An assembly configured to prevent damage to an object during manufacture thereof is provided including a first housing having a substantially hollow interior. An exposed first planar surface of the first housing includes an inlet port and a plurality of small openings formed about the periphery. The inlet port, the hollow interior, and the plurality of small openings form a fluid flow path through the assembly. A second housing similar in size and shape to the first housing, has an exposed second planar surface. An intermediate layer is arranged between the first housing and the second housing. A cross-section of the intermediate layer is configured to change shape in response to a compression force applied thereto by the first housing and the second housing to form a seal separating an exterior portion of the objection exposed to the plurality of small openings from an interior surface of the object.

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.

An assembly configured to prevent damage to an object during manufacture thereof is provided including a first housing having a substantially hollow interior. An exposed first planar surface of the first housing includes an inlet port and a plurality of small openings formed about the periphery. The inlet port, the hollow interior, and the plurality of small openings form a fluid flow path through the assembly. A second housing similar in size and shape to the first housing, has an exposed second planar surface. An intermediate layer is arranged between the first housing and the second housing. A cross-section of the intermediate layer is configured to change shape in response to a compression force applied thereto by the first housing and the second housing to form a seal separating an exterior portion of the object exposed to the plurality of small openings from an interior surface of the object.

A rotor blade is provided. The rotor blade includes a blade portion, a tip cap formed to define a dimple, a fastener and a doubler. The fastener includes a flat-headed shaft and is disposable such that the flat-headed shaft extends through the blade portion and the tip cap at the dimple. The fastener is configured to urge the blade portion toward the tip cap. The doubler includes a dimpled portion disposable between the tip cap and a portion of the flat-headed shaft at the dimple and an exterior portion. The exterior portion is disposable flush with respective exterior surfaces of the blade portion and the flat-headed shaft.

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.

Features for a tail-sitter aircraft having efficiently designed propulsive elements are disclosed. The aircraft may have a tail with landing mounts to support the aircraft in a vertical position for takeoff and landing. The aircraft may have a hybrid propulsion system including an electric power source, such as a generator and an electric motor, and a prime power subsystem, such as an internal combustion engine. The electric and prime power subsystems may be used controllably in varying amounts depending on the phase of flight, such as takeoff, horizontal flight, landing, or maneuvers. The aircraft may have blades with piezo elements to provide shape-changing capability to the blade. The shape of the blade, such as the pitch and/or twist, may be controllably changed for optimal efficiency with the blade depending on phase of flight. The blade shape may be changed from a rotor-like shape during takeoff and landing, to a propeller-like shape during horizontal flight.

A preceramic resin formulation comprising a polycarbosilane preceramic polymer, an organically modified silicon dioxide preceramic polymer, and, optionally, at least one filler. The preceramic resin formulation is formulated to exhibit a viscosity of from about 1,000 cP at about 25? C. to about 5,000 cP at a temperature of about 25? C. The at least one filler comprises first particles having an average mean diameter of less than about 1.0 ?m and second particles having an average mean diameter of from about 1.5 ?m to about 5 ?m. Impregnated fibers comprising the preceramic resin formulation are also disclosed, as is a composite material comprising a reaction product of the polycarbosilane preceramic polymer, organically modified silicon dioxide preceramic polymer, and the at least one filler. Methods of forming a ceramic matrix composite are also disclosed.

A structure (10) for aircrafts, includes a part (20) including a metal leading edge (30), the leading edge (30) being covered by a coating (40) having a thickness which is less than or equal to ten micrometers and having a hardness higher than six hundred in the Vickers hardness test (HV). According to a mode of embodiment, the coating (40) is a multilayer stainless steel coating consisting of a superposition of layers with a low nitrogen gradient and layers with a high nitrogen gradient, the layers having a thickness essentially equal to a micrometer. An aircraft including such a structure is also described.

A system, method, and apparatus for a co-bonded electroformed abrasion strip are disclosed. A disclosed method for making a unitary abrasion strip for a fluid dynamic surface includes manufacturing or identifying a first metallic section having an overlap region on a first end of the first metallic section. The method further includes manufacturing or identifying an overlap region disposed on the first end of the first metallic section by preparing the first end of the first metallic section. Also, the method includes creating a second metallic section onto the overlap region on the first end of the first metallic section by performing a first electro-deposition process on the first end of the first metallic section; where the first metallic section, the overlap region, and the second metallic section together form a unitary, inseparable abrasion strip for a fluid dynamic surface.

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.