A bond fixture includes a support structure and a first assembly coupled to the support structure. The first assembly includes a frame defining a chamber and a first pressure pad and second pressure pad coupled to the frame opposite one another and positioned within the chamber. The second pressure pad is movable to control a pressure applied by the first pressure pad and the second pressure pad.

A replacement tip section for a rotor blade, from which a legacy tip section was removed, includes a blade tip portion configured to be attached to an intermediate section of the rotor blade after removal of the legacy section. The intermediate section has a connection feature at an end of the intermediate section to which the blade tip portion is attachable. The replacement tip section includes a transition region configured to be attached to a forward end of the connection feature. The transition region is configured to form a leading edge of the rotor blade and extends from the blade tip portion to form an opening into which the intermediate section is attached. The transition region includes a first end having a first airfoil that conforms to the intermediate section airfoil at the connection feature, and a second end having a second airfoil that conforms to the blade tip portion.

An acoustic system for an Urban Air Mobility (UAM) vehicle may comprise: a first shroud configured to be disposed around a rotor of the UAM vehicle, the first shroud comprising: a radially inner wall configured to be spaced radially outward from a blade tip of a rotary blade of the rotor, the radially inner wall including a perforated portion; and a hollow chamber defined by an internal surface of the first shroud and the radially inner wall.

An acoustic system for an Urban Air Mobility (UAM) vehicle may comprise a first shield configured to be disposed around a rotor of the UAM vehicle, the first shield having an annular shape, the first shield configured to be disposed radially outward from a blade tip of a rotary blade, the first shield configured to redirect sound waves from a substantially radial direction to a second direction, the second direction being orthogonal to the radial direction.

A flight direction indication system for an aerial vehicle having a plurality of rotors includes: for each of the plurality of rotors, at least one rotor blade having a plurality of light sources arranged along a radial extension of the rotor blade; and a control unit, coupled to the plurality of light sources of the rotor blades of the plurality of rotors. The control unit is configured to effect a coordinated control of the plurality of light sources of the rotor blades of the plurality of rotors, with the coordinated control yielding an image or a sequence of images across the plurality of rotors to an observer of the aerial vehicle and to to control the plurality of light sources of the rotor blades of the plurality of rotors on the basis of a momentary flight direction of the aerial vehicle.

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.

A rotor for a hover-capable aircraft is described that comprises: a hub rotatable about a first axis and at least two blades hinged to the hub; each blade comprises a main portion hinged to the hub and a tip portion, which is arranged radially outermost with respect to first axis with respect to the corresponding main portion; the tip portion of each blade is movable with respect to the corresponding main portion of that blade; the tip portion of each blade is selectively movable with respect to the corresponding main portion of that blade between a first position, in which it defines a dihedral or anhedral angle with respect to the corresponding main portion; and a second position, in which it defines a positive or negative sweep angle with respect to the corresponding main portion.

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.

A rotor blade has a spanwise axis, a root comprising an anchor having an anchor surface configured to form at least one of a normal angle relative to the spanwise axis and an acute angle relative to the spanwise axis, and a selectively removable tip comprising a connector having a connector surface configured to complement the anchor surface.

A method of assisting in rotor speed control in a rotorcraft can include measuring a rotor speed with a sensor; detecting a droop in the rotor speed beyond a lower droop limit; and commanding a decrease in collective in response to the rotor speed drooping beyond the lower droop limit. A system of assisting in rotor speed control in a rotorcraft, the system can include: a computer having a control law, the control law operable to generate a decrease collective command to an actuator in response to a rotor speed decreasing below a lower droop limit; wherein the lower droop limit is below a normal lower rotor speed range.