GB722842A - Aileron, flap, and dive brake - Google Patents

Abstract

722,842. Aircraft ailerons, flaps, and dive brakes. NORTHROP AIRCRAFT, Inc. June 12, 1952, No. 14871/52. Class 4. [Also in Group XXIX] A combination aileron, landing flap, and dive brake control system for aircraft comprises an aileron on each side of the aircraft, having a nose section 5 hinged to the aircraft and a pair of superposed surfaces 1 and 2 hinged to the nose section, power means outside the ailerons adapted to rotate them on their hinges, landing flap control means connected to said power means to move the aileron in the same sense between neutral and down positions to act as flaps, flap follow-up means connected to said flap control means to move with the ailerons as moved by said flap control means, hydraulic dive brake power means in each of said nose sections connected to move the superposed surfaces 1 and 2 to open or closed positions, and a landing flap switch 106 connected to energize said dive brake power means in either of two directions, said switch being operated by said flap follow-up means to open the surfaces 1 and 2 when the ailerons read said down position, and to close the surfaces when the ailerons leave the down position. The flap is shown in Fig. 13 with the aileron depressed by 30 degrees, and the rear flaps opened to include 60 degrees, being the position adopted as a landing flap. The pilot has available 15 degrees of differential movement. Referring, to Fig. 2, 11 is the pilot's aileron control, lateral movement of which rotates the quadrant 12 through cables 10. Member 16 then rocks the lever 17, to which is attached the internally threaded member 21. Link 22 is threaded into member 21, and forms the operating piston of the valve 23 of fluid-pressure servomotor 24. Movement of lever 17 results in fluid being admitted to one side or the other of motor 24; which moves with respect to its fixed piston 25 until valve 23 is restored to its original position with respect to link 22. Aileron 5 is thus operated by a follow-up power relay. The cables 10a to the other aileron are crossed to provide differential movement. Similar movement, to use the ailerons as landing flaps, is obtained by providing bias on links 22 by rotating the member 21 via shaft 34 by the linkage shown, from the pilot's landing flap control. This latter comprises a reversible chaser mechanism. Two levers are pivoted on one axis, and connected by a spiral spring stressed by revolving one lever round the axis a certain number of times, and just passing the other lever. The levers are then kept apart by two pins. One is fast with the pilot's control lever, pivoted to the same axis, and the other is fast.to a pulley, also on the same axis. Movement of the control lever in either direction separates the levers, the spring then forcing the other lever to follow up, as fast as the pin on the now-rotating pulley will allow. When the follow up is complete, no forces act on the pilot's control lever or the pulley. At the extreme flaps down position, the pulley operates a switch 83, shown in Fig. 10, to render the dive brake control inoperative, as will be shown later. Cables from the flap control pulley pass to the lever 91, shown in Fig. 7, and operate to rock the lever about the point of contact of cable 97 with groove 96, and to control the servomotor 81, which operates the landing flap mechanism of Fig. 2. Rotation of member 34 in Fig. 2 also results in rotation of member 100, Fig. 7, whereupon nut 102 fast to cable 98 provides follow up feed back to lever 91 to cut off motor 81. In the extreme flaps down position, lever 91 operates switch 106, shown in Fig. 10, which will open the surfaces 1 and 2 to the position shown in Fig. 13. Fig. 3 shows the dive brake mechanism. Servomotor 35 and piston 36 constitute an expansible link, which link, when expanded, operates the levers 41, 42, 47 and 48 to open the surfaces 1 and 2, the two parts of a surface shown as 1 in Fig. 3 being integral with each other, and the two parts 2 being integral. The valve 53 is electrically operated by the pilots' control, a three-way switch with positions "open", "close" and "neutral" (no action). This control is shown at 60, Fig. 10. One of the dive brake surfaces on each wing operates a crankshaft, whose rotation sets a potentiometer connected in a synchronizing circuit which ensures that the dive brakes operate in unison. The crankshaft also operates a switch 125 when the flaps are opened to enclose 5 degrees, to prevent creep, as shown later with reference to Fig. 10. A further switch 129 is operated when the flaps enclose an angle of 60 degrees, although the switch operating lever can run on until the flaps enclose 120 degrees. Referring now to Fig. 10, switch 83 is usually in the position shown, whereupon the dive brake control can make contact by levers 61 or 63 to operate the "open" or "close" solenoids of valves 53, Fig. 3, through the synchronizer. When, however, the pilot's flap control is at its extreme position, switch 83 is actuated, and the dive brake control is disconnected. When the flaps reach 30 degrees down, switch 106 of Fig. 7 is actuated, and as seen in Fig. 10, the dive brake "open" solenoids are operated, until, at 60 degrees open, contact 129 is broken as described above, and the final landing flap position of Fig. 13 is reached. When the landing flap control is not in use and the dive brake control is operable, cable 140 leads from the positive bus bar 135 to switch 125, so that when, as described above, the dive brake surfaces creep 5 degrees apart, contact is made and the "close" solenoids operated. Normal differential aileron control of between 13 degrees and 15 degrees is available to the pilot at all times. Limits of movement for the dive brakes are surfaces 1 and 2 120 degrees apart, switch 129 not being in circuit unless the flaps are lowered for landing, when the limit is 60 degrees.