Textron Inc.
Differential Rotor Speed Resonance Avoidance System

Abstract:

An aircraft having a differential rotor speed resonance avoidance system. The aircraft includes an airframe having structural elements subject to resonant vibration at critical frequencies. A thrust array is coupled to the airframe. The thrust array includes at least four rotor systems distributed about the airframe, each rotor system operable over a range of rotor speeds. A flight control system is operably associated with the thrust array and is configured to independently control the rotor speed of each rotor system. While preserving flight dynamics during flight operations, the flight control system selectively increases the rotor speed of some of the rotor systems by a speed delta and decreases the rotor speed of others of the rotor systems by the speed delta to avoid generating excitation frequencies by the rotor systems at the critical frequencies.