Patent ID: 9623963
Date: 2017-04-18
CPC Classifications: B64C,Y10T

Claim:
1. A partly cruciform flexbeam of a bearingless main rotor system of a helicopter with a hub drive and an airfoil blade, said partly cruciform flexbeam comprising: a flexbeam head with a flat bearing laminate at one end, the flexbeam head being adapted for releasable connection to the airfoil blade; a root end, the root end being opposed to the flexbeam head, the root end being adapted for releasable connection to the hub drive, and a flexbeam body between the flexbeam head and the root end, the flexbeam body being torsion soft with a substantially cruciform cross section, the substantially cruciform cross section of the flexbeam body comprising bars and fillets, the bars being integral with and essentially perpendicular to the fillets and the bars being in line with the flexbeam head, the flexbeam body being assembled along the respective bars and fillets to the substantially cruciform cross section with separations at least along the fillets, wherein the fillets and the bars include a plurality of rovings, the plurality of rovings extending from at least beyond the separations along the fillets of the flexbeam body and along the flexbeam head, and at least two L-shaped integral tissue layers extending from in between of the flexbeam body up to an entire width of the flexbeam head with the rovings in between at the flexbeam head, wherein the at least two L-shaped integral tissue layers are alternating with the rovings of the flexbeam head and/or with supplemental rovings.