that the TM is false. The road never goes backwards, and to emulate that illusion as physics is, well....dare I say it....obviously funny.

It's done: you have all been had by a pair of wannabe cranks.

Is that a "yes"?

If that's a "yes", dare I ask which end of the treadmill you're referring to?

 

[humber]

Is that a "yes"?

If that's a "yes", dare I ask which end of the treadmill you're referring to?

The two are not related.

 

[semper]

Save the Albatross

So, if an albatross wanted to fly ... it would at all costs avoid Humber's usual blap.

Please help save the Albatross, this magnificent bird does not deserve to have its integrity smeared in any way by Humberian word sewerage. I'm sure everyone here will automatically know to disregard whatever he may have said above, here is something much more likely to be correct;

http://esoaring.com/albatros_presentation_esa.pdf

 

[A.T.]

That said, it still seems to me that there are some significant advantages to the BB design over a conventional sail craft. (Although its extra mechanical complexity is certainly a disadvantage.)

The transmission creates very big problems, as the speeds rise.

It is traveling at a more advantageous angle with respect to the wind.

Just the chassis. The airfoils are still going off-DDW. I don't see any inherent advantage here.

And an optimized symmetrical dual prop configuration would allow the wheels to evenly dig in (with no side loads) to achieve max traction and minimal skidding.

You might have no side loads, but instead you get huge tangential loads on the wheels. I have once computed them for speeds comparable to the Greenbird record, and there were in the order of magnitude of the normal force. So traction does become a problem here.

 

[humber]

You might have no side loads, but instead you get huge tangential loads on the wheels.

Which are relieved when the tires scrub.

I have once computed them for speeds comparable to the Greenbird record, and there were in the order of magnitude of the normal force. So traction does become a problem here.

Green bird maintains long periods with that force. Breaking traction would cause it to travel further and so defeat itself.
The BB is a clumsy way of making a machine that exploits wind gradients.

As for the tacking prop, put yourself on the roof of a car traveling downwind faster than the wind. Put your hand out and try and reduce the force that is driving it backwards. See if you can do that for more than the extent of your reach, and that moving it in circles won't help.

It's a phony, from one end to the other.
So to all of Spork's little circle of Carteers...you've been had.

 

[humber]

Please help save the Albatross, this magnificent bird does not deserve to have its integrity smeared in any way by Humberian word sewerage. I'm sure everyone here will automatically know to disregard whatever he may have said above, here is something much more likely to be correct;

http://esoaring.com/albatros_presentation_esa.pdf

And supports everything I said. No matter how you try and change it, one blade gains energy which it loses, when it is at the bottom of the turn, and adds energy to the cart from the wind, when at the top of the turn.
Albatrosses are a a bit more elegant at that task.

 

[mender]

As for the tacking prop, put yourself on the roof of a car traveling downwind faster than the wind. Put your hand out and try and reduce the force that is driving it backwards. See if you can do that for more than the extent of your reach, and that moving it in circles won't help.

More of your hand-waving, humber? Have you also tried flapping your arms? Flopping about like a fish? Chasing carts in a circle with a fan? Running a non-wind cart on a treadmill?

Let us know how well those work out for you.

http://www.youtube.com/watch?v=grbSQ6O6kbs
"You're not fooling anyone you know."

 

[semper]

And supports everything I said. No matter how you try and change it, one blade gains energy which it loses, when it is at the bottom of the turn, and adds energy to the cart from the wind, when at the top of the turn.
Albatrosses are a a bit more elegant at that task.

What you say is generally of no value. Nonetheless it appears you accept that there are several different devices capable of engaging mass systems in motion to effect propulsion and that the direction and speed obtained can be considered downwind faster than the wind. Yet the Albatross does not "tack" according to your definition since it is in no way connected to the ground. You are now trying to make the point (wrongly) that the BB used the wind gradient to go ddwfttw, if that were the case, it still went ddwfttw. You really are as clueless as you are pointless.

 

[jduffy77]

Is that a "yes"?

If that's a "yes", dare I ask which end of the treadmill you're referring to?

I truly believe that very few posters, now or ever, truly grasp the depth of Humber's ignorance, especially in the matter of the TM equivalence.

We can stand so in awe of his ability as a troll that we can sometimes lose sight of what exactly his position is at any given moment. In fact one of the tools he uses to generate responses is slipping perfectly valid but irrelevant truths from wikipedia amongst these absurdities. Of course this is not the only trick he employs. I thought cold one summed it up perfectly some time ago. He also "manages to maintain a kind of just barely plausible deniability. His responses are always vague, and nearly always contain a bunch of small errors that might be typos and therefore prevent the reader from being certain they know what he meant. At the same time with an accuracy too great to be unintentional he gets everything major wrong, which makes people reply out of hope they can explain to him why. When he occasionally really gets backed into a corner he lapses into near total gibberish as a defense. And he makes effective use of flat-out lies and intentional misrepresentations to generate outrage (and therefore responses)."

Anyway, regarding the TM all the words come down to one absurdity. Humber will say things like the TM is the road but he will not place himself on the road. It really is that simple. Whether he believes it or not I don't think we will ever really know; but this one absurd idea is the entire foundation which his 8 million plus words have been built on. He imagines an absolute observer and therefore a fixed inviolate reference frame. From this everything he has ever said can be extrapolated. The one true observer, the one true velocity, the one true distance.

 

[windgrins]

JDuffy is making sense

I truly believe that very few posters, now or ever, truly grasp the depth of Humber's ignorance, especially in the matter of the TM equivalence.

We can stand so in awe of his ability as a troll that we can sometimes lose sight of what exactly his position is at any given moment. In fact one of the tools he uses to generate responses is slipping perfectly valid but irrelevant truths from wikipedia amongst these absurdities. Of course this is not the only trick he employs. I thought cold one summed it up perfectly some time ago. He also "manages to maintain a kind of just barely plausible deniability. His responses are always vague, and nearly always contain a bunch of small errors that might be typos and therefore prevent the reader from being certain they know what he meant. At the same time with an accuracy too great to be unintentional he gets everything major wrong, which makes people reply out of hope they can explain to him why. When he occasionally really gets backed into a corner he lapses into near total gibberish as a defense. And he makes effective use of flat-out lies and intentional misrepresentations to generate outrage (and therefore responses)."

Anyway, regarding the TM all the words come down to one absurdity. Humber will say things like the TM is the road but he will not place himself on the road. It really is that simple. Whether he believes it or not I don't think we will ever really know; but this one absurd idea is the entire foundation which his 8 million plus words have been built on. He imagines an absolute observer and therefore a fixed inviolate reference frame. From this everything he has ever said can be extrapolated. The one true observer, the one true velocity, the one true distance.

To be honest, I believe that Humber is really starting to run off all the Newbies that are actually trying to understand and learn something.

It would be nice for all concerned, if Humber would try to state a clear objection using the agreed upon meaning of the words, justify it with accepted physics principles, and actually listen to the responses. It's pretty clear this is not going to occur so I personally will only respond when there is some actual coherent info presented, as I would spend an inordinate amount of time responding to nonsense, otherwise.

Regards,

WindGrins

 

[Jack by the hedge]

The two are not related.

Now that's disappointing. I had foolishly assumed your reply to my question would bear some relation to my question.
I guess we will, in fact, never know.

 

[Jack by the hedge]

The BB is a clumsy way of making a machine that exploits wind gradients.

We already did the calculation using your formula and your figures and saw that wind gradients cannot possibly account for its travelling at 2.8x windspeed. Wind gradients can't explain it. Forget about wind gradients.

ETA This was back in post #1906, if anyone's curious. Humber's figures for wind gradient produce a windspeed at the highest point reached by the prop blade which is up to 6½% higher than the windspeed at the hub. So he's proposing the cart can accelerate to 280% of windspeed by exploiting a small portion of the blade's swept area where the wind is 106.5% of the measured windspeed.

 

[A.T.]

As for the tacking prop, put yourself on the roof of a car traveling downwind faster than the wind. Put your hand out and try and reduce the force that is driving it backwards.

Humber still cannot find any errors in my diagram, so he desperately tries to replace the efficient airfoil with something that has a lower L/D ratio.

 

[A.T.]

We already did the calculation using your formula and your figures and saw that wind gradients cannot possibly account for its travelling at 2.8x windspeed. Wind gradients can't explain it. Forget about wind gradients.

If it was powered by wind gradients, it would be even more amazing. It would still be a wind-powered vehicle that goes DDWFTTW. But additionally it would be the most efficient wind powered vehicle.

 

[windgrins]

One of the circular arguments

We already did the calculation using your formula and your figures and saw that wind gradients cannot possibly account for its travelling at 2.8x windspeed. Wind gradients can't explain it. Forget about wind gradients.

ETA This was back in post #1906, if anyone's curious. Humber's figures for wind gradient produce a windspeed at the highest point reached by the prop blade which is up to 6½% higher than the windspeed at the hub. So he's proposing the cart can accelerate to 280% of windspeed by exploiting a small portion of the blade's swept area where the wind is 106.5% of the measured windspeed.

JBTH,

Thanks for providing the earlier data. Even if the gradient was 150% and the BB somehow managed to tap into this for the result, as long as it was going faster than WS at the top of the prop, it would have achieved the DDWFTTW claim in contradiction to the post. This was clearly illustrated as having been achieved by the high streamer on the BUFC cart in earlier videos. Even if this were the case, Spork and JB's only error would be in attribution of the principle by which it achieved this. Clearly this isn't so, however.

I agree that this is an interesting but insignificant criticism on Humber's part but it seems that his plan is "death by a thousand cuts" (even if they are done with a very dull dull knife)!

I applaud your effort in trying to explain. Actually, I should say, I applaud your efforts in explaining. Lack of understanding here is not due to a lack of clarity on your part.

Regards,

WindGrins

 

[humber]

Humber still cannot find any errors in my diagram, so he desperately tries to replace the efficient airfoil with something that has a lower L/D ratio.

It's laughably wrong. You have no magic cart. It's all BS. All of it.

 

[humber]

We already did the calculation using your formula and your figures and saw that wind gradients cannot possibly account for its travelling at 2.8x windspeed. Wind gradients can't explain it. Forget about wind gradients.

ETA This was back in post #1906, if anyone's curious. Humber's figures for wind gradient produce a windspeed at the highest point reached by the prop blade which is up to 6½% higher than the windspeed at the hub. So he's proposing the cart can accelerate to 280% of windspeed by exploiting a small portion of the blade's swept area where the wind is 106.5% of the measured windspeed.

Take the integral over half a cycle at 120prm, and there is more than enough energy to feed the carts 300J/sec demand.