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Electroboom: How Right IS Veritasium?! Don't Electrons Push Each Other??
electrodacus:
--- Quote from: dunkemhigh on July 07, 2022, 06:04:16 pm ---
--- Quote ---Power out can not be larger than power in without energy storage being involved
--- End quote ---
It is only you that suggests there is more power out than in, and you're no doubt only doing that so you can wheezle in your favourite energy storage rubbish. At least a stuck record would eventually wear out...
--- End quote ---
When you say that power taken at the wheel make sense as you out that power in to propeller.
You slow down the vehicle when you extract power at the wheel and if you where to put the exact same amount of power at the propeller there is no gain so it will not make sense to do that.
Wind can provide power to vehicle only when vehicle speed is lower than wind speed and if you say get 100W at some point from wind and you steal 40W at the wheel to put ideal case 40W in to propeller for propulsion you still have net 100W so you do nothing.
a) Vehicle can be accelerated by all 100W from wind.
b) Vehicle can be accelerated by 60W from wind + 40W you take at the wheels and put all in propeller still 100W ideal case.
So please let me know if you disagree with b) then let me know how it works without involving energy storage and without violating the energy conservation law.
PlainName:
--- Quote ---You slow down the vehicle when you extract power at the wheel and if you where to put the exact same amount of power at the propeller there is no gain so it will not make sense to do that.
--- End quote ---
How do you know? Have you done the sums? I know you haven't because a) they're not simple and b) you reject the only equation that makes sense (for no good reason - what, exactly, is wrong with it? You won't say, other than something something too big something).
PlainName:
--- Quote ---b) Vehicle can be accelerated by 60W from wind + 40W you take at the wheels and put all in propeller still 100W ideal case.
--- End quote ---
Wrong, sorry.
It takes almost nothing to maintain speed. It doesn't take 60W to accelerate - it takes whatever is available over the practically nothing that maintains speed. There is no drag the normal speed vs power curves you might want to consult are not relevant.
And you don't take 40W or whatever from the wheel - just a bit more than the practically nothing that maintains speed would be fine. So we are looking at maybe 5% being taken via the wheel, and whatever slower speed relates to 5% less power from the direct wind. If you want 100% to be 100W I'm sure you can do the maths. (Actually, it could be anything from 0.001% to 99.9% - solving the equation would tell you what value, if there is a working value, would do the biz.)
And that is it. The question is whether that 5% of power can produce thrust that at least equals the lost speed due to 5% less direct wind power. But recall that most of the power is used in accelerating up to speed, so the reduction may not be very much at all.
Forget your 100/60/40 splits - that might be appropriate when the thing is stationary but not when it is in full flight.
SiliconWizard:
So. Have we revolutionized EE yet? :popcorn:
electrodacus:
--- Quote from: dunkemhigh on July 07, 2022, 08:16:00 pm ---
--- Quote ---b) Vehicle can be accelerated by 60W from wind + 40W you take at the wheels and put all in propeller still 100W ideal case.
--- End quote ---
Wrong, sorry.
It takes almost nothing to maintain speed. It doesn't take 60W to accelerate - it takes whatever is available over the practically nothing that maintains speed. There is no drag the normal speed vs power curves you might want to consult are not relevant.
And you don't take 40W or whatever from the wheel - just a bit more than the practically nothing that maintains speed would be fine. So we are looking at maybe 5% being taken via the wheel, and whatever slower speed relates to 5% less power from the direct wind. If you want 100% to be 100W I'm sure you can do the maths. (Actually, it could be anything from 0.001% to 99.9% - solving the equation would tell you what value, if there is a working value, would do the biz.)
And that is it. The question is whether that 5% of power can produce thrust that at least equals the lost speed due to 5% less direct wind power. But recall that most of the power is used in accelerating up to speed, so the reduction may not be very much at all.
Forget your 100/60/40 splits - that might be appropriate when the thing is stationary but not when it is in full flight.
--- End quote ---
Thanks for answering.
Ideal case you need no energy to maintain speed.
But to accelerate the vehicle you need energy.
You have some wind power available to vehicle depending on wind speed relative to vehicle (wind speed - vehicle speed) and equivalent surface area of the vehicle on witch wind interacts with.
I just gave an example of 100W available from wind to vehicle.
All this 100W will accelerate the vehicle. If you take anything at the wheel I gave 40W as an example then only 60W are available for vehicle acceleration so acceleration rate will be lower. If you then use the 40W at the propeller ideal case you get back to 100W of acceleration power but nothing more.
I will like to know exactly what part you disagree with but to me it seems that you think taking 40W at the wheel will not reduce the available acceleration by exactly that amount.
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