Helicopters: How Do They Fly? How Does It Works ?
Helicopters fly using the same aerodynamic concepts that airplanes use; they use an airfoil to generate lift. The difference is that helicopters generate vertical thrust while aircraft generate horizontal thrust. When an airplane moves forward, the air flows across the wing and produces downwash which creates lift; the airplane has to gain enough speed for this force to overcome weight. When helicopter blades, or airfoils, begin spinning, it produces downwash which then creates lift. Speed is an important factor in generating enough force to overcome the weight in a helicopter as well. Vertical thrust allows a helicopter to take off vertically and hover.
The upper swashplate and the rotor blade system is attached to the rotor shaft, or mast, and they all begin rotating at the same time. A helicopter is controlled by the pilot with a collective, cyclic, two pedals, and the throttle. The collective is used to control the swashplate, which adjusts the blade pitch equally. A swashplate has two plates: one rotates with the rotor and one is fixed. A bearing is between the two plates. The upper plate is connected to the blades with a pitch change arm. The lower plate is connected to hydraulic servos which can raise, lower, or tilt the plate. Once this occurs, the pitch of the blades shift.