Month in the Patent Office

Abstract

An aeroplane adapted to remain controllable at low speeds and high angles of incidence has automatically moving slot‐forming planes along the leading edge of each wing, camber‐varying flaps at the trailing edge interconnected to the stabilising plane and capable of being locked by the pilot in various positions, and additional normally closed slots at the wing tips which open only when the main slots are open and the usual ailerons are depressed. The slot closing element connected to each aileron may also project above the upper surface of the wing to break up the air stream on that side of the machine on which for the time being the aileron is raised. These features are shown applied to a low‐wing monoplane with widely spaced landing wheels. Slot‐forming planes 35, Fig. 4, are carried by curved tubes 40 moving between guide rollers 41 carried by brackets on the front spar of the plane. They normally nest against the leading edge of the plane and move forwards automatically as the stalling angle is approached. Camber varying flaps 29, Figs. 4 and 9, and ailerons 28, Fig. 5, are pivoted to the trailing edge of the wing and have their forward edges so shaped that slots 47 are formed when the flaps or ailerons are depressed, the slots being substantially closed in the neutral and raised positions of the flaps and ailerons. The flaps 29 are interconnected to the stabilising plane 26, the leading edge of which is raised and lowered by links 55, and both are moved simultaneously by a lever 33 provided with a detent engaging with a locking quadrant 51. The air pressure on the plane 26 partially balances that on the flaps as regards their reaction on the lever 33. A rod 53 which actuates the plane 26 is connected to a lever 33a, Fig. 10, and the lever 33 has a quadrant 59 to which the flap cables are connected, the two levers 33, 33a being adjustably connected by screw‐and‐nut mechanism 34 in order to vary the relative adjustment of the stabiliser plane and flaps. At the forward edge of each wing tip opposite each aileron a slot 37, Fig. 5, is formed, which is normally closed at its lower end by a plate 63 connected by a lost‐motion link 64 to the slot‐forming plane 35, and at its upper end by a pivoted quadrant 67 connected to the corresponding aileron by a lost‐motion device 70. When the aileron is depressed, or raised beyond a certain amount, the quadrant is respectively withdrawn into the plane to open the slot or projected beyond the upper surface to disturb the streamline flow and reduce the lift on that wing tip. Springs 71, 72 normally centre the quadrant 67. The plate 63 only moves to open the slot 37 when the main slot is open. The wing spars 88, 89, Fig. 12, are connected to the lower edge of the fuselage and braced to the upper edge by struts 90, 91 with intermediate braces 92, 93, The rear struts 91 may be upwardly arched. The landing wheel axles are carried by hinged struts 95 and supported from the front spars by telescopic struts 96 with shock‐absorbers 82.