Patent GB-442015-A (GB)
Title: Improvements relating to aircraft
IPC: B64C27/02
Filed: 1934-07-27
Abstract: 442,015. Aircraft with rotary wing systems. KAY GYROPLANES, Ltd., KAY, D., and DYER, J. W., 18, Atholl Crescent, Edinburgh. July 27, 1934, No. 22021. [Class 4] In aircraft of the type in which lift is derived wholly or partly from an overhead rotary wing system or rotor which turns about a more or less vertical mast or other rotor supporting member which is adapted to be tilted and/or displaced bodily, mechanism is provided for varying the angles at which the rotor blades are set to the general plane of rotation of the rotor comprising a control member accommodated within the rotor hub supporting mast or equivalent and operatively connected to the incidence-varying mechanism and so constructed or arranged as to be capable of following the tilting and /or bodily displacement of the mast or equivalent. As shown in Fig. 1, a hollow rotor supporting mast 1 is tiltably mounted on a fixed part 84 of the aircraft in the manner described in Specification 442,016 and carries, by means of journal bearings 6, 8 and combined thrust and journal bearing 7, a rotor hub 4 formed with four pairs of spaced arms 12, 13, Fig. 2. Rotor blade spars 28 are articulated by substantially vertical pivot pins to link blocks 20 journalled on zed-crank members 17 of the type described in Specification 285,213, [Class 114], which are keyed to axles 14 rotatably carried by bearings formed in the arms 12, 13. Swinging of the blades in the plane of rotation is limited by combined damping and wing folding devices comprising bushes 30A. Droop of link blocks 20 is limited by stops 23, Fig. 1, adapted to engage shoulders 24 formed on a disc 25 secured to the rotor hub. The angle of incidence of each blade is adapted to be varied simultaneously and equally by turning the axle 14 of each zed-crank member. To this end rotor supporting mast 1 is provided with an internal screw thread to receive a correspondingly screwed part of a control spindle 31. Spindle 31 projects beyond mast 1, is reduced in diameter, and screw-threaded at its upper end 34. At its lower end spindle 31 is secured within a sleeve 35 provided with longitudinal internal key-ways 41 to receive a plate 39 secured to an operating spindle 40 connected by a universally jointed shaft 43 to the spindle of a cable drum 51 rotatably mounted in fixed support 48. Provision is thus made for rocking movement of rotor mast 1 with respect to the support 48. An operating collar 61, formed with four pairs of radially extending lugs 62, 63, Fig. 2, is rotatably mounted on spindle 31 between ball bearings 64 and 65 retained by cones 68, 69, respectively, which are screwed to spindle 31. A hollow hub extension member 57 which is bolted to the top flange of the hub and closed at its upper end by a dust cover 60 is formed with radial lugs 58, 59 between which are secured transverse pins 71 serving as fulcra for incidence control arms 72. The inner ends of arms 72 engage pins 74 carried by each pair of lugs 62, 63 on collar 61. A fork 75 is connected by a pin 76 to the outer end of each arm 72 and is coupled to a socket 77, Fig. 3, by an adjusting link 78. Socket 77 receives a ball-ended pin 79 secured at the outer end of a lever 81, Fig. 2, keyed to zed crank axle 14. Also keyed to each axle is a lever 83, Fig. 1, formed with a projection 84 to which one end of a tension spring 85 is hooked, the opposite end of which is hooked to an anchor plate 86 secured to hub 4. Each lever 83 is also formed with a stop 87 co-operating with its adjacent lug 12 and serving to define the maximum permitted angle of incidence. The action of springs 85 is to facilitate quick movement of the blades from negative to positive incidence, to minimize the effects of backlash in the operating mechanism and lastly to act as a safety device in the event of failure of the control mechanism. Means may be provided for adjusting the value of the maximum permitted angle of incidence. The means for producing axial movement of control spindle 31 comprise cables 93, 94, Fig. 4, wound around the grooves in drum 51, and attached to a grooved quadrant 97 fixed to a spindle 98 rotatable in a bearing carried by fuselage side members, and turnable by control lever 100. Control lever 100, Fig. 5, works in a slot formed in the out-turned flange 106 of a quadrant bracket 107 and carries a spring-loaded safety catch 108 which may be engaged in either a notch 115 in the " running-up " (no lift) position or in a notch 117 in the normal flight position. In addition the lever may be locked in any adjusted position by a spring loaded catch engaging in notches formed in the underside of flange 106, the catch being freed by depression of a knob 112. A lever 119 secured to quadrant spindle 98 is connected by a link 120 to a lever 121 fixed to a spindle 122 carrying a pointer 123 movable near a scale marked with the angles of incidence of the rotor blades. Secured to pointer 123 is a plate 125 to which is connected the clutch trip operating link described in Specification 442,015, and connected to lever 121 is the linkage for operating the rotor drive disengaging device described in Specification 442,014. Specifications 442,013 and 442,137 also are referred to.