swashplate

A swashplate is a mechanical assembly used in rotorcraft to translate pilot or control system inputs into controlled changes in rotor blade pitch. It typically consists of two concentric plates: a stationary lower swashplate attached to the rotor mast and a rotating upper swashplate connected to the blade pitch links.

The lower, non-rotating plate receives cyclic and collective inputs through pushrods or control arms. Through a bearing stack, this motion is transferred to the upper, rotating plate, which spins with the rotor while maintaining the same tilt relative to the mast. A set of blade pitch links runs from the upper swashplate to the individual blade pitch horns. As the lower plate tilts and moves up or down, these links adjust each blade’s pitch, producing cyclic pitch changes as the blades rotate and, simultaneously, collective pitch changes to alter overall lift.

In typical helicopter and many RC-model configurations, the swashplate arrangement allows two types of control: cyclic control, which tilts the rotor disk to steer the craft, and collective control, which changes the pitch of all blades to increase or decrease lift. The system enables coordinated, rapid changes in blade pitch without twisting the rotor shaft, and it requires precision alignment and low-friction bearings to minimize play and wear.

Variations exist, but the common design uses a stationary lower plate driven by the control system and a rotating upper plate that transmits pitch changes to the blades through multiple links. The swashplate is a central element of rotorcraft flight control, balancing responsiveness, stability, and mechanical complexity.