Abstract: An aircraft includes an airframe with first and second wings having a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. First and second yaw vanes extend aftwardly from the fuselage. A flight control system is configured to direct the thrust vector of the coaxial rotor system and control movements of the yaw vanes. In a VTOL orientation of the aircraft, differential operation of the yaw vanes and/or differential operations of first and second rotor assemblies of the coaxial rotor system provide yaw authority for the aircraft. In a biplane orientation of the aircraft, collective operation of the yaw vanes provides yaw authority for the aircraft.

Abstract: A propulsion assembly for an aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The propulsion assembly includes a housing coupled to the fuselage of the aircraft. A coaxial rotor system includes a first rotor assembly and a second rotor assembly that are rotatable about a common axis of rotation. The first rotor assembly counter-rotates relative to the second rotor assembly. A motor assembly is operably associated with the coaxial rotor system. The motor assembly provides torque and rotational energy to the first rotor assembly and the second rotor assembly. A gimbal assembly couples the coaxial rotor system to the housing such that the coaxial rotor system is tiltable relative to the fuselage to generate a thrust vector.

Abstract: An aircraft includes an airframe with first and second wings having a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. Tail assemblies are coupled to wingtips of the first and second wings each having an elevon that collectively form a distributed array of elevons. A flight control system is configured to direct the thrust vector of the coaxial rotor system and to control movements of the elevons such that the elevons collectively provide pitch authority and differentially provide roll authority for the aircraft in the biplane orientation. In addition, when the flight control system detects an elevon fault, the flight control system is configured to perform corrective action responsive thereto at a distributed elevon level or at a coordinated distributed elevon and propulsion assembly level.

Abstract: An aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The aircraft has an airframe including first and second wings with a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. A flight control system is configured to direct the thrust vector. In the VTOL orientation, the first wing is forward of the fuselage, the second wing is aft of the fuselage and the coaxial rotor system is configured to provide thrust in line with a yaw axis of the aircraft. In the biplane orientation, the first wing is below the fuselage, the second wing is above the fuselage and the coaxial rotor system is configured to provide thrust in line with a roll axis of the aircraft.

Abstract: An aircraft includes an airframe with first and second wings having a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. First and second yaw vanes extend aftwardly from the fuselage. A flight control system is configured to direct the thrust vector of the coaxial rotor system and control movements of the yaw vanes. In a VTOL orientation of the aircraft, differential operation of the yaw vanes and/or differential operations of first and second rotor assemblies of the coaxial rotor system provide yaw authority for the aircraft. In a biplane orientation of the aircraft, collective operation of the yaw vanes provides yaw authority for the aircraft.

Abstract: An aircraft includes an airframe with first and second wings having a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. First and second yaw vanes extend aftwardly from the fuselage. A flight control system is configured to direct the thrust vector of the coaxial rotor system and control movements of the yaw vanes. In a VTOL orientation of the aircraft, differential operation of the yaw vanes and/or differential operations of first and second rotor assemblies of the coaxial rotor system provide yaw authority for the aircraft. In a biplane orientation of the aircraft, collective operation of the yaw vanes provides yaw authority for the aircraft.

Abstract: Filtering device for filtering cerebrospinal fluid are disclosed. An example filtering device may include a filter housing having an inlet for receiving cerebrospinal fluid from a patient and an outlet for returning filtered cerebrospinal fluid to the patient. The filter housing may include a plurality of layers coupled together and defining a fluid pathway therein between the inlet and the outlet. A filtering section may be defined within the filter housing along the fluid pathway. The filtering section may include a widened region of the fluid pathway that is configured to slow the passage of fluid therethrough.

Abstract: A propulsion assembly for an aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The propulsion assembly includes a housing coupled to the fuselage of the aircraft. A coaxial rotor system includes a first rotor assembly and a second rotor assembly that are rotatable about a common axis of rotation. The first rotor assembly counter-rotates relative to the second rotor assembly. A motor assembly is operably associated with the coaxial rotor system. The motor assembly provides torque and rotational energy to the first rotor assembly and the second rotor assembly. A gimbal assembly couples the coaxial rotor system to the housing such that the coaxial rotor system is tiltable relative to the fuselage to generate a thrust vector.

Abstract: An aircraft includes an airframe with first and second wings having a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. Tail assemblies are coupled to wingtips of the first and second wings each having an elevon that collectively form a distributed array of elevons. A flight control system is configured to direct the thrust vector of the coaxial rotor system and to control movements of the elevons such that the elevons collectively provide pitch authority and differentially provide roll authority for the aircraft in the biplane orientation. In addition, when the flight control system detects an elevon fault, the flight control system is configured to perform corrective action responsive thereto at a distributed elevon level or at a coordinated distributed elevon and propulsion assembly level.

Abstract: An aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The aircraft has an airframe including first and second wings with a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. A flight control system is configured to direct the thrust vector. In the VTOL orientation, the first wing is forward of the fuselage, the second wing is aft of the fuselage and the coaxial rotor system is configured to provide thrust in line with a yaw axis of the aircraft. In the biplane orientation, the first wing is below the fuselage, the second wing is above the fuselage and the coaxial rotor system is configured to provide thrust in line with a roll axis of the aircraft.

Abstract: An aircraft includes an airframe with first and second wings having a fuselage extending therebetween. A propulsion assembly is coupled to the fuselage and includes a counter-rotating coaxial rotor system that is tiltable relative to the fuselage to generate a thrust vector. First and second yaw vanes extend aftwardly from the fuselage. A flight control system is configured to direct the thrust vector of the coaxial rotor system and control movements of the yaw vanes. In a VTOL orientation of the aircraft, differential operation of the yaw vanes and/or differential operations of first and second rotor assemblies of the coaxial rotor system provide yaw authority for the aircraft. In a biplane orientation of the aircraft, collective operation of the yaw vanes provides yaw authority for the aircraft.

Abstract: An aircraft is operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The aircraft includes an airframe having first and second wings with first and second pylons extending therebetween forming a central region. A two-dimensional distributed thrust array and a flight control system are coupled to the airframe. A nose cone and an afterbody are each selectively coupled to the airframe. In a cargo delivery flight configuration, the nose cone and the afterbody are coupled to the airframe such that the nose cone and the afterbody each extend between the first and second wings and between first and second pylons to form a cargo enclosure with an aerodynamic outer shape. In a minimal drag flight configuration, the nose cone and the afterbody are not coupled to the airframe such that air passes through the central region during flight.

Abstract: Systems and methods include providing an aircraft with a tail rotor system having a tail rotor housing that forms a cambered airfoil between an upper cambered surface and a lower cambered surface of the tail rotor housing. The cambered airfoil design of the tail rotor housing is capable of providing sufficient lifting force of an aircraft to offload the tail rotor during forward flight, thereby eliminating the need for a traditional vertical stabilizer or fin. The tail rotor blades of the tail rotor system are disposed within an aperture in the tail rotor housing, which minimizes or preferably eliminates exposure of the tail rotor blades to edgewise airflow typically encountered during forward flight, thereby allowing rigid rotor hubs, both in-plane and out-of-plane, to be used in the tail rotor system while also reducing noise output of the tail rotor system.

Abstract: An aircraft is operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The aircraft includes an airframe having first and second wings with first and second pylons extending therebetween forming a central region. A two-dimensional distributed thrust array and a flight control system are coupled to the airframe. A nose cone and an afterbody are each selectively coupled to the airframe. In a cargo delivery flight configuration, the nose cone and the afterbody are coupled to the airframe such that the nose cone and the afterbody each extend between the first and second wings and between first and second pylons to form a cargo enclosure with an aerodynamic outer shape. In a minimal drag flight configuration, the nose cone and the afterbody are not coupled to the airframe such that air passes through the central region during flight.

Abstract: Systems and methods include providing an aircraft with a tail rotor system having a tail rotor housing that forms a cambered airfoil between an upper cambered surface and an lower cambered surface of the tail rotor housing. The cambered airfoil design of the tail rotor housing is capable of providing sufficient lifting force of an aircraft to offload the tail rotor during forward flight, thereby eliminating the need for a traditional vertical stabilizer or fin. The tail rotor blades of the tail rotor system are disposed within an aperture in the tail rotor housing, which minimizes or preferably eliminates exposure of the tail rotor blades to edgewise airflow typically encountered during forward flight, thereby allowing rigid rotor hubs, both in-plane and out-of-plane, to be used in the tail rotor system while also reducing noise output of the tail rotor system.

Abstract: Aspects of the embodiments of the present disclosure are directed to a window panel having a bubble form. The window panel is a push-out window that permits emergency egress from an aircraft, such as a rotorcraft. The bubble form is designed and selected such that the window panel will remain secured in a window frame of the aircraft at a level cruising speed of 120 knots true air speed. In embodiments, the window panel remains secured in the window frame at 120 ktas and a sideslip of at least 6 degrees.

Abstract: A gear and drive system utilizing the gear include teeth. Each of the teeth has a first side and a second side opposite the first side that extends from a body of the gear. For each tooth of the gear, a first extended portion is attached to the first side of the tooth to divert flow of fluid adjacent to the body of the gear to reduce windage losses that occur when the gear rotates. The gear may be utilized in drive systems that may have high rotational speeds, such as speeds where the tip velocities are greater than or equal to about 68 m/s. Some embodiments of the gear may also utilize teeth that also have second extended portions attached to the second sides of the teeth to divert flow of fluid adjacent to the body of the gear to reduce windage losses that occur when the gear rotates.

Abstract: A gear and drive system utilizing the gear include teeth. Each of the teeth has a first side and a second side opposite the first side that extends from a body of the gear. For each tooth of the gear, a first extended portion is attached to the first side of the tooth to divert flow of fluid adjacent to the body of the gear to reduce windage losses that occur when the gear rotates. The gear may be utilized in drive systems that may have high rotational speeds, such as speeds where the tip velocities are greater than or equal to about 68 m/s. Some embodiments of the gear may also utilize teeth that also have second extended portions attached to the second sides of the teeth to divert flow of fluid adjacent to the body of the gear to reduce windage losses that occur when the gear rotates.