why aren’t there human-piloted quad-rotors?
In: 11
the square-cube law and power to weight ratio. those little toy quads barely lift themselves, and the overwhelming majority of their weight is their own motors and a battery.
if you make it 5 times bigger, it’s gonna weigh 125 times as much *at least*, and motors don’t scale like that.
gasoline has a lot more energy for its weight than batteries, and turbine engines have much higher power at the size you need to move people around. the problem with gas power is that it’s a lot better to have 1 big engine than 4 smaller ones, and splitting mechanical power is dramatically more difficult.
you also encounter problems with control. quads steer by changing the speed of their rotors. for tiny plastic rotors with variable speed electric motors, that’s no big deal. bigger blades have more momentum. they don’t change speed as readily and experience a lot more stress when they do. gas powered engines also don’t like changing speed at all. which helicopters can change rotor speed, much of the control is actually done by changing the angle the blades hit the air.
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