GB713352A - Improvements in or relating to rotary wing aircraft - Google Patents

Abstract

713,352. Helicopters. UNITED AIRCRAFT CORPORATION. Nov. 13,1951 [March 30, 1951], No. 26539/51. Class 4 A rotary wing aircraft comprises a generally horizontal flapping hinge pin journaled in a hub structure, a flapping link secured rigidly to said pin and movable bodily therewith in said hub journal, said pin having an extension on one side of said flapping link, a sleeve journaled on said extension, a damper including co-operating piston and cylinder elements, a pivotal connection between said sleeve and one of said damper elements, and a pivotal connection between the other damper element and said hub structure. The rotor shaft 15 is splined to a hub 32 bolted to spaced plates 38 and 40 extended radially to form three arms 42 which are supported by spacers 54 secured by bolts 56. Each pair of arms 42 carries a vertical drag hinge 58 journaled in needle bearings 60 and 62 and a thrust race 63 is provided in the lower and thicker arm. The drag hinge pin is secured at its ends by nuts 64, 66 enclosed by caps 68, 70. The enlarged central part of the drag hinge pin is bored horizontally to accommodate two roller bearings 74 and 76, Fig. 2, within which rotates a bearing sleeve 84 mounted on a flapping hinge pin 78 and clamped between the inner faces of a fork fitting 82 to which'the pin 78 is secured by an integral shoulder 86 and a nut 88. The fork 82 is extended by a spindle 90 on which are journaled a blade root end fitting 92 and a pitch control horn 94 connected for rotary movement by a slidable pin 96 on the horn seating within a boss 98 on the fitting 92. If the pin 96 is released the rotor blade may be rotated about its longitudinal axis before the blades are folded. The flapping hinge pin 78 is extended by a spindle 104 that carries bearings 108, 110 on which is rotatably supported a forked sleeve 106 to which is pivotally attached at 114 the cylinder of a drag movement shock absorber 112, preferably of the type described in Specification 641,076. the piston rod of which is connected at 118 to a pair of adjoining arms 42. The plate 40 carries a depending collar 18 connected by a scissors linkage to the rotating element 30 of a swashplate. the arms of which are connected by links 100 to the horns 94. The non-rotating element 28 is controlled by links 102.