Merged DDWFTTW in a “Real” Wind

[Myriad]

No efficiency issues. Practical examples of >60% can be readily found.

Show me any working system that converts braking heat into usable power. Then we can evaluate its efficiency.

Power stations manage.
Don't like that? Then thermocouple or Peltier devices can be used to generate current directly from the heat.

Power stations do not convert braking heat into usable power. Show me a working system that uses thermocouples or Peltier devices to convert braking heat into usable power, then we can evaluate their efficiency.

No more so than the prop. The energy is not stored for re-use, just part of the transfer.

KERS systems store the energy for re-use. If you're just talking about a generator directly powering a motor, that could work for a downwind faster than the wind cart, but it is not a KERS system.

The cart is traveling 20mph, and the wind is 15mph.
F will be in the opposite direction, so opposing the cart.

A spinning prop can generate thrust in the direction of travel in the presence of a headwind. The Blackbird's prop does so, for example (as do all airplane props).

A more or less efficient PM machine?

No, more or less efficient extraction of power from a moving fluid stream.

Meaning that you can't or won't supply a reference that supports tacking props?

I have not made any claims about tacking props, so I see no reason to provide references for same. Whether you "doubt" tacking props or not is no concern of mine.

No meteorological text or authority will support averaging of the wind direction.

Not true. http://www.ndbc.noaa.gov/wndav.shtml

NALSA are not omnipotent, but a sailing club, who assigned one member using borrowed and uncalibrated instruments.

How they want to measure and verify their records is up to them. You have a better way? Start your own club, spend decades organizing competitions, events, and publications to establish a reputation among participants sufficient to make them care about what records you endorse, and then put your way into effect.

Or you can try to convince NALSA to change their minds. But you do not appear to be making any effort to do that, perhaps because you recognize that your arguments are not convincing.

Respectfully,
Myriad

 

[A.T.]

Or you can try to convince NALSA to change their minds. But you do not appear to be making any effort to do that, perhaps because you recognize that your arguments are not convincing.

He announced to contact NALSA, but didn't do it, because some "authority" was supposed to check his arguments first. Then a while later he said that convincing NALSA is not important to him anymore...

 

[humber]

Show me any working system that converts braking heat into usable power. Then we can evaluate its efficiency.

And where is your evidence that the cart meets your demand?
There is no limit that does not apply to any other proposal.
A reverse compression turbine can achieve 60%

Even Peltier works:

Peltier 15%, but can do better
Vcart = 20m/s
Vwind = 15m/s
Vprop = 5m/s

F_thrust = F_wheel Vc/Vp*n

Assuming the same 89% for the motor and prop.

n = 0.15*.89*.89 =.11

Vc/vp = 4

Fthrust = F_wheel*4*0.11

Always greater than F_wheel for any value.

Power stations do not convert braking heat into usable power. Show me a working system that uses thermocouples or Peltier devices to convert braking heat into usable power, then we can evaluate their efficiency.

Don't need to.

KERS systems store the energy for re-use. If you're just talking about a generator directly powering a motor, that could work for a downwind faster than the wind cart, but it is not a KERS system.

Then steam or peltier

A spinning prop can generate thrust in the direction of travel in the presence of a headwind. The Blackbird's prop does so, for example (as do all airplane props).

NASA say not.

No, more or less efficient extraction of power from a moving fluid stream.

NASA say not

I have not made any claims about tacking props, so I see no reason to provide references for same. Whether you "doubt" tacking props or not is no concern of mine.

It's not your cart. There are claims that the cart tack because of the prop
Countless references to that.

Not true. http://www.ndbc.noaa.gov/wndav.shtml

Not relevant. There are two methods: Averaging over 10minutes or more.
The instruments are designed to meet a known standard; NIST. That make relative comparison valid.
If you want to get fussy, then the NIST requirement that the vane should be more than 10m from an obstructing surface has not been met.
10 minute averaging has not been met. The instruments transient response is related to that. 10 seconds is not valid.

There are average and component methods. One used for instantaneous readings.
The data sampling rate of 5Hz, is well below the 320Hz, used for that purpose.

But...

1. The first wind averaging technique applies to those measurements reported by all DACT, VEEP, and ARES payloads.

Fixed use, not mobile.

The average wind speed is the simple scalar average of the wind speed observations. A "unit-vector" average is used to calculate the average wind direction. In this technique, unity serves as the length of the vector, and the wind direction observations serve as the orientation of the vector.

Refers to the derivation, not the result. How the chart data is found not the "average"

The u and v components are then calculated for each observation. Next, the average u and v components are computed and the average wind direction is derived from "arctan(u/v)." Note that this technique will produce greater wind speeds than if a true vector average was used.

Not the mean. So again no support
Arctan is vectorial. There are many other methods too. All applied according to circumstance.

2. The second method, used to calculate average speed and direction reported by NDBC's older GSBP payloads, is a true vector average. In this scheme, the magnitude of the vector is represented by the wind speed observation and the direction observations are used for the orientation. The vectors are then broken down into their u and v components. All u and v components are then averaged separately. The resulting average speed and direction are calculated from the Pythagorean Theorem and "arctan(u/v)," respectively.

Again not the arithmetic mean.
RMS = root mean squared.

So Now you have to tell me why my whacky thermal cart, is any different from the BB.

 

[humber]

humber is broken.

I would be interested to see what you have to say, and how you manage to contradict NASA. Be assured I know how that math is derived.

 

[I Ratant]

No. They turn because the cart moves forwards.
...

.
The natural direction of rotation for a freewheeling prop ... disconnected from the wheels.. is, when viewed from behind the vehicle as in the video these images are from, is counter-clockwise.
That the prop rotates clockwise says the wheels start its rotation.
The prop is a rotating sail which pushes the cart which turns the wheels which turn the prop on the downwind moving cart that Jack built.
When the connection to the wheels is lost, the prop rotates in the windmilling direction and the cart loses forward (downwind) speed.

 

[humber]

.
The natural direction of rotation for a freewheeling prop ... disconnected from the wheels.. is, when viewed from behind the vehicle as in the video these images are from, is counter-clockwise.
That the prop rotates clockwise says the wheels start its rotation.
The prop is a rotating sail which pushes the cart which turns the wheels which turn the prop on the downwind moving cart that Jack built.
When the connection to the wheels is lost, the prop rotates in the windmilling direction and the cart loses forward (downwind) speed.

Exactly. The only possibility is that something pushes the cart, to push the wheels, that turn the prop. That something is the bluff area of the cart.

ETA:

.
The prop is a rotating sail which pushes the cart which turns the wheels which turn the prop on the downwind moving cart that Jack built.

That is true of the linear force. If the rotor where simply un-geared (or even fixed) it would be a sail, just like the rest of the cart's body.
But the angular component turns the wheels backwards, so opposes the cart.
In the trial run, the cart is already 10 degrees off ddw. That reduces the opposing turbine force, but increases the bluff area presented to the wind.

 

[A.T.]

They[wheels] turn because the cart moves forwards.

....pushes the cart which turns the wheels ...

Just as I said.

 

[humber]

Just as I said.

The wheel spontaneously turns does it?
I have you trying to tell me that a PM machine will work if the efficiency is high enough. ROFL.

 

[Jack by the hedge]

The wheel spontaneously turns does it?

The wind pushes on the static prop like a sail. That pushes the cart forwards. That turns the wheels...

Are you really incapable of understanding even how the cart moves off from a standstill?

 

[Jack by the hedge]

A spinning prop can generate thrust in the direction of travel in the presence of a headwind. The Blackbird's prop does so, for example (as do all airplane props).

NASA say not.

You think NASA say spinning propellers can't generate thrust into a headwind?

Maybe that's why NASA like to use rockets instead of propellers.
Or maybe you just don't understand what NASA say either.

 

[A.T.]

They[wheels] turn because the cart moves forwards.

The wheel spontaneously turns does it?

Alexia still not getting any better?

 

[humber]

The wind pushes on the static prop like a sail. That pushes the cart forwards. That turns the wheels...

Are you really incapable of understanding even how the cart moves off from a standstill?

But you can say exactly that of a failed upwind cart.

There is a torque component, or do you think the L/D ratio is so low, there isn't any? If you win the sail argunent, then you lose the prop argument.

There are 16 foot ceiling fans too. They use up to 10 blades and turn at 75-100rpm. Driven by an 1800W motor.

But they don't take the roof off. How much thrust do you think a 2 blade prop, turning at a fraction of an rpm can produce?

 

[A.T.]

Are you really incapable of understanding even how the cart moves off from a standstill?

Oh, he knows exactly how it works: Spork hits the brake, to prevent it from going backwards upwind, and that forces it to go downwind... (no kidding, that was one of his explanations)

 

[humber]

It's the "intuition-brain teaser" Shtick, that is the problem.
At first there is the objection that it can't work, but comes conversion. But now, examination is bringing back the doubts and reasons why you were initially skeptical, such as it sounds like PM. Yet, you are now trying to convince me, that my PM proposal could work...

 

[Jack by the hedge]

But you can say exactly that of a failed upwind cart.

There is a torque component, or do you think the L/D ratio is so low, there isn't any? If you win the sail argunent, then you lose the prop argument.

No problem at all. The wind pushes forward on the static prop, but it also tries to turn the prop. The turning force acting via teh drive chain tries to turn the wheels backwards and move the cart into the wind. But the forwards push produces a greater torque at the wheels via contact with the ground, so the net torque turns the wheels forwards.

 

[jduffy77]

It's the "intuition-brain teaser" Shtick, that is the problem.
At first there is the objection that it can't work, but comes conversion. But now, examination is bringing back the doubts and reasons why you were initially skeptical, such as it sounds like PM. Yet, you are now trying to convince me, that my PM proposal could work...

You haven't mentioned a PM proposal, you tried to and failed.

 

[humber]

You haven't mentioned a PM proposal, you tried to and failed.

It has not failed. There are thermal to electricity devices that have reached 38% efficiency. But that is not the point, because there is always a gain in thrust. Over-unity cranks, don't claim large gains, because large gains are obvious so can't be hidden in the data, but also because any gain at all, is success, because you can put that back into the device and increase it again.
Same with the cart. Any gain will ramp itself up.

 

[humber]

No problem at all. The wind pushes forward on the static prop, but it also tries to turn the prop.
The turning force acting via teh drive chain tries to turn the wheels backwards and move the cart into the wind.

yes.

But the forwards push produces a greater torque at the wheels via contact with the ground, so the net torque turns the wheels forwards.

Nope. If it drives it one way, it drives it another with equal force.
But it's worse than that. Newton says that the wheels at the ground will produce an equal and opposite force to the pushing. If you say the net force is increased then that is obviously wrong, and would result in spontaneous motion. Not even Aristotle, let alone Newton.

 

[jduffy77]

It has not failed. There are thermal to electricity devices that have reached 38% efficiency. But that is not the point, because there is always a gain in thrust. Over-unity cranks, don't claim large gains, because large gains are obvious so can't be hidden in the data, but also because any gain at all, is success, because you can put that back into the device and increase it again.
Same with the cart. Any gain will ramp itself up.

It sounds like you forgot the wind again. All that matters is whether the thrust from the prop exceeds the drag force and efficiency losses from whatever is being used to spin the prop.

 

[Myriad]

And where is your evidence that the cart meets your demand?

(1) The carts work. They would not work if they didn't transfer power efficiently enough.

(2) Assessment of the means of power transmission. A reasonably designed and manufactured geared shaft, chain drive, or (especially) reel to reel transmission is highly efficient by nature.

There is no limit that does not apply to any other proposal.
A reverse compression turbine can achieve 60%

Even Peltier works:

Peltier 15%, but can do better
Vcart = 20m/s
Vwind = 15m/s
Vprop = 5m/s

F_thrust = F_wheel Vc/Vp*n

Assuming the same 89% for the motor and prop.

n = 0.15*.89*.89 =.11

Vc/vp = 4

Fthrust = F_wheel*4*0.11

Always greater than F_wheel for any value.

Really? F_wheel * 0.44 > F_wheel?

Wrong.

Not that your equation is close to valid in the first place. How does that singularity when Vcart = Vwind and Vp = 0 come about?

Don't need to.

If no system exists for using the energy of braking heat, then your guesses about the efficiency of such a system are meaningless. It's like saying a 1000 Kg car could be accelerated to escape velocity using less than 510 gallons of gasoline, based on energy equivalence calculations, without regard for the actual engineering of how to do it.

NASA say not.

NASA does not say that propellers cannot generate forward thrust into a headwind.

NASA say not

NASA does not say that energy cannot be extracted from moving fluid streams.

It's not your cart. There are claims that the cart tack because of the prop
Countless references to that.

If you're satisfied that there are countless references, then you don't need me to provide any.

Not relevant. There are two methods: Averaging over 10minutes or more.
The instruments are designed to meet a known standard; NIST. That make relative comparison valid.
If you want to get fussy, then the NIST requirement that the vane should be more than 10m from an obstructing surface has not been met.
10 minute averaging has not been met. The instruments transient response is related to that. 10 seconds is not valid.

There are average and component methods. One used for instantaneous readings.
The data sampling rate of 5Hz, is well below the 320Hz, used for that purpose.

You claimed that no meteorological authority would support averaging of wind direction. I showed that NOAA, a meteorological authority, uses various methods of averaging wind direction. Your blanket claim is false.

You might try a more specific claim, such as "no meteorological authority engages in averaging of wind direction while conducting vehicle performance tests." Which might possibly be true, if only because meteorological authorities don't generally conduct vehicle performance tests in the first place.

So Now you have to tell me why my whacky thermal cart, is any different from the BB.

I did. It is much less efficient, and therefore will not work in the real world, since the inefficiency causes the prop thrust to fall below the "braking" force under likely operating conditions. However, in principle, it could work if the power transfer could be made efficiently enough, and it were otherwise properly engineered with the correct ratio of prop advance to ground speed. Your version merely replaces the simple reliable mechanical power transmission with an elaborate, cumbersome, and inefficient friction-brakes-and-heat-engine system.

Respectfully,
Myriad