An aircraft is provided including an airframe, an extending tail, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly with a plurality of blades rotating in a first plane and a lower rotor assembly with a plurality of blades rotating in a second plane, each of the blades having a root end, a midpoint, and a tip end. A translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe. The blades of the upper rotor assembly and the blades of the lower rotor assembly are indexed to improve tip end clearance between pairs of tip ends in the crossing plane as the tip ends move in respective first and second sinusoidal paths.

An aircraft is provided including an airframe, an extending tail, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly with an upper blade and a lower rotor assembly with a lower blade. A first antenna in one of upper blade and the lower blade, and a second antenna in the other of the upper blade and the lower blade. An oscillator to apply an excitation signal to the first antenna. A blade proximity monitor to monitor a magnitude of the excitation signal and an output signal from the second antenna to determine a distance between the upper blade and the lower blade.

A rotorcraft including a rotor hub, a pitch housing moveable relative to the rotor hub about at least a feather axis and a flap axis, the pitch housing defining an internal volume, a bearing pin, the inboard end portion of the bearing pin being fixedly connected to the rotor hub, wherein the bearing pin defines the feather axis, a spherical bearing connected to the inboard end portion of the pitch housing and defining the flap axis, wherein the bearing pin extends through the spherical bearing, a rotor blade connected to the outboard end portion of the pitch housing, and a sensor assembly positioned in the internal volume and operatively connected to both the pitch housing and the outboard end portion of the bearing pin.

A virtual reality system includes a drone including a rotor, a display, an audio speaker, a body harness having adjustable straps, and one or more processors in operative communication with the display, the audio speaker, and the drone. The drone may be fixed to the body harness. The one or more processors may be configured to issue audio-visual content to the display and audio speaker and control the rotor based on the issued audio-visual content.

A method of visualizing track and balance performance includes receiving data indicating track and balance of a rotary blade and receiving a constraint. A first performance level based on the data is determined. A second performance level based on the data and the constraint is determined. The first and second performance levels are displayed on a display unit for visualizing differences between the first and second performance levels.

A method of adjusting a rotary blade includes receiving performance data for a rotary blade, receiving an adjustment constraint for the rotary blade, defining an adjustment space for alternative adjustment solutions for the rotary blade including a plurality of alternative adjustment solutions, and calculating expected performance for one of the plurality of alternative adjustment solutions. Based on the expected performance of the one of the plurality of alternative adjustment solutions, the method determines whether to calculate expected performance for another of the plurality of alternative adjustment solutions.

According to one embodiment, a gauge display prioritization system comprises a priority engine and an output engine. The priority engine is operable to receive a measurement from a first sensor associated with a first aircraft component and a measurement from a second sensor associated with a second aircraft component, select a prioritization criterion based on the received measurements, and select one priority measurement from the received measurements based on the prioritization criterion. The output engine is operable to instruct a gauge disposed within a cockpit to display information representative of the one priority measurement to a pilot.

An embodiment of a tracker system for determining the distance of a moving object from a predefined reference point is disclosed. The system uses a phase-based signal extraction technique for determining the traversal time of the object through a predefined angular region. The first embodiment of the system includes a weather-resistant enclosure (12), two photodiodes (21) with narrow fields of view, four light-emitting diodes pulsed at high frequencies (20), collimating optics (15) for use with the light-emitting diodes, focusing optics (14) for use with the photodiodes, and an analog circuit for signal extraction (FIG. 7). FIG. 2 shows each component in the first embodiment. Phase-based signal processing identifies time intervals over which the object is within the angular region, from which the distance to the object is calculated (FIG. 1). Alternative embodiments are also discussed.

Devices, methods and systems are provided for monitoring movement of an object, such as rotation of a blade or other airfoil. One exemplary tracking device includes a first emitter to emit first radiation along a first line of sight, a first detector proximate the first emitter to detect the first radiation, a second emitter to emit second radiation along a second line of sight, and a second detector proximate the second emitter to detect the second radiation.

A method of assembling a rotor blade assembly includes determining a first spanwise moment of a first component of the rotor blade assembly and comparing the first spanwise moment to a target first spanwise moment. The first spanwise moment of the first component is adjusted based on a result of the comparison. A second spanwise moment of a second component of the rotor blade assembly is determined and compared to a target second spanwise moment. The second spanwise moment of the second component is adjusted based on a result of the comparison. The first component is assembled to the second component, resulting in a rotor blade assembly meeting a target spanwise moment of the rotor blade assembly.