5
   

I don't understand how this car works.

 
 
spork
 
  1  
Reply Tue 13 Jul, 2010 04:27 pm
>>"By the way, Spork had you talk Dr. Dan Kammen ..."

I'll tell you what. Phrase that as an english sentence and I'll answer it. In the meantime there's only one reasonable way to settle this. You're SURE it's impossible, and I'm pretty darn confident it IS possible. You have no desire to debate it or try and understand it, so why don't we leave it down to a bet. I'll give you 10:1 odds - your $10K against my $100K. How confident are you in dollars and cents?

Cycloptichorn
 
  2  
Reply Tue 13 Jul, 2010 04:28 pm
@spork,
Quote:
I'll give you 10:1 odds - your $10K against my $100K. How confident are you in dollars and cents?


He's not confident at all, he just is too invested to back down and save face.

Cycloptichorn
0 Replies
 
sirclicksalot
 
  2  
Reply Tue 13 Jul, 2010 04:45 pm
@BillRM,
Quote:
why spend the time mounting one hell of a costly, in terms of time at least, campaign to silent questioners ?

Costly? In terms of time? Not really, refuting your clumsy, ignorant and pointless posts is a rather trivial exercise for competent people.

As spork mentioned, we know you are not a skeptical questioner but simply a denier. The reason is that you have never demonstrated the skills or background to determine if the cart can work or not. In fact it is blazingly obvious that you don't have any valid reason either to believe it works or to believe it doesn't work. Why you chose to believe it doesn't work is proper fodder for psychologists, psychiatrists and sociologists; I am none of those but in the end my amateur opinion is that it's easier to simply claim "fake", perhaps to get attention like a spoiled child, even if you can't back the claim up and end up suffering ridicule as a result.

Bill, you don't have to be silent, but the nonsensical detritus you pointlessly posted up to this point have been consistently wrong and have consistently contributed nothing (zip, nil, naught, nought, zilch, zot, nada, bupkis, zero, diddly squat) to the discussion. Your pointless posts can only serve to confuse smarter people who have a chance of actually understanding the cart. Fortunately the pattern of your pointless posts fits that of a troll so anybody reading more than a few of them will quickly realize their lack of value and ignore them. Even so it should be an overwhelmingly obvious conclusion to everyone, except perhaps to you, backed up by over a month of evidence, that you could exercise simple politeness to everyone else by not posting anything at all.

Bill, your pointless posts are of no more use to this thread than if you believed the cart did work, because even then your pointless posts would still only confuse people as you have not the skills to constructively contribute to this thread either way. Your pointless posts are a destructive and unwanted force here.
0 Replies
 
georgeob1
 
  1  
Reply Tue 13 Jul, 2010 05:12 pm
Let's imagine our vehicle (with a fixed mechanical connection between propeller and wheels, and a non steerable fixed pitch propeller) is on level ground with a tail wind and travelling at exactly the speed of the wind. In that situation there is zero relative motion between the surrounding airstream and the vehicle. The only forces acting on the vehicle are
(1) the wheel friction which will tend to slow the vehicke down;
(2) The thrust of the rotating propeller which will push it forward
(3) The drag force on the propeller blades which creates a torsional moment tending to slow the propeller and the wheels down.

Thus the vehicle can accelerate to a speed greater than the wind speed (i.e. experience a relative wind from ahead) only if the thrust of the rotating propeller exceeds the combination of wheel friction and propeller blade drag.

It is conceivable that this may occur with a very light vehicle with very low wheel friction and a very efficient propeller with a very high lift/grag ratio for its propeller blades.

However if the vehicle goes any faster it will begin to experience bulk air drag which will quickly eliminate any net forward thrust.

How much faster than the wing speed (in percent) is it claimed this thing can go?
Cycloptichorn
 
  1  
Reply Tue 13 Jul, 2010 05:23 pm
@georgeob1,
2.85x or so

Cycloptichorn
0 Replies
 
sirclicksalot
 
  1  
Reply Tue 13 Jul, 2010 05:24 pm
@georgeob1,
Quote:
How much faster than the wing speed (in percent) is it claimed this thing can go?


Assuming you mean wind not wing, the current Blackbird team is expecting a NALSA BOD-verified steady-state directly down wind value of 250% over windspeed (i.e. cart speed over the ground of 3.5 times the true windspeed).
0 Replies
 
ThinAirDesigns
 
  1  
Reply Tue 13 Jul, 2010 06:12 pm
@georgeob1,
georgeob1:
Quote:
Let's imagine our vehicle (with a fixed mechanical connection between propeller and wheels, and a non steerable fixed pitch propeller) is on level ground with a tail wind and travelling at exactly the speed of the wind.

Ok

Quote:
In that situation there is zero relative motion between the surrounding airstream and the vehicle.


This is where you go wrong, and until you get it right, there's no point in going further with your scenario.

While it's true that there is no relative motion between the surrounding airstream and the vehicle *chassis*, there is PLENTY of relative motion between the surrounding airstream and the *airfoils* of the vehicle. The airfoils are running at an angle to the wind the same as a sailboat's sail on a broad reach.

Once you get this straight, I'll be happy to continue and answer your questions.

JB

BillRM
 
  1  
Reply Tue 13 Jul, 2010 06:26 pm
@spork,
Spork you poor baby as you know experts in physics one with Noble prizes are stating the same thing I had been IE this is a free energy device that can not work.

Yes Spork I can see why you would wish to run away from that fact.

If I am wrong and this craft work then some of the best minds on earth are also wrong.

Could be but I am still betting it is far more likely then not that this is a hoax.

ebrown p
 
  1  
Reply Tue 13 Jul, 2010 06:30 pm
@BillRM,
Bill,

When your Nobel Price winner changes his mind, will you? (apparently he is already dithering).
georgeob1
 
  1  
Reply Tue 13 Jul, 2010 06:44 pm
@ThinAirDesigns,
ThinAirDesigns wrote:

georgeob1:
Quote:
Let's imagine our vehicle (with a fixed mechanical connection between propeller and wheels, and a non steerable fixed pitch propeller) is on level ground with a tail wind and travelling at exactly the speed of the wind.

Ok

Quote:
In that situation there is zero relative motion between the surrounding airstream and the vehicle.


This is where you go wrong, and until you get it right, there's no point in going further with your scenario.
I wrote "the vehicle", not the prop blades.

ThinAirDesigns wrote:

While it's true that there is no relative motion between the surrounding airstream and the vehicle *chassis*, there is PLENTY of relative motion between the surrounding airstream and the *airfoils* of the vehicle. The airfoils are running at an angle to the wind the same as a sailboat's sail on a broad reach.

Once you get this straight, I'll be happy to continue and answer your questions.

JB
If you'll read what I wrote you will see that I had that straight from the beginning. Now please answer my questions.


[/quote]
BillRM
 
  1  
Reply Tue 13 Jul, 2010 06:46 pm
@ebrown p,
I will read why he had change his mind and go from there.

It is hard for some people to not grant great credit to claims that something had indeed work in front of witnesses even it all commonsense and all known laws of nature state otherwise. Even for some scientists that should know better.

Knowing a little bit about free energy hoaxes that had work out over the centuries it is however not hard for me to do so.

If you wish me to believed in something like the Blackbird you need to bring a mountain of proof that could not be fake in any way or in any manner.

So beyond NALSA report I would like some group that could not be involved in any possible hoax to build a similar craft and get similar results.

As I had said there been too must social engineering over this matter already but one thing is for sure the equations that were claimed by the Blackbird supporters to be simple and beyond question are not to a Noble prize scientist.





0 Replies
 
ThinAirDesigns
 
  1  
Reply Tue 13 Jul, 2010 06:48 pm
@BillRM,
Quote:
Yes Spork I can see why you would wish to run away from that fact.


ROFLAO!!

"run away"? ??? ??? That's Kaman, not us -- we bring his name up as often as we can.

We think it's HILARIOUS that a Nobel prize winning physics prof get's it wrong initially (no shame there) but once he figures out that it's real (and he has now) he runs away and makes now waffly comments.

His latest statement is pretty funny in it's fuzzyness.

JB
georgeob1
 
  1  
Reply Tue 13 Jul, 2010 06:48 pm
@georgeob1,
ThinAirDesigns wrote:

georgeob1:
Quote:
Let's imagine our vehicle (with a fixed mechanical connection between propeller and wheels, and a non steerable fixed pitch propeller) is on level ground with a tail wind and travelling at exactly the speed of the wind.

Ok

Quote:
In that situation there is zero relative motion between the surrounding airstream and the vehicle.


This is where you go wrong, and until you get it right, there's no point in going further with your scenario.
I wrote "the vehicle",not the prop blades. There IS NO relative motion between the airstream and the vehicle. Yes the propeller is turning at a speed proportional to the forward speed of the vehicle relative to the ground.

ThinAirDesigns wrote:

While it's true that there is no relative motion between the surrounding airstream and the vehicle *chassis*, there is PLENTY of relative motion between the surrounding airstream and the *airfoils* of the vehicle. The airfoils are running at an angle to the wind the same as a sailboat's sail on a broad reach.

Once you get this straight, I'll be happy to continue and answer your questions.

JB
If you'll read what I wrote you will see that I had that straight from the beginning.
In fact the propeller airfoils are running at an angle to the relative wind (in this condition) at an angle determine by the propeller blade's fixed pitch, since the only relative motion between blades and air is due to propeller rotation.

Now please answer my questions.



[/quote]
ThinAirDesigns
 
  1  
Reply Tue 13 Jul, 2010 06:54 pm
@georgeob1,
georgeob1:
Quote:
I wrote "the vehicle" ,not the prop blades.


Just so you know, the prop blades are part of the vehicle and thus your statement: "In that situation there is zero relative motion between the surrounding airstream and the vehicle." is false.

Quote:
If you'll read what I wrote you will see that I had that straight from the beginning


I've read what you wrote -- even posted it above, and it includes a false statement. Now, it's fine if you wish to correct that false statement -- we all make mistakes, but trying to pretend it's true when it's false isn't a good way forwards.

JB
georgeob1
 
  1  
Reply Tue 13 Jul, 2010 07:00 pm
@ThinAirDesigns,
Now you are quibbling and being evasively pedantic. At a apeed over the ground equal to the speed of the trailing wind an anamometer mounted on the vehicle would register zero relative wind speed - even though the propeller is indeed turning.. There would be no forces acting on the vehicle other than gravity and those I listed in my original post.

Now please answer the questions.
sirclicksalot
 
  3  
Reply Tue 13 Jul, 2010 07:06 pm
@BillRM,
Quote:
experts in physics one with Noble prizes are stating the same thing I had been

Same as you, inferring some sort of intelligence by association? I don't think so. They are wrong because they made the wrong assumptions and came to the wrong conclusion using the right methods; once they straighten out their assumptions they will come to the right conclusion. You, on the other hand, haven't a clue as to what the right methods are even though you have been handed the right assumptions on a platter. So there is no possibility for you to actually understand why it would work or not work.

Inferring they are the same in any way as you is like saying the person waiting at the stop light and the drunk that rear ended him are the same because they both had an accident.

Quote:
[...] I am still betting it is far more likely then not that this is a hoax.

That is not literal betting of course, because you do not know, and you have know way of knowing, whether it is a hoax. Spork and many others will literally bet you any amount of money you like at odds of at least 10:1. That's the only way he will ever make any money off of this.

Your continued denigration of the ThinAirDesign team is both willful and ignorant, and therefore also shameful.
0 Replies
 
ThinAirDesigns
 
  1  
Reply Tue 13 Jul, 2010 07:08 pm
@georgeob1,
Quote:
In fact the propeller airfoils are running at an angle to the relative wind (in this condition) at an angle determine by the propeller blade's fixed pitch, since the only relative motion between blades and air is due to propeller rotation.


That may be another true statement or false statement (currently, I suspect false), but it's just a bit convoluted for me to know for sure.

The last part is certainly true - at wind speed, the propeller rotation is indeed responsible for 100% of the relative airflow.

The first part is suspect -- but it depends on how you are using the term "running at an angle". The *angle of attack* (AOA) is most definitely determined by the pitch of the prop, but what most folks would consider the "running angle" (the angle at which the blade moves *through* the air) is most definitely NOT determined by the pitch of the prop.

Quote:
Now please answer my questions.


Please make your statements accurate.

I really AM willing to answer your questions, but truly we have to have some agreement as to what your statements actually mean before I can accurately address them.

JB
0 Replies
 
ThinAirDesigns
 
  1  
Reply Tue 13 Jul, 2010 07:12 pm
@georgeob1,
Quote:
Now you are quibbling and being evasively pedantic.


Nonsense -- this is science, not philosophy. Debates *often* are simply caused by a lack of definition. What you call 'running angle' someone else may call AOA and since they can be two different things, it pays to get on the same page.

JB

0 Replies
 
parados
 
  1  
Reply Tue 13 Jul, 2010 07:14 pm
@georgeob1,
george,

I'm not sure if you realize that the prop is acting as a prop and pulling the vehicle forward just as the prop does on your plane. The only difference is they are using the rolling wheels instead of an engine to turn their propeller.

So all they need is the energy from the wind pushing forward to be used efficiently enough to add the propeller's thrust to get more forward motion.
0 Replies
 
ThinAirDesigns
 
  1  
Reply Tue 13 Jul, 2010 07:19 pm
@georgeob1,
Quote:
Now please answer the questions.


To be fair, I can only find one question and it was answered quite well TWICE before I addressed you.

Quote:
How much faster than the wing speed (in percent) is it claimed this thing can go?


Several of these devices have been discussed on this thread. Since you don't seem to like the answers you were already given (which were related to the vehicle in the OP), are you asking about any one in particular, or are you asking what is the *theoretical* upper bound on top speed of a device of this design?

JB

0 Replies
 
 

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