Patent GB-385789-A (GB)
Title: Improvements in or relating to helicopters
IPC: B64C27/04
Filed: 1932-03-02
Abstract: 385,789. Helicopters. CAMPENS, D. R., 65, Avenue Elisabeth, Berchem, Antwerp, Belgium. March 2, 1932, No. 6328. Convention date, April 17, 1931. [Class 4.] A helicopter comprises a cross-shaped fuselage having a frame at each end of the transverse member carrying a lifting propeller, a tractor propeller at the front end of the longitudinal fuselage member, a stabilizing propeller at the rear end of this member, an automatic coupling system for the lifting propellers, means to control the operation of the lifting, stabilizing and tractor propellers, and control means for horizontal flight comprising ailerons mounted under the transverse member, a rudder, and elevators. In one embodiment, Figs. 2 and 3, a fuselage 1 .. 4 is formed by trellis-work girders. Frames 5, 6 are mounted for oscillating movements about transverse axes between the front and rear endplates of the girder 3, 4, the frames being connected by crossed rods 7, 8. The frames carry radial engines 9, 10 driving propellers 11, 12 in opposite directions through upwardly extending shafts 13, 14. Reversing gear boxes below the engines transmit the drive to flywheels 17, 18. Small cooling fans are mounted on the shafts 13, 14. The lifting air screws are mounted to rotate freely on ball bearings on the driving shafts and are coupled up automatically by means of arms 73, Figs. 16 and 17, pivoted to the shaft and carrying weights 74. When the shaft is rotated by the engine the weights fly outwardly and cause the arms to engage in castellations formed in the propeller, which is thus keyed to the shaft. The stabilizing air screw 25 is driven from the engine 23 which also drives the tractor air screw 24 through a clutch. The drive to air screw 25 comprises a reversing gear. Ailerons 31, elevators 32, and rudder 33 are provided as shown in Fig. 4. The landing gear comprises wheels 19, 20, 27, 28 mounted on shock absorbers at the four corners of the frame 1 .. 4. Means operable by the pilot are provided for locking the oscillating frames 5, 6. In a modification these frames are fixed at an oblique angle to one another and the flywheels and gear boxes are omitted, in which case the engines 34 may be mounted directly on the propeller shafts or may be arranged as shown in Fig. 7 the ailerons 31 being arranged below the transverse girder. In a further modification the inward inclination of the propellers is obtained by constructing the transverse frames with a large dihedral angle. The Specification contains a mathematical analysis of the conditions under which a helicopter screw operates and illustrates what is stated to be the optimum blade form. According to the Specification as open to inspection under Sect. 91 the transmission mechanism, Fig. 15 (Cancelled), between engine 23 and stabilizing screw 25 comprises a gear shift lever 45 pivoted at 46 and having a selector fork at its lower end engaging a double gear wheel keyed to shaft 53 which is geared by bevel gearing to the shaft of air screw 25. Movement of the hand-lever in either direction from one gear to another, first causes disengagement of clutch 62 through the rod and lever system 64, 65, 66 then applies a brake 61 to shaft 60, then disengages the brake, engages the required gear and reengages clutch 62. The brake 61 comprises two anti-friction surfaces carried by parallel rods 51 which in the neutral position of lever 45 grip the shaft 60 of propeller 25 between them. Stops are arranged to limit the movement of the sliding double gear wheel and a toothed sector is provided for hand-lever 45. This subject-matter does not appear in the Specification as accepted.