Various examples are provided related to flight duration enhancement for rotorcraft and multicopters. In one example, a rotorcraft or multicopter includes one or more rotors, and one or more nozzles positioned in relationship to at least one corresponding rotor. The one or more nozzles can modulate, reshape, redirect, or adjust downwash produced by the corresponding rotor. The one or more nozzles can dynamically modulate, reshape, redirect, or adjust the downwash below the rotorcraft or multicopter. The one or more nozzles can be morphed or reshaped to dynamically modulate, reshape, redirect, or adjust the downwash using, e.g., a stochastic optimization framework and/or a motif-based auto-controller.

Various examples are provided related to flight duration enhancement for rotorcraft and multicopters. In one example, a rotorcraft or multicopter includes one or more rotors, and one or more nozzles positioned in relationship to at least one corresponding rotor. The one or more nozzles can modulate, reshape, redirect, or adjust downwash produced by the corresponding rotor. The one or more nozzles can dynamically modulate, reshape, redirect, or adjust the downwash below the rotorcraft or multicopter. The one or more nozzles can be morphed or reshaped to dynamically modulate, reshape, redirect, or adjust the downwash using, e.g., a stochastic optimization framework and/or a motif-based auto-controller.

A rotor blade system having a plurality of rotor blades, wherein at least one of the rotor blades includes an outer surface having generally opposing first and second surfaces, the rotor blade including a fluid flow altering surface positioned relative to one of the first or second surfaces which is moveable between first and second positions, wherein movement of the fluid flow altering surface is effected by an expandable member.

A rotor blade system having a plurality of rotor blades, wherein at least one of the rotor blades includes an outer surface having generally opposing first and second surfaces, the rotor blade including a fluid flow altering surface positioned relative to one of the first or second surfaces which is moveable between first and second positions, wherein movement of the fluid flow altering surface is effected by an expandable member.

The present disclosure presents systems, apparatuses, and methods of active flow controls for dissipating tip vortices. In this regard, a method comprises positioning one or more fan-shaped plasma actuators on an end surface of a tip of one or more airfoils of an aircraft, wherein the fan-shaped plasma actuators are surface compliant with the surface of the tip of the one or more airfoils; and activating the one or more fan-shaped plasma actuators during a flight of the aircraft, wherein at least one tip vortex generated by a flight of the aircraft is reduced by an introduction of one or more vortices generated by the one or more fan-shaped plasma actuators on the end surface of the tip of the one or more airfoils of the aircraft. Other systems, apparatuses, and methods are also presented.

A tracking wedge, a rotor and a method for modifying a movement of air over a tracking wedge. According to aspects of the disclosure, a tracking wedge used to correct the tracking of a helicopter rotor blade may include one or more acoustic management mechanisms. The acoustic management mechanisms may change the manner in which air moves over the surface of the tracking wedge. In some examples, changing the manner in which air moves over the surface of the tracking wedge may reduce noise generated by the use of the tracking wedge.

A tracking wedge, a rotor and a method for modifying a movement of air over a tracking wedge. According to aspects of the disclosure, a tracking wedge used to correct the tracking of a helicopter rotor blade may include one or more acoustic management mechanisms. The acoustic management mechanisms may change the manner in which air moves over the surface of the tracking wedge. In some examples, changing the manner in which air moves over the surface of the tracking wedge may reduce noise generated by the use of the tracking wedge.

A propeller blade comprises a blade root coupled to a rotor hub and a blade tip. The propeller blade is composed of airfoil cross-sections, each cross-section a distance away from the rotor hub. Each airfoil is designed with particular structural characteristics that improve the overall amount of thrust generated on the quadcopter. Namely, each airfoil possesses a β angle and chord length whose values depend on the distance of that airfoil from the rotor hub. For example, the relationship between an airfoil's β angle and its distance from the rotor hub is described by a power law. Additionally, the relationship between an airfoil's chord length and its distance from the rotor hub is described using a polynomial regression. Compared to current, off the shelf propeller blades, the current propeller blade embodiment achieves the same thrust at a lower RPM, thereby yielding benefits in reduced acoustic noise and improved response time.

A propeller blade comprises a blade root coupled to a rotor hub and a blade tip. The propeller blade is composed of airfoil cross-sections, each cross-section a distance away from the rotor hub. Each airfoil is designed with particular structural characteristics that improve the overall amount of thrust generated on the quadcopter. Namely, each airfoil possesses a β angle and chord length whose values depend on the distance of that airfoil from the rotor hub. For example, the relationship between an airfoil's β angle and its distance from the rotor hub is described by a power law. Additionally, the relationship between an airfoil's chord length and its distance from the rotor hub is described using a polynomial regression. Compared to current, off the shelf propeller blades, the current propeller blade embodiment achieves the same thrust at a lower RPM, thereby yielding benefits in reduced acoustic noise and improved response time.

Various embodiments of an airfoil and machines with airfoils are disclosed. The airfoils include a thicker leading airfoil portion and a thinner trailing airfoil portion. In one embodiment, the leading airfoil portion is formed by bending a body of the airfoil back toward itself. In another embodiment, the leading airfoil portion has a solid geometry and includes two elliptic surfaces. To prevent detachment of airflow, the leading airfoil portion includes at least two arc portions or surfaces that act to direct the airflow down to the trailing airfoil portion in a manner that stabilizes vortexes that may form in the region of changing thickness.