Recent content by guest1
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Undergrad Minimum force to keep a mass floating in the air
Hmm..Ok, I think I get it now (and it bears out mine and a colleague's calculations prior to posting this thread) Flow rate and velocity imparted on the air should be linked for rotors of constant size - so possibly there is a fixed relation to power if we stipulate a certain area and that the... -
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Undergrad Minimum force to keep a mass floating in the air
Somehow I can't really believe that. If you make the rotorblades on a helicopter wider then you can turn it slower but the amount of air you need to shove downwards remains the same. You need to continually shove some air downwards or your object will fall. You can't reduce that to zero. Moving... -
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Undergrad Minimum force to keep a mass floating in the air
The point was: pure vertical thrust. no wings. no horizontal component. no balloon. There has to be some way to calculate the minimum impulse I need to impart on air (or the amount and speed of reactive mass) in order to keep station? -
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Undergrad Force Required to Accelerate M2 w/ Equal Masses M1 & M2
scratch that...brain failure -
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Undergrad Minimum force to keep a mass floating in the air
Sort of. I was simply wondering whether there is a lower limit for the power needed to generate the kind of thrust which would allow a certain mass to remain stationary in the air (or lift off infinitely slowly). I'm specifically talking about thrust here not any sort of buoyancy or lift... -
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Undergrad Minimum force to keep a mass floating in the air
I know that one could lift the mass (theoretically) infinitely slowly using a 0.0001W source. But in reality that just doesn't work (if you attach it to a string and pull it upwards with such a power source it would lift off the floor but I'm talking about flying contraptions here) You can... -
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Undergrad Minimum force to keep a mass floating in the air
Zero is what I get, too - but that's not a real useful answer. The question came about like this: Let's say I want to build some sort of flying contraption that is able to lift the mass of 1kg into the air. What would be the lowest power energy source I would need for this (in the absence of... -
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Undergrad Minimum force to keep a mass floating in the air
This is bugging me and maybe someon can help me find the obvious mistake: I want to calculate the minimum power needed to keep a mass of 1 kg floating in mid air. The naive approach is this: The mass falls 5 meters in one second so to get to the original position I have to invest an...