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 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 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: 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: 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 and apparatus for reducing roll of rotorcraft landing in autorotation may include executing a flight with a rotorcraft. The flight may include first, second, and third portions ordered sequentially. During the first portion, the rotorcraft may be flown with the rotor exclusively in autorotation. During the second portion, the rotorcraft may be flown with the rotor powered at least partially by an engine of the rotorcraft, which may increase the rotational speed of the rotor. During the third portion, the rotorcraft may be flown with the rotor exclusively in autorotation. The flight and the third portion may terminate simultaneously with a touch down of the rotorcraft. Kinetic energy stored in the rotor during the second portion, during the third portion, bring the ground speed of the rotorcraft to substantially zero before touching down.

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 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: 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 and apparatus for reducing roll of rotorcraft landing in autorotation may include executing a flight with a rotorcraft. The flight may include first, second, and third portions ordered sequentially. During the first portion, the rotorcraft may be flown with the rotor exclusively in autorotation. During the second portion, the rotorcraft may be flown with the rotor powered at least partially by an engine of the rotorcraft, which may increase the rotational speed of the rotor. During the third portion, the rotorcraft may be flown with the rotor exclusively in autorotation. The flight and the third portion may terminate simultaneously with a touch down of the rotorcraft. Kinetic energy stored in the rotor during the second portion, during the third portion, bring the ground speed of the rotorcraft to substantially zero before touching down.

Abstract: A method and apparatus for enabling high speed flight in a rotorcraft are disclosed. The method may include executing a flight with a rotorcraft. The flight may include a first portion and second portion ordered sequentially. During the first portion, the rotorcraft may be flown with the rotor exclusively in autorotation. Once sufficient airspeed is obtained, the flight may transition to the second portion. Wherein, substantially all of the weight of the rotorcraft may be supported by one or more fixed wing surfaces of the rotorcraft. Thus, during the second portion, the rotor may be completely unloaded. To keep the rotor stable by turning, the rotor may be powered during the second portion by an engine of the rotorcraft by way of a prerotation system.