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Mess with your minds: A wind powered craft going faster than a tail wind speed.
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fourfathom:

--- Quote from: Psi on September 19, 2021, 03:56:31 am ---It seems that most peoples arguments against the results of blackbird are that the wind was going faster than stated.
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All I needed to see was the wind indicator telltale (like we have on sailboats).  Blackbird and other craft have ribbons or something similar and they have shown the ribbons streaming backwards for extended periods of time.  This shows, without question, that the craft is moving downwind faster than the wind. 

Yes, there is windspeed differential (slower closer to the ground) and the relatively low placement of the telltale on Blackbird isn't ideal.  But I've seen videos of similar craft with multiple wind indicators above and below the propeller radius.  These also stream backwards.
fourfathom:

--- Quote from: electrodacus on September 19, 2021, 01:16:33 am ---
--- Quote from: fourfathom on September 19, 2021, 12:02:08 am ---Here's a demonstration I like (most have probably already seen it), and it's pretty similar to the moving paper test.  In this one the upper board represents the wind, and the floor represents the ground, so there's no reference frame issue.  And there's no energy storage, and it can continue, faster than the "wind", forever.

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That demonstration is wrongly interpreted.
The floor is the wind and the vehicle travels on the moving lumber.
Small wheels are the generator wheels and the large wheel is the motor wheel. Please look closer to understand how that works.
So what is shown there is a vehicle traveling at about 2.8x lower speed on the lumber (road) powered by the floor (wind) in the opposite direction.

--- End quote ---

And I say you are the one misinterpreting the demonstration.  The floor is the ground and the board is the wind.
electrodacus:

--- Quote from: Psi on September 19, 2021, 03:56:31 am ---A good demo might be

- Toroidal pipe, maybe 4inch diameter and 1m toroid radius.
- Angled air in/out tubes to get known air flow moving around the tube.
- Small cart with propeller and ball bearing wheels touching 3 or 4 sides of the tube. (so it can move freely around the toroid)
- Could test with water or air flowing around the tube, water might make coupling/gearing easier to show the effect.
- The relationship of air flow into tube and speed of cart around toroid should be very different if the effect happens vs does not happen.

It seems that most peoples arguments against the results of blackbird are that the wind was going faster than stated.
So this would allow windspeed to be known/measurable

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I have no doubt that blackbird exceeded wind speed and it did so with sufficient margins not be be a measurement error.
If you replace air with water then it will no longer work as air is a compressible medium and that is how energy is stored and without energy storage vehicle can not exceed water speed as water is not compressible.
electrodacus:

--- Quote from: fourfathom on September 19, 2021, 04:29:45 am ---And I say you are the one misinterpreting the demonstration.  The floor is the ground and the board is the wind.

--- End quote ---

You say I misinterpret the demo based on what ?
The small wheels in contact with the floor are the generator wheels and they power the motor wheel witch is the large wheel that drives on the lumber at about 2.8x lower speed than floor and opposite to floor moving direction.

Only one interpretation can be correct and it the the one I mentioned.
Labrat101:
The ribbon at the front faced backward during the test so even if the wind speed did increase wouldn't make any difference.
When the ribbon indicator move from facing forward to backward. Its going faster than tail wind speed.
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