You sure does Humber. You just keeps working around stuff, there ya go, easy fella.
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Merged DDWFTTW in a “Real” Wind
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You sure does Humber. You just keeps working around stuff, there ya go, easy fella.
ThinAirDesigns
Graduate Poster
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The motion of an object is defined by its centre of mass. That moves ddw.
The centre of mass of a tacking boat does not move ddw.
Mark Drela, a supposed supporter of ddwfftw, has written many papers on propellers and not one of them mentions the idea of tacking. He is not alone.
It's your assumptions. I could do it another way. Load cells are electrical.
I could arrange for the way they are stacked to operate hidden switches,
and then spin you a yarn.
Similarly, by trial and error, I could find out how to keep the cart on the TM, and then spin you a yarn about Galileo. One may be intentional, and the other through ignorance.
There are many cases where the relative air is zero, so that alone is not enough to claim the TM is like windspeed. Supporting evidence would be needed to separate one possibility from the other. I have calculated the force, and it is negligible, and you can test that yourself. That rules out the windspeed claim.
Michael C
Graduate Poster
The extraordinary "stacked scales" theory started out on TalkRational. Yevgheni (the other staunch opponent of the downwind cart, who posted here as "Christoph"), was desperately trying to find reasons why the cart on the treadmill could act differently to the cart on the road. He came up with the idea that the normal force on a treadmill would be less than that on the road. He even claimed to have tested this idea himself with bathroom scales. I explained to him that there is no way that the normal force could be different, and gave him the reference of the New Scientist article to show how the accuracy of bathroom scales can be affected by the surface they are placed on.
Humber jumped in to tell us that if you put one set of scales on top of another, each will read half because "the displacement of the spring is divided between the two":
http://talkrational.org/showthread.php?p=1189410#post1189410
It's worth reading some of the discussion from that post onwards, to see some really weird bits of the humberverse. From the way humber is now acting it's pretty clear that he's realised that his simple statement that "each will read half" was a mistake, but he's never, ever going to admit it.
Instead, he now claims that it is possible to make the scales do that, but it's "far from simple" to achieve. But he's not going to show us how to achieve this effect, because he is obviously incapable of making it happen.
Jack by the hedge
Safely Ignored
Sometimes an approximation simplifies a calculation, but sometimes it ignores vital information.
In this case, confronted with the fact that any point on the blades of the propeller does not follow a simple DDW path, your reaction is to say "ignore that". You have zero justification for doing so and any conclusions you base on doing so are garbage.
Right. He is right. It's not about the scales.
It was to show Uncool that his world of spherical cows, may not be all there is. The process may involve;
http://en.wikipedia.org/wiki/Socratic_method
What you make of that, is no concern of mine, but uncool has good math talent.
There is a certain irony that you use stuffed childrens' toys to peddle your nescience.
ETA:
Cotton reels in the 21st Century. A reel rolls 6" with each turn. Pull on the thread so there is tension. Leave the hand where it is and move, but do not roll the reel 6" towards the hand.
How much slack thread do you have? Doh.
Wheels involve both linear and angular motion. By your own "Galilean Transforms", the linear motion of the belt in opposition to the linear motion of cart's wheel, cancels out the linear motion, leaving only the angular.
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Jack by the hedge
Safely Ignored
Thanks. I think that clears the matter up - humber did make a basic error and can't admit it.
I do not think you are lying, I know you are lying. A double lie actually since you also said that others have not tested it.
Funny stuff Humber. Why don't you have someone help you test your theory. A baseball bat might help too. Hint: Wear a helmet.
I assume you think the shape of a propeller has no affect whatsoever, it could be completely flat and it would have the identical thrust performance, correct?
That's why the cart uses a propeller.
His papers all mention the idea of tacking, just as all other texts about props do. It is not explicit because the word tacking is from sailing and because it is completely obvious. Show me a text book on stochastic analysis which mentions the idea of addition or defines the + sign.
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Others NOT tested it?
This is another lie. I told you I have repeated the test. I told you the results.
http://www.rcgroups.com/forums/showthread.php?t=1077012
Utter fabrication. Post one.
Confabulation. Post one.
Oh, that's a good one. Physics book do not explicitly state that faeries do not exist.
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Oh, my, thanks for the link. It appears he wasn't claiming any connection back then between the article and stacking scales, but now perhaps thinks there is.
Clarify Humber, was your link meant as a yes answer to the question that the shape of a prop is irrelevant?
http://en.wikipedia.org/wiki/Blade_pitch
Now you're getting it.
What do you mean by "the solution is far from simple"? It sounds very simple here:
http://talkrational.org/showthread.php?p=1189410#post1189410
humber said:
http://www.rcgroups.com/forums/showthread.php?t=1077012
And how it thrust calculated By Spork in the submission?
Thrust = Shaft Power/Velocity
Shaft power = whatever is left of the generator power after losses
Velocity = Vp, the velocity of the headwind.
And how it thrust calculated By Spork in the submission?
Thrust = Shaft Power/Velocity
Shaft power = whatever is left of the generator power after losses
Velocity = Vp, the velocity of the headwind.
Oh, so slowly grasping at the remaining straws. I have repeatedly asked you not to re-post my drawings.
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And how it thrust calculated By Spork in the submission?
Thrust = Shaft Power/Velocity
Shaft power = whatever is left of the generator power after losses
Velocity = Vp, the velocity of the headwind.
And where is the mention of a tacking force?
And the paper by Dr Drela?
I tell you what I am getting. That the cart, the TM and the trial are as fabricated as your claims.
There is no tacking force associated with a propeller.
EHocking
Penultimate Amazing
yes, I've found that electricity from nuclear power plants heat up an equipment room faster than electricity from hydro-electric schemes. Must be the water-cooling potential of the hydro.
No, I was just asking if this is the "far from simple" solution:
http://talkrational.org/showthread.php?p=1189410#post1189410
humber said:
It doesn't sound "far from simple" to me. But the question is: does it work?
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