US 12,391,376 B2
Tail rotor head of a rotary wing aircraft and blade holder
Mario Caminada, Ernetschwil (CH); and Michal Skrzynski, Zürich (CH)
Assigned to Kopter Group AG, (CH)
Appl. No. 17/923,156
Filed by Kopter Group AG, Mollis (CH)
PCT Filed Apr. 16, 2021, PCT No. PCT/EP2021/059970
§ 371(c)(1), (2) Date Nov. 3, 2022,
PCT Pub. No. WO2021/223984, PCT Pub. Date Nov. 11, 2021.
Claims priority of application No. 00537/20 (CH), filed on May 6, 2020.
Prior Publication US 2023/0348052 A1, Nov. 2, 2023
Int. Cl. B64C 27/82 (2006.01); B64C 27/48 (2006.01)
CPC B64C 27/82 (2013.01) [B64C 27/48 (2013.01); B64C 2027/8254 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A tail rotor head of a shrouded tail rotor for a rotary wing aircraft, comprising:
at least a pitch control unit;
a tail rotor hub comprising an inner cylindrical wall and an outer cylindrical wall coaxial with the inner cylindrical wall, the inner cylindrical wall comprising a first plurality of openings, the outer cylindrical wall comprising a second plurality of openings, wherein each of the first plurality of openings is aligned with one of the second plurality of openings,
a plurality of tail rotor blade holders arranged extending through the first and second plurality of openings and the pitch control unit,
wherein for each of the plurality of tail rotor blade holders:
a tail rotor blade is detachably connected to a blade holding part of the tail rotor blade holder;
a tension torsion strap is detachably mounted holder to a strap holding part of the tail rotor blade holder, the strap holding part and the blade holding part being arranged at a linear distance from one another on the tail rotor blade holder,
wherein the tension torsion strap is arranged to run from the tail rotor head, at least partly through the tail rotor blade holder, and radially outward in a direction of the tail rotor blade;
wherein the tension torsion strap is arranged fixed in the strap holding part by a strap holding bolt, while one end of the tail rotor blade is detachably fixed independently and spaced apart from the tension torsion strap in a bracket interior of a mounting bracket with at least one blade bolt passing a bore in the blade holding part;
wherein the blade holding part is located outside of the tail rotor hub, and
wherein the blade holding part further comprises a flange arranged abutting to the strap holding part, the flange comprising a circumference adapted to an opening in the tail rotor hub.