As the title says, why do Hueys have 2 blades, while most others have 4, or the Sea Stallion has 6? And if you put 6 on a 4, does that mean more lift and better performance?
In: 490
Short answer; weight, more blades mean more thrust, but more expense to build and maintain and more weight that needs to be moved around, costing fuel.
Long answer; fewer blades are desirable as they generate less drag and have less weight. Ideally a helicopter would use only one blade, but imaging a single blade spinning at high speed and you can probably see the issues that would create
As the weight of a helicopter goes up, the speed at which a set of rotors must be spun goes up. Wind resistance goes up with the square of the speed with which something is going through the air, so higher rotation speed mean exponentially more energy spent to spin them. This becomes far worse as the tips of the blades approach the speed of sound.
After some speed, as determined by the engineer, it becomes more practical to add more blades and reduce the rotation speed accordingly
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