Down wind faster than the wind

[humber]

Naturally you are under no obligation to respond to my posts. However, I ask that if you do choose to respond, you have the courtesy to address the actual statements I made. I said nothing about trolleys, holes, compartments, boats, or the possibility of acceleration.

My role here is to seek clarity. If there is disagreement then I want to clarify the source of the disagreement. However, I'm beginning to wonder whether we are actually disagreeing over clarity itself -- that is, the possibility that while I and others are seeking clarity you are seeking deliberately to avoid it. That possibility does you no credit, so I hope it's not the case.

(Please keep in mind that the people here who have hundreds or thousands of posts are clearly not arguing against you because they've followed you here from some other forum for that purpose. We are some of the most outspoken skeptics in the world, and we have a lot of experience distinguishing valid physics from "woo" claims. If I or any other skeptics here were to conclude that the phenomenon under discussion here were contrary to the laws of physics, we would spare no criticism. For instance, since that would make the DDFTTW claim a paranormal claim, we would try our hardest to convince TAD or spork to accept Randi's Million Dollar Challenge forcing them to demonstrate that claim under controlled, fraud-proof conditions. We would question in earnest whether there were any fans or towing devices outside the video frames. Indeed, I don't regard anything presented by TAD and spork airtight proof of the effectiveness of their designs, and if for example I were considering investing money in a venture to market the things I would insist on seeing stronger evidence, perhaps involving wind tunnel tests and neutral observers. But airtight proof is not the question at hand. The question is whether the effect they're claiming is possible, and the answer from physics is that it is. It is an "ordinary" claim and as such, is very well supported by the "ordinary" evidence they've provided.)

The only portion of your post that is comprehensible in the context of mine that you quoted, is this:




If you claim so, you are welcome to point out which variables have been neglected due to simplification, and how they cause the conclusions to be wrong.

However, I don't think that's correct. My examples are experiments that could clearly be done, and I describe the results to be expected. Nothing is simplified. A real van, on a real road, with a real treadmill and the real DDFTW model, would produce the results I describe: indistinguishable from the treadmill tests already recorded on video.

Respectfully,
Myriad

I was not ignoring you, Myriad. You are right, in that the imagined tests would agree with the simulator, but that is because both are equally flawed.

There are people who claim they are physicists. If they are, then not on this planet. This device has as much chance of windspeed travel as going to the moon.

It is almost absurd, yet it is supported beyond its value. I have put a hole in it, but have not yet sunk it.

The overall idea, is that if you travel at windspeed, then there will be no wind. Well, that's only true in a very limited sense. Air is not a homogeneous material, it flows about. It can't not be there in the literal sense that is being promoted. There is limited, differential velocity, but wind there is. There would be much turbulence, and even if not, what if it slows?

Two bodies travelling at different velocities are in the same frame. Inertial frames are separated by acceleration, not velocity.
How do you know when you are moving, other than by looking? You feel the acceleration, and that cannot be isolated by putting the cart in a truck.

All thoughts of acceleration have been ignored. Matter interacts through momentum. When you need to move a particle, then it must be accelerated.
This is true of drag. You must push or pull the air aside.
The treadmill ignores all matters of acceleration. It is in the hand and then 'instantaneously' it is at windspeed.

Now, there is one contradiction that stood out from all the Startrek science.
Difficult to deny. It is supposed to represent windspeed, but it can't because it is almost stopped. Oh, that's some "frame difference", just mentally add the windspeed to it. How convenient. It is both windspeed and stopped.

The cart is at a precarious balance between being pulled forward, and back. It is on a knife edge, between those two states. It cannot actually move, because it must violate that balance in order to do so. It is trapped.

Ask yourself what does it tell me about the cart at windspeed? Nothing.
Apart from the fact that the propellor spins, then it may as well be on the floor.

But that's not the most important thing. How does it get to the supposed windspeed? As you must know, vehicles are limited by their ability to overcome drag. There is a maximum velocity, at which the drive and drag balance. To go faster, you need more power, which creates more drag.
None of these matters are addressed by the treadmill. It is 100% artifice.

Whoever claims that this cart is capable of windspeed is perhaps a fantasist, but whoever claims that they have evidence of it doing so, is a liar. 100% on that.

Do not even think about thinking about putting money in this. I was waiting for the subject of "investment" to appear. I am not sure they will be back.

 

[humber]

First of all JB doesn't speak for me, nor do I speak for him.

Here are the two PM's you sent me:

1) "PM me"

2) "OK I have a better idea. Put money paypal to maximum. I do the same. Makes it easier. "

Neither one makes a lick of sense. You PM'd me to say "PM me"!? What should I PM you? Perhaps I could PM you the words "PM me".

And please explain what you're talking about with regard to PayPal. Are you actually suggesting that I should simply trust you to send me $100K via paypal after proving you wrong? Like I said, these make less sense than the arguments you attempt to make about "physics".

Nice try, both of you. Oh yes, here fishy, fishy.

 

[ThinAirDesigns]

Humber:

I was waiting for the subject of "investment" to appear. I am not sure they will be back.

ROFLAO!

Just to be clear, the "investment" comment by Myriad was merely a hypothetical. He was commenting on the level of "proof" he would require *IF* we were looking for investment.

The device is a fun but ultimately useless conversation piece. There's nothing to patent as it's been done for years. There's nothing to market as it makes most folk just shrug their shoulders and say "whatever"

I have not been, nor ever will be looking for investment -- proving people wrong is just a hobby for me.

Just making the record clear on that point.

JB

 

[humber]

What a lot of trouble for a toy worth $100K. It was fun.

ETA:
Oh, yes I forgot. In all your simulations, you have to take the simulator with you.

 

[spork]

Do not even think about thinking about putting money in this. I was waiting for the subject of "investment" to appear. I am not sure they will be back.

Interestingly enough you are the ONLY one considering putting $100K into this. But for $50 or less you could build your own and save yourself a much bigger and much less wise investment.

 

[sol invictus]

What a lot of trouble for a toy worth $100K. It was fun.

ETA:
Oh, yes I forgot. In all your simulations, you have to take the simulator with you.

So you've realized you're wrong and you're welching on the bet?

That happened even soon than I was expecting.

 

[humber]

I'll make a note of that and pin it to the $100K you hoped to get from me.
Right next to the calculations I am sure you had prepared

 

[ThinAirDesigns]

Me:

the cart *without the prop* but with the same mass will win

-

JW

Why?

Because wheels that are turning a fan are harder to turn than wheels that are not turning a fan.

It's like having two soapbox derby cars lined up and putting a parachute on one of them -- it's not hard to figure which one will win.

JB

 

[sol invictus]

I'll make a note of that and pin it to the $100K you hoped to get from me.
Right next to the calculations I am sure you had prepared

So that's a yes then.

Too bad - it was entertaining while it lasted.

 

[ThinAirDesigns]

Sol:

So that's a yes then.

He's certainly welching on the bet -- but still not admitting he's wrong.

The very worst sort of welching ... Humber wants to keep his money *and* his position.

JB

 

[JWideman]

JB said: "the cart *without the prop* but with the same mass will win"

JWideman said: "why?"

The cart with the prop will accelerate more slowly due the the moment of inertia of the prop. It will take energy to get it spinning.

It will have a slower steady state rate of descent because it will be in autorotation exactly like a helicopter with an engine out.

I didn't think of that. Okay, I was just trying to come up with a conclusive demonstration without the treadmill. How about a slope long enough for the prop to get up to speed, and start the race at the point the prop has spun up?

 

[CyCrow]

Jwideman: still not the same. With no wind, the prop will act as an aerodynamic brake. In fact, a windmilling prop has much more drag than a stopped prop.

// CyCrow

 

[CyCrow]

OK, probably futile, but anyway...

In physics, an inertial frame of reference is a frame of reference which belongs to a set of frames in which physical laws hold in the same and simplest form. (from wikepedia).

Momentum and energy is not conserved when you switch reference frames.

Moving downwind at a high fraction of the windspeed is trivial, it's a question of ground drag vs aerodynamic drag. What the treadmill demonstrates is breaking through that limit and accelerating against an apparent headwind by transfering power from the wheels to the prop. This is unintuitive, and for some people apparently incomprehensible, but does not break any laws of physics.

I'll reiterate: can iceboats sail (steady state) with a greater downwind velocity vector than the true wind speed?

// CyCrow

 

[ThinAirDesigns]

JW:

How about a slope long enough for the prop to get up to speed, and start the race at the point the prop has spun up?

No matter what speed you start the race, the soapbox derby car with the parachute will lose.

No matter what speed you start the race, the cart with the prop will lose.

JB

 

[Brian-M]

I've an idea for the $100K Humbler/Spork challenge.
Treat it as if it were the JREF $1m challenge.

Spork has a device that he claims can defy Humbler's understanding of the laws of physics, so set things up as you were testing someone presenting a perpetual motion machine for the JREF challenge. In both cases it's not therory that's the conclusive evidence, but operation.

Here's a suggested protocol...

Equipment:

- Novelty Bubble-Blowing machine
- Laser Level
- Cameras
- DDWFTTW device

Use the laser level to locate a long stretch of perfectly level road.
Wait for a windy day, with the wind blowing in parallel to the road.
Set up the bubble-blowing machine upwind to provide a visual reference of wind-speed.
Record the DDWFTTW device's travel. If it can consistently and repeatedly accelerate to and maintain greater speed than the bubbles, then Spork wins and Humbler is humbled.

If variations of the wind-speed might be an issue of contention, then the experiment can be performed in a wind tunnel, or a hall with an air-blower instead.

 

[JWideman]

JW:


No matter what speed you start the race, the soapbox derby car with the parachute will lose.

No matter what speed you start the race, the cart with the prop will lose.

JB

CyCrow's explanation was sufficient, thanks. I figured that once up to speed the generated thrust would overcome the drag, but I didn't count on the spinning prop having more drag.
Okay, what if the prop is left on but disengaged? Is there any way to compensate for the additional drag on the other cart?

 

[ThinAirDesigns]

Brian-M:

If variations of the wind-speed might be an issue of contention, then the experiment can be performed in a wind tunnel, or a hall with an air-blower instead.

While I'm quite sure that for 100k spork will happily perform both treadmill and street tests, I do have to comment on one item in the above that comes up a lot:

People often say "test it in a wind tunnel". We have. That's *EXACTLY* what the tread mill IS equivilent to ... both physics wise and practicality wise.

Think about it -- the reason we use wind tunnels is to take an experiment that would otherwise take say miles, and shorten it up until it fits into a short space. Don't want to move the car? ... move the air instead. Don't want to move the plane? ... move the air instead. We don't want the ground to 'move' in the above, so we stop it and move the air. In the cart case, it's the air moving that makes the test take up sooo much space -- so we stop it and move the ground.

A wind tunnel is designed to be the most controllable and instrumentable environment for testing upwind vehicles. If you were going to devise the most controllable and instrumentable environment to test a downwind vehicle -- a treadmill IS it.

Traditional wind tunnels long enough to test a vehicle like this are not the domain of this sort of simple science -- the operators would say "what's wrong with a freakin' treadmill morons?"

JB

 

[spork]

Okay, what if the prop is left on but disengaged?

If the prop is left on but disengaged with little or no torque required to turn it, it will typically cause far more drag than a prop that is locked in one position. Oddly enough, this is a bit of a brainteaser in its own right, capable of causing just as much commotion as the problem we're discussing.

But there are a couple of very straightforward ways to demonstrate this.

1) imagine a helicopter at 10K' agl with its rotors not spinning. Now imagine that same heli in autorotation (blades freewheeling). The first case is a rock. The second case is a glider, and the heli comes to a feather soft touchdown

2) Imagine a glider with no forward speed. It's a rock. But let it glide forward. Now the same exact wing area gives you loads of lift.

 

[spork]

Probably my favorite thing about this thread is that on page 14 the only tag on this thread is still "over unity". We should dedicate this to humber.

 

[ThinAirDesigns]

Okay, what if the prop is left on but disengaged? Is there any way to compensate for the additional drag on the other cart?

-

You can balance out the drag and weight of both carts in all sorts of various ways - all you will have proven is that carts of equal weights and equal drags will tie in a downhill race: not something about which there is much debate.

Your questions about the coast test are a bit like a bunch of ice-boaters showing up on a big race day to find the winds calm. They say "let's push our boats around the lake and see which one performs the best" ... they clearly don't learn much. Someone says "Let's tilt the frozen lake up on an angle and then we can still race from one end to the other".

Ok, let's suppose they do just that: which boat will win the race? If they all weigh the same, the one with the least drag of course. Unfortunately, that won't tell you a much about who would have won the event if the winds had been blowing. It might be an interesting contest, but not related in any significantly valid way.

You can't effectively test a device designed to run on energy without said energy: A lightbulb test involves a difference in electrical charges. A hydro turbine test water moving from high to low pressure. A wind powered device test needs relative motion between surface and air.

Of course individual components can be tested outside of their composite environment but it takes someone who understands the entire device to start out with to understand how individual performance effects the whole.

JB