Patent GB-293932-A (GB)
Title: Improvements in and relating to sustaining helices for aircraft
IPC: B64C27/54
Filed: 1927-05-05
Abstract: 293,932. Pescara, R. P. May 5, 1927. Machines with rotary wing systems; balancing. - In a rotary wing-system the wings of which are horizontally hinged at their roots to a freely rotating hub, when desired the wings may be restrained against their flapping movement and tilting of the general axis may be corrected by decentralizing the thrust by manual adjustment of ailerons attached to the wings. The control is displaced through a right angle in a direction opposite to that of the rotation of the wing system to compensate for the gyroscopic couple. In the construction shown, the longerons 10, 11 of the blades are connected bv horizontal hinges 12 to a hub mounted on bearings 15, 16 on a tubular mast 14. Collars 48 on the longerons 10, 11 are pivoted to links 50 which terminate in piston heads 51 working in tubes 47 pivoted to a roller bearing 36 slidable on the mast 14. The inner race of the bearing 36 carries arms 37 which pass through slots in the mast and are fixed to a rod 39 terminating in a threaded portion 40 passing through a nut 41 engaged by a worm 42 at the end of a shaft rotatable by the pilot by a handle 44. By rotation of the latter the bearing 36 may be raised or lowered, and in the upper position shown in dotted lines the longerons 10, 11 are free to rise from stops 34, 35 by turning about the hinges 12, whilst in the lower position, shown in full lines, the piston heads 51 are brought up against the end pieces 52 and the longerons 10, 11 are held rigidly against the stops 34, 35. In the latter position the ailerons may be manually controlled to correct tilt through mechanism comprising a pin 17 projecting from the centre of a disc 21 slung on gimbals inside the tubular mast 14. The pin 17 slides within the ball portion 23 of a ball and socket joint the outer part of which is provided with arms 25 which pass through the mast and support an annular bearing 26, 27, the outer race 27 of which is provided opposite each wing with arms 28 to which are pivoted sleeves 29. The sleeves 29 are keyed on the outside to have a straight sliding movement within sockets 30 in the hub 13, and on the inside are formed with helical grooves in which engage screws 31 connected through cardan joints 33 to the aileron control shafts 32 : the joints 33 are positioned at the hinge joints 12. By rocking the disc 21 the annular bearing 26, 27 is moved in a horizontal plane out of its position concentric with the tubular mast 14 and causes a cyclic variation of the incidence of the ailerons and the thrust is correspondingly displaced. Four equidistant points on the periphery of the disc 21 are connected by cables 53 - - 56 to four points on the edge of a disc 121 slung on gimbals in a casing in the fuselage and having projecting from its centre a control lever 61. The connecting points of the cables 53 - - 56 on the disc 21 are displaced 90‹ with respect to the connecting points of these cables on the disc 121, in the opposite direction to that of the rotation of the wing- system, so that if the mast 14 tilts compensation is automatically made for the gyroscopic couple when the pilot makes the instinctive movement of the lever 61 in the opposite direction to that of the tilt. According to a modification a helical spring may be interposed between the piston 51 and the head 52 of the tube 47 to limit the stresses transmitted to the mast when the bearing 36 is in its lower position.