The invention relates to an aircraft with a longitudinal central axis, comprising: a fuselage structure (2) which is designed to accommodate persons and/or payload; a wing structure (3) which has at least two wing halves (3.1) which are attached to the fuselage structure (2) and which have a fuselage-side main region (H) and a tip region (S); at least one forward propulsion unit (4) which is designed to generate a forward force, acting in the direction of the central axis, on the aircraft; at least four lifting propulsion units (5) which are designed to generate a lift force, acting in the direction of the central axis, on the aircraft.

A propeller includes a plurality of blades that extends outward in a radial direction of a rotation central axis relative to the rotation central axis, and includes an end that is located on an opposite side of the rotation central axis. Each of the plurality of blades has a maximum angle of elevation in a position ranging from 30% to 60% with the rotation central axis as a starting point of a radius of a circle that passes through the end of each of the plurality of blades with the rotation central axis as a center, the maximum angle of elevation being a maximum of an angle of elevation in each of the plurality of blades. A change in the angle of elevation in a longitudinal direction of each of the plurality of blades is within 10 degrees per 5% of the radius. A change in the longitudinal direction of a cross-sectional maximum blade thickness is within 20% of a maximum blade thickness of each of the plurality of blades per 5% of the radius, the cross-sectional maximum blade thickness being a maximum blade thickness in a cross section of each of the plurality of blades, the cross section being orthogonal to the longitudinal direction. A change in a chord length of each of the plurality of blades in the longitudinal direction is within 20% of a maximum of the chord length in each of the plurality of blades per 5% of the radius.

A propeller includes a plurality of blades that extends outward in a radial direction of a rotation central axis relative to the rotation central axis, and includes an end that is located on an opposite side of the rotation central axis. Each of the plurality of blades has a maximum angle of elevation in a position ranging from 30% to 60% with the rotation central axis as a starting point of a radius of a circle that passes through the end of each of the plurality of blades with the rotation central axis as a center, the maximum angle of elevation being a maximum of an angle of elevation in each of the plurality of blades. A change in the angle of elevation in a longitudinal direction of each of the plurality of blades is within 10 degrees per 5% of the radius. A change in the longitudinal direction of a cross-sectional maximum blade thickness is within 20% of a maximum blade thickness of each of the plurality of blades per 5% of the radius, the cross-sectional maximum blade thickness being a maximum blade thickness in a cross section of each of the plurality of blades, the cross section being orthogonal to the longitudinal direction. A change in a chord length of each of the plurality of blades in the longitudinal direction is within 20% of a maximum of the chord length in each of the plurality of blades per 5% of the radius.

A propeller blade for an unmanned aerial vehicle (“UAV”) is disclosed. The UAV includes a plurality of lift propellers and at least one thrust propeller. Each of the plurality of thrust propellers includes a thrust propeller blade coupled to a hub of the thrust propeller. The thrust propeller blade is configured such that a centrifugal force acting on the thrust propeller blade causes a thrust propeller disk area to increase from a first disk area when the UAV is in a first operational state to a second disk area when the UAV is in a second operational state.

Embodiments are directed to a rotor blade comprising a blade tip attached to the outboard end of the rotor blade. The blade tip has at least two sides that are tapered together to an edge. The length of the blade tip extending away from the outboard end to the edge is a distance that is greater than half the thickness of the outboard end. When the rotor blade is operating in a folded configuration, air flows over the sides in a direction generally parallel to a longitudinal axis of the rotor blade. The sides have profiles that minimize or prevent separation of the air flow from the blade tip.

An ice protection system may include a blade and an electrothermal heater including a carbon nanotube (CNT) element and a metal element. The CNT element may be a CNT fabric or a CNT yarn. The metal element may be coupled to the CNT element via a metallization process, or the like. The electrothermal heater element may include an electric sheet resistivity between 0.01 and 0.5 ohms/square.

An ice protection system may include a blade and an electrothermal heater including a carbon nanotube (CNT) element and a metal element. The CNT element may be a CNT fabric or a CNT yarn. The metal element may be coupled to the CNT element via a metallization process, or the like. The electrothermal heater element may include an electric sheet resistivity between 0.01 and 0.5 ohms/square.

A propeller system for a tail section of an aircraft includes a propeller hub located at the tail section of the aircraft, a plurality of propeller blades mounted to and extending outwardly from the propeller hub, a propeller shaft coupled to the propeller hub and operable to rotate the propeller hub about an axis of rotation, and a propeller gearbox connected to the propeller shaft. The propeller gearbox is fluidly cooled by an airflow within the tail section. A spinner assembly surrounds the propeller hub. The spinner assembly includes at least one outlet opening formed therein downstream from the propeller hub relative to the airflow. The spinner assembly is rotatable to draw the airflow into at least one cooling flow inlet formed in the tail section and across the propeller gearbox to cool the propeller gearbox and out the at least one outlet opening.

A propeller system for a tail section of an aircraft includes a propeller hub located at the tail section of the aircraft, a plurality of propeller blades mounted to and extending outwardly from the propeller hub, a propeller shaft coupled to the propeller hub and operable to rotate the propeller hub about an axis of rotation, and a propeller gearbox connected to the propeller shaft. The propeller gearbox is fluidly cooled by an airflow within the tail section. A spinner assembly surrounds the propeller hub. The spinner assembly includes at least one outlet opening formed therein downstream from the propeller hub relative to the airflow. The spinner assembly is rotatable to draw the airflow into at least one cooling flow inlet formed in the tail section and across the propeller gearbox to cool the propeller gearbox and out the at least one outlet opening.

A bond fixture for bonding a component includes a frame defining a chamber for receiving the component. A first pad and a second pad are mounted to the frame. At least one of the first pad and the second pad is movable relative to the frame to adjust a pressure applied to the component. A caul assembly is adapted to be disposed in thermal communication with the component. The caul assembly heats a localized portion of the component.