Patent ID: 8128367

Claim:
A rotor blade for a bearingless rotor of a rotorcraft defining a blade radius direction and a blade depth direction, the rotor blade comprising: a flapwise-flexible and lead-lag-flexible rotor blade attachment region for articulation of a control rod; an inner rotor blade segment; and an outer rotor blade segment disposed outside the inner rotor blade segment relative to the blade radius direction, the inner rotor blade segment including a blade root region and an aerodynamically effective rotor blade profile having a front profile region and a rear profile region relative to the blade depth direction, the front profile region including 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, wherein at least a portion of the front profile region and the rear profile region are separated by a separation distance in the inner rotor blade segment, wherein the torsional flexibility of the front profile region and the separation distance decrease with increasing blade radius in the inner rotor blade segment, wherein, in the outer rotor blade segment, the front and the rear profile region are embodied as a closed, torsionally stiff profile, and wherein the inner rotor blade segment includes an inner subregion and an adjacent outer subregion relative to the blade radius direction, wherein, in the inner subregion, the rear profile region forms a closed profile having a front separating skin strip, and is completely separated from the front profile region by a slot disposed between the separating skin strip and the spar, and wherein at an inner portion of the outer subregion, the rear profile region and the front profile region are joined to one another on their upper profile side by means of a covering skin strip, and, with increasing blade radius the separating skin strip assumes an arc-shaped conformation having a vertex and limbs associated with the rear and the front profile regions respectively, a height of the vertex decreasing with increasing blade radius.