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

--- Quote from: Alex Eisenhut on December 24, 2021, 01:55:57 am ---
By stored energy, ie the kinetic energy of the moving vehicle as it moves up to wind speed. It never experiences a relative zero wind speed as it approaches wind speed, as the propeller is always blowing backwards. It will reach some sort of equilibrium state but wind is not that steady.

The kinetic energy of the vehicle is being drained by the propeller contraption, luckily, the wind keeps blowing, much like this thread.

Here's the main question; you surely consider yourself deeply scientific: so, for a theory to be scientific it must be falsifiable. What evidence would you accept to show your theory is false?

https://en.wikipedia.org/wiki/Falsifiability

--- End quote ---

Blackbird continues to accelerate after it exceeds wind speed meaning kinetic energy of the vehicle continues to increase thus it can not be the one powering the vehicle at that stage.

It is quite easy. Show that vehicle acceleration rate continues to increase instead of decreasing or show that vehicle can maintain speed after there no longer is any acceleration.
It is super clear that acceleration rate drops it can be easily measured and is observed on both the large blackbird and the treadmill model.
Since that drops it will get to zero acceleration that will be the point where I say the vehicle will start to slow down while you claim it will continue to stay at that speed.

But all the theoretical analysis like Derek's (vehicle speed - wind speed) will predict increased rate of acceleration and that is just never observed or measured in any real test.
So there is not even the need for any other test than the ones already performed to show that the equations Derek and others claim to express how this vehicle works are not matching reality.
electrodacus:

--- Quote from: thm_w on December 24, 2021, 02:02:59 am ---
--- Quote from: electrodacus on December 23, 2021, 06:33:24 pm ---Yes that bicycle calculator is incorrect (you are not the only one to get this wrong so that includes those people that did the calculator)
That calculator will say you can drive at 1km/h in 230km/h headwind with just 300W (easy for a cyclist)
This is maybe 80km/h no where near 230km/h and here is what happens
youtube.com/watch?v=IoX-JUPvrwo

--- End quote ---

That is not "maybe 80km/h", it says in the article "over 100km/h". How would you possibly stay upright?
and how would you stay upright traveling at 1km/h?

--- End quote ---

What you see in the video is about 80km/h at most. The article probably mentioned peak gust speed as they like to exaggerate as much as possible. I live in a windy area and we get fairly frequent 60km/h with 80km/h gusts and the max I ever seen here was 110km/h gusts.

But irrelevant of the speed 80 or 100km/h the bicycle calculator claims 300W is just enough power to drive at 1km/h in 230km/h winds and that is order of magnitude higher power than needed for even 100km/h.
Each 2x increase in wind speed increases the wind power by 8x
fourfathom:

--- Quote from: electrodacus on December 24, 2021, 02:05:15 am ---But all the theoretical analysis like Derek's (vehicle speed - wind speed) will predict increased rate of acceleration and that is just never observed or measured in any real test.
So there is not even the need for any other test than the ones already performed to show that the equations Derek and others claim to express how this vehicle works are not matching reality.

--- End quote ---

The geared-wheel and the pulled-yo-yo models don't predict continuous acceleration.  They show downwind travel at some fixed multiple of windspeed.  Once they accelerate to that speed they will remain at that speed.
electrodacus:

--- Quote from: fourfathom on December 24, 2021, 02:14:18 am ---
The geared-wheel and the pulled-yo-yo models don't predict continuous acceleration.  They show downwind travel at some fixed multiple of windspeed.  Once they accelerate to that speed they will remain at that speed.

--- End quote ---

Again (I repeated this many times) but none of the wheels only vehicles can demonstrate direct down wind only direct upwind equivalent. You are just confusing the input of the vehicle with the output.
On Blackbird direct downwind the input is the wind + pressure differential pushing the vehicle up to wind speed then above that is just the pressure differential that pushes the vehicle.
On direct upwind the wind is always powering the vehicle but vehicle works in short charge discharge cycles not continues and that is exactly how all wheels only toys work (all of them) as there is no pressure differential since air (compressible fluid) is not involved there.
fourfathom:

--- Quote from: electrodacus on December 24, 2021, 02:25:27 am ---Again (I repeated this many times) [...]

--- End quote ---

There are none so blind as those who will not see.
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