Dynamic rotor-phasing unit

A dynamic rotor-phasing unit can phase rotors in-flight for dynamic rotor tuning and in an idle state for aircraft storage. The input and output shafts can be clocked (e.g., rotated) from 0 degrees apart to in excess of 360 degrees apart or from 0 degrees apart to 140 degrees apart. Such rotation can minimize the footprint of an aircraft for stowing purposes, as the rotor blades can be folded to fit within a smaller area without disconnecting the drive system. Additionally, the unit can allow tiltrotor blades to be clocked during flight, which can allow the live-tuning of the aircraft's rotor dynamics. A fail-safe rotary actuator can rotate a stationary planet carrier to clock the input shaft and the output shaft. Alternatively, an actuator can position a slider housing to clock the input shaft and the output shaft.