Abstract: A rotor craft changes a torsional angle of a blade by driving an actuator. The rotor craft includes a plurality of torsion applying mechanisms that each twist a proximal end portion of a corresponding blade relative to a distal end portion of the corresponding blade about a center axis A of the blade. Each blade includes a spar having a proximal end portion connected to a hub and a skin in which the spar is inserted, such that a distal end portion of the skin and a distal end portion of the spar are connected to each other, and such that other portions of the skin than the distal end portion are rotatable relative to the spar about a center axis of the spar. The hub includes a hub body mounted to a main rotor shaft, and a hub arm that connects the spar to the hub body.

Abstract: A rotor craft changes a torsional angle of a blade by driving an actuator. The rotor craft includes a plurality of torsion applying mechanisms that each twist a proximal end portion of a corresponding blade relative to a distal end portion of the corresponding blade about a center axis A of the blade. Each blade includes a spar having a proximal end portion connected to a hub and a skin in which the spar is inserted, such that a distal end portion of the skin and a distal end portion of the spar are connected to each other, and such that other portions of the skin than the distal end portion are rotatable relative to the spar about a center axis of the spar. The hub includes a hub body mounted to a main rotor shaft, and a hub arm that connects the spar to the hub body.

Abstract: A bearingless hub structure for a rotary-wing aircraft is provided, the structure including a hub body adapted to be securely connected to a rotor mast, a plurality of flexible beam members provided integrally with the hub body to extend radially outwardly, a pitch housing encircling each of the flexible beam members, and having a radially outward end portion which is rigid with a radially inward end portion of a rotor blade, a spherical bearing positioned adjacent to a radially inward end portion of the flexible beam member for supporting the pitch housing, a lead-lag damper positioned between the flexible beam member and the pitch housing, and the flexible beam members each having a flexible plate portion which is of a low bending rigidity in a flapping direction, a flexible portion provided radially outwardly of the flexible plate portion having a low bending rigidity in the lead-lag direction, and a twist-flex portion provided radially outwardly of the flexible portion.

Abstract: A bearingless hub structure for rotary-wing aircrafts comprising a hub body ecured to a rotor shaft, a plurality of radially extending flexbeams integrally formed with the hub body, and pitch housings enclosing each of the flexbeams in spaced relationship, the pitch housing having a radially outer end portion rigidly secured to an inboard end of a rotor blade and a radially inner end portion supported by a spherical bearing in the vicinity of a root end of said flexbeam.The flexbeam consists of a flexible element of low lead-lag stiffness and a torsion element of low torsional stiffness located radially outside the flexible element. The flexible element consists of two beam-like members having radially inner ends spaced in the lead-lag direction and extending radially outward with narrowing the distance between them, the beam-like member having radially outer end connected to a radially inner end of the torsion element.

Abstract: Disclosed is a filter-coated phosphor having phosphor particles coated with filter particles formed of pigments of the same color as that of light emitted from the phosphor, the phosphor particles coated with the filter particles being additionally coated with a borate compound. According to this filter-coated phosphor, the filter particles never exfoliate from the surfaces of the phosphor particles in a slurry, satisfactory dispersibility is obtained in the slurry, and the slurry pH is stable. A phosphor screen of a color picture tube obtained with use of the filter-coated phosphor exhibits highly outstanding contrast and luminous efficiency.