Patent GB-440476-A (GB)
Title: Improvements in and relating to aircraft
IPC: B64C27/82
Filed: 1934-04-27
Abstract: 440,476. Controlling helicopters. WILKENING, F. W., Arlington Road, Penn Valley, Pennsylvania, U.S.A. April 27, 1934, No. 28751/35. Convention date, Feb. 2, 1934. Divided out of 437,521. [Class 4] An aircraft has a driven rotor and aerofoil surfaces disposed in two fore and aft groups symmetrically disposed about the rotor axis within the rotor slip-stream, each surface being permanently fixed substantially parallel with the direction of normal flight and so cambered as to produce torque on the aircraft in the direction of rotation of the rotor. In one form, Fig. 1, the fusilage frame is extended at each end to support aerofoils 46a, 46b, 46c, 46d, which are set with their leading edges upwards as shown in Fig. 5, and disposed at a lifting angle with respect to the rotor slipstream in such manner as to produce lifting forces tending to rotate the fuselage in the same direction and about the same axis as the rotor. Aerofoils 46 comprise hinged flaps 47 by means of which their lift may be varied. Control mechanism therefor, Fig. 4, comprises an endless cable 49 connected to link rods 48e, 48f interconnecting opposed pairs of flaps. Cable 49 is connected through two cross strands 49b, 49c to oppositely directed horns 51, 52 of two coaxially mounted rudder bars 53, 54 respectively, arranged adjacent the pilot's seat 55. As shown, pushing forward with the right foot on rudder bar 53 will move all four control flaps in the direction to increase the effective camber of aerofoils 46 whilst similar actuation of rudder bar 54 swings the flaps into the dotted line position of Fig. 5 in which the lift of the aerofoils is approximately neutralized. Longitudinal and lateral control of the aircraft is effected by the means described in Specification 437,715. The undercarriage comprises three wheels of the freely trailing castor type, the rear wheel 64, Fig. 3, being mounted by a strut which may be raised or lowered by the pilot by means such as a thread and nut actuated by a worm wheel and worm. In a modified form, Fig. 10, the elevator is dispensed with and longitudinal control is effected by tilting the rotor relative to the fuselage. Fuselage 67 is suspended below an assembly comprising the power plant, rotor, and antitorque aerofoils by means of a generally horizontal transverse pivot 70 placed slightly above the static centre of gravity of this assembly but as close as possible to the rotor hub. The power plant is enclosed by a fairing 65 and one or more of aerofoils 46 may embody surface radiators. in which case frame members 66 may be tubular to serve to convey the cooling liquid to-and-from the radiating surfaces. Rotor tilting is effected by means comprising a sprocket 69 rigidly attached to the power plant coaxially with pivot 70 and connected through chain 72 to sprocket 71 rotatably mounted in the fuselage and operatively connected by lever 73 and link 78 to a control column 74. A fixed pin 59 is mounted at the rear end of the anti-torque surfaces. A vertical rudder may be similarly mounted. The control means for flaps 47 may be similar to those shown in Fig. 4, the control cable being led into the fuselage by means concentrically or coaxially disposed with relation to pivot 70. Ailerons 77 may be mounted directly on the fuselage and operated by sideways movement of column 74. The landing gear in this form is not adjustable. In a further modification, Fig. 9, the fuselage 16 and anti-torque aerofoils 47 are inclined relative to the motor axis as indicated in dotted lines in order to reduce the head resistance during high speed horizontal flight. Further in order to compensate the tendency to sideways displacement of the craft due to the fixed central position of the rotor the anti-torque aerofoils may be inclined to the direction of flight as shown in Fig. 7. The aircraft may have means for altering the rotor pitch in accordance with the engine torque as described in Specification 437,521.