Abstract: A rotor blade (1) with an exterior shell (20) extending in a span and chord wise direction and at least one control flap (4) extending in essentially span wise direction to said exterior shell (20). Load transmission means inside said blade chamber (7) comprise piling type housings (13) respectively with one actuator (8, 9), one flap drive (10, 11) and a longitudinal girder (15). Said at least one piling type housing (13) comprises at least one upper strap (14) and at least one lower strap (14) oriented essentially in said chord direction in between said longitudinal girder (15) on the one side and the support for said at least one actuator (8, 9) on the other side, each of said upper and lower straps (14) being symmetric aligned in chord direction relative to at least two pivot bearings (35, 36). Said upper and lower straps (14) are stiff in chord direction and flexible in span wise direction.

Abstract: A rotor blade (1) with an exterior shell (20) extending in a span and chord wise direction and at least one control flap (4) extending in essentially span wise direction to said exterior shell (20). Load transmission means inside said blade chamber (7) comprise piling type housings (13) respectively with one actuator (8, 9), one flap drive (10, 11) and a longitudinal girder (15). Said at least one piling type housing (13) comprises at least one upper strap (14) and at least one lower strap (14) oriented essentially in said chord direction in between said longitudinal girder (15) on the one side and the support for said at least one actuator (8, 9) on the other side, each of said upper and lower straps (14) being symmetric aligned in chord direction relative to at least two pivot bearings (35, 36). Said upper and lower straps (14) are stiff in chord direction and flexible in span wise direction.

Abstract: A planar flexbeam unit (1, 40) as interface between a rotor shaft (2) and a multi-blade rotor, especially for a multi-blade main rotor of a helicopter. The planar flexbeam unit (1, 40) comprises a plurality of essentially planar torque arms (3-7, 41-46), each torque arm (3-7, 41-46) having essentially a concave profile (8) along its radial extension and being integral with its adjacent torque arms (3-7, 41-46). Each of said torque arms (3-7, 41-46) comprises two bundles (10-14) of straight, essentially uni-directional fibers agglomerated by a hardened synthetic resin and arranged along the essentially concave profile (8) along its radial extension. Each of said bundles passing into two essentially opposed torque arms (3-7, 41-46) without remarkable change of direction.

Abstract: An aerodynamic profile includes a main profile body defining a profile depth direction and being shear-flexible in the profile depth direction, a tension-stiff and compression-stiff upper covering skin, a tension-stiff and compression-stiff lower covering skin, wherein the upper and lower covering skins envelope the main profile body, a bearingless and hingeless rear profile deformation region disposed at a rear edge region, and at least one actuator disposed in the main profile body. The at least one actuator is configured to initiate a flexural motion of the main profile body resulting in a curvature of the upper and lower covering skins and to deform the rear profile deformation region and so as to yield a flap deflection directed opposite to a direction of the flexural motion.

Abstract: A rotor blade for a bearingless rotor of a rotorcraft includes a flapwise-flexible and lead-lag-flexible rotor blade attachment region, an inner rotor blade segment, and an outer rotor blade segment. The inner rotor blade segment includes a blade root region and an aerodynamically effective rotor blade profile having a front profile region and a rear profile region relative to a blade depth direction. The front profile region includes a spar disposed in the blade root region and extending in the blade radius direction, the front profile region and spar embodied as a torsionally flexible hollow body in a region of the inner rotor blade segment, and the rear profile region being torsionally stiff. The front profile region and the rear profile are separated by a separation distance in the inner rotor blade segment. The torsional flexibility of the front profile region and the separation distance decreases with increasing blade radius in the inner rotor blade segment.

Abstract: An aerodynamic profile includes a main profile body defining a profile depth direction and being shear-flexible in the profile depth direction, a tension-stiff and compression-stiff upper covering skin, a tension-stiff and compression-stiff lower covering skin, wherein the upper and lower covering skins envelope the main profile body, a bearingless and hingeless rear profile deformation region disposed at a rear edge region, and at least one actuator disposed in the main profile body. The at least one actuator is configured to initiate a flexural motion of the main profile body resulting in a curvature of the upper and lower covering skins and to deform the rear profile deformation region and so as to yield a flap deflection directed opposite to a direction of the flexural motion.

Abstract: A rotor blade for a bearingless rotor of a rotorcraft includes a flapwise-flexible and lead-lag-flexible rotor blade attachment region, an inner rotor blade segment, and an outer rotor blade segment. The inner rotor blade segment includes a blade root region and an aerodynamically effective rotor blade profile having a front profile region and a rear profile region relative to a blade depth direction. The front profile region includes a spar disposed in the blade root region and extending in the blade radius direction, the front profile region and spar embodied as a torsionally flexible hollow body in a region of the inner rotor blade segment, and the rear profile region being torsionally stiff. The front profile region and the rear profile are separated by a separation distance in the inner rotor blade segment. The torsional flexibility of the front profile region and the separation distance decreases with increasing blade radius in the inner rotor blade segment.

Abstract: A rotor blade arrangement for a bearingless rotor of a helicopter includes a flexbeam connecting an airfoil blade to a rotor head, and a control sleeve surrounding the flexbeam. The control sleeve is relatively stiff, but the flexbeam has portions that are flexible so as form a fictitious flapping hinge, lead-lag hinge, and torsion axis, which respectively enable flapping, lead-lag pivoting, and torsional movements of the airfoil blade. The inboard end of the control sleeve is secured to the root end of the flexbeam near the rotor head to prevent lateral displacements therebetween. Damping elements are arranged within the enclosure of the control sleeve at a location between the fictitious lead-lag hinge of the flexbeam and the transition region at which the flexbeam transitions into the airfoil blade.