Abstract: Apparatus and methods is used for controlling yaw of a rotorcraft in the event of one or both of low airspeed and engine failure. A yaw propulsion provides a yaw moment at low speeds. The yaw propulsion device may be an air jet or a fan. A pneumatic fan may be driven by compressed air released into a channel surrounding an outer portion of the fan. The fan may be driven by hydraulic power. Power for the yaw propulsion device and other system may be provided by a hydraulic pump and/or generator engaging the rotor. Low speed yaw control may be provided by auxiliary rudders positioned within the stream tube of a prop. The auxiliary rudders may one or both of fold down and disengage from rudder controls when not in use. A power take-off engages a rotor and is engaged in response to detecting a loss of engine power.

Abstract: A rotor system is disclosed for a reactive drive rotary wing aircraft. Apparatus and methods are disclosed for maintaining the rigidity of the rotor and eliminating play between flight controls and the rotor by mounting swashplate actuators to a flange rigidly secured to the mast. Apparatus and methods are disclosed for thermal management of the rotor in order to avoid bearing failure or loss of bearing preload. Methods include modulating the temperature of oil pumped over one or more of the mast bearing, swashplate bearing, and spindle bearing. The temperature of air passively or actively drawn through rotor may also be modulated to maintain bearing temperature within a predetermined range. Structures for reducing pressure losses and drag on components due to air flow through the rotor are also disclosed. A rotor facilitating thermal management by oil and air flow is also disclosed.

Abstract: A rotorcraft may include an airframe and a rotor connected to the airframe. The rotor may include a hub and a rotor blade connected to the hub to extend radially away therefrom. The rotor blade may include biasing fibers, oriented to increase the twist of the rotor blade in response to an increase in the speed of rotation of the rotor corresponding to a mission, task, or maneuver.

Abstract: An aircraft is disclosed having an engine and a propeller mounted to a fuselage. An empennage mounts to the aircraft and includes first and second horizontal stabilizers separated by a distance greater than the diameter of a stream tube of the propeller at the horizontal stabilizers. A rudder extends between the horizontal stabilizers and is positioned within the stream tube of the propeller. A bulkhead is positioned rearwardly from the cockpit and oriented perpendicular to a longitudinal axis of the airframe. A tailboom and engine are mounted to the airframe by means of the bulkhead having the engine mounted between the tailboom and a lower edge of the bulkhead. Landing gear may mount to the bulkhead proximate a lower edge thereof.

Abstract: A combined fixed and rotary wing aircraft may operate in vertical takeoff mode relying on the rotary wing, exclusively, and may completely change over to flight support by the fixed wing at higher advance ratios. Advance ratios may exceed not only the typical advance ratios of less than 0.5 but may exceed 1, and may even exceed 2. At the higher advance ratios, the rotary wing may be completely unloaded, the aircraft relying on the fixed wing for vertical support and airfoil lift. To maintain stability in the rotary wing, configuration, autorotation must continue. To power autorotation, without presenting a large area and drag, an anemometer-type flap system may selectively open and close to increase drag on the retreating blades, and provide minimum drag on the advancing blades.

Abstract: Apparatus and methods for controlling yaw of a rotorcraft in the event of one or both of low airspeed and engine failure are disclosed. A yaw propulsion provides a yaw moment at low speeds. The yaw propulsion device may be an air jet or a fan. A pneumatic fan may be driven by compressed air released into a channel surrounding an outer portion of the fan. The fan may be driven by hydraulic power. Power for the yaw propulsion device and other system may be provided by a hydraulic pump and/or generator engaging the rotor. Low speed yaw control may be provided by auxiliary rudders positioned within the stream tube of a prop. The auxiliary rudders may one or both of fold down and disengage from rudder controls when not in use.

Abstract: A rotorcraft is disclosed. The rotorcraft may include an airframe and a rotor connected to the airframe. The rotor may include a hub and at least one rotor blade having a tip jet. The rotorcraft may further include a plurality of compressors for generating compressed air and a network of conduits connecting the outlets of the plurality of compressors with every tip jet of the rotor. The rotorcraft may further include a control system preventing back flow through each outlet of the plurality of compressors.

Abstract: Apparatus and methods for controlling yaw of a rotorcraft in the event of one or both of low airspeed and engine failure are disclosed. A yaw propulsion provides a yaw moment at low speeds. The yaw propulsion device may be an air jet or a fan. A pneumatic fan may be driven by compressed air released into a channel surrounding an outer portion of the fan. The fan may be driven by hydraulic power. Power for the yaw propulsion device and other system may be provided by a hydraulic pump and/or generator engaging the rotor. Low speed yaw control may be provided by auxiliary rudders positioned within the stream tube of a prop. The auxiliary rudders may one or both of fold down and disengage from rudder controls when not in use.

Abstract: A rotor system is disclosed for a reactive drive rotary wing aircraft. Rigidity of the rotor is enhanced and play between flight controls and the rotor are eliminated by mounting swashplate actuators to a flange rigidly secured to the mast. Thermal management of the rotor is performed in order to avoid bearing failure or loss of bearing preload. Methods include modulating the temperature of oil pumped over one or more of the mast bearing, swashplate bearing, and spindle bearing. The temperature of air passively or actively drawn through rotor may also be modulated to maintain bearing temperature within a predetermined range. Structures for reducing pressure losses and drag on components due to air flow through the rotor are also disclosed. Thermal management of a rotor may be performed by oil and air flow.

Abstract: Apparatus and methods are disclosed for manufacture of a composite structure, such as a composite rotor blade spar or composite rotor blade. A first mold may define a first mold surface and a second mold may include a rigid layer and a heated layer secured to the rigid layer and defining a second mold surface. A plurality of heating elements embedded in the second mold may be activated according to different temperature progressions to cure portions of the uncured composite rotor blade positioned coextensive therewith. In some embodiments, the second mold defines a root portion and first and second branch portions. A shear web placed between the branch portions may be bonded to a blade skin positioned within the mold. The rotor blade may include a rotor blade spar having leading and trailing edge fairings secured thereto or the blade spar may define a complete airfoil contour.

Abstract: A heliplane operates with a fixed wing at high velocities, and particularly at high advance ratios, while using a rotary wing maintained in motion at all speeds. At high advance ratios, the rotor wing eventually may be rotated primarily to maintain its stability, rather than depending upon the majority of lift. Meanwhile, a collective pitch control is provided and located between pilot and copilot. A single control provides control of both collective pitch and throttle by both pilots. One pilot will have to operate the control with the left hand, while the other may use their right hand. Nevertheless, both throttles push away from the pilot, regardless of which one is in control of the aircraft, while a single collective lever is relied upon.

Abstract: Apparatus and methods for controlling yaw of a rotorcraft in the event of one or both of low airspeed and engine failure are disclosed. A yaw propulsion device, such as an air jet or a fan may be used. A pneumatic fan may be driven by compressed air released into a channel surrounding an outer portion of the fan. Power for the yaw propulsion device and other system may be provided by a hydraulic pump and/or generator engaging the rotor. Low speed yaw control may be provided by auxiliary rudders positioned within the stream tube of a prop. The auxiliary rudders may one or both of fold down and disengage from rudder controls when not in use. Apparatus for generating horizontal lift imbalance induced a tail boom positioned within the downwash of a rotor may also be used, including compressed air vents or lateral or trailing edge flaps.

Abstract: A method for equalizing rolling moments at high advance ratios is disclosed including impelling an aircraft in a forward direction at an airspeed by means of a thrust source and rotating a rotor of the aircraft at an angular velocity with respect to the airspeed effective to cause a positive total lift on each blade due to air flow over the blades in the retreating direction when the blade is moving in the retreating direction. The rotor includes an even number of blades placed at equal angular intervals around the rotor hub. One or both of cyclic pitch and rotor angle of attack are adjusted such that a rolling moment of the retreating blade due to reverse air flow is between 0.3 and 0.7 times a rolling moment on the advancing blade due to lift.

Abstract: A rotorcraft may include an airframe and a rotor connected to the airframe. The rotor may include a plurality of blades defining ducts along the length thereof and vents in fluid communication with the ducts. Flow from through the vents may be controlled by valves with piezoelectric actuators. The valves may be adjusted to achieve a lift profile suited for an operational mode such as vertical, autorotative, or unloaded flight. The lift profile may vary along the length of the blade and may vary cyclically with rotation of the blade. The lift profile may be chosen to approximate a figure of merit for the rotor suitable for a given operational mode.

Abstract: An aircraft is disclosed having an engine and a propeller mounted to a fuselage. An empennage mounts to the aircraft and includes first and second horizontal stabilizers separated by a distance greater than the diameter of a stream tube of the propeller at the horizontal stabilizers. A rudder extends between the horizontal stabilizers and is positioned within the stream tube of the propeller. A bulkhead is positioned rearward from the cockpit and oriented perpendicular to a longitudinal axis of the airframe. A tailboom and engine are mounted to the airframe by means of the bulkhead having the engine mounted between the tailboom and a lower edge of the bulkhead. Landing gear may mount to the bulkhead proximate a lower edge thereof. Systems and methods redistribute fuel among laterally, vertically, and longitudinally opposed fuel tanks to maintain a center of gravity in a dynamically stable position.

Abstract: An aircraft is disclosed having an engine and a propeller mounted to a fuselage. An empennage mounts to the aircraft and includes first and second horizontal stabilizers separated by a distance greater than the diameter of a stream tube of the propeller at the horizontal stabilizers. A rudder extends between the horizontal stabilizers and is positioned within the stream tube of the propeller. A bulkhead is positioned rearwardly from the cockpit and oriented perpendicular to a longitudinal axis of the airframe. A tailboom and engine are mounted to the airframe by means of the bulkhead having the engine mounted between the tailboom and a lower edge of the bulkhead. Landing gear may mount to the bulkhead proximate a lower edge thereof.

Abstract: Apparatus and methods for controlling yaw of a rotorcraft in the event of one or both of low airspeed and engine failure are disclosed. A yaw propulsion device, such as an air jet or a fan may be used. A pneumatic fan may be driven by compressed air released into a channel surrounding an outer portion of the fan. Power for the yaw propulsion device and other system may be provided by a hydraulic pump and/or generator engaging the rotor. Low speed yaw control may be provided by auxiliary rudders positioned within the stream tube of a prop. The auxiliary rudders may one or both of fold down and disengage from rudder controls when not in use. Apparatus for generating horizontal lift imbalance induced a tail boom positioned within the downwash of a rotor may also be used, including compressed air vents or lateral or trailing edge flaps.

Abstract: A rotorcraft is disclosed. The rotorcraft may include an airframe comprising a mast defining an interior cavity, at least one compressor connected to the airframe, and a rotor. The rotor may include a hub and a rotor blade. The hub may connect to the mast to rotate with respect thereto. The hub may also define an interior cavity. The rotor blade may form a radial conduit extending radially therewithin. A flow of compressed air generated by the at least one compressor may pass from the at least one compressor, through the interior cavity defined by the mast, through the interior cavity defined by the hub, and into the radial conduit. A swashplate assembly controlling pitch of the rotor blade may be located exterior to the hub and mast. Accordingly, the swashplate assembly may not be heated by the flow of compressed air.

Abstract: A fairing system may be assembled about a rotor of a rotorcraft to present an aerodynamically quasi-static region that rotates in an airstream, as well as certain extensions that sweep through the airstream as the rotor hub passes through the air. A spherical interface between the extensions on the rotor hub fairing and the base or root portion of each blade fairing provides three degrees of freedom permitting lead-lag, flapping, and blade pitch pivoting in the blade, while still maintaining an aerodynamic profile that will minimize drag.

Abstract: A rotorcraft may include an airframe and a rotor connected to the airframe. The rotor may include a hub and a rotor blade connected to the hub to extend radially away therefrom. The rotor blade may include biasing fibers, oriented to increase the twist of the rotor blade in response to an increase in the speed of rotation of the rotor corresponding to a mission, task, or maneuver.