When carrying the brief case, you do the work, not the handle.
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Merged DDWFTTW in a “Real” Wind
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When carrying the brief case, you do the work, not the handle.
So many posts, in such a short time. Those two charts really show how you have all been duped.
Despite the obvious fraud, you continue to support the claim, so are now knowingly and willingly being duped.
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The handle tension in it, so no work is done by the handle. The person moving the briefcase does all the work. Spork is wrong again, when he states that the work on the magnets or chains of the truck do work according to the FOR.
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Afraid that you do. The x axis represents 0 degrees between the cart and the wind. It is quite clear that the cart's performance suffers as the difference approaches zero, so ddw, and then improves when that difference increases.
There are many such examples, and even larger changes in wind direction.
The record is a complete and utter fraud.
A very interesting display of cult mentality in the face of direct refutation.
What I think he is saying is something like "you can't fill up a swimming pool with a garden hose because the pool holds more water than the hose can hold." He's forgetting that the hose is continually supplying water.
-- Roger
Afraid not, You labeled the data as true wind direction. 0 would represent the reference direction, if consistent with the record run, that direction is due East.
There is nothing on that chart indicating cart direction.
Yes there is, but you are unaware of what that is, and no matter what offset you would hope to assign to save face,the cart gets worse when the difference falls and improves when it increases. There are trials where that process repeats, and the cart fails completely. The record is an absolute and deliberate fraud, and that is obvious to all rational people.
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CORed
Penultimate Amazing
(bolding mine)
OMG! This is scandalous. The wind shifted after the trial was over, which of course invalidates the trial. Why, I'll bet sometime in the week after the trial was terminated, the wind was blowing 180 degrees off. Congratulations humber, you've exposed the fraud.
Now that's entertainment. You've been slacking lately humber, but now you're coming up with the kind of absurdity I've come to expect from you.
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Not at all.
What you seem to be misunderstanding is that the mass being pushed doesn't matter. The "72 kg mass of air moving at 7 m/s" produces about 158N of force.
If you had a rocket motor that produced the same thrust as the propeller and you stuck the motor in the side of the moon, it could, given enough time, accelerate the moon by 9 m/s.
As long as the thrust of the propeller is great enough to overcome the drag and friction of the cart, it will accelerate the cart.
-- Roger
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No there isn't, and I am unaware of it because you do not show it.
tobermoryphil
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Humber- don't forget to show us exactly where Spork increased the pitch on the VP prop- that might just affect the acceleration.
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I've been playing with another propeller program called Prop. Designer, which is set up for larger, slower props, though the efficiencies are still 10% less than max theoretical.
I used spork's chord information, but letting the program set the pitch and cl, and using the Clark Y airfoil, I set up a specific theoretical prop for my "CrapBird".
I tried the prop that would match the performance in my example, but it wouldn't seem to go much faster than 9 m/s. So I changed the design point to match the best it could do in a 7 m/s wind, which for this dog was about 13 m/s, and calculated the net force for each .5 m/s faster than windspeed (this program doesn't do static thrust).
I also had to change the bottom sprocket to 27 teeth to get the right rpm, lots of design considerations I'm learning about.
Anyway, here it is with constant pitch:
Not even nearly a growing force predicted by theory. In fact, no where near constant either.
Here it is with an expert at the prop pitch control:
At least with adjustable pitch it can get through the null period.
I used spork's chord information, but letting the program set the pitch and cl, and using the Clark Y airfoil, I set up a specific theoretical prop for my "CrapBird".
I tried the prop that would match the performance in my example, but it wouldn't seem to go much faster than 9 m/s. So I changed the design point to match the best it could do in a 7 m/s wind, which for this dog was about 13 m/s, and calculated the net force for each .5 m/s faster than windspeed (this program doesn't do static thrust).
I also had to change the bottom sprocket to 27 teeth to get the right rpm, lots of design considerations I'm learning about.
Anyway, here it is with constant pitch:
Not even nearly a growing force predicted by theory. In fact, no where near constant either.
Here it is with an expert at the prop pitch control:
At least with adjustable pitch it can get through the null period.
Attachments
In your dreams, and it quite obviously fails no matter what. There are at least 10 other charts, so far found, that show the cart is poor when ddw. Mostly, the runs are total failures below and above WS. A rise in speed with the change in wind direction, that passes, so the cart bombs.
It's a scam. Learn from that.
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Playing. Good choice of word.
Jack by the hedge
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The problem, as I see it, is that if you insist on using the ground frame only, and you consider forces acting between objects which are all in motion relative to that frame, then things get a little bit more complicated than that.
Consider pushing an object across a table with a force of 1N and it moves away from you at a steady 1ms-1. There is a force of 1N acting on the object and it is travelling at 1ms-1 so the power applied is force x distance / time = 1 joule per second or 1 watt.
Now repeat the experiment on a train travelling at 50ms-1. The object is still experiencing a force of 1N but now it is travelling at 51ms-1. So how much power is being transferred to the object? 51 watts or 1 watt?
Obviously it's still 1 watt. So why is the calculation of force x distance now wrong?
The friction that opposes the movement of the object is from the tabletop, not the ground. So the relevant work done is against this friction and the force x distance calculation has to consider the distance travelled by the object relative to the table. To remain in the ground frame, you have to subtract its velocity from the object's velocity to get the right answer.
To calculate the energy transferred to the cart by a 160N push, you need to know what the mixture of counteracting forces are (torque at the wheels and drag through the air) and calculate the work done using the distance travelled relative to each.
Not true, as I have shown, the numbers balance perfectly well using 9 meters in all cases.
Except for the calculation of drag and thrust forces of course. but for energy in the ground frame, its those forces X 9
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It is pretty obvious that PPG argues from pure gut feeling, without understanding of physics. The mass of the cart "sounds much", so no matter what the math says, it "feels like" it cannot work, and that bothers him.
Funnily he now tries to convince himself that other people are equally bothered by it.
I have to hit my quota or spork won't pay me.
Really, I'm not even responding to all of your posts, so I think you still have me beat on a daily average basis. I could make a chart . . .
They show raw wind data that is consistent with a tornado or data that needs to be processed a bit more to gather any meaning from it.
I'm still hoping for tornado.
I did notice you didn't mention your imaginary cart in this response. Giving up on that claim, are you?
Jack by the hedge
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Well I suppose that if PPG decided that his hand was indeed applying 51 joules per second pushing the object across the tabletop in a train, but then calculated the frictional loss as if it were travelling at 51ms-1, his calculations would balance too. It wouldn't make him right.
Hmm. That comes across a bit more combative than intended. What I mean is - which bit's wrong?
I suspect profpangloss is making those posts for Dodge69's benefit, because he shows willingness to accept ideas, and asks relevant questions.
However, he need not do so for any reason other than that, because the trial data clearly shows the cart is a failure and deliberate deception.
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