5
   

I don't understand how this car works.

 
 
BillRM
 
  1  
Reply Mon 12 Jul, 2010 11:39 am
@sirclicksalot,
Quote:
Your weight and pully thought experiment is another irrelevant analogy.


Here is another such irrelevant analogy for you.

You know this is fun let go back to the old flat bed truck with a wind generator on it and going at wind speed.

Power is now zero but that is because the generator is not connected to the ground I can hear you saying and the prop is not turning.

Ok, we now lower an extra wheel to the ground and chain the generator to the wheel spinning the prop just like in the blackbird and now for some strange reason we can tap into the wind once more and we are generating power from the wind.

The energy to spin the wheel/prop is not coming out of the engine of the truck but from the wind force in some manner plus added energy if the Blackbird people are to be believe.

Now there is nothing of magic about a wheel turning on the ground. Instead of chaining the prop to the wheel we drive the generator with a battery power electric motor at the same RPMs as the wheel on the ground did and then we should be able removed the battery and take the power off the wind generator to keep the prop turning away forever along with added power.

We are now back to a form of a perpetual motion machine.




Cycloptichorn
 
  1  
Reply Mon 12 Jul, 2010 11:40 am
@BillRM,
The prop runs in reverse of the way you are positing in this example.

Cycloptichorn
0 Replies
 
OCCOM BILL
 
  1  
Reply Mon 12 Jul, 2010 11:48 am
@OCCOM BILL,
Not sure where the confusion remains. Maybe this will help:

http://img46.imageshack.us/img46/134/sailcarexplanation.jpg
ThinAirDesigns
 
  1  
Reply Mon 12 Jul, 2010 12:15 pm
@OCCOM BILL,
Occom Bill -- two animations directly related to your image example:

http://www.youtube.com/watch?v=za_rPKSwiyc&feature=related

http://www.youtube.com/watch?v=Ufk6HVWdSzE&feature=related
0 Replies
 
OCCOM BILL
 
  1  
Reply Mon 12 Jul, 2010 12:35 pm
@OCCOM BILL,
Further simplification:

http://img694.imageshack.us/img694/7983/sailcarexplanation2.jpg
Just like an airplane with the wind at it's back, the propeller's greater speed pushes air back into the oncoming air. The wheels act as the "TIE THIS LINE OFF" in the example above, even as they harnass the power to turn the prop.
0 Replies
 
BillRM
 
  1  
Reply Mon 12 Jul, 2010 12:38 pm
@sirclicksalot,
Sorry, I never design props, however your basic equations look wrong.

To start with power from the props should have a square relationship to velocity of air over the props and I do not see that in your equations.

In fact one would think that the equation would look like this power=constant*V(airflow over props)^2

In any case, I will need to look up the basic equations dealing with props and thrust and air flow before I can address your equations and I have other matters to attend to now.
sirclicksalot
 
  1  
Reply Mon 12 Jul, 2010 12:39 pm
@BillRM,
Quote:
Here is another such irrelevant analogy [incoherent strawman blah blah blah and ta daah!] perpetual motion machine.


Well you are right, that was indeed irrelevant.

Can you do a force and energy balance on that scheme, even one to prove it would not work? Can you discern the differences between that scheme and the cart?

No, of course not.

First of all, you haven't the chops to do a cogent force and energy balance to get yourself out of a wet paper bag. Competent people figure out how the cart works; really competent people have been building the thing for years. Smart but unschooled people who don't get it yet keep their mouth shut and study it. The rest can't disprove it, won't make the effort to study it, and instead publish rants that only point out how clueless they are. Given that the cart works and has repeatable results over forty years, guess which group you are in.

Second of all, Jack Welch said something like promote your top people, train the middle, and fire the bottom. Guess which of those groups you are in. I'm back in the briar patch and done with you, tar baby. I have more important things to do than try to communicate with yet another atechnical dilettante that couldn't find his keester with both hands and a flashlight. Show some competence (just once and for the first time, even to say "I don't understand") and you have a right to post here. Otherwise, do the rest a favor and peddle your nonsense elsewhere.
spork
 
  1  
Reply Mon 12 Jul, 2010 12:48 pm
>> "Since a propeller is able to apply force against the ambiant wind; the propeller itself acts as a VERY large sail. "
.
The propeller isn't simply acting as a large sail. As you observed earlier, no size of sail will get you past wind speed directly downwind. The prop acts as an actuator disk - accelerating air relative to the cart (and decelerating it relative to the ground).

>>"To help get your head around it; consider how air acts in a venturi. Similarly, this design is able to capture force from a greater area, and squeeze it into a smaller one for greater speed.'
.
I'm worried about this analogy. But I'll assume you're describing the fact that the wheels move over the road faster than the cart moves through the air. And yes, that's the key to the whole thing (in at least one of the many valid approaches).
.
On the BillRM matter, can we all agree he's clearly a troll?
sirclicksalot
 
  1  
Reply Mon 12 Jul, 2010 12:56 pm
@BillRM,
Quote:
To start with power from the props should have a square relationship to velocity of air over the props and I do not see that in your equations.

In fact one would think that the equation would look like this power=constant*V(airflow over props)^2


No, only someone with your lack of expertise would think and then publish something like that.

Have you never heard of dimensional analysis? Without even looking up prop design info, to make the units correct it is

P = k * air density * blade area * V^3

, but

F = C * air density * blade area * V^2

is already implicit in the force terms.

Look, if you haven't the chops to do something that simple, you'll never contribute anything to this thread.
0 Replies
 
Pepijn Sweep
 
  1  
Reply Mon 12 Jul, 2010 01:01 pm
@BillRM,
WattCar
0 Replies
 
BillRM
 
  1  
Reply Mon 12 Jul, 2010 01:03 pm
@sirclicksalot,
Well well well for a moment I was getting the impression that we would enjoy a civil conversation at least over the relationship between power and airflow velocity and thrust as it related to props.

There still should be a power of 2 relationship when it come to airflow speed over props and energy and power to and from the props in my opinion.
sirclicksalot
 
  1  
Reply Mon 12 Jul, 2010 01:20 pm
@spork,
Quote:
On the BillRM matter, can we all agree he's clearly a troll?


My simple vote is "yea," though I guess that's obvious from my previous post.

But I am still not clear on the definition of troll [url]http://en.wikipedia.org/wiki/Troll_(Internet)[/url ]: is it the knowledgeable one(s) who know the right answer and support the brainteaser (trolling bait as in fishing) to spin up the clueless, the message that does it, or the clueless one unable to challenge and eventually overcome their intuition that ends up ranting?

Actually, he hasn't ranted as much as just been consistently wrong; whether his posts have been intentionally inflammatory or willfully ignorant or just ignorant gets into motive and is a tough call. He's obviously been exposed to the jargon and either doesn't know how to, or won't, use it correctly.

But yeah, definitely a waste of time which seems to be the main thrust of your query.
0 Replies
 
sirclicksalot
 
  1  
Reply Mon 12 Jul, 2010 01:24 pm
@BillRM,
civil conversation? that ship pretty much sailed by your own doing many posts ago. civil conversation involves listening to others, making an attempt to understand them, and not repeating the same discredited statements over and over. up to now civility has been pretty much a one way street as far as you are concerned.
0 Replies
 
sirclicksalot
 
  1  
Reply Mon 12 Jul, 2010 01:30 pm
@BillRM,
Quote:
There still should be a power of 2 relationship when it come to airflow speed over props and energy and power to and from the props in my opinion.


I'll take a few centuries of proper analysis and Sir Isaac Newton's opinion over yours, if you don't mind.

You know, as a straight man (aka Stooge) you are entitled to 60% of the take, as the comic I only get 40%.
BillRM
 
  1  
Reply Mon 12 Jul, 2010 02:05 pm
@sirclicksalot,
A supporter of Energy from nowhere and you are turning to Newton!!!!!!

In any case I was right that the thrust of a prop have a v^2 relationship as in this long and lovely equation T=(p*Va^2*D^2)X(fr*(N*D/Va)).

If you wish to find the meanings of the others terms look them up yourself.

The power output of a wind turbine is also a square relationship to the wind speed.

Better luck next time.

sirclicksalot
 
  1  
Reply Mon 12 Jul, 2010 03:18 pm
@BillRM,
Quote:
A supporter of Energy from nowhere and you are turning to Newton!!!!!!


Nobody but you is making the claim that the cart gets Energy from nowhere, but being as you haven't any idea, can't learn, and won't learn, how it works, that doesn't bother anybody.

Quote:
In any case I was right that the thrust of a prop...


"I was right" - boy you don't get to say that very often, eh? Of course, even when you do it's false; in fact you were not right because in the previous post you said power, not thrust, was proportional to V^2 (and you said it again; see below). So get a clue, Stooge. That formula is for Thrust, not power. And as Thrust is Force it has exactly the squared relationship wrt velocity that I stated without any need to look it up, like probably everyone else who understands the cart (i.e. not you). And no thank you, I don't need to look up the meanings of the other terms.

And if this is true:

Quote:
The power output of a wind turbine is also a square relationship to the wind speed.


then Sir Newton is turning over in his grave, but what really gets him spinning is your even bigger gaffe in thinking that both thrust and power can have the same power law relationship to the wind speed. And gee, whaddya know, there it is at http://www.awea.org/faq/windpower.html (and elsewhere):

Quote:
Wind Turbine Power:

  P = 0.5 x rho x A x Cp x V^3 x Ng x Nb


Velocity bloody cubed just like I said, you hack.

"Are you getting all of this down or am I talking too fast?" Humphrey Bogart/Sam Spade, The Maltese Falcon.
BillRM
 
  1  
Reply Mon 12 Jul, 2010 03:24 pm
@sirclicksalot,
Poor baby you do no know just enough to make a fool of yourself and no more there is a square relationship between force and thrust and wind speed and there happen to also be a square relationship between power outputs of wind turbines.

Sorry if you do not care for the information.
ThinAirDesigns
 
  1  
Reply Mon 12 Jul, 2010 03:27 pm
Just as he believes that the conservation of energy law also means conservation of force and conservation of speed, apparently BillRM doesn't know the difference between thrust and power.

JB
sirclicksalot
 
  1  
Reply Mon 12 Jul, 2010 03:51 pm
@BillRM,
Quote:
Better luck next time


Bill, if you should ever get to the point that you know what you are talking about, you'll learn that being right is not luck.

Quote:
Poor baby ...


Wow. Just wow. You are unable to put two, or even one, cogent thought(s) together, or even understand the implications of the most basic statements. Are you a bot? Is English not your first language?

Your last six statements at least have been dead wrong (I'm not counting the mistakes you repeated). Six for six. Do you see a trend? If you ever grokked DDWFTTW the rest of us would be forced to doubt it.

Quote:
Sorry if you do not care for the information.


You give me some information that is not prima facie false and I'll care for it (not that I'm holding my breath), but the sewage you spout is not worth my time.
0 Replies
 
BillRM
 
  1  
Reply Mon 12 Jul, 2010 03:54 pm
@ThinAirDesigns,
I do know that when the wind doubles you get roughly four times the power out of a wind turbine!

And I do not need to make up news accounts names to support my own postings either something that is becoming clear is happening big time here.

Beside the physics the approach of the supporters of this claim in itself is such that it smell of a hoax as there would be no need for this kind of strong arm selling if this was for real.

Anyhow how long is this hoax going to go forward before ending?

The cold fusion one went on for a year or more and you guys had been playing on the net with this nonsense for over a year.

What is behind all this effects to convince people when you know in the end it will fall apart?

Oh as a footnote not a word of this testing had shown up on the NASLA website as of yet.





 

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