In a flying object, a PCU has a plurality of operation modes in which an engine and/or a motor generator is used as a driving source for a pusher propeller. In accordance with the state of the flying object, the PCU controls the engine, a clutch, and the motor generator in one of the operation modes.

In a flying object, a PCU has a plurality of operation modes in which an engine and/or a motor generator is used as a driving source for a pusher propeller. In accordance with the state of the flying object, the PCU controls the engine, a clutch, and the motor generator in one of the operation modes.

The device disclosed herein allows a user to maintain the outboard stabilator of a Blackhawk helicopter. The device, which comprises a kit, allows a user to remove damaged outdoor stabilator bushings from a Blackhawk. Upon removal, the device enables a user to install new outdoor stabilator bushings. Additionally, the device allows a user to ream the newly installed outdoor stabilator bushings so that the outboard stabilator may be reinstalled upon the Blackhawk and safely flown.

One embodiment includes a multistage infrared suppression exhaust system for an aircraft, including: a stage one including a first exhaust conduit to receive a first exhaust air flow at a first temperature-pressure product T.sub.1P.sub.1, a second exhaust conduit to receive a second exhaust air flow at a second temperature-pressure product T.sub.2P.sub.2, and a flow integrator mechanically configured to mix the first exhaust air flow with the second exhaust air flow in an integration chamber while preventing back pressure into the second exhaust conduit; and a stage two including a stage two cooling airflow to cool the mixed first and second exhaust air flows.

An unmanned rotorcraft has a lift module having a propulsion system and coaxial rotors driven in rotation by the propulsion system. The rotorcraft includes a payload support system adapted to couple an external payload directly to the lift module. The rotorcraft is devoid of provisions for human passengers.

A flow control method is a flow control method of controlling flow around a blade of a rotary wing, a plasma actuator being disposed at the blade. The flow control method includes: determining a characteristic frequency ratio that is a characteristic value among frequency ratios, each of the frequency ratios being a ratio between an actuator driving frequency and an angle of attack changing frequency, the actuator driving frequency being a frequency of an applied voltage applied to the plasma actuator, the angle of attack changing frequency being a frequency at which an angle of attack of the blade changes in accordance with a rotation angle of the blade; setting the actuator driving frequency such that the frequency ratio becomes the characteristic frequency ratio; and applying a voltage of the set actuator driving frequency to the plasma actuator to control the flow around the blade.

A flow control method is a flow control method of controlling flow around a blade of a rotary wing, a plasma actuator being disposed at the blade. The flow control method includes: determining a characteristic frequency ratio that is a characteristic value among frequency ratios, each of the frequency ratios being a ratio between an actuator driving frequency and an angle of attack changing frequency, the actuator driving frequency being a frequency of an applied voltage applied to the plasma actuator, the angle of attack changing frequency being a frequency at which an angle of attack of the blade changes in accordance with a rotation angle of the blade; setting the actuator driving frequency such that the frequency ratio becomes the characteristic frequency ratio; and applying a voltage of the set actuator driving frequency to the plasma actuator to control the flow around the blade.

In one aspect, there is provided a rotary blade movement system including a retaining member configured to receive a rotor blade, a graspable arm, and a coupling mechanism operable to removably couple the retaining member to the graspable arm. The rotor blade movement system is configured to enable a user to adjust the position of the rotor blade by moving the graspable arm. The coupling mechanism can be a ball and socket joint. In one aspect, there is a method of rotating a rotor blade using a rotary blade movement system.

A slip ring assembly includes a stationary element, a rotatable element rotatable relative to the stationary element, and a liquid metal contact electrically coupling the rotatable element to the stationary element. The liquid metal contact includes a metallic material having a melting temperature that is less than zero degrees Celsius and a boiling temperature that is greater than four-hundred degrees Celsius to electrically couple an electrical device fixed relative to the rotatable element to an electrical device fixed relative to the stationary element through the liquid metal contact.

A slip ring assembly includes a stationary element, a rotatable element rotatable relative to the stationary element, and a liquid metal contact electrically coupling the rotatable element to the stationary element. The liquid metal contact includes a metallic material having a melting temperature that is less than zero degrees Celsius and a boiling temperature that is greater than four-hundred degrees Celsius to electrically couple an electrical device fixed relative to the rotatable element to an electrical device fixed relative to the stationary element through the liquid metal contact.