Sikorsky Aircraft Corporation

Edward W Gronenthal

David G Matuska

Robert C Moffitt

David G Matsuka

W Donald Jepson

A retraction/extension mechanism (70) for a Variable Diameter Rotor system (10), the Variable Diameter Rotor system (10) having a plurality of rotor blade assemblies (16) mounted to and rotating with a rotor hub assembly (18) about an axis of rotation (20), each rotor blade assembly (16) having inboard and outboard blade sections (24, 22) wherein the outboard blade section (22) telescopically mounts to the inboard blade section (24). The retraction/extension mechanism (70) includes a reeling assembly (80) disposed in combination with the outboard blade section (22) of each rotor blade assembly (16) and an epicyclic gear train (100) disposed in combination 7ith the rotor hub assembly (18) and the reeling assembly (80). The epicylic gea2 train is, furthermore, operative for driving the reeling assembly (80) so as to effect telescopic transition of the outboard blade sections (22) with respect to the inboard blade sections (24).

Retraction/extension mechanism for variable diameter rotors

A torque tube/spar assembly (100) for transferring operational loads of a Variable Diameter Rotor blade assembly (16) to a rotor hub assembly (18) and includes a torque tube member (24), a spar member (30) and a bearing assembly (40a, 40b) for telescopically mounting the spar member (30) to the torque tube member (24) and furthermore defines an internal channel (62) for housing a retraction/extension mechanism (64) which mounts to an internally formed restraint surface (86) of the spar member (30) and is operative to vary the length of the rotor blade assembly (18). The torque tube member (30) has a substantially constant external geometry along the length of bearing assembly engagement and defines a root end region (102), a tip end region (106) and an intermediate transition region (104) disposed therebetween. The spar member (30) has a substantially constant internal geometry and defines a root end region (110), a first transition (112), an intermediate region (114), a second transition region (116), a restraint region (118) and a tip end region (120). Each of the various regions of the torque tube and spar members (24, 30) have a characteristic stiffness value wherein the characteristic values (104m, 106m) of the intermediate transition and tip end regions (104,106) of the torque tube member (24) are less than the characteristic stiffness value (102m) of the root end region (102) thereof, and wherein the characteristic stiffness value (118m) of the restraint region (118) of the spar member (30) is greater than said characteristic stiffness values (114m, 120m) of the intermediate and tip end regions (114, 120) thereof, and wherein the characteristic stiffness value (114m) of the intermediate region (114) is less than the characteristic stiffness values (110m, 112m, 116m, 118m) of the root end, first transition, second transition and restraint regions (110, 112, 116, 118).

Torque tube/spar assembly for variable diameter helicopter rotors

A Variable Diameter Rotor (VDR) system (4) having telescoping odd and even blade assemblies (O.sub.b, E.sub.b) wherein the odd blade assemblies define a radial length R.sub.O and the even blade assemblies define a radial length R.sub.E. Each blade assembly (O.sub.b, E.sub.b) defines an internal chamber (64) for accepting a positioning mechanism (70) operative to effect telescopic translation of the blade assemblies (O.sub.b, E.sub.b) such that the radial length R.sub.E of the even blade assemblies (E.sub.b) is equal to the radial length R.sub.O of the odd blade assemblies (O.sub.b) in a first operating mode, and such that the radial length R.sub.E is between about 70% to about 95% of the length R.sub.O in a second operating mode. The positioning mechanism (70) includes a centrifugal restraint assembly (80) disposed within each internal chamber (64), a stop surface (64s) formed internally of each internal chamber (64), and an actuation mechanism (90) operative for transpositioning the centrifugal restraint assemblies (80) within the internal chambers (64) such that, in one operating mode, the centrifugal restraint assemblies (80)are disposed in abutting engagement with the stop surfaces (64s) and, in another operating mode, the actuation mechanism (90) is disposed in abutting engagement with the centrifugal restraint assemblies (80) of at least one of the blade assemblies (O.sub.b, E.sub.b). The actuation mechanism includes a reeling assembly (110) having a cylindrical drum (112) disposed internally of the rotor assembly (8), end fixities (114) disposed internally of the chambers (64) and operative for engaging and disengaging the centrifugal restraint assembly (80), straps (116) for mechanically coupling the end fixities (114) to the cylindrical drum (112), and a drive mechanism (120) for effecting rotation of the cylindrical drum (112).

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Shelton, CT, United States of America

Edward W Gronenthal