A rotorcraft including a fuselage, one or more motor-driven rotors for vertical flight, and a control system. The motors drive the one or more rotors in either of two directions of rotation to provide for flight in either an upright or an inverted orientation. An orientation sensor is used to control the primary direction of thrust, and operational instructions and gathered information are automatically adapted based on the orientation of the fuselage with respect to gravity. The rotors are configured with blades that invert to conform to the direction of rotation.

A method of forming a rotor blade, including forming at least one of a partial upper skin, a partial lower skin, and a partial support network using an additive manufacturing process; and forming a first receptacle in at least a one of the partial upper skin, the partial lower skin, and the partial support network using the additive manufacturing process. The first receptacle is configured to receive of at least one of an electronic component and a mechanical component. In some embodiments, there is a method of manufacturing a rotor blade that includes forming a first locating receptacle in at least one of the upper skin, the lower skin, and the support network using the additive manufacturing process; and positioning at least one of the upper skin, the lower skin, and the support network in a desired position on a fixture based, in part, on the first locating receptacle.

A system for changing a shape a structural spar includes, in an exemplary embodiment, a plurality of adjoining structural strips axially aligned to form the structural spar. At least one of the structural strips is formed from a shape memory alloy. The system also includes a temperature control system to control a temperature of the at least one shape memory alloy strip. Heat applied to the at least one shape memory alloy strip causes the structural spar to twist or bend.

The present invention includes an apparatus for protecting an aerodynamic surface from erosion including a screen capable of being applied to a leading edge of the aerodynamic surface; and an erosion protection coating applied to the screen before or after the screen is applied to the leading edge, wherein the erosion protection coating protects the aerodynamic surface from erosion.

Aspects of the present disclosure provide coatings and methods for depositing coatings onto surfaces. In one aspect, a method for forming a coating includes applying a composition to a surface of a component, the composition including a first polymer, a second polymer that is a fluoropolymer, an isocyanate, and a curative. The method includes curing the mixture at a first temperature of about 50 C. or greater and increasing the first temperature to a second temperature of about 80 C. or greater. The method includes obtaining a coating disposed on the surface of the component, the coating having a thickness of from about 10 mils to about 50 mils and a void density of less than 5 voids of size 0.5 mm or greater per cm.sup.2.

An erosion protection system (EPS) has a first erosion protection unit (EPU) having a first ligament and a first scale attached to the first ligament, the first scale having an outer hardness that is greater than a hardness of the first ligament. The EPS also has a second EPU having a second ligament and a second scale attached to the second ligament, the second scale having an outer hardness that is greater than a hardness of the second ligament. The EPS also has an interstitial space between the first ligament and the second ligament wherein at least one of (1) the first scale overlaps at least a portion of the second EPU and (2) the second scale overlaps at least a portion of the first EPU.

A rotorcraft including a fuselage, one or more motor-driven rotors for vertical flight, and a control system. The motors drive the one or more rotors in either of two directions of rotation to provide for flight in either an upright or an inverted orientation. An orientation sensor is used to control the primary direction of thrust, and operational instructions and gathered information are automatically adapted based on the orientation of the fuselage with respect to gravity. The rotors are configured with blades that invert to conform to the direction of rotation.

In some embodiments, a rotorcraft includes an engine, a rotor hub assembly mechanically coupled to the engine and a plurality of rotor blade assemblies rotatably mounted to the rotor hub assembly. Each of the rotor blade assemblies includes a rotor blade having a leading edge and an erosion shield system extending spanwise along the leading edge of the rotor blade. The erosion shield system includes a plurality of erosion shield segments positioned adjacent to one another forming joints therebetween wherein, the joints deform responsive to strain experienced by the rotor blade, thereby isolating the erosion shield segments from at least a portion of the strain experienced by the rotor blade.

A propeller according to an embodiment includes a hub and a series of blades extending outward from the hub. Each blade of the series of blades includes a core and a skin covering the core. The core may be formed of a ceramic first material and the skin is formed of a second material different than the ceramic first material. The ceramic first material of the core may be ceramic Si.sub.3N.sub.4 (silicon nitride), yttria-toughened zirconia ceramic, or alumina-zirconia ceramic, and the second material of the skin may be a polymer. The polymer skin is configured to function as a shock absorber protecting the ceramic core, and the ceramic core is configured to provide rigidity to maintain the shape of the propeller blades under aerodynamic loading, which enables improved aerodynamic efficiency and reduced noise generation.

In an implementation, a rotor blade (alternatively referred to herein as blade) for a helicopter or other aircraft may include an outer layer. The outer layer may define a cavity. The outer layer may at least partially correspond to an airfoil, e.g., a wing. One or more inserts may be included within the cavity and be encompassed thereby. The first insert may have a density of at least 0.6 pounds per cubic inch.