Abstract: An exemplary ducted fan with an optimized stator includes a duct surrounding a rotor hub from which blades radially extend and the stator having a stator span extending horizontally across an inside diameter of the duct, the stator having a stator chord extending from a leading edge to a trailing edge, wherein a length of the stator chord varies across the stator span.

Abstract: An exemplary ducted fan includes a circular duct surrounding a rotor hub from which blades radially extend, a stator having a stator leading edge and a stator trailing edge, and a stator chord line extending from the stator leading edge to the stator trailing edge, the stator chord line substantially equal to a duct radius from the rotor hub to an outer surface of the duct.

Abstract: An exemplary ducted fan with an optimized stator includes a duct surrounding a rotor hub from which blades radially extend and the stator having a stator span extending horizontally across an inside diameter of the duct, the stator having a stator chord extending from a leading edge to a trailing edge, wherein a length of the stator chord varies across the stator span.

Abstract: In one embodiment, a tiltrotor aircraft may comprise a fuselage; a biplane wing coupled to the fuselage, wherein the biplane wing comprises an upper wing structure and a lower wing structure; a plurality of tiltrotors coupled to the biplane wing; and at least one engine to power the plurality of tiltrotors.

Abstract: One embodiment is a method including defining a maximum deflection for a first axis of a control surface axis of an aircraft; defining a maximum deflection for a second axis of the control surface; and creating a graphical representation of the maximum deflection for the first and second control surface axes. The method further includes determining an angle of rotation of a structure on which the control surface is carried, wherein the angle of rotation is relative to a body of the aircraft; rotating the graphical representation in accordance with the determined angle of rotation; calculating a distance between a point representing a selected combination of roll moment and yaw moment and each edge of the graphical representation; and calculating a control surface deflection based on the calculated distances.

Abstract: A rotorcraft comprises a fuselage, a tail boom, a rotor system, and a centrifugal blower system. The centrifugal blower system comprises a centrifugal blower configured to generate thrust using an airflow, wherein the centrifugal blower is located within the tail boom. The centrifugal blower system also comprises a plurality of ducts configured to control the thrust generated by the centrifugal blower, wherein the plurality of ducts is located on a portion of the tail boom surrounding the centrifugal blower, and wherein the plurality of ducts comprises one or more adjustable ducts configured to vary a size of an associated duct opening.

Abstract: In one aspect, there is provided an aircraft, including a fuselage having a longitudinal axis extending from a front portion through an aft portion; first and second tail members extending from the aft portion; a first cross-flow fan system rotatably mounted to the first tail member; and a second cross-flow fan system rotatably mounted to the second tail member. The first and second cross-flow fan systems are configured to provide a forward thrust vector and an anti-torque vector on the aircraft. The first and second cross-flow fan systems can have a rotational axis oriented generally vertically. In another aspect, there is an aircraft including a fuselage having a front portion and a tail portion; and a cross-flow fan system supported by the tail portion. Embodiments include a cross-flow fan system retrofittable onto an aircraft and methods for retrofitting an aircraft with a cross-flow fan system.

Abstract: An aspect provides an aircraft including a fuselage and a cross-flow fan system attached to the fuselage. The cross-flow fan system including a cross-flow fan assembly associated with a rotatable wing member having an exterior aerodynamic surface. In one aspect, there is provided an aircraft with a fuselage having a forward portion and an aft portion; a first cross-flow fan system rotatably attached to the left side of the forward portion of the fuselage; a second cross-flow fan system rotatably attached to the right side of the forward portion of the fuselage; a third cross-flow fan system rotatably attached to the left side of the aft portion of the fuselage; and a fourth cross-flow fan system rotatably attached to the right side of the aft portion of the fuselage.

Abstract: A variable thrust cross-flow fan system for an aircraft including a rotatable wing member having a first housing member; an actuator assembly operably coupled to the first housing member; and a variable thrust cross-flow fan assembly including a first and second driver plates having a plurality of blades rotatably mounted therebetween. The plurality of blades has a circular path of travel when rotating and includes a control assembly coupled to the plurality of blades to generate a variable thrust force. The control assembly includes a control cam that is substantially non-rotatable relative to the first and second driver plates and a hinge member that is fixedly connected to the control cam and to the first housing member at a hinge axis. Rotation of the first housing member by the actuator assembly imparts rotation of the control cam about the hinge axis, thereby changing the direction of the variable thrust force.

Abstract: One embodiment is a method including defining a maximum deflection for a first axis of a control surface axis of an aircraft; defining a maximum deflection for a second axis of the control surface; and creating a graphical representation of the maximum deflection for the first and second control surface axes. The method further includes determining an angle of rotation of a structure on which the control surface is carried, wherein the angle of rotation is relative to a body of the aircraft; rotating the graphical representation in accordance with the determined angle of rotation; calculating a distance between a point representing a selected combination of roll moment and yaw moment and each edge of the graphical representation; and calculating a control surface deflection based on the calculated distances.

Abstract: In one embodiment, an apparatus comprises a shaft, a rotor, and a cam surface. The shaft comprises a spiral spline along a length of the shaft. The rotor comprises a blade extending from the rotor and a tubular hole extending into the rotor. The tubular hole comprises a spiral groove configured to mate with the spiral spline on the shaft. Relative rotation between the spiral spline and the spiral groove causes the rotor to linearly move along the shaft. The cam surface comprising a recession. The blade nesting in the recession to constrains rotation of the rotor about the shaft and allows linear movement of the rotor along the shaft.

Abstract: In one embodiment, a tiltrotor aircraft may comprise a fuselage; a biplane wing coupled to the fuselage, wherein the biplane wing comprises an upper wing structure and a lower wing structure; a plurality of tiltrotors coupled to the biplane wing; and at least one engine to power the plurality of tiltrotors.

Abstract: In one embodiment, an apparatus comprises a shaft, a rotor, and a cam surface. The shaft comprises a spiral spline along a length of the shaft. The rotor comprises a blade extending from the rotor and a tubular hole extending into the rotor. The tubular hole comprises a spiral groove configured to mate with the spiral spline on the shaft. Relative rotation between the spiral spline and the spiral groove causes the rotor to linearly move along the shaft. The cam surface comprising a recession. The blade nesting in the recession to constrains rotation of the rotor about the shaft and allows linear movement of the rotor along the shaft.

Abstract: In one embodiment, a rotorcraft comprises a fuselage, a tail boom, a rotor system, and a centrifugal blower system. The centrifugal blower system comprises a centrifugal blower configured to generate thrust using an airflow, wherein the centrifugal blower is located within the tail boom. The centrifugal blower system also comprises a plurality of ducts configured to control the thrust generated by the centrifugal blower, wherein the plurality of ducts is located on a portion of the tail boom surrounding the centrifugal blower, and wherein the plurality of ducts comprises one or more adjustable ducts configured to vary a size of an associated duct opening.

Abstract: An aspect provides an aircraft including a fuselage and a cross-flow fan system attached to the fuselage. The cross-flow fan system including a cross-flow fan assembly associated with a rotatable wing member having an exterior aerodynamic surface. In one aspect, there is provided an aircraft with a fuselage having a forward portion and an aft portion; a first cross-flow fan system rotatably attached to the left side of the forward portion of the fuselage; a second cross-flow fan system rotatably attached to the right side of the forward portion of the fuselage; a third cross-flow fan system rotatably attached to the left side of the aft portion of the fuselage; and a fourth cross-flow fan system rotatably attached to the right side of the aft portion of the fuselage.

Abstract: In one aspect, there is provided an aircraft, including a fuselage having a longitudinal axis extending from a front portion through an aft portion; first and second tail members extending from the aft portion; a first cross-flow fan system rotatably mounted to the first tail member; and a second cross-flow fan system rotatably mounted to the second tail member. The first and second cross-flow fan systems are configured to provide a forward thrust vector and an anti-torque vector on the aircraft. The first and second cross-flow fan systems can have a rotational axis oriented generally vertically. In another aspect, there is an aircraft including a fuselage having a front portion and a tail portion; and a cross-flow fan system supported by the tail portion. Embodiments include a cross-flow fan system retrofittable onto an aircraft and methods for retrofitting an aircraft with a cross-flow fan system.

Abstract: A variable thrust cross-flow fan system for an aircraft including a rotatable wing member having a first housing member; an actuator assembly operably coupled to the first housing member; and a variable thrust cross-flow fan assembly including a first and second driver plates having a plurality of blades rotatably mounted therebetween. The plurality of blades has a circular path of travel when rotating and includes a control assembly coupled to the plurality of blades to generate a variable thrust force. The control assembly includes a control cam that is substantially non-rotatable relative to the first and second driver plates and a hinge member that is fixedly connected to the control cam and to the first housing member at a hinge axis. Rotation of the first housing member by the actuator assembly imparts rotation of the control cam about the hinge axis, thereby changing the direction of the variable thrust force.