How helicopter flies?

Answer 1

First you need to understand lift and how it is generated. If you do a Google image search for "airfoil" you can see what it looks like. The top has a curve to it and the bottem is flat. As the airfoil passes through the air, lets say at a speed of 1, the air going over the top of the airfoil must travel at a higher rate of speed, maybe 1.5, that the air giong under the flat bottem. This is known as Bernoulli's Principle or lift. Now, if you take 2 or more long thin airfoils or blades and attach them to a center mast and provide a means for them to tilt and twist you have a basic rotor head of a helicopter. As the blades are spun through the air they create lift, much like if you have your hand out the car window. If you incrase the pitch of the blades by twisting them so the front edge goes up you get more lift and the helicopter goes up. If you tilt the blades to the left, fore example the helicopter will go left. Everything has an equal and opposite reaction. In this case if you turn the rotor blades to the left or counter clockwise the body of the helicopter (fusealage) will want to turn to the right. This is where the tail rotor comes into play. It pushes air to the left to keep the fusealage from turning. If you want to turn the helicopter to the left then you would incrase the pitch of the tail rotor blades to over come the twisting force of the helicopter. To turn to the right you would reduce the pitch of the tail rotor blades and let the helicopter twist agians the main rotor.