Electroboom: How Right IS Veritasium?! Don't Electrons Push Each Other??

[Naej]

I asked the recoil on the bat.
You can compute it with these formulae: https://en.wikipedia.org/wiki/Elastic_collision#One-dimensional_Newtonian
Are you afraid to compute it in case it will lead to more than 2Ws? (coefficient of performance>1)

Fine I will waste more of my time most likely.

Vehicle was 300kg driving at 20m/s relative to ground through a space filled with balls traveling in the same direction at just 10m/s
Starting vehicle kinetic energy 0.5 * 300kg * 20m/s² = 60000Ws 
We take 2Ws from the wheel so 60000Ws - 2Ws = 59998Ws
New vehicle speed sqrt(59998 / (300 * 0.5)) = 19.9996666m/s
Bat now has the 2Ws available to hit a ball you mentioned 1000kg ball but it makes no difference for the vehicle as you will see
When the bat hits the ball it will take 2Ws from the ball kinetic energy and transfer to vehicle (ideal case).

What's the momentum transferred from the ball to the bat? (It's not 2J, that's energy)
What is the recoil?
You can assume the collision is elastic.

You think you're very good at physics, surely you should be able to apply the formula from wikipedia.

[electrodacus]

What is anti-thrust? Is it blowing the wrong way or what? No, forget that - that's just another dead cat you're playing.

You can argue where and how the power is stolen some other message. We don't care if the vehicle is speeding up, down, sideways or outside the wire, but just this once please answer this single thing.

You agree that the turning prop, HOWEVER IT'S POWERED, is producing thrust in the rearward direction?

When air particles or 1.2kg balls hit the vehicle they provide the vehicle with kinetic energy when the vehicle hits the balls it loses kinetic energy.

No I do not agree.
At no point the propeller on direct downwind blackbird is producing thrust.
If propeller was say connected to an electric motor and a battery then yes propeller will produce trust.

Direct down wind blackbird has a single source of power than that is wind power so the thrust is done by the air particles hitting the vehicle exactly the same as with a sail vehicle.
The role of the propeller is to create a pressure differential using wind power as input.
If you have two blackbird vehicle identical one in a compressible fluid  and one in a non compressible fluid with same density.
What you will observe is that in the non compressible fluid the vehicle will accelerate much faster to some speed lower than fluid speed and remain at that speed constantly.
The other vehicle in compressible fluid will take much longer to get to same speed as part of the energy will be use to create a pressure differential (store energy) and while it took longer it had more time at low speeds to collect/store a lot of energy witch then it uses to exceed wind speed for some limited amount of time.

[electrodacus]

What's the momentum transferred from the ball to the bat? (It's not 2J, that's energy)
What is the recoil?
You can assume the collision is elastic.

You think you're very good at physics, surely you should be able to apply the formula from wikipedia.

Do you need anything other than energy ? I even calculated the speed for you witch is proportional with energy as mass is not changing.

It is like me saying that a DC-DC converter can not output more energy than it gets at the input.
And then to that you first saying that efficiency can be over 100% at which I can not have any other replay than you need to relearn physics.
Then you now ask about things but what about the higher voltage or higher current not realizing that they are not relevant as if one increases the other will need to decrease so that output power is never higher than input power.

You just have no grasp on the concept of energy.

[Naej]

What's the momentum transferred from the ball to the bat? (It's not 2J, that's energy)
What is the recoil?
You can assume the collision is elastic.

You think you're very good at physics, surely you should be able to apply the formula from wikipedia.

Do you need anything other than energy ? I even calculated the speed for you witch is proportional with energy as mass is not changing.

It is like me saying that a DC-DC converter can not output more energy than it gets at the input.
And then to that you first saying that efficiency can be over 100% at which I can not have any other replay than you need to relearn physics.
Then you now ask about things but what about the higher voltage or higher current not realizing that they are not relevant as if one increases the other will need to decrease so that output power is never higher than input power.

You just have no grasp on the concept of energy.

What you don't realize is that there's a ton of energy in the ball moving at 10m/s, so energy can be conserved even if the car accelerates.
You just have no grasp on the concept of momentum, which is why you can't compute the recoil on the bat.
And it's ok, but you have to believe people who do, and they tell you: the bat recoil gives more energy to the car than what it took from the wheel.
Energy is conserved but you must not forget energy outside the car or else you say wrong things.

[gnuarm]

I have learned things from ED.  I have learned to spot the fallacious argumentative style used by many in other fields.  Rather than discussing the scenario at hand, they divert to discuss a different scenario that is not the same, even if appearing to be the same in some ways.  They also confuse the issue, by insisting on certain rules that don't apply in the same way as they were originally conceived.  There are other techniques of avoiding the truth. 

I have not learned why it is that people, who also have learned what I've learned about this discussion style, are still willing to continue to discuss the issue.  Clearly the guy is either A) really, really stupid, or B) enjoying being the mule so much, that he just can't quit. 

Which is it, A or B?

[electrodacus]

What you don't realize is that there's a ton of energy in the ball moving at 10m/s, so energy can be conserved even if the car accelerates.
You just have no grasp on the concept of momentum, which is why you can't compute the recoil on the bat.
And it's ok, but you have to believe people who do, and they tell you: the bat recoil gives more energy to the car than what it took from the wheel.
Energy is conserved but you must not forget energy outside the car or else you say wrong things.

I told you exactly how much energy is in that ball 50000Ws
I also told you how much was taken from it and delivered to the vehicle and that was ideal case 2Ws

So what are you asking exactly ?
You just do not get what energy is.

Momentum is useless when you already know the kinetic energy.
momentum is m*v while kinetic energy is 0.5 * m * v²
You can get the speed of the ball and the vehicle both from momentum and from kinetic energy. The result will not be different. 

[PlainName]

No I do not agree.
At no point the propeller on direct downwind blackbird is producing thrust.
If propeller was say connected to an electric motor and a battery then yes propeller will produce trust.

Really? Seriously? The propeller has knowledge of its power source?

Either you're using the wrong words (to match your wrong equation) or their real meaning has escaped you.

[PlainName]

I have not learned why it is that people, who also have learned what I've learned about this discussion style, are still willing to continue to discuss the issue.

Perhaps because we are not so much different - whether you have the right or wrong idea, are clever or stupid, the Internet has to be corrected

[Naej]

Momentum is useless when you already know the kinetic energy.

Clearly you never learned physics.
It's ok but stop believing you're the best, and that what you say must be true just because you wrote it, or you'll never learn anything with this kind of attitude.

Alright so here's how it works.
I replaced the 1t balls by walls, and this is how the car is propelled: a ball (elastically) bounces on the wall, then on the car, then it is accelerated back towards the wall.

Speeds in ground reference frame:
- wall : 10m/s
- car : 20m/s
- ball : -10m/s

Using 50J for the ball, you get a mass of 1kg.

Because 1kg<<1t, you get a collision like on a wall.
So in the reference frame of the ball, the speed of the bat is (approximately) its opposite.
It is -10-10=-20 m/s and turns into 20m/s, which in the ground reference frame is 30 m/s.

Because 1kg<< the mass of the car, you also get a collision like on a wall.
In the reference frame of the car, the speed of the ball is 30-20=10 m/s, so the reflected ball is at -10 m/s, which in the ground reference frame is 10 m/s.
You need to remove 20 m/s to restart the cycle, so you take the energy for it at the wheel.
In the reference frame of the car, the speed must go from -10 m/s to -30m/s so you need 1/2*1kg*(30²-10²)=400J to accelerate the ball.

The momentum gained is m*delta v=m*(30-(-30))=60 kgm/s, which means you can add delta p*car speed=1200 J to the car kinetic energy in the ground reference frame.
You remove the 400J taken at the wheel and you just added +800J to the car.
Repeat until reaching the desired speed.

Now if you don't believe this:
1) make sure you really understand momentum, reference frames, energy (there are high school physics books out there)
2) tell me where I'm wrong
3) don't talk about supercapacitors

[electrodacus]

Really? Seriously? The propeller has knowledge of its power source?

Either you're using the wrong words (to match your wrong equation) or their real meaning has escaped you.

What is the only way moving air particles (wind) interact with the vehicle ?
Since for direct downwind version of blackbird air particles are the only thing driving the vehicle even after vehicle exceeds wind speed (because the way energy is stored is by creating a pressure differential) there is no time where propeller has propulsion role just role of sail and help with energy storage.
It is like you saying that a sail pushes the air particles and not the other way around.
So when a air particle or a 1.2kg ball hits the propeller blade that is all the propulsion that vehicle will see.
While in motion both propeller and air particle or ball move but since all the energy to accelerate the vehicle comes from air molecule or 1.2kg ball the net interaction between propeller blade witch rotates in tandem with vehicle speed as it is connected through a fixed gear to wheels will be provided by the air/wind and not propeller which is actually powered by wind.
Propeller will not know that it exceeded wind speed since as long as propeller is concerned it is still being hit by air particles due to pressure differential stored energy.

The air particle / 1.2kg ball analogy always hits with more energy than it is hit back by the propeller that is why the vehicle accelerates as vehicle uses that excess to increase the kinetic energy and thus speed. 

[electrodacus]

Clearly you never learned physics.
It's ok but stop believing you're the best, and that what you say must be true just because you wrote it, or you'll never learn anything with this kind of attitude.

Alright so here's how it works.
I replaced the 1t balls by walls, and this is how the car is propelled: a ball (elastically) bounces on the wall, then on the car, then it is accelerated back towards the wall.

Speeds in ground reference frame:
- wall : 10m/s
- car : 20m/s
- ball : -10m/s

Using 50J for the ball, you get a mass of 1kg.

Because 1kg<<1t, you get a collision like on a wall.
So in the reference frame of the ball, the speed of the bat is (approximately) its opposite.
It is -10-10=-20 m/s and turns into 20m/s, which in the ground reference frame is 30 m/s.

Because 1kg<< the mass of the car, you also get a collision like on a wall.
In the reference frame of the car, the speed of the ball is 30-20=10 m/s, so the reflected ball is at -10 m/s, which in the ground reference frame is 10 m/s.
You need to remove 20 m/s to restart the cycle, so you take the energy for it at the wheel.
In the reference frame of the car, the speed must go from -10 m/s to -30m/s so you need 1/2*1kg*(30²-10²)=400J to accelerate the ball.

The momentum gained is m*delta v=m*(30-(-30))=60 kgm/s, which means you can add delta p*car speed=1200 J to the car kinetic energy in the ground reference frame.
You remove the 400J taken at the wheel and you just added +800J to the car.
Repeat until reaching the desired speed.

Now if you don't believe this:
1) make sure you really understand momentum, reference frames, energy (there are high school physics books out there)
2) tell me where I'm wrong
3) don't talk about supercapacitors

You are getting very close to understanding pressure differential energy storage.

There is no wall but there are other ball's that that this ball interacting will vehicle will bounce on to similar to your wall idea.  It looks like a wall a little bit because there are so many small balls in real air compared to 1.2kg balls spaced 1m apart.
The air density is 1.2kg per m³ thus the 1.2kg ball analogi witch is spaced 1m apart.

Now with a non compressible gas there will be no bounce (elastic type collisions) is like balls are already all in contact with each other and can flow around another but will not bounce (there is no compression to be had).

As you explained with the wall analogy this is what can make a higher concentration of balls in the back of the propeller compared to the front or bat if you prefer that.


With a sail vehicle that is stationary you still have a pressure differential between back side and front side of the sail.
Since the balls (air molecules) bounce back of the sail and other balls come from the back there is a higher concentration of balls on the back side of the sail while there are very few balls on the back just what comes in from the side due to low pressure.
The difference is that as the sail vehicle starts to move pushed by all this bouncing balls on the back of the sail the pressure difference drops and by the time vehicle is at wind speed there is no pressure differential at all so same numbers of particles hit the back and front of the sail at random just from thermal motion.

With the propeller connected to wheels vehicle the initial conditions are exactly the same and the blades on the propeller act the same way as the sail.
but as soon as vehicle starts to move pushed by wind part of the kinetic energy the air molecule / ball provided the vehicle with will be put in the propeller so subtracted from what could have been vehicle kinetic energy thus vehicle takes longer to accelerate than the sail vehicle but the fact that the sail hits back (with less energy else vehicle could not move)  means part of the energy is used to maintain this pressure differential (it still drops) but much slower  meaning that by the time the vehicle is at wind speed there is still significant amount of stored energy and as far as vehicle is concerned is like the wind still blows relative to vehicle.


Maybe the treadmill model is even simpler to understand as there is no wind indoors but during the initial phase when you need to keep the vehicle on the treadmill this pressure differential is created  using energy from the treadmill.
As soon as you release the vehicle vehicle can no longer take any energy from treadmill but it has the stored pressure differential that pushes the vehicle against the treadmill direction.
What you called the wall has no 0m/s relative to ground (ground not treadmill surface) but there are particles bouncing between that stationary wall and propeller blades.
But this pressure differential while partly recycled as the vehicle moves forward using some of the energy to supply friction and returning the rest the pressure differential drops and so is the acceleration rate that depends on that.


Sorry for the very long explanation. I just got a bit excited as you start to understand the pressure differential energy storage in compressible fluids.
In a non compressible fluid the balls touch each other and there is no elastic energy to be stored they will just be pushed by the so called wall and so same vehicle with propeller/similar construction in a incompressible fluid could never exceed wind/flow speed.             

[PlainName]

Really? Seriously? The propeller has knowledge of its power source?

Either you're using the wrong words (to match your wrong equation) or their real meaning has escaped you.

... there is no time where propeller has propulsion role ...

That wasn't the question. You've effectively said that if a propeller is turning, it isn't having any interaction with the air. That's like saying air going through a turbine doesn't exert a force on the blades under any circumstances.

Oh, but you allow that if the propeller knows it's powered by a particular source, it can interact with the air.

How can your other stuff make sense if something this basic is misunderstood?

[electrodacus]

That wasn't the question. You've effectively said that if a propeller is turning, it isn't having any interaction with the air. That's like saying air going through a turbine doesn't exert a force on the blades under any circumstances.

Oh, but you allow that if the propeller knows it's powered by a particular source, it can interact with the air.

How can your other stuff make sense if something this basic is misunderstood?

No that is not what I'm saying. Obviously propeller will have interaction with air is just not directly accelerating the vehicle.
You get that wind (moving air particles) is the only energy input in this system.
The only way for air to transfer the energy to vehicle is through collisions with vehicle body and that includes the propeller blades.
As propeller blade start to rotate powered with part of the wind power they will hit back the particles that hit the blades.
If wind / moving air particles provide 1000W based on gear ratio selection a percentage of this will be taken at the wheels say 400W and put in a say 70% efficient propeller.
So remaining 600W is used to increase vehicle kinetic energy while the 400W * 0.7 = 280W will push back against those wind particles mostly increasing the pressure differential (or more like not allowing the pressure differential to decrease that fast).

If this vehicle will have been in a non compressible fluid so that those 280W could be used to increase pressure differential then this design will have been incredibly useless as you will have gotten 600W + 280W = 880W of increase in vehicle kinetic energy instead of just 600W in increased vehicle kinetic energy + 280W put in to storage and so not able to exceed wind / flow speed thus you were better off with an equivalent size sail to get all 1000W instead of just 880W of acceleration.       

[Naej]

You are getting very close to understanding pressure differential energy storage.

Yeah I understand dams and pneumatic systems.
But here there is no fluid, so you can't make up some nonsense about fluid energy storage.
There's only kinetic energy storage.

[electrodacus]

You are getting very close to understanding pressure differential energy storage.

Yeah I understand dams and pneumatic systems.
But here there is no fluid, so you can't make up some nonsense about fluid energy storage.
There's only kinetic energy storage.

You may have seen the graph below. Air is a compressible fluid (gas). Link to source https://en.wikipedia.org/wiki/Axial_fan_design
Do you think that below graph is wrong / incorrect ?
The red line is the propeller as seen from the side and this is how the air(compressible fluid) will look around the blackbird if motion was from right to left.
 If you agree with the fact that there is a pressure difference between the two sides of the propeller swept area (a disk) then you will also agree that will require energy to create and also this pressure differential pulls and pushes the propeller witch is attached to the vehicle so it pulls and pushes the vehicle.

That swept area of the propeller on blackbird is about 20m² and if you take just 1m on each side and the that volume will be 20m³ on each side of the propeller and for just a 2.5% above and below ambient pressure so ambient is about 100kPa then say 102.5kPa for P2 and 98.5kPa for P1 the total energy stored there is about 28Wh and that is about 4x more than needed to accelerate the 300kg blackbird to 13m/s (their speed record).

[PlainName]

That wasn't the question. You've effectively said that if a propeller is turning, it isn't having any interaction with the air. That's like saying air going through a turbine doesn't exert a force on the blades under any circumstances.

Oh, but you allow that if the propeller knows it's powered by a particular source, it can interact with the air.

How can your other stuff make sense if something this basic is misunderstood?

No that is not what I'm saying. Obviously propeller will have interaction with air is just not directly accelerating the vehicle.

Again, that wasn't the question. The question was: does the turning propeller produce thrust? Nothing about acceleration.

You get that wind (moving air particles) is the only energy input in this system.

Frankly, I seem to get that a lot more than you do!

The only ...

Sorry, had to cut all the obfuscation. Talk of this many W or that many W is irrelevant. That can come much later once we know what we are trying to apply them to. Currently, you seem to think that the  propeller has no effect because, 100W. Forget throwing 1.2kg balls around - either it has an effect (even if that is just air moving 0.000001m/s into a headwind of 20000mph), or it doesn't. Once we're clear on that we can come up with some formula for figuring out just what effect it will be, where the power comes from and goes, etc.

[Naej]

You are getting very close to understanding pressure differential energy storage.

Yeah I understand dams and pneumatic systems.
But here there is no fluid, so you can't make up some nonsense about fluid energy storage.
There's only kinetic energy storage.

You may have seen the graph below. Air is a compressible fluid (gas). Link to source https://en.wikipedia.org/wiki/Axial_fan_design
Do you think that below graph is wrong / incorrect ?
The red line is the propeller as seen from the side and this is how the air(compressible fluid) will look around the blackbird if motion was from right to left.
 If you agree with the fact that there is a pressure difference between the two sides of the propeller swept area (a disk) then you will also agree that will require energy to create and also this pressure differential pulls and pushes the propeller witch is attached to the vehicle so it pulls and pushes the vehicle.

That swept area of the propeller on blackbird is about 20m² and if you take just 1m on each side and the that volume will be 20m³ on each side of the propeller and for just a 2.5% above and below ambient pressure so ambient is about 100kPa then say 102.5kPa for P2 and 98.5kPa for P1 the total energy stored there is about 28Wh and that is about 4x more than needed to accelerate the 300kg blackbird to 13m/s (their speed record).

I'm glad you agree that my mechanical example shows that you can accelerate beyond the speed of matter around you.

Now, you say that there is 4 kPa difference on an area of 20m². This means a force of 80000N on the propeller.
Neglecting friction, this would imply 27 G's on the 300kg car.
I'd say you're a bit off, by a factor of around 200.

Of course the 1m you invented is probably as valid as the 4kPa…
More importantly the whole point you're trying to make is pretty silly: yes the propeller slows down the wind around the vehicle, yes there is stored energy in the propeller blades. Who cares? It means that not only the car can go at 3 times the speed of wind but also store energy. 

Perhaps you want to claim, without evidence, that the prop can be connected to an engine to accelerate the car even faster. Do you see the prop slowing down significantly while the car is accelerating? No.

[electrodacus]

Again, that wasn't the question. The question was: does the turning propeller produce thrust? Nothing about acceleration.

Frankly, I seem to get that a lot more than you do!


Sorry, had to cut all the obfuscation. Talk of this many W or that many W is irrelevant. That can come much later once we know what we are trying to apply them to. Currently, you seem to think that the  propeller has no effect because, 100W. Forget throwing 1.2kg balls around - either it has an effect (even if that is just air moving 0.000001m/s into a headwind of 20000mph), or it doesn't. Once we're clear on that we can come up with some formula for figuring out just what effect it will be, where the power comes from and goes, etc.

It is like discussing about the energy conservation for a DC-DC converter and you asking "is there not an output current on the DC-DC converter?"
Or you may say that current output is higher than input current instead of looking at input and output power or even better energy.

Do you understand the analogy that I made above and why talking about input/output voltage and current is irrelevant.
Unless you want to dimension the wires / fuses or in mechanical equivalent the strength of different mechanical components you do not care about current/voltage (speed/forces).

To go even further with the DC-DC converter analogy is like you having two DC-DC converters.

One connected with input to a power supply say that 200W, 20V, 10A CC-CV and the other DC-DC converter connected with input to the output of the first DC-DC and the output to the input of that first DC-DC.

If you seen that you will think that is incredibly silly to have two DC-DC converters connected this way. But that is how blackbird is designed.

Now you are asking if the second DC-DC converter contributes to the output of the first DC-DC converter. Will that not seem a silly question to ask ? 

[PlainName]

two DC-DC converters

And off you go again.

Well, you are very skilled. Pity that particular skill is only useful to the likes of politicians rather than engineers.

OK, I give up.

[electrodacus]

I'm glad you agree that my mechanical example shows that you can accelerate beyond the speed of matter around you.

Now, you say that there is 4 kPa difference on an area of 20m². This means a force of 80000N on the propeller.
Neglecting friction, this would imply 27 G's on the 300kg car.
I'd say you're a bit off, by a factor of around 200.

Of course the 1m you invented is probably as valid as the 4kPa…
More importantly the whole point you're trying to make is pretty silly: yes the propeller slows down the wind around the vehicle, yes there is stored energy in the propeller blades. Who cares? It means that not only the car can go at 3 times the speed of wind but also store energy. 

Perhaps you want to claim, without evidence, that the prop can be connected to an engine to accelerate the car even faster. Do you see the prop slowing down significantly while the car is accelerating? No.

It was an example to show that energy is stored there thus there is an energy storage device.
When I made the calculations I used energy stored there and not pressure and volume.
The shape of the volume as you seen in that graph is quite complex and a lot larger than just 20m³ I was using.
And of course you will be right to say that forces will be to high if the volume was that small at that pressure delta.

I'm not talking about the kinetic energy stored in the propeller (flywheel effect). I'm talking in pressure differential energy storage.


Are you just ignoring that there is a pressure differential as seen in that graph P2-P1 ?
I used some random average pressure values and a super small volume to show how much energy can be stored (way more than needed)
The pressure as seen in the graph is not constant in that volume it drops gradually to atmospheric pressure as you get away from the propeller.
Also that pressure is not pushing only against the propeller but also against the air at atmospheric pressure surrounding that volume.

I'm not claiming to be an expert in fluid dynamics (in fact I barely got a passing grade at university in fluid mechanics) all I claim is that energy is stored there and that stored energy is both valid for sails as well as for rotating propellers.
Is just that for a sail that pressure differential drops to zero as it gets to wind speed while a propeller connected to wheels maintains most of that pressure differential by using the wind energy while vehicle is below wind speed.
That pressure differential will start to drop for the propeller version also even before getting to wind speed and will continue to drop as the vehicle speed exceeds wind speed as that energy covers the vehicle friction losses.


What you think accelerates the treadmill model as there is zero wind speed in that much more controlled experiment? 

[electrodacus]

And off you go again.

Well, you are very skilled. Pity that particular skill is only useful to the likes of politicians rather than engineers.

OK, I give up.

Do you disagree with the analogy ?


The exact first thing I imagined when I saw Derek's first video about Blackbird was the motor generator overunity scam devices

The difference is that those use a flywheel as energy storage and blackbird uses pressure differential.
Both of them falsely claim they will run forever and have excess energy to power other things.

[HuronKing]

Can you make a bicycle go faster than you can pedal?

[electrodacus]

Can you make a bicycle go faster than you can pedal?

Seems like a vague question.
Are you referring at the fact that changing gear while pedaling at same rate changes the bike speed relative to ground ?
If you yes but while you pedal at same RPM as before changing the gear if you bike drives faster you will need to put out much force on the pedals than before so power is increased to increase speed.

With wind powered vehicle the problem is that as vehicle approaches wind speed the wind power available to vehicle approaches zero.

The only way wind can interact with vehicle is by collision with vehicle body including the propeller blades if it has a propeller.
Maybe the treadmill model is better as there is no wind but still it advances against the treadmill direction of travel.  What do you think pushes the vehicle in that direction?

[Nominal Animal]

Equilibrium models cannot properly describe the physical phenomena at hand –– suitable craft going downwind ––, because in the real world, wind speed is not constant, nor does it have a perfectly stable direction.

When you simplify the situation enough so you can apply equilibrium physics, you're essentially discussing how a toy on a rail in a perfect wind tunnel behaves.  I don't think that is useful; it's not what happens in real life.

Consider a wind pattern where you have some base wind speed X, with a roughly sinusoidal component on top (although the exact shape or frequency does not matter, as long as the changes occur in relatively short timeframes, say on the scale of seconds, and they're symmetric, not affecting the average wind speed –– this is more or less quite typical wind behaviour).  For now, let's assume it stays in the same direction.

Instead of a fabric sail, let's imagine you have wanes that act like a one-way valve: when the craft velocity is below wind speed, the wanes catch the wind, and when the craft velocity is above wind speed, the wanes let the wind pass through mostly unhindered.  It won't be perfect, but all we're looking for here is asymmetry.

Even on a fixed straight track in a wind tunnel, that craft will reach a speed that exceeds the average wind speed.  If there were no losses, it would reach the maximum repeated wind speed.  Some, perhaps most of the time, it is exceeding the wind speed, only getting additional power from the gusts, "peaks".
It is quite analogous to the behaviour of charge in a capacitor.

The second thing is the wind direction.  When sailing on sea, you don't get the best efficiency by catching the wind like a parachute: you get best speed by using your sail like the wing of an airplane (very similar flow profile, too).  You can make a pretty good sailboat by making a vertical wing (like the ones on aeroplanes, but vertical) that you can rotate around its vertical axis.  Now, I do not claim to know or understand fluid dynamics (physics sub-field that deals with the flow of liquids and gases) nor sailing, but it should be obvious that wind direction, even small changes from directly downwind, hugely affect the situation.

In particular, even if the craft itself had wheels running in a direct line, it could have a cylindrical arrangement for its "sails", rotating vertically, so that in effect its sails would be jibing even if the craft itself was going straight.

Again, an equilibrium condition examination (where the craft is traveling exactly at wind speed with any such arrangement not rotating) is not useful, because the equilibrium state is a point that only exists in carefully controlled situations, and not in practice.
Plus, pressure differentials in the wind make the fluid dynamics even weirder.

As to the equilibrium scenario discussed ad nauseatum above, I have no opinion, because it is quite uninteresting to me, being overly simplified and unrealistic.

[Naej]

What you think accelerates the treadmill model as there is zero wind speed in that much more controlled experiment?

I told you before, in the wind reference frame the ground has kinetic energy. It's obvious but you thought I were a fool.
In the treadmill model, which is nothing more than blackbird in the wind reference frame, the treadmill is providing the energy (and I'm afraid I want to add: obviously).

The difference is that those use a flywheel as energy storage and blackbird uses pressure differential.
Both of them falsely claim they will run forever and have excess energy to power other things.

Yes and wind turbines too. Some claim they will run for decades and have excess energy to power other things. Crazy right? It must violate the conservation of energy.