Abstract: A pylon tracking system for a tiltrotor aircraft includes first and second pylons each having a mechanically redundant pylon conversion actuator with first and second drive systems. A position sensor system includes a first rotary position sensor coupled to the first drive system of the first pylon, a second rotary position sensor coupled to the second drive system of the first pylon, a third rotary position sensor coupled to the first drive system of the second pylon and a fourth rotary position sensor coupled to the second drive system of the second pylon. A flight control computer is configured for cascaded communication with the position sensor system providing at least one excitation voltage to the position sensor system and receiving at least one set of sine and cosine feedback voltages from the position sensor system to identify a differential pylon angle between the first and second pylons during pylon conversion.

Abstract: A pylon tracking system for a tiltrotor aircraft including first and second pylons each having a pylon conversion actuator with primary and backup drive systems. The pylon tracking system includes a plurality of rotary position sensors including a first rotary position sensor coupled to the primary drive system of the first pylon, a second rotary position sensor coupled to the backup drive system of the first pylon, a third rotary position sensor coupled to the primary drive system of the second pylon and a fourth rotary position sensor coupled to the backup drive system of the second pylon. A flight control computer is in communication with the plurality of rotary position sensors and is configured to process feedback therefrom to identify a differential pylon angle between the first and second pylons during pylon conversion operations.

Abstract: A rotorcraft has a drive system including a main rotor coupled to a main rotor gearbox to rotate the main rotor at a rotor speed, a main engine coupled to the drive system to provide a first power, a supplemental engine coupled, when a first clutch is engaged, to the drive system to provide a second power additive to the first power, and a control system operable to control the main engine and the supplemental engine to provide a total power demand, where the main engine is controlled based on variations in rotor speed and a power compensation command to produce the first power, and the supplemental engine is controlled to produce the second power in response to a supplemental power demand.

Abstract: An aircraft is described and includes an aircraft body, a gearbox housing containing a lubricant, and a remote gearbox lubricant level gauging (RGLLG) system including a light source that when activated illuminates an interior of the gearbox housing; at least one light tube for transmitting light from inside the gearbox housing to an observer end of the RGLLG system, and at least one indicator at the observer end of for indicating a level of the lubricant contained within the gearbox based on the light transmitted via the at least one light tube.

Abstract: A rotorcraft has a drive system including a main rotor coupled to a main rotor gearbox to rotate the main rotor at a rotor speed, a main engine coupled to the drive system to provide a first power, a supplemental engine coupled, when a first clutch is engaged, to the drive system to provide a second power additive to the first power, and a control system operable to control the main engine and the supplemental engine to provide a total power demand, where the main engine is controlled based on variations in rotor speed and a power compensation command to produce the first power, and the supplemental engine is controlled to produce the second power in response to a supplemental power demand.

Abstract: A method of operating a multi-engine drive system of an aircraft includes driving a main rotor of the aircraft by a main engine of the multi-engine drive system at an operating speed of the main engine, operating a supplemental engine of the multi-engine drive system at approximately 80% of an operating speed of the supplemental engine, wherein, during the operating step, a clutch interoperably coupled to the supplemental engine is interoperably decoupled from the main rotor and, responsive to a command to interoperably engage the clutch, if the clutch successfully engages such that the clutch is interoperably coupled to the main rotor, providing, by the supplemental engine, power to the main rotor.

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: A rotor-regulation system includes a rotor that includes a plurality of rotor blades, a rotor mast operable to drive the rotor, and a rotor disc-brake system operable to modulate rotation of the rotor mast.

Abstract: Systems and methods include providing an aircraft with a direct drive dual-concentric valve (D3V) having a body, an outer secondary spool coaxially located within a bore of the body and linearly displaceable relative to the body, an inner primary spool coaxially located within a bore of the secondary spool and linearly displaceable relative to the secondary spool and the body. A plurality of piezo stacks is coupled to a first end of the primary spool, and applying a voltage to at least one of the piezo stacks causes an output stroke of the plurality of the piezo strokes for displacing the primary spool. The secondary spool is displaced together with the primary spool relative to the body if displacement of the primary spool relative to the secondary spool cannot occur.

Abstract: A torque measurement system determines torque on a shaft by monitoring angular deflection of the shaft under load using phase shift measurements. Calibration of the system uses a defined offset that is determined using a reference operating condition. The offset calibration value is determined for a rotorcraft using the following steps: defining a reference operational condition in which the shaft is rotating, estimating the torque at the reference condition based on aerodynamic knowledge of the rotors coupled to the shaft, operating the shaft at the reference operational condition, capturing sensor data to determine the phase difference at the operational condition, and associating the phase difference and an estimated torque as a calibration value to enable calculation of torque in the torque measurement system.

Abstract: A system includes a driver monitor system configured to receive information about driver operation, a relationship table comprising information about an expected relationship between driver operation and a preload force, and a driver controller configured to control a driver in response to the information about driver operation and according to the relationship table. A method of managing a preload force includes providing a first component, providing a second component for compression against the first component, operating a driver to move the first component into contact with the second component, monitoring an operation of the driver, and determining an expected preload force in response to the operation of the driver.

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: A rotorcraft has a drive system including a main rotor coupled to a main rotor gearbox to rotate the main rotor at a rotor speed, a main engine coupled to the drive system to provide a first power, a supplemental engine coupled, when a first clutch is engaged, to the drive system to provide a second power additive to the first power, and a control system operable to control the main engine and the supplemental engine to provide a total power demand, where the main engine is controlled based on variations in rotor speed and a power compensation command to produce the first power, and the supplemental engine is controlled to produce the second power in response to a supplemental power demand.

Abstract: A method of operating a multi-engine drive system of an aircraft includes driving a main rotor of the aircraft by a main engine of the multi-engine drive system at an operating speed of the main engine, operating a supplemental engine of the multi-engine drive system at approximately 80% of an operating speed of the supplemental engine, wherein, during the operating step, a clutch interoperably coupled to the supplemental engine is interoperably decoupled from the main rotor and, responsive to a command to interoperably engage the clutch, if the clutch successfully engages such that the clutch is interoperably coupled to the main rotor, providing, by the supplemental engine, power to the main rotor.

Abstract: A multimode clutch assembly is positioned in a powertrain of a rotorcraft. The clutch assembly includes a freewheeling unit having a driving mode in which torque applied to the input race is transferred to the output race and an overrunning mode in which torque applied to the output race is not transferred to the input race. A bypass assembly has an engaged position that couples the input and output races of the freewheeling unit. An actuator assembly shifts the bypass assembly between engaged and disengaged positions. An engagement status sensor is configured to determine the engagement status of the bypass assembly. In the disengaged position, the overrunning mode of the freewheeling unit is enabled such that the clutch assembly is configured for unidirectional torque transfer. In the engaged position, the overrunning mode of the freewheeling unit is disabled such that the clutch assembly is configured for bidirectional torque transfer.

Abstract: A system includes a driver monitor system configured to receive information about driver operation, a relationship table comprising information about an expected relationship between driver operation and a preload force, and a driver controller configured to control a driver in response to the information about driver operation and according to the relationship table. A method of managing a preload force includes providing a first component, providing a second component for compression against the first component, operating a driver to move the first component into contact with the second component, monitoring an operation of the driver, and determining an expected preload force in response to the operation of the driver.

Abstract: A rotor-regulation system includes a rotor that includes a plurality of rotor blades, a rotor mast operable to drive the rotor, and a rotor disc-brake system operable to modulate rotation of the rotor mast.

Abstract: An aircraft includes an electronically controlled engine (ECE) and a first and a second throttle control assembly. The first throttle control assembly includes a first throttle fly button configured to command a FLY mode and a first throttle idle button configured to command an IDLE mode. The second throttle control assembly includes a second throttle fly button configured to command the FLY mode and a second throttle idle button configured to command the IDLE mode.

Abstract: A rotorcraft comprising a rotor blade designed to flap about a hinge point, a measurement system designed to measure blade flapping, and a processing system designed to alter blade flapping measurements. The processing system further comprises a correction process to alter a blade flapping measurement dependent on rotor RPM or rotor torque.

Abstract: A rotor-regulation system includes a rotor comprising a plurality of blades, a mechanically driven hydraulic pump, a rotor drive shaft operable to drive the rotor and the mechanically driven hydraulic pump, and a throttling valve coupled to the mechanically driven hydraulic pump and operable to modulate rotation of the rotor.