Abstract: In an embodiment, an aircraft includes a drive system, a main engine coupled to the drive system to provide first power, and a supplemental engine coupled to the drive system to provide second power additive to the first power. The aircraft also includes a control system to control the main engine and the supplemental engine to optimize usage of the supplemental engine. The control system is operable to maintain the supplemental engine in a reduced power state at least until a determination is made that supplemental power is needed to satisfy a total power demand of the drive system. The control system is also operable to determine that supplemental power is needed to satisfy the total power demand of the drive system. The control system is further operable to increase a power level of the supplemental engine in response to the determination that supplemental power is needed.

Abstract: One embodiment includes a rotary aircraft, including: a main drive rotor; an aircraft body mechanically coupled to the main drive rotor; and first and second flight assist wings passively rotatably coupled to the aircraft body.

Abstract: An aircraft includes an airframe with first and second wings having a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. First and second yaw vanes extend aftwardly from the fuselage. A flight control system is configured to direct the thrust vector of the coaxial rotor system and control movements of the yaw vanes. In a VTOL orientation of the aircraft, differential operation of the yaw vanes and/or differential operations of first and second rotor assemblies of the coaxial rotor system provide yaw authority for the aircraft. In a biplane orientation of the aircraft, collective operation of the yaw vanes provides yaw authority for the aircraft.

Abstract: A rotor system for a rotorcraft includes a rotor hub having a plurality of blade grips coupled thereto. Each blade grip has a rotor blade coupled thereto. A fairing is disposed at least partially around the rotor hub. Each of a plurality of lead-lag dampers is coupled to at least a respective one of the blade grips. Each lead-lag damper has a damper heat exchanger and a fluid pump operably associated therewith. A fairing heat exchanger is in fluid communication with the damper heat exchangers and the fluid pumps. Each lead-lag damper is configured to drive the respective fluid pump responsive to damping operations to pump a cooling fluid from the respective damper heat exchanger to the fairing heat exchanger.

Abstract: A blade pitch adjustment mechanism includes a pitch cylinder having a first face and pitch slots extending longitudinally from the first face, a blade sleeve having a second face and a blade slot extending longitudinally from the second face, the blade sleeve is configured to be rotationally positioned in the pitch cylinder with the second face located with the first face, wherein the blade slot and the pitch slots are cooperative to form keyway, corresponding to a discrete blade pitch, when the blade slot is aligned with a pitch slot.

Abstract: A propulsion assembly for an aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The propulsion assembly includes a housing coupled to the fuselage of the aircraft. A coaxial rotor system includes a first rotor assembly and a second rotor assembly that are rotatable about a common axis of rotation. The first rotor assembly counter-rotates relative to the second rotor assembly. A motor assembly is operably associated with the coaxial rotor system. The motor assembly provides torque and rotational energy to the first rotor assembly and the second rotor assembly. A gimbal assembly couples the coaxial rotor system to the housing such that the coaxial rotor system is tiltable relative to the fuselage to generate a thrust vector.

Abstract: An aircraft includes an airframe with first and second wings having a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. Tail assemblies are coupled to wingtips of the first and second wings each having an elevon that collectively form a distributed array of elevons. A flight control system is configured to direct the thrust vector of the coaxial rotor system and to control movements of the elevons such that the elevons collectively provide pitch authority and differentially provide roll authority for the aircraft in the biplane orientation. In addition, when the flight control system detects an elevon fault, the flight control system is configured to perform corrective action responsive thereto at a distributed elevon level or at a coordinated distributed elevon and propulsion assembly level.

Abstract: An aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The aircraft has an airframe including first and second wings with a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. A flight control system is configured to direct the thrust vector. In the VTOL orientation, the first wing is forward of the fuselage, the second wing is aft of the fuselage and the coaxial rotor system is configured to provide thrust in line with a yaw axis of the aircraft. In the biplane orientation, the first wing is below the fuselage, the second wing is above the fuselage and the coaxial rotor system is configured to provide thrust in line with a roll axis of the aircraft.

Abstract: An aircraft includes an airframe with first and second wings having a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. First and second yaw vanes extend aftwardly from the fuselage. A flight control system is configured to direct the thrust vector of the coaxial rotor system and control movements of the yaw vanes. In a VTOL orientation of the aircraft, differential operation of the yaw vanes and/or differential operations of first and second rotor assemblies of the coaxial rotor system provide yaw authority for the aircraft. In a biplane orientation of the aircraft, collective operation of the yaw vanes provides yaw authority for the aircraft.

Abstract: A blade pitch adjustment mechanism includes a pitch cylinder having a first face and pitch slots extending longitudinally from the first face, a blade sleeve having a second face and a blade slot extending longitudinally from the second face, the blade sleeve is configured to be rotationally positioned in the pitch cylinder with the second face located with the first face, wherein the blade slot and the pitch slots are cooperative to form keyway, corresponding to a discrete blade pitch, when the blade slot is aligned with a pitch slot.

Abstract: A rotor system for a rotorcraft includes a rotor hub having a plurality of blade grips coupled thereto. Each blade grip has a rotor blade coupled thereto. A fairing is disposed at least partially around the rotor hub. Each of a plurality of lead-lag dampers is coupled to at least a respective one of the blade grips. Each lead-lag damper has a damper heat exchanger and a fluid pump operably associated therewith. A fairing heat exchanger is in fluid communication with the damper heat exchangers and the fluid pumps. Each lead-lag damper is configured to drive the respective fluid pump responsive to damping operations to pump a cooling fluid from the respective damper heat exchanger to the fairing heat exchanger.

Abstract: An aircraft includes an airframe with first and second wings having a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. First and second yaw vanes extend aftwardly from the fuselage. A flight control system is configured to direct the thrust vector of the coaxial rotor system and control movements of the yaw vanes. In a VTOL orientation of the aircraft, differential operation of the yaw vanes and/or differential operations of first and second rotor assemblies of the coaxial rotor system provide yaw authority for the aircraft. In a biplane orientation of the aircraft, collective operation of the yaw vanes provides yaw authority for the aircraft.

Abstract: One embodiment includes a rotary aircraft, including: a main drive rotor; an aircraft body mechanically coupled to the main drive rotor; and first and second flight assist wings passively rotatably coupled to the aircraft body.

Abstract: An aircraft includes an airframe with first and second wings having a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. First and second yaw vanes extend aftwardly from the fuselage. A flight control system is configured to direct the thrust vector of the coaxial rotor system and control movements of the yaw vanes. In a VTOL orientation of the aircraft, differential operation of the yaw vanes and/or differential operations of first and second rotor assemblies of the coaxial rotor system provide yaw authority for the aircraft. In a biplane orientation of the aircraft, collective operation of the yaw vanes provides yaw authority for the aircraft.

Abstract: An aircraft includes an airframe with first and second wings having a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. Tail assemblies are coupled to wingtips of the first and second wings each having an elevon that collectively form a distributed array of elevons. A flight control system is configured to direct the thrust vector of the coaxial rotor system and to control movements of the elevons such that the elevons collectively provide pitch authority and differentially provide roll authority for the aircraft in the biplane orientation. In addition, when the flight control system detects an elevon fault, the flight control system is configured to perform corrective action responsive thereto at a distributed elevon level or at a coordinated distributed elevon and propulsion assembly level.

Abstract: An aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The aircraft has an airframe including first and second wings with a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. A flight control system is configured to direct the thrust vector. In the VTOL orientation, the first wing is forward of the fuselage, the second wing is aft of the fuselage and the coaxial rotor system is configured to provide thrust in line with a yaw axis of the aircraft. In the biplane orientation, the first wing is below the fuselage, the second wing is above the fuselage and the coaxial rotor system is configured to provide thrust in line with a roll axis of the aircraft.

Abstract: A propulsion assembly for an aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The propulsion assembly includes a housing coupled to the fuselage of the aircraft. A coaxial rotor system includes a first rotor assembly and a second rotor assembly that are rotatable about a common axis of rotation. The first rotor assembly counter-rotates relative to the second rotor assembly. A motor assembly is operably associated with the coaxial rotor system. The motor assembly provides torque and rotational energy to the first rotor assembly and the second rotor assembly. A gimbal assembly couples the coaxial rotor system to the housing such that the coaxial rotor system is tiltable relative to the fuselage to generate a thrust vector.