US 11,858,621 B2
Harmonic control actuator for aircraft
William A. Welsh, North Haven, CT (US); and Jason A. Satira, Derby, CT (US)
Assigned to Lockheed Martin Corporation, Bethesda, MD (US)
Filed by Lockheed Martin Corporation, Bethesda, MD (US)
Filed on Jan. 24, 2022, as Appl. No. 17/582,853.
Prior Publication US 2023/0286648 A1, Sep. 14, 2023
Int. Cl. B63H 5/08 (2006.01); B64C 27/605 (2006.01); B64C 27/64 (2006.01); F16H 1/32 (2006.01); B64C 27/12 (2006.01); B64D 45/00 (2006.01)
CPC B64C 27/605 (2013.01) [B64C 27/12 (2013.01); B64C 27/64 (2013.01); F16H 1/32 (2013.01); B64D 2045/0085 (2013.01); F16H 2001/323 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A rotary blade aircraft comprising:
an airframe;
a rotor shaft driven about a rotor axis relative to the airframe;
a plurality of rotor blades coupled to the rotor shaft to be driven by the rotor shaft about the rotor axis, each rotor blade having a longitudinal axis;
a swashplate assembly coupled to the plurality of rotor blades, the swashplate assembly operable to move the plurality of rotor blades about the respective longitudinal axis;
a hydraulic control servo coupled between the airframe and the swashplate assembly, the hydraulic control servo operable to move the swashplate assembly relative to the rotor axis; and
a harmonic control actuator coupled between the airframe and the swashplate assembly, the harmonic control actuator operable independently relative to the hydraulic control servo to move the swashplate assembly relative to the rotor axis to reduce vibration at selected frequencies in the airframe.