A blade in which the aerodynamic profiles of a blade root, a blade neck and a central part of a profiled zone of the blade respectively comprise a leading edge section and a trailing edge section that are symmetrical to each other relative to an axis of symmetry. The present disclosure also concerns a method for constructing such a blade. The axis of symmetry is perpendicular to a segment connecting the leading edge to the trailing edge of each profile and is positioned in the middle of the segment. An intermediate upper surface section and an intermediate lower surface section connect the leading edge section and the trailing edge section in order to respectively form a lower surface of the aerodynamic profile.

A flow control method is a flow control method of controlling flow around a blade of a rotary wing, a plasma actuator being disposed at the blade. The flow control method includes: determining a characteristic frequency ratio that is a characteristic value among frequency ratios, each of the frequency ratios being a ratio between an actuator driving frequency and an angle of attack changing frequency, the actuator driving frequency being a frequency of an applied voltage applied to the plasma actuator, the angle of attack changing frequency being a frequency at which an angle of attack of the blade changes in accordance with a rotation angle of the blade; setting the actuator driving frequency such that the frequency ratio becomes the characteristic frequency ratio; and applying a voltage of the set actuator driving frequency to the plasma actuator to control the flow around the blade.

A propeller includes a blade. The blade includes a blade root, a blade tip disposed away from the blade root, a blade front surface, and a blade back surface. The blade also includes a front edge connecting a first side of each of the blade front surface and the blade back surface. The blade also includes a rear edge connecting a second side of each of the blade front surface and the blade back surface. The blade further includes a first suppression member formed by a portion of the front edge adjacent to the blade tip bending toward a first direction. The first direction is a direction from the front edge to the rear edge. The first suppression member is configured to suppress a spanwise air flow.

A propeller includes a blade. The blade includes a blade root, a blade tip disposed away from the blade root, a blade front surface, and a blade back surface. The blade also includes a front edge connecting a first side of each of the blade front surface and the blade back surface. The blade also includes a rear edge connecting a second side of each of the blade front surface and the blade back surface. The blade further includes a first suppression member formed by a portion of the front edge adjacent to the blade tip bending toward a first direction. The first direction is a direction from the front edge to the rear edge. The first suppression member is configured to suppress a spanwise air flow.

A yaw control system for a helicopter having an airframe that includes a tailboom includes one or more tail rotors rotatably coupled to the tailboom and a flight control computer implementing an airframe protection module. The airframe protection module includes an airframe protection monitoring module configured to monitor one or more flight parameters of the helicopter and an airframe protection command module configured to modify one or more operating parameters of the one or more tail rotors based on the one or more flight parameters of the helicopter, thereby protecting the airframe of the helicopter.

The invention discloses a method and modified aerodynamic apparatuses: fluid pushers-off and fluid motion-sensors, making enable efficient implementation and use of a controllable enhanced jet-effect, either the waving jet-effect, the Coanda jet-effect, the lift-effect, the effect of thrust, the Venturi effect, and/or the de Laval jet-effect, all are controllable using the Peltier effect and/or the Seebeck effect. The modified aerodynamic apparatuses are geometrically shaped and supplied with built-in thermoelectric devices, wherein the presence of the thermoelectric devices provides for new functional properties of the modified aerodynamic apparatuses. The method solves the problem of effective control of the operation of modified aerodynamic apparatuses such as airfoil wings of a flying vehicle, convergent-divergent nozzles, loudspeakers, and detectors of acoustic waves, all of a highly-efficient functionality.

A data transmission method and a sending end device are provided. The method is applied to short-range wireless communication based on a high carrier frequency. During the process of a sending end device sending data to be transmitted to a receiving end device, the method includes: after short-range wireless communication interrupted between the sending end device and the receiving end device is restored, the sending end device querying recorded transmission information, wherein the transmission information is used to indicate a data block, transmission of which is not completed, in the data to be transmitted; and the sending end device sending, to the receiving end device, the data block, transmission of which is not completed, in the data to be transmitted.

An autogyro rotor blade for generating lift by autorotation defines a root-side inner profile region, which has a first profile. The inner profile region has a tip-side main profile region, which has a second profile different from the first profile, and a profile depth curve that decreases monotonically in the longitudinal direction of the autogyro rotor blade from the region of the blade root in the direction of the blade tip. The autogyro rotor blade has a twist having a twist curve that decreases monotonically from the region of the blade root in the direction of the blade tip. The twist curve has a variable slope in the inner profile region and/or main profile region, and therefore the twist curve is concavely curved in this region.

An autogyro rotor blade for generating lift by autorotation defines a root-side inner profile region, which has a first profile. The inner profile region has a tip-side main profile region, which has a second profile different from the first profile, and a profile depth curve that decreases monotonically in the longitudinal direction of the autogyro rotor blade from the region of the blade root in the direction of the blade tip. The autogyro rotor blade has a twist having a twist curve that decreases monotonically from the region of the blade root in the direction of the blade tip. The twist curve has a variable slope in the inner profile region and/or main profile region, and therefore the twist curve is concavely curved in this region.

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.