Helicopters are popular and most widely used flying machines that can take off vertically and fly in any direction in accordance to wills/desire of pilot in command. The design of helicopter was formulated for the first time by Leonardo Da Vinci but was limited to theory only and failed in real life. Later on, Russian- Born Igor Sikorsky invented the realistic and practical design of helicopter and was able to takeoff from the ground that wrote his name in golden page history. At present, the helicopters are used in several fields such as : military, Transportation, Rescue operations and so on.
How does a helicopter fly?
Helicopter is the flying machine which comprises of rotor blades. Some helicopters have one main rotor and another tail rotor whereas some have dual rotor that rotates in opposite direction to each other so that there is not need of tail rotor. Let’s talk about general helicopters having Main Rotor and Tail Rotor. When the rotor blades start to rotate and pilot starts to increase the pitch by pulling collective lever of helicopter then, the air flow around the airfoil in such a way that the pressure above the airfoil is low and below are high. As we know, air flows from high pressure to low pressure similarly, the air flowing below the airfoil starts to provide upward force known as lift. Thus, the helicopter lifts from the ground. For the forward, backward, sidewards flight there is cyclic stick in helicopter which is controlled by pilot. When pilot moves cyclic forward then connecting rods of swash plate pushes the plate to forward tilted position so that helicopter moves forward. For backward flight, pilot pulls cyclic stick such that the connecting rods tilt the swash plate in backward position. Similarly, for sidewards movement, pilot pushes cyclic left or right so that swash plate tilts in sidewards position so helicopter moves sidewards.
Tail rotor and its uses in helicopter.
Helicopters are equipped with tail rotor. Tail rotor is small rotating blades mounted in the end of back of the helicopter which is controlled by anti torque pedals. When main rotor starts to rotate, tail rotor also rotates in order to overcome the torque created by main rotor which tries to rotate the fuselage of helicopter in opposite direction. So, tail rotor is also known as anti torque rotor.