The swash plate used in helicopters is a fundamental mechanical component that controls the helicopter's rotor system. The swash plate changes the angle of the rotor blades to control the helicopter's flight direction and movements. Its function is to transfer the inputs from the pilot's control stick to the rotor disk.

In helicopters, lift is generated by rotors that rotate, powered by one or more engines, moving in a horizontal plane. These rotors are called main rotor blades. The lift force is created as the main rotor moves through the air by rotating. As the main rotor turns around its axis, the helicopter itself attempts to rotate in the opposite direction of the main rotor's rotation. This is called the torque reaction. The tail rotors counteract this torque reaction created by the main rotor, keeping the helicopter stable. In helicopters without a tail rotor and with dual main rotors, the rotors rotate in opposite directions to balance the torque created by each other. Each blade in the main rotor shares the generated lift force equally. The blades must also carry the dynamic loads that occur during helicopter flight, in addition to the static weight of the helicopter. Therefore, large helicopters used for load-bearing typically have four or more main rotor blades. The same principle applies to the tail rotor blades, and when the main rotor blade count is high, the number of tail rotor blades increases accordingly. The excess number of tail rotor blades is due to the need to counterbalance the torque generated by the main rotor.

The swash plate is typically made from lightweight and durable materials like high-strength steel, aluminum, or titanium and consists of two main parts:

• Fixed Plate: Mounted to the body and does not rotate. It receives the movements from the pilot's control sticks.
• Rotating Plate: Rotates with the rotor shaft. It transfers the motion received from the fixed plate to the rotor blades.

Swash Plate Operating Principle

• Collective Pitch Control: Both plates of the swash plate move up or down together. This movement changes the angle of all the blades equally, allowing for vertical movements such as takeoff or landing.
• Cyclic Pitch Control: The fixed plate tilts, causing motion to the rotating plate. This causes the rotor disk to tilt, which results in forward, backward, rightward, or leftward movement of the helicopter.

The swash plate is a critical component in helicopter design. In advanced models, more precise control is achieved using electromechanical actuators or fly-by-wire systems.