Abstract: The present disclosure provides sol-gel films and substrates, such as vehicle components, having a sol-gel film disposed thereon. At least one sol-gel formulation has about 10 wt % or less water content based on the total weight of the sol-gel formulation and comprises an organosilane, a metal alkoxide, an acid stabilizer, and an organic solvent. At least one vehicle component comprises a sol-gel coating system comprising a metal substrate and a sol-gel formulation disposed on the metal substrate. The sol-gel formulation has about 10 wt % or less water content based on the total weight of the sol-gel formulation and comprises an organosilane, a metal alkoxide, an acid stabilizer, and an organic solvent.

Abstract: A rotor assembly comprises a rotor hub and rotor-blade assemblies. The rotor hub comprises rotor-blade supports. Each rotor-blade assembly is coupled to a respective one of the rotor-blade supports and comprises a flap axle, a hub connector, a rotor blade, and a torsion strap. The flap axle extends through a respective one of the rotor-blade supports and has a central flap-axle axis. The hub connector is pivotable relative to a rotor-blade support about the central flap-axle axis and defines a central hub-connector axis. The rotor blade is coupled to and is pivotable relative to the hub connector, and, together with the hub connector, is pivotable relative to a respective one of the rotor-blade supports about the central flap-axle axis. The torsion strap has a first end, coupled to the rotor blade, and a second end, through which the flap axle passes.

Abstract: The present disclosure provides sol-gel films and substrates, such as vehicle components, having a sol-gel film disposed thereon. At least one sol-gel formulation has about 10 wt % or less water content based on the total weight of the sol-gel formulation and comprises an organosilane, a metal alkoxide, an acid stabilizer, and an organic solvent. At least one vehicle component comprises a sol-gel coating system comprising a metal substrate and a sol-gel formulation disposed on the metal substrate. The sol-gel formulation has about 10 wt % or less water content based on the total weight of the sol-gel formulation and comprises an organosilane, a metal alkoxide, an acid stabilizer, and an organic solvent.

Abstract: The present disclosure provides methods for forming sol-gels, sol-gel films and substrates, such as vehicle components, having a sol-gel film disposed thereon. At least one method of forming a sol-gel includes mixing a metal alkoxide, an acid stabilizer, and an organic solvent to form a first mixture having about 10 wt % or less water content based on the total weight of the first mixture. The method includes mixing an organosilane with the first mixture to form a second mixture having about 10 wt % or less water content based on the total weight of the second mixture.

Abstract: The present disclosure provides methods for forming sol-gels, sol-gel films and substrates, such as vehicle components, having a sol-gel film disposed thereon. At least one method of forming a sol-gel includes mixing a metal alkoxide, an acid stabilizer, and an organic solvent to form a first mixture having about 10 wt % or less water content based on the total weight of the first mixture. The method includes mixing an organosilane with the first mixture to form a second mixture having about 10 wt % or less water content based on the total weight of the second mixture.

Abstract: The present disclosure provides methods for forming sol-gels, sol-gel films and substrates, such as vehicle components, having a sol-gel film disposed thereon. At least one method of forming a sol-gel includes mixing a metal alkoxide, an acid stabilizer, and an organic solvent to form a first mixture having about 10 wt % or less water content based on the total weight of the first mixture. The method includes mixing an organosilane with the first mixture to form a second mixture having about 10 wt % or less water content based on the total weight of the second mixture.

Abstract: A rotor assembly comprises a rotor hub and rotor-blade assemblies. The rotor hub comprises rotor-blade supports. Each rotor-blade assembly is coupled to a respective one of the rotor-blade supports and comprises a flap axle, a hub connector, a rotor blade, and a torsion strap. The flap axle extends through a respective one of the rotor-blade supports and has a central flap-axle axis. The hub connector is pivotable relative to a rotor-blade support about the central flap-axle axis and defines a central hub-connector axis. The rotor blade is coupled to and is pivotable relative to the hub connector, and, together with the hub connector, is pivotable relative to a respective one of the rotor-blade supports about the central flap-axle axis. The torsion strap has a first end, coupled to the rotor blade, and a second end, through which the flap axle passes.

Abstract: The present disclosure provides sol-gels, sol-gel films and substrates, such as vehicle components, having a sol-gel film disposed thereon. At least one sol-gel is the reaction product of an organosilane, a metal alkoxide, an acid stabilizer, and an organic solvent, the sol-gel having about 10 wt % or less water content based on the total weight of the sol-gel. At least one vehicle component comprises a sol-gel coating system, comprising a metal substrate and a sol-gel disposed on the metal substrate, and the sol-gel is the reaction product of an organosilane, a metal alkoxide, an acid stabilizer, and an organic solvent, the sol-gel having about 10 wt % or less water content based on the total weight of the sol-gel.

Abstract: The present disclosure provides methods for forming sol-gels, sol-gel films and substrates, such as vehicle components, having a sol-gel film disposed thereon. At least one method of forming a sol-gel includes mixing a metal alkoxide, an acid stabilizer, and an organic solvent to form a first mixture having about 10 wt % or less water content based on the total weight of the first mixture. The method includes mixing an organosilane with the first mixture to form a second mixture having about 10 wt % or less water content based on the total weight of the second mixture.

Abstract: The present disclosure provides sol-gel films and substrates, such as vehicle components, having a sol-gel film disposed thereon. At least one sol-gel formulation has about 10 wt % or less water content based on the total weight of the sol-gel formulation and comprises an organosilane, a metal alkoxide, an acid stabilizer, and an organic solvent. At least one vehicle component comprises a sol-gel coating system comprising a metal substrate and a sol-gel formulation disposed on the metal substrate. The sol-gel formulation has about 10 wt % or less water content based on the total weight of the sol-gel formulation and comprises an organosilane, a metal alkoxide, an acid stabilizer, and an organic solvent.

Abstract: A joint assembly includes a first component formed from a first material and a second component including a portion that extends at least partially into the first component and that has an uneven outer profile. The first material is configured to form the first component into a shape that is substantially complementary to a shape of the portion to facilitate restricting movement of the second component in an axial direction.

Abstract: Systems and methods for blade attachment are proved. The systems and methods include an aircraft system having a rotor hub including a blade connector and a composite blade including a lug fitting assembly. The lug fitting assembly includes a fitting core including a lug fitting aperture, a lug bushing coupled within the lug fitting aperture, and an outer fitting substantially surrounding the fitting core.

Abstract: Methods of co-curing aligned annular supports in a tubular region of a composite structure, such as a rotor blade, are disclosed. Methods include assembling an uncured composite structure by positioning an inboard annular support and an outboard annular support around an arbor, forming reinforcement fiber into a tubular region in contact with the supports, and applying a matrix material to the reinforcement fiber. The inboard and outboard annular supports are substantially composed of metal. Methods also include concentrically aligning the arbor and the supports along a common axis by applying heat to cause differential expansion of the arbor with respect to the supports, wherein the differential expansion causes an interference fit of the supports against the arbor. Methods also include curing the uncured composite structure to form the composite structure.

Abstract: A joint assembly is provided. The joint assembly includes a first component formed from a first material and a second component including a portion that extends at least partially into the first component and that has an uneven outer profile. The first material is configured to form the first component into a shape that is substantially complementary to a shape of the portion to facilitate restricting movement of the second component in an axial direction.

Abstract: Systems and methods for blade attachment are proved. The systems and methods include an aircraft system having a rotor hub including a blade connector and a composite blade including a lug fitting assembly. The lug fitting assembly includes a fitting core including a lug fitting aperture, a lug bushing coupled within the lug fitting aperture, and an outer fitting substantially surrounding the fitting core.

Abstract: A method for reducing bearing stress in a composite structure is disclosed. A composite structure comprises at least one coupling hole for coupling to the composite structure, and at least one bushing structure is coupled to the at least one coupling hole. A metal bushing retainer structure is coupled to the at least one bushing structure and the composite structure.

Abstract: A composite structural member is provided. The structural member includes a tubular shaft having a mating region of stiffness, and possibly thickness, greater than another region of said shaft. The shaft defines a lumen, and a fitting is disposed in the lumen. The fitting has a coupling region that defines at least one recessed portion bounded by one or more non-recessed portions, and the mating region mates with the coupling region of said fitting. As such, the shaft and fitting are mechanically restrained from at least some relative movement due to interference of the shaft and the fitting. A sleeve may be coupled to said shaft, for example, by including a tubular inner surface that proximately surrounds at least part of said shaft and mating region, for discouraging expansion of the mating region of said shaft.

Abstract: A composite structural member is provided. The structural member includes a tubular shaft having a mating region of stiffness, and possibly thickness, greater than another region of said shaft. The shaft defines a lumen, and a fitting is disposed in the lumen. The fitting has a coupling region that defines at least one recessed portion bounded by one or more non-recessed portions, and the mating region mates with the coupling region of said fitting. As such, the shaft and fitting are mechanically restrained from at least some relative movement due to interference of the shaft and the fitting. A sleeve may be coupled to said shaft, for example, by including a tubular inner surface that proximately surrounds at least part of said shaft and mating region, for discouraging expansion of the mating region of said shaft.

Abstract: A composite structural member is provided. The structural member includes a tubular shaft having a mating region of stiffness, and possibly thickness, greater than another region of said shaft. The shaft defines a lumen, and a fitting is disposed in the lumen. The fitting has a coupling region that defines at least one recessed portion bounded by one or more non-recessed portions, and the mating region mates with the coupling region of said fitting. As such, the shaft and fitting are mechanically restrained from at least some relative movement due to interference of the shaft and the fitting. A sleeve may be coupled to said shaft, for example, by including a tubular inner surface that proximately surrounds at least part of said shaft and mating region, for discouraging expansion of the mating region of said shaft.

Abstract: In an exemplary variable area nozzle, a fixed duct section has an inlet and an outlet oriented approximately perpendicular to the inlet. A controllable nozzle member is disposed adjacent the outlet of the fixed duct section. The controllable nozzle member has an area that is adjustable to maintain a substantially constant nozzle pressure ratio. The controllable nozzle member may include first and second flap doors hinged and pivotable in opposite directions between an open position and a closed position and that also may be hinged and pivotable in a same direction so thrust from gas exiting the nozzle is vectorable. When disposed in rotor tips of an aircraft capable of rotary wing flight and fixed wing flight, the variable area nozzle may maintain a substantially constant nozzle pressure ratio near an optimized nozzle pressure ratio as the aircraft transitions from rotary wing flight to fixed wing flight.