Messerschmitt-Boelkow-Blohm Gmbh

Messerschmitt-Bolkow-Blohm Gmbh

Hans Derschmidt

Hubert Frommlet

Hermann Sahlstorfer

The wing blades of a hingeless and bearingless multiblade rotor are connected to a substantially rigid rotor hub by spar sections elastically twistable and bendable in the flapping direction and in the lead-lag direction. The mounting positions on the periphery of the rotor hub for connection of the spar sections of the respective blades are off-set relative to the angular position of the corresponding blades to which they are connected. Further, the mounting positions for the spar sections of each rotor blade are situated on the periphery of the half side or far side of the rotor hub, facing away from the respective rotor blade. A rear spar section of each mounted rotor blade with reference to the direction of rotation, overlaps the front spar section of the immediately following rotor blade but with free clearance and spacing between the overlapping spar sections in the direction of the rotor axis so that the maximum bendable length of the elastic spar sections is afforded without interference between the blades. The effective or virtual flapping hinges and lead-lag hinges of each blade is shifted closer to the rotor axis thereby minimizing the masses necessary for propeller moment compensation, and static and dynamic balancing of the rotor blades, as well as reducing the required steering forces.

Hingeless and bearingless multiblade rotor for rotary wing aircraft

A rotor, especially for rotary wing aircraft, is constructed without flapping hinges and without lead-lag hinges. The rotor comprises a rigid rotor head and rotor blades secured to the rotor head by flexible coupling rods, for example, made of fiber reinforced composite material. One end of each rod is secured to the rotor head. The other end of each rod is secured to the root of the respective rotor blade. The rods are so arranged that their central longitudinal axes coincide with a generatrix of two coaxial cones having a central axis. One of the cones is located with its base in the respective rotor blade while the other cone is located with its base in the rotor head. This type of structure is surprisingly simple, yet capable of transferring substantial forces between the rotor head on the one hand and the rotor blades on the other hand.

Rotor without flapping hinges and without lead-lag hinges

The present rotor head for a helicopter is free of flapping hinges and free of drag or lagging hinges. The rotor blades or wings are connected to the rotor head by a plurality of connecting plates which are flexible to bending moments. These plates are inserted into the blade roots of the helicopter wings and connected to the rotor head proper. The planes defined by these connecting plates intersect in the axis of the rotor blades or wings.

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Putzbrunn, Germany

Hans Derschmidt