A method of designing a rotor blade for a rotary aircraft includes establishing a target thrust-weighted solidity of the rotor blade, calculating a reverse flow circle of the rotor blade at a target forward speed of the rotary aircraft, inboard of the reverse flow circle, decreasing chord of the rotor blade relative to a baseline rotor blade possessing the target thrust-weighted solidity, and outboard of the reverse flow circle, increasing the chord of the rotor blade relative to the baseline rotor blade. The rotor blade possesses the target thrust-weighted solidity of the baseline rotor blade and improved stall margin or speed margin at the target forward speed relative to the baseline rotor blade.

Wingtip shields are described. In one embodiment, a wingtip shield includes an inner surface facing a high-pressure side of an airfoil. The airfoil is attached to the main body. The wingtip shield also includes an outer surface configured opposite from the inner surface. The wingtip shield is attachable to the airfoil along a peripheral edge of the airfoil from a first point of a leading edge of the airfoil to a second point of a trailing edge of the airfoil. A first span distance from the first point at the leading edge to the main body is less than a second span distance of the second point at the trailing edge to the main body.

A rotor blade configured to couple to a rotor assembly having an axis of rotation includes a blade radius R between the axis of rotation and an outboard end of the rotor blade when coupled to the rotor assembly. When an inboard end of the rotor blade is coupled to the rotor assembly at about x/R=0.10, between about 18 percent and about 22 percent of the total mass of the rotor blade is located between about x/R=0.88 and about x/R=0.93, x corresponding to a radial location of the rotor blade measured from the axis of rotation.

The disclosed rotorcraft includes a rotor blade and a prime mover. The rotor blade extends in a radial direction. The prime mover is configured to rotate the rotor blade. The rotor blade includes a blade body and a blade end portion. The blade end portion is disposed on an outer side of the blade body in the radial direction. The blade end portion includes a leading edge (i.e., an edge facing the rotational direction) that tilts in a rotational direction to the outer side in the radial direction. The disclosed configuration reduces noise produced by the rotorcraft.

The disclosed embodiments are directed to an eVTOL aircraft comprising a fuselage, wings mounted to the fuselage, where the wings comprise an undercambered lower surface, and an array of ducted fans mounted to the undercambered lower surface, wherein each fan in the array of ducted fans further comprises a duct and a plurality of rotor blades, each of the plurality of rotor blades comprising a zero sweep leading edge and an elliptical trailing edge.