A gearbox system includes a first drive gear rotatable about an axis of rotation and a second drive gear disposed coaxial with the first drive gear and rotatable about the axis of rotation. An input shaft provides a first torque and includes an input gear. Driving pinions are operably connected to the input gear and positioned between the first drive gear and the second drive gear compliantly along a direction parallel to the axis of rotation. Each driving pinion drives the first drive gear in a first direction about the axis of rotation and drives the second drive gear in a second direction opposite the first direction about the axis of rotation. Each driving pinion transfers an equal second torque to the first drive gear and the second drive gear.

An aircraft and method of operating an aircraft. The aircraft includes a temperature sensor and a processor. The temperature sensor that obtains an optical signal indicative of a temperature at a selected location of an outer surface of the aircraft. The processor is configured to determine the temperature at the selected location from the optical signal, and operate the aircraft based on the temperature at the selected location.

A control system for an aircraft, the system including a pilot input device configured to receive a pilot input, a plurality of sensors, each of the plurality of sensors positioned on a corresponding landing gear of the aircraft and configured to sense a parameter on the corresponding landing gear, and a controller in communication with the plurality of sensors, the controller configured to calculate an output command based on the pilot input and the sensed parameters of the landing gear, the output command including instructions for controlling a rotor of the aircraft.

A control system for an aircraft, the system including a pilot input device configured to receive a pilot input, a plurality of sensors, each of the plurality of sensors positioned on a corresponding landing gear of the aircraft and configured to sense a parameter on the corresponding landing gear, and a controller in communication with the plurality of sensors, the controller configured to calculate an output command based on the pilot input and the sensed parameters of the landing gear, the output command including instructions for controlling a rotor of the aircraft.

A coaxial rotor system for a rotorcraft includes a mast, a top rotor assembly and a bottom rotor assembly. The top rotor assembly is coupled to the distal end of the mast. The bottom rotor assembly includes a motor configured to provide rotational energy to the mast, thereby rotating the top rotor assembly. The bottom rotor assembly experiences a torque reaction force responsive to the motor rotating the mast such that the top and bottom rotor assemblies counter rotate.

A coaxial rotor system for a rotorcraft includes a mast, a top rotor assembly and a bottom rotor assembly. The top rotor assembly is coupled to the distal end of the mast. The bottom rotor assembly includes a motor configured to provide rotational energy to the mast, thereby rotating the top rotor assembly. The bottom rotor assembly experiences a torque reaction force responsive to the motor rotating the mast such that the top and bottom rotor assemblies counter rotate.

An extension assembly for a rotor system for rotating a plurality of rotor blades about a rotor axis with a central rotor hub that defines the rotor axis includes a beam assembly and a first bearing assembly. The beam assembly is configured to attach to the central rotor hub and is positioned at least partially within a corresponding one of the plurality of rotor blades. The first bearing assembly is configured to be fastened to the beam assembly and to at least one of a leading edge or a trailing edge of the corresponding one of the plurality of rotor blades.

An extension assembly for a rotor system for rotating a plurality of rotor blades about a rotor axis with a central rotor hub that defines the rotor axis includes a beam assembly and a first bearing assembly. The beam assembly is configured to attach to the central rotor hub and is positioned at least partially within a corresponding one of the plurality of rotor blades. The first bearing assembly is configured to be fastened to the beam assembly and to at least one of a leading edge or a trailing edge of the corresponding one of the plurality of rotor blades.

A method and system for generating a set of values for respective ones of a set of parameters used in determining rotor blade profiles for a corotating coaxial rotor system. The method comprises establishing a ratio of respective desired thrusts of an upper rotor and a lower rotor of the corotating coaxial rotor system based on a desired performance of the corotating coaxial rotor system; and determining the set of values of the set of parameters from the desired thrusts ratio based on an equal rotation speed condition between the upper rotor and the lower rotor of the corotating coaxial rotor system, wherein the set of parameters includes torques of the upper rotor and the lower rotor.

A method and system for generating a set of values for respective ones of a set of parameters used in determining rotor blade profiles for a corotating coaxial rotor system. The method comprises establishing a ratio of respective desired thrusts of an upper rotor and a lower rotor of the corotating coaxial rotor system based on a desired performance of the corotating coaxial rotor system; and determining the set of values of the set of parameters from the desired thrusts ratio based on an equal rotation speed condition between the upper rotor and the lower rotor of the corotating coaxial rotor system, wherein the set of parameters includes torques of the upper rotor and the lower rotor.