Patent GB-357585-A (GB)
Title: Improvements in aircraft controls
IPC: B64C13/00
Filed: 1930-06-25
Abstract: 357,585. Controlling aircraft. AIRCRAFT IMPROVEMENT CORPORATION, 543, East 132nd Street, New York, U.S.A.- (Assignees of Medvedeff, N. J. ; Beechurst, New York, U.S.A.) June 25, 1930, No. 19316. Convention date, March 30. [Class 4.] A compound control surface comprises a forward portion and a rearward portion pivoted thereto, the two portions normally floating as a unit with the air flow and means being provided for locking the forward portion in its last self-assumed position and for deflecting the rearward portion of the compound surface with respect to the forward portion. In an application to an aeroplane, Fig. 3, ailerons, each of which comprises a forward main portion 3 to the trailing edge of which is pivoted a flap 4, are arranged at the wing tips, the main aileron portions 3 being fixed to spindles 5 rotatably mounted in the wings 1. So long as the control column 9, Fig. 4, is not moved laterally the ailerons which are statically and aerodynamically balanced are free to move under the action of the wind forces, the flaps 4 being in line with the main parts 3. Movement of the column laterally locks the parts 3 in whatever position they have assumed and effects differential adjustment of the flaps 4. The wings are rabbeted as shown in Fig. 3, to accommodate housings 7 enclosing the flap-adjusting mechanism. The flaps 4 are pivoted by a shaft 6 which extends through an arcuate slot 8 in the housing 7, Fig. 12, and carries a lever 25 operated by a rod 24 passing through a longitudinal slot in the shaft 5 which forms the pivotal axis of the main aileron 3. A pinion 22 also mounted in the slot meshes with the teeth of a rack 23 formed on rod 24 thus effecting adjustment of flap 4 when rotated by the means shown in Fig. 4. These comprise a cable 16 attached to column 9 above its fore and aft pivot 13 and passing round pulleys 17, 18, 19 to extend in line with the shaft 5 to a pulley 20 integral with the pinion 22, thence to a corresponding system of pulleys on the other side of the aircraft. The main ailerons 3 are interconnected by means of duplicate cables 27, Figs. 5 and 12, to move simultaneously up or down. Cables 27 are attached at their upper ends to pins 33 disposed on either side of the shaft 5 and extending through arcuate slots in the outer side of housing 7, and at their lower ends to the corresponding end of one of two racks 26, Fig. 7 (only one of which is shown), mounted side by side in front of the pivot 13 of the control column and carried by parallel link gear which permits them limited lateral and up and down movement. A fixed rack 34 is arranged beneath the movable racks 26. Levers 35 hinged on either side of the column carry rollers 40 and are interconnected by a spring 38 which urges stops 37 on the levers against the column. Lateral movement of the column causes one or other of the rollers 40 to depress the slidable racks 26 into engagement with the fixed rack 34 thus locking the main ailerons 3 whilst the flaps 4 are being adjusted. In an alternative arrangement shown diagrammatically in Fig. 15, the main aileron portions 3 are normally free to swing independently of one another being locked by lateral movement of column 9 as before but adapted to be operated differentially together with their associated flaps by lateral movement of the column beyond normal limits when necessary to obtain very powerful rolling moments. Fig. 15 shows each part 3 connected by cables 52, 53 to the opposite ends of a rackbar 26, the cables being so disposed that movement of both rackbars in the same direction causes differential movement of parts 3. Similar means to those previously described are provided for locking the rackbars on lateral movement of column 9, but in this form the racks 34a are adapted to be traversed by screwed shafts after a given movement of the column has been exceeded, carrying the raeks 26 with them to rock the main ailerons 3. The means for effecting this traversing movement are described in detail and comprise two slide members having lugs for the engagement of projecting pins on the column 9. Extreme movement of the column in either direction causes the pins to engage the lugs and carry the slide members along. Movement of the slides is transmitted by cable gear to toothed sectors meshing with pinions geared to the screwed shafts effecting the traversing of the racks 34a whereby these shafts are rotated to traverse both racks in the same direction and thus rock the main ailerons 3 in opposite senses. Means are provided for returning the slide members and hence the racks 34a to their central position when the control column is returned to its central position.