Author Topic: Mess with your minds: A wind powered craft going faster than a tail wind speed.  (Read 147166 times)

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Online CatalinaWOW

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Don't worry about my feelings, I'm a big boy, I can handle it. Will I'll have no clue what you would have said because you think I have reduced mental capability or because you just can't provide an argument?
You keep saying that at wind speed a sail has no power, yet when I give you an example of sail traveling below wind speed, you deflect and avoid.


So let's focus not on generic, but on this specific example.
And yes, this vehicle does have an external energy source - the wind.

I do think people mental capabilities are very different.
There is no wind power available to a sail vehicle traveling at wind speed. There is of course plenty of power available to a sail traveling below wind speed. The slower it travels relative to wind speed the higher the available wind power.
It is clearly seen form the equation that I constantly post here.

Pw = 0.5 * air density * area * (wind speed - vehicle speed)3

I even provided examples. Maybe you got here more recently and did not see them but here is one example just for you

area 1m2
air density 1.2kg/m3
Wind speed 20m/s
Vehicle speed:
a)0m/s
b)5m/s
c)10m/s
d)15m/s
e)20m/s
Wind power available to vehicle
a)4800W
b)2025W
c)600W
d)75W
e)0W

A.  Have you read the paper provided by IanB?

B.  You claim you have the correct equation.  Which is clearly preposterous because it doesn't show the effect of the fan (propeller).  Take the really simple case of a fan with blades parallel to the direction of motion.  These blades subtract power, stirring the air and creating heat.  Conceptually with a large enough gear ratio the vehicle would not attain perceptible motion regardless of wind speed.  So your equation is at best part of the story.  It is a perhaps correct equation for a flat plate on a frictionless vehicle, but isn't a representation of the vehicle in question.  Adding angle of attack for the blades and an efficient airfoil shape further adds to the complexity of a correct description.  At this point I refer you to A. again, which is a clear and understandable description of the entire system.
 

Online Kleinstein

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...
The main point I want to make since this is ester to understand (at least is what I was thinking) is that there is no wind power available to a direct down wind traveling at or above wind speed.
I provided the correct equation and anyone that is not agreeing with that equation is welcome to provide the correct one.
Nobody can claim to understand a wind powered only vehicle without being able to provide an equation describing the amount of wind power available to vehicle.

Using the wind power available is not at all an easy way to look at the problem. Calculating the available wind power depends on the method used to harness the power and it is not really clear which way is the best. At least I don't know an expression for the available wind power. I consider the way with calculating the maximum awailable wind power a very difficult way. The point here is that it is not enough to show a result, but one would also need to derive that result from known parts. This may need rather envolved aero-dynaimics  - a field I am not good at and would best avoid. One some-times should also know the areas one is not good at or areas that are just difficult and maybe just lack simple solutions.

However I know that the avaiable wind power is not the same as the power needed to drive into the head wind. The available wind power is power that is available - so there is already plenty of power around, why should one need the same power once again. For opposing forces it is about a balance of forces, not a balance of power. In some cases (1 D and 100% efficient adapted gears and only 1 ref frame) it may look that it works with power, but that does not mean this is the right way. Wind power generally not 100% efficient and is pure power based calculation likely does not work.

The problem is a bit one sided: it is often quite difficult to show that something is not possible, while if a claimed construction is possible it is often relatively easy to proof that it is working in deed. Compare it a bit to Phytagoras law, that is easy to proof and Fermat's last Theorem which is really hard to proof.
Calculating the maximum wind power would in theory be a way to to show what is impossible, but it is a really hard way and would need lots of explainations on how the power is derived. I would expect this more like a 100 page work, and maybe still open to debate. The proof that the blackbird vehichle indeed works is in comparison simple, more like 10-20 lines.
Things get a bit easier by limiting the calculation to the give working principle (prop to push and wheels for the power) and see if there is enough power around from the wheels to drive the prop. It is about just doing the math: more power from the wheel side and this principle is possible, more power needed for the prop and this idea does no work ( it would still not exclude a different working principle).

For the proof that the blackbird vehicle does indeed work, there is no need to calculate the maximum available power. One does not even need to calculation the available power to such a vehicle. It is enough to show that there is actually some power available. Everything else, like the maximum possible velocity as a function of friction and prop efficiency is a bonus: see the linked old paper from this post https://www.eevblog.com/forum/chat/mess-with-your-minds-a-wind-powered-craft-going-faster-than-a-tail-wind-speed/msg3905936/#msg3905936.
 

Offline PlainName

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Quote
The energy storage is a separate equation and it is not relevant since I claim energy storage is involved

How would you demonstrate this energy storage? Just saying it's involved does mean a thing - you could just as easily say starlight pushes it all. But if we wanted to demonstrate that air is compressible, we could do that easily enough. So, how would you demonstrate that an unconstrained volume of air can store energy for a significant period (where 'significant' is more than 1 second)?
 

Offline gnuarm

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You ignored the rest of my post just as I expected you would.  if you looked at the calculations you would see that the force is only multiplied by the vehicle speed to get the power required to maintain speed.  But you don't want to admit that, so you ignored it.  That was my first prediction, that you would duck the question.

You are hopeless.  You know you are wrong, but refuse to discuss it in any meaningful way.  Silly rabbit.  Trix are for kids. 

Yeah, I do pity anyone depending on you for sound engineering.  I don't believe you even have a technical job.  How may quarters???

:) So I correct your mistake and you are saying that I ignored your post ?
You should do a test and see that your assumption is wrong.
You just believe the same absurd thing that those people that designed those online bicycle calculators.
Like 300W is plenty to bike at 1km/h against a 230km/h head wind.  People that say that is a possibility are just clueless.

Yes, you ignored this...

Quote
Now, forget wind.  Lets say there is a drag on the vehicle defined by

Fdrag = Kdrag * (vehicle speed)2

What is the power required to maintain the speed of this vehicle?

Yes, you absolutely ignored this.  There is no wind, no air in fact.  Some drag against a vehicle that is powered internally through the wheels.
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Offline gnuarm

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You can be offended if you want but you do not even deserve an answer as it will be a long and involved one from me and you will have no clue of what I just said.

That is correct, no one has any idea of what you have been saying and you don't either.  That is our point, but because you don't understand even what you say, you can't possibly understand what others say.
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Offline gnuarm

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@electrodacus,

Is it possible to get an summary from start to finish about why it is impossible?
Examples and illustrations along to way would be helpful so that I can follow all the steps.
I'm really struggling to follow the thought process here. Guess I'm not smart enough. So please put it as plainly as possible.

This is exactly what happens when people try to talk to Andrea Rossi about his "eCAT" LENR heat generator (cold fusion).  He baffles and confuses everyone he talks to.  When he gets someone too sophisticated to be confused, he cuts off all communication with them.  That's where ED differs.  He keeps talking and talking and talking allowing everyone to see how bad his ideas are.
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Offline gnuarm

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@ electrodacus

Your Forum is also full of stupid answers .. Now you have plagued us with your stupidity of Not seeing what is true life Working .
 If it works don't brake it . Your Maths is no better than a 1st grader . Just picking up numbers @ random will never solve this .
 Nor will you ever learn . and worst still your not willing to learn .
As hard as it is for you to except you are making a terrible mistake .
      Maybe it would have been a wise questions to ask what are our Degree's   :popcorn:

One of the things many people don't pick up on is that he never says you can't go downwind faster than the wind.  He says you can't do it without "storage and release" of energy.  That energy comes from the wind, so it doesn't matter at all if it is stored and released.  It is still powered only by the wind.

The crazy part of what he says is that the blackbird can't maintain the motion for any length of time while we have seen it travel for some hundreds of yards and continue to accelerate.  ED wishes to deny this simply because no one has gone a hundred miles with the wind.  ED has failed to provide a distance that would prove the blackbird can travel on the "stored" energy.  So there is no way to prove him wrong by experiment.  Even if someone traveled from the Pacific to the Atlantic he would claim it was running on energy stored in the pressurized area behind the sail.  In reality that would probably only power the craft for a second if the wind abruptly stopped.  Otherwise it would just be momentum. 
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Offline gnuarm

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"extra thrust" ?  You get that vehicle is only powered by wind ? There is no extra thrust and all the thrust as in the case of a sail is provided by the wind.
But the propeller is spinning.  A spinning propeller pushes air.  This is called thrust and it must exist in the local region around the propeller.  Surely this thrust has an effect when applied to the surrounding air.

If propeller has no input power or if the input power is taken from the output power (always smaller than input) then vehicle will just slow down and not accelerate.

You skipped over the question.

I asked about the interaction between this thrust and the surrounding air.

And he will continue to skip answering and other evasions.
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Offline gnuarm

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Friends, I found this thread by accident. There appears to be no consensus. 54 pages is beyond my strength, but I saw the film. This is incredible! New horizons are before us!

 Unfortunately, I still have questions. First of all - the car moves faster than the wind, that is, it moves in the oncoming air flow ?! Tell me, why is this impossible with complete calm? After some initial impulse, of course. No, no, a perpetual motion machine is impossible.

 And one more thing, it seems to me that the ribbon (speed indicator) is in the aerodynamic shadow (or inside the vortex) and much lower than the propeller, where the wind is slower.

 Finally, regarding the background for the invention. Under certain conditions, the movement of a sailboat at an angle to the wind can have a higher speed than the wind. But not in the direction the wind is blowing!

Tacking is normally used for going upwind where any movement is considered good and there's no expectation of going faster than the wind. 

Interesting to note the sail boat is much more effective if the sail is shaped like an airfoil generating lift.  Likewise it is the airfoil on the propellers that allow the car to travel upwind.  The wind resistance is low compared to the force generated by the propeller driving the wheels because the angle of the blades is nearly parallel with the wind.  The lift of the airfoil is what provides the force that rotates the propeller and therefore the wheels. 

It is a very simple process once it is properly understood.  The trick is not fooling yourself into thinking it is more complicated than it really is as some people seem to be quite able to do.  Stored energy indeed! 
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Offline gnuarm

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Friends, I found this thread by accident. There appears to be no consensus. 54 pages is beyond my strength, but I saw the film. This is incredible! New horizons are before us!

 Unfortunately, I still have questions. First of all - the car moves faster than the wind, that is, it moves in the oncoming air flow ?! Tell me, why is this impossible with complete calm? After some initial impulse, of course. No, no, a perpetual motion machine is impossible.

 And one more thing, it seems to me that the ribbon (speed indicator) is in the aerodynamic shadow (or inside the vortex) and much lower than the propeller, where the wind is slower.

 Finally, regarding the background for the invention. Under certain conditions, the movement of a sailboat at an angle to the wind can have a higher speed than the wind. But not in the direction the wind is blowing!

What film have you seen ?  The one made by Derek / Veritasium ?

It is not impossible as demonstrated to drive faster than wind direct down wind but the way that happens is by storing energy before exceeding wind speed and then using that stored energy to exceed wind speed for a limited amount of time.

Yes, limited by the lifetime of the universe maybe.  It's so funny that this guy insists on taking his position in spite of evidence against it and insisting that the entire body of scientific knowledge is wrong in the process!   This guy would have manned the ramparts at the Alamo and continued fighting even after he was dead!
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Online bdunham7

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The wind resistance is low compared to the force generated by the propeller driving the wheels because the angle of the blades is nearly parallel with the wind.  The lift of the airfoil is what provides the force that rotates the propeller and therefore the wheels. 

It is a very simple process once it is properly understood. 

It is fairly simple, but you have it backwards.  The propeller is driven by the wheels.  If you posit the wind driving the propeller somehow, ED's theories would be right since the interaction between the propeller and the wind is dependent on the windspeed relative to the vehicle.  The way it works when the vehicle speed is the same as the windspeed is the propeller reacts with apparently still air, neglecting a bit of turbulence, and that allows it to continue to push the vehicle even when it already at or above windspeed.
« Last Edit: December 30, 2021, 11:33:06 pm by bdunham7 »
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Offline fourfathom

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Stored pressure-difference energy?  I was looking up explosive shock-wave overpressure propagation, and even at only 1 PSI, the pressure-wave is moving about 70 MPH (about 700 MPH at much higher pressures).  The idea that wind-pressure builds up behind a surface (and a surface that is slowly accelerating towards windspeed), and somehow this accumulated open-space pressure will persist for minutes, or even seconds, is pretty ridiculous.
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Offline gnuarm

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When going at a very low speed, that is low RPM on the pedeal on will not be able to get 300 W. The driver has the same problem as the vehicle: it is hard to get the same power, as the forces have to go up.
The problem why going 1 km/h again a 40 km/h head wind with a normal bicyle is not possible is not because the 300 W are needed, but because it is hard to produce even 30 W at such a low speed, as this needs very high force.
The is just not enough force to produce 100 W at a very low speed. So if the magic (..)³ expression would be true one would never be able to start from a stand still aginst any headwind. One allways starts with infinitesimal low speed and thus infintesimal small (essentially zero) mechanical power.

There is no need to repeat the supposed formula for the maximum available wind power for the moving vehicle. Without a good source or maybe an acceptable explaination this is worthless like repeating "The earth is flat.".

The (w-v)³ type equation is not only withput a good source, but in addition also proven wrong (see above).

Your assumption that power is required to accelerate the vehicle is not correct.  At a stand still the force can be anything, but with velocity zero the power is zero.  f = a • m, p = f • v

If the force applied equals the force from the wind, the net acceleration is zero and the velocity remains at zero so no power.

No fancy math required, just a clear understanding of how to apply the science and math. 
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Offline gnuarm

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It is clearly seen form the equation that I constantly post here.

Unfortunately, regardless of your claims your equation does not apply to the Blackbird-type vehicles, where there is a propeller connected to wheels rolling on the ground.

Mostly because it is the WRONG equation for figuring the power generated at the wheels.  He can't understand how to think about the problem and refuses to learn because he doesn't want to have to say, "I was wrong".  Rather he makes the rest of the universe, including real world tests, wrong. 
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Online IanB

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Your assumption that power is required to accelerate the vehicle is not correct.  At a stand still the force can be anything, but with velocity zero the power is zero.  f = a • m, p = f • v

If the force applied equals the force from the wind, the net acceleration is zero and the velocity remains at zero so no power.

No fancy math required, just a clear understanding of how to apply the science and math.

I really don't think that Kleinstein was saying that huge power is actually required to accelerate the vehicle. To the contrary, Kleinstein was pointing out how unreasonable such an idea would be.
 

Offline gnuarm

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Other people call it thrust - and you call it a pressure differential - but the question is on the energy storage.

Rather than running around with words - where we all seem to get nowhere - it would make life so much easier if you could provide the formula which tells us how much energy is stored.

If this was a non compressible fluid like water then there will be no pressure differential and no energy storage just thrust.

Here you are exactly wrong.  "non compressible" is just a term, not reality.  Just like everything in existence water can be compressed.  It just doesn't change volume much when doing so.  This is how sound waves travel in water, by compression.  So there will be compression of the water behind a propeller and therefore energy storage.  Not that it matters one whit.  The tiny energy stored in the air or water around a propeller is insignificant compared to the energy needed to propel the vehicle.


Quote
Simplest analogy that I can think of right now and it is visual enough will be pushing a vehicle with another vehicle having just a solid bar connecting them (non compressible fluid like water) or having a spring between them (compressible fluid like air).

Just like water solids are compressible and will store energy. 


Quote
The spring is an energy storage device and it is moving together with the pushed vehicle. As any analogy it has limitations but a compressible fluid can be used to store energy and a propeller can be used to increase the pressure differential thus energy can be stored.

So are you saying that if the propeller were in water and the wheels were on land, the vehicle would exceed the speed of the water easily with no storage? 


Quote
This may be hard for some to understand as most will think that there is no way to maintain this pressure differential and there is not much I can do about this.

No, it is you who is saying the pressure can't be maintained.  We all say the pressure storage is irrelevant and only exists as a result of the propeller pushing against the wind.  All of your equations are wrong because they don't take into account the speed of the air pushed through the propeller.

The wind does push against the prop, it pushes the air which is exiting the prop.  The net speed of the air pushing on the prop is the sum of the wind speed and the air speed from the prop relative to the prop.  The net force on the propeller then is set by the sum of the wind speed minus the speed of the vehicle PLUS the speed of the air through the propeller relative to the vehicle. 


Quote
The main point I want to make since this is ester to understand (at least is what I was thinking) is that there is no wind power available to a direct down wind traveling at or above wind speed.

Unless the vehicle is pushing against the wind.


Quote
I provided the correct equation and anyone that is not agreeing with that equation is welcome to provide the correct one.

You provided a correct equation for the force from the wind (except you didn't consider the speed of the propeller exhaust).  You don't understand at all how much power is exerted by the wheels of the vehicle and won't even discuss that.  You keep talking about the "available power in the wind" which is not the question.


Quote
Nobody can claim to understand a wind powered only vehicle without being able to provide an equation describing the amount of wind power available to vehicle.

That's not the issue being discussed by anyone but you.  The power generated by the wheels is zero if the vehicle is not moving wrt the ground. 

In addition you did not consider the exhaust speed in your wind power equation.  So when the propeller is pushing against the wind this provides more available power than you are calculating!
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Offline gnuarm

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Your assumption that power is required to accelerate the vehicle is not correct.  At a stand still the force can be anything, but with velocity zero the power is zero.  f = a • m, p = f • v

If the force applied equals the force from the wind, the net acceleration is zero and the velocity remains at zero so no power.

No fancy math required, just a clear understanding of how to apply the science and math.

I really don't think that Kleinstein was saying that huge power is actually required to accelerate the vehicle. To the contrary, Kleinstein was pointing out how unreasonable such an idea would be.

I had a conversation with people in another place about what determines the acceleration of a car, torque or horsepower.  Like ED, they could not grasp the fundamentals of physics and one even claimed that instantaneous power was "just" a math concept and had no bearing on the real world, impossible to obtain or measure.  Weird. 

So I'm a bit sensitive to people not understanding that with speed being zero power is ALWAYS zero.  With constant force as the speed ramps up, the power also ramps.  That's why ICE typically have a ramping power curve until the internal movement of the air fuel mixture is overly restricted. 

It's really funny that ED can't understand such a simple concept and things the vehicle has significant power when it is not moving.  He also doesn't understand that the force from a brake is no different from any other force.

The guy is one for the books.  I wonder how long people will continue to discuss this with him.  I wonder how many hours he has spent on being wrong?  Days?  Weeks?  He probably could have started a small business with the time he has invested in this.  But not one having anything to do with physics or engineering.
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Offline Labrat101

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@ gnuarm
You haven't seen his website or his personal forum.
 It's worth looking at ..   :phew:
« Last Edit: December 31, 2021, 08:24:08 am by Labrat101 »
"   All Started With A BIG Bang!! .  .   & Magic Smoke  ".
 

Offline Brumby

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@ gnuarm
You haven't seen his website or his personal forum.
 It's worth looking at ..   :phew:

Why am I apprehensive............?    :scared:
 

Offline Labrat101

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@ gnuarm
You haven't seen his website or his personal forum.
 It's worth looking at ..   :phew:

Why am I apprehensive............?    :scared:
I was thinking more on the lines of us collectively, I know that every one here, are more than Qualified if not over qualified .
 That we should Nominate  electrodacus  For a Nobbled Prize of being the first person to redefine all known physics & Engineering
 That everyone else has Just  "Got it Wrong" ,
  Only He alone understands how every thing works . His theory's will now be the new known Law's
  So all our diploma's  of Dr . BA, MA , etc etc are Now all null & void  .
  :-DD :-DD :-DD :-DD
 
« Last Edit: December 31, 2021, 11:59:10 am by Labrat101 »
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Offline gnuarm

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The wind resistance is low compared to the force generated by the propeller driving the wheels because the angle of the blades is nearly parallel with the wind.  The lift of the airfoil is what provides the force that rotates the propeller and therefore the wheels. 

It is a very simple process once it is properly understood. 

It is fairly simple, but you have it backwards.  The propeller is driven by the wheels.  If you posit the wind driving the propeller somehow, ED's theories would be right since the interaction between the propeller and the wind is dependent on the windspeed relative to the vehicle.  The way it works when the vehicle speed is the same as the windspeed is the propeller reacts with apparently still air, neglecting a bit of turbulence, and that allows it to continue to push the vehicle even when it already at or above windspeed.

Maybe we are talking past each other.  In the downwind case the wheels drive the propeller.  In the upwind case the propeller drives the wheels.  That's why I had trouble understanding the upwind case, because if the wind pushes on the propeller very hard it will run downwind, with the propeller turning backwards by the wheels.  But because the propeller is nearly feathered there is very little resistance to the wind.  However the airfoil gives enough lift to spin the propeller in the correct direction which pushes the vehicle upwind. 

I didn't understand this until I looked at the angle of the blades in the videos.  Look at the two videos and you will see the downwind car starts with the blades full on to the wind while the upwind car starts with the blades feathered (parallel to the wind).
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Offline gnuarm

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Stored pressure-difference energy?  I was looking up explosive shock-wave overpressure propagation, and even at only 1 PSI, the pressure-wave is moving about 70 MPH (about 700 MPH at much higher pressures).  The idea that wind-pressure builds up behind a surface (and a surface that is slowly accelerating towards windspeed), and somehow this accumulated open-space pressure will persist for minutes, or even seconds, is pretty ridiculous.

Yes, as soon as the force from the propeller stops, the pressure behind the propeller dissipates.  The idea that the blackbird ran for minutes or even just seconds from the energy in this pressure is absurd.  There is just not that much of it.  Then he takes close up photos of gears nearly slipping and talking as if the micro level of energy involved in that is providing the necessary energy for faster travel.  It's pure BS.

Every car with a clutch has springs in the clutch plate to absorb some of the shock of a sudden engagement.  What ED is saying is that the energy stored in these springs would somehow provide extra power to the car to go faster.
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Offline gnuarm

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@ gnuarm
You haven't seen his website or his personal forum.
 It's worth looking at ..   :phew:

Yeah, I just took a look.  I don't see anything terrible.  The website is pretty amateurish, but it doesn't show the lack of understanding of physics this conversation does.  I think he started on page 4 or 5 and we are on page 56 now.
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Offline fourfathom

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Then he takes close up photos of gears nearly slipping and talking as if the micro level of energy involved in that is providing the necessary energy for faster travel.  It's pure BS.

The whole stick-slip hysteresis energy storage explanation is silly.  If there is a stick-slip cycle then energy is stored and released during the cycle.  If ED's explanation were true, the vehicle would be varying above and below windspeed at the cycle rate.  But the downwind speed of the vehicle through many of these nonexistent "cycles" remains faster than windspeed.
We'll search out every place a sick, twisted, solitary misfit might run to! -- I'll start with Radio Shack.
 
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Offline Labrat101

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  • Renovating Old Test Equipment & Calibration ..
Maybe we are talking past each other.  In the downwind case the wheels drive the propeller.  In the upwind case the propeller drives the wheels.  That's why I had trouble understanding the upwind case, because if the wind pushes on the propeller very hard it will run downwind, with the propeller turning backwards by the wheels.  But because the propeller is nearly feathered there is very little resistance to the wind.  However the airfoil gives enough lift to spin the propeller in the correct direction which pushes the vehicle upwind. 
I did mention this about the feathering of this type of propeller a good many pages back . and also the vortex affect
 that are created which is an important factor . as the vortex is like entering a slip stream  .
 This is also better explained in the PDF that IanB  showed a link to .
Also I did mention a few examples of this being used in torpedoes as a similar thing happens in water.
The torpedo will accelerate though the vortex  with almost Zero friction .
Also mentioned is that the Blackbird front wheels will also start to lift off the ground when the aerofoils are moved into
thrust so the drag from the front will drop and will allow the extra acceleration .
 The Maths are 3 Dimensional  . ED is working in only 2 Dimensional this is why the numbers will never be correlated.
 This I tried explaining but as usual just ignored or not understood .
 So if every one was to read and understand This very nice working PDF . Snoopy will be able to travel again faster than tail wind .. without all the BS etc .

  Happy new Year to every one ..  And may the force be with you .. :popcorn:

With complements from IanB
This was first done as long ago as 1969. Reference here: https://projects.m-qp-m.us/donkeypuss/wp-content/uploads/2009/06/Bauer-Faster-Than-The-Wind-The-Ancient-Interface.pdf


 
« Last Edit: December 31, 2021, 05:36:06 pm by Labrat101 »
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