A bond fixture for bonding a component includes a frame defining a chamber for receiving the component. A first pad and a second pad are mounted to the frame. At least one of the first pad and the second pad is movable relative to the frame to adjust a pressure applied to the component. A caul assembly is adapted to be disposed in thermal communication with the component. The caul assembly heats a localized portion of the component.

In one aspect, the present disclosure provides a system for reducing vibrations or stresses in a rotor blade system. The system may include at least three rotor blades configured to be rotated about a main rotor axis, where each of the three rotor blades may be adjusted by at least one electrically-adjustable control rod of a plurality of control rods. The plurality of control rods may include a first number of control rods forming a first group, and the plurality of control rods may include a second number of control rods forming a second group. A first circuit for may activate or deactivate the first group of control rods, and a second circuit may activate or deactivate the second group of control rods.

In one aspect, the present disclosure provides a system for reducing vibrations or stresses in a rotor blade system. The system may include at least three rotor blades configured to be rotated about a main rotor axis, where each of the three rotor blades may be adjusted by at least one electrically-adjustable control rod of a plurality of control rods. The plurality of control rods may include a first number of control rods forming a first group, and the plurality of control rods may include a second number of control rods forming a second group. A first circuit for may activate or deactivate the first group of control rods, and a second circuit may activate or deactivate the second group of control rods.

A tiltrotor aircraft is designed to accommodate rotors of different diameters, as well as corresponding wings and fuselages with different span and length, while maintaining very high parts commonality, especially with respect to drive train and power source. This enables design and operation of a fleet of such aircraft with significantly different rotor diameters, which are nevertheless optimized for different missions. In preferred embodiments the rotors are configured to have high stiffness and low weight to reduce aero-structural dynamic issues across the fleet. Also in preferred embodiments drive systems are designed for a full range of speed, torque, and power associated with all intended rotors. Turboshaft engine speeds are restricted to a narrow RPM range, so that a single gearset can be replaced to achieve the desired rotor RPM. Also in preferred embodiments, aircraft in a fleet can differ in folded length, empty weight, payload length by up 50%.

A main rotor blade 1, which is the main rotor blade 1 for a high-velocity helicopter, includes: a blade root part 10 having a length of 30% or more of a rotor radius R; and a blade main body 20 continuous with the blade root part 10. Preferably, a cross-sectional shape of the blade root part 10 satisfies (x/a).sup.m+(y/b).sup.m=1 and a>b, where m: arbitrary number, x: chord length direction, and y: blade thickness direction.

Composite airfoils of the present disclosure comprise a root section including a first surface. The airfoils comprise an intermediate section having a first surface and coupled with the root section at a first end. The airfoils comprise a tip section having a first surface and coupled at a first end with a second end of the intermediate section. The airfoils comprise a conductive material layer adjacent at least one of the first surface of the root section, the first surface of the intermediate section, and the first surface of the tip section. The conductive material comprises a first polymer, a second polymer, and a sulfonic acid.

Composite airfoils of the present disclosure comprise a root section including a first surface. The airfoils comprise an intermediate section having a first surface and coupled with the root section at a first end. The airfoils comprise a tip section having a first surface and coupled at a first end with a second end of the intermediate section. The airfoils comprise a conductive material layer adjacent at least one of the first surface of the root section, the first surface of the intermediate section, and the first surface of the tip section. The conductive material comprises a first polymer, a second polymer, and a sulfonic acid.

An example of a hub for a tail rotor includes a body configured to couple to a mast of a rotor system, a trunnion disposed within the body, first and second shafts disposed on opposite sides of the trunnion, first and second end plates secured to the body, and first and second end bearings, the first end bearing disposed between the first shaft and the first end plate and the second end bearing disposed between the second shaft and the second end plate.

An example of a hub for a tail rotor includes a body configured to couple to a mast of a rotor system, a trunnion disposed within the body, first and second shafts disposed on opposite sides of the trunnion, first and second end plates secured to the body, and first and second end bearings, the first end bearing disposed between the first shaft and the first end plate and the second end bearing disposed between the second shaft and the second end plate.

A propeller system for a tail section of an aircraft includes a propeller hub located at the tail section of the aircraft, a plurality of propeller blades mounted to and extending outwardly from the propeller hub, a propeller shaft coupled to the propeller hub and operable to rotate the propeller hub about an axis of rotation, and a propeller gearbox connected to the propeller shaft. The propeller gearbox is fluidly cooled by an airflow within the tail section. A spinner assembly surrounds the propeller hub. The spinner assembly includes at least one outlet opening formed therein downstream from the propeller hub relative to the airflow. The spinner assembly is rotatable to draw the airflow into at least one cooling flow inlet formed in the tail section and across the propeller gearbox to cool the propeller gearbox and out the at least one outlet opening.