Merged DDWFTTW in a “Real” Wind

[sol invictus]

Your incoherence rivals your innumeracy.

 

[Llyricist]

I think he's trying to compare the traction of the propeller in air with the traction of a thread on glass.

Of course he uses the term friction because it allows him not to differentiate between wheels and simple solid to solid contact.

 

[Jack by the hedge]

Turn the wheel clockwise by hand. That represents the generator that Spork has attached to the wheel ( see his submission to NALSA)
The prop will turn CW. That is the prop mode.
At the same time, use a finger to turn the prop CW, to represent the added wind power.
What happens to the force applied at the wheel?

[qimg]http://www.internationalskeptics.com/forums/attachment.php?attachmentid=21441&stc=1&d=1300490591[/qimg]

Error! Instead of turning the prop with your finger, push the prop forward with your finger. That represents the added wind power.

In fact, if you carefully push forwards on the propeller blade, you will find that not only does the cart move forward but, as it moves, the prop turns and as it turns, the prop blade slides across your fingertip. Note that due to the wheels turning the prop, it turns in the counterintuitive direction - it "climbs away" from your finger. Consequently the cart has moved forward further than your fingertip has moved. Directly downfinger faster than the finger.

 

[humber]

Your incoherence rivals your innumeracy.

Oh and BTW, like so many journals, each contains material upon its merit.
You left out this bit
"If a manuscript is otherwise acceptable as a contribution, the inclusion of new results is not an insurmountable barrier to publication."

Yes, the algebra is quite OK. I will give you an "A"

But, that has led you to confuse the behavior of two concentric wheels of differing diameters, with two gears mounted on separate shafts.

In the first case, the angular velocity of one, is forced to be the same as the other. That is not the case with separate gears. That poses a restriction on "trading force for velocity"

Now, the analysis involving the friction, and the moment of the reel, will give you some "insight", into your error. Can you do that?

 

[humber]

Error! Instead of turning the prop with your finger, push the prop forward with your finger. That represents the added wind power.

In fact, if you carefully push forwards on the propeller blade, you will find that not only does the cart move forward but, as it moves, the prop turns and as it turns, the prop blade slides across your fingertip. Note that due to the wheels turning the prop, it turns in the counterintuitive direction - it "climbs away" from your finger. Consequently the cart has moved forward further than your fingertip has moved. Directly downfinger faster than the finger.

No. That won't work. As I said, if you posit any other means by which the wind can drive the cart, then you don't need the gears.
The force you are describing, can't be differentiated form the force turning the prop, unless you hold to that the ground it turning it. Cranky.
Secondly, the force will come from the headwind, so will push the cart backwards.

 

[Modified]

No. That won't work. As I said, if you posit any other means by which the wind can drive the cart, then you don't need the gears.
The force you are describing, can't be differentiated form the force turning the prop, unless you hold to that the ground it turning it. Cranky.

Wrong. If you push directly forward on the blade, it will slide across your finger and drive the cart forward faster than your finger, until the blade slides past your finger.

Are you really saying this can't happen? Please, a simple yes or no answer for once.

Secondly, the force will come from the headwind, so will push the cart backwards.

There is never any headwind on the effective surface of the prop of the dwfttw cart. The effective surface is always moving slower than the wind, and the wind is always applying a force to it.

 

[Jack by the hedge]

No. That won't work. As I said, if you posit any other means by which the wind can drive the cart, then you don't need the gears.
The force you are describing, can't be differentiated form the force turning the prop, unless you hold to that the ground it turning it. Cranky.
Secondly, the force will come from the headwind, so will push the cart backwards.

This is gibberish. It does work. Why do you think the cart doesn't need gears? Since the wheels drive the propeller they each have to turn at some fixed ratio. How better to do that than with gears?

What exactly does "The force you are describing, can't be differentiated form the force turning the prop, unless you hold to that the ground it turning it" mean? The wind force acting on the propeller can be resolved into two components: one (partially) opposes the rotation of the propeller and the other pushes the propeller forwards. What part of that confuses you?

There is a force from the headwind, and that does drag on the cart, but it does not drag on the propeller blades. The blades are rotating at an appropriate speed such that the pitched blades are screwing through the air faster than the cart is moving forwards into the air.

 

[humber]

Wrong. If you push directly forward on the blade, it will slide across your finger and drive the cart forward faster than your finger, until the blade slides past your finger.

Are you really saying this can't happen? Please, a simple yes or no answer for once.

But that in no way helps you. Air is a fluid, and transfers force by momentum.
If you simply push without sliding, that is pushing. But of course, the "finger" spans the whole blade.
That still leaves you with two choices, "sliding" or not.
The force does not turn the blade, so is a linear force opposing motion.
or it turns the blade ans works to reduce the force at the wheel.

It's really very simple. You are now trying to explain away a pro PM machine, that was described in a way that led you to believe it wasn't. It did that, by not working. It could only "work" if it were a PM machine.

There is never any headwind on the effective surface of the prop of the dwfttw cart. The effective surface is always moving slower than the wind, and the wind is always applying a force to it.

Nonsense. If that were to happen then you could not extract power.

 

[humber]

This is gibberish. It does work. Why do you think the cart doesn't need gears? Since the wheels drive the propeller they each have to turn at some fixed ratio. How better to do that than with gears?

What exactly does "The force you are describing, can't be differentiated form the force turning the prop, unless you hold to that the ground it turning it" mean? The wind force acting on the propeller can be resolved into two components: one (partially) opposes the rotation of the propeller and the other pushes the propeller forwards. What part of that confuses you?

no confusion, It's BS. You bought it.

There is a force from the headwind, and that does drag on the cart, but it does not drag on the propeller blades. The blades are rotating at an appropriate speed such that the pitched blades are screwing through the air faster than the cart is moving forwards into the air.

Sorry, but all the other carteers have made calculations that flatly contradict you. Yevgheni has shown them to be false. You can find that at Rational Skeptic.
Allsee was involved, and LLrycist was his bulldog and apologist. Faced with the conclusions of their own math, the ran away.

 

[Jack by the hedge]

If you simply push without sliding, that is pushing. But of course, the "finger" spans the whole blade...

If it helps you to grasp the concept, either imagine pushing with a toothpick or pushing a full-size cart's prop with your finger.

The cart moves forward and the pitched blade slides across your finger until the trailing edge slips off. The cart has moved forwards by the same amount as your finger plus the depth of the pitch of the blade.

 

[Llyricist]

no confusion, It's BS. You bought it.



Sorry, but all the other carteers have made calculations that flatly contradict you. Yevgheni has shown them to be false. You can find that at Rational Skeptic.



Allsee was involved, and LLrycist was his bulldog and apologist. Faced with the conclusions of their own math, the ran away.

wrong again, faced with his gross error in calculating the energy loss of the air, your hero ran away and made more gross errors of bookkeeping that were simply irrelevant.

 

[Jack by the hedge]

no confusion, It's BS. You bought it.



Sorry, but all the other carteers have made calculations that flatly contradict you. Yevgheni has shown them to be false. You can find that at Rational Skeptic.
Allsee was involved, and LLrycist was his bulldog and apologist. Faced with the conclusions of their own math, the ran away.

It seems you have run out of logical arguments for now.

You don't understand it yet, but I still have hopes for you.

If you have maths which might help make your point, feel free to offer it.

In the meantime, keep thinking about pushing on the propeller blade and its sliding across your finger in the opposite direction than it would if it were free to turn. You can do this.

 

[Jack by the hedge]

P.S. I would still like to know what "The force you are describing, can't be differentiated form the force turning the prop, unless you hold to that the ground it turning it" means.

 

[humber]

If it helps you to grasp the concept, either imagine pushing with a toothpick or pushing a full-size cart's prop with your finger.

The cart moves forward and the pitched blade slides across your finger until the trailing edge slips off. The cart has moved forwards by the same amount as your finger plus the depth of the pitch of the blade.

But that does not help you.
Take the cart off the ground and use a hairdryer to represent the headwind.
The rotor will turn the same way as when it is in the wind. If it didn't it would oppose the cart.
There is a headwind, or the streamer is wrong.

You have been sold BS. The trial is BS.
The forthcoming upwind cart is already marked as doing that. It will deceive in the same way.
The rules for the formal trials are not arbitrary. The height is restricted, so that the carts CAN'T exploit the gradient.

 

[humber]

It's as plain as can be. It's in your responses. You must be taking my point, in order to oppose it, so you then struggle to find ways around it.

 

[humber]

The wind is not a finger. The average velocity of an air molecule at room temperature is 500m/s.

 

[Jack by the hedge]

Take the cart off the ground and use a hairdryer to represent the headwind.
The rotor will turn the same way as when it is in the wind. If it didn't it would oppose the cart.
There is a headwind, or the streamer is wrong.

Correct. The prop would be turned by the hairdryer in the same direction it turns when it's running.

But of course when it's driven by the wheels, the prop is turning faster than that. Fast enough that the wind pressure is not acting on the front of the blade but on the back.

 

[Jack by the hedge]

The wind is not a finger. The average velocity of an air molecule at room temperature is 500m/s.

Yet somehow sails and propellers work. Must be magic.

 

[humber]

Correct. The prop would be turned by the hairdryer in the same direction it turns when it's running.

But of course when it's driven by the wheels, the prop is turning faster than that. Fast enough that the wind pressure is not acting on the front of the blade but on the back.

Not possible. The prop and wheel speeds are fixed.
And what drives the wheel to drive the prop?
See, PM, but with a sugar coating.

 

[humber]

Yet somehow sails and propellers work. Must be magic.

Yes, the average velocity then becomes 500m/s +/- WS.
The mean path between molecular collisions, is reason there is not a 500m/s wind in your lounge.