GB365537A - Improvements in air brakes for aircraft - Google Patents

Abstract

365,537. Air brakes for aircraft. BLACK, H. D., The Island, Uxbridge, Middlesex. Oct. 16,1930, No. 31041. [Class 4.] An aircraft air brake comprises a surface or surfaces normally maintained in a position' wherein they are inoperative to vary the normal flight of the aircraft but automatically moved into a position transverse to the line of flight on contact of the tail of the machine and the ground. Brake surfaces 1, Fig. 1, are nested above and below a tail plane 3 to which they are pivotally attached at 2. Levers 4 on the surfaces 1 are connected by links 5 to a plate 6 having a pin-and-slot connection with the vertical arm of a bell-crank lever 8 mounted on a transverse spindle 10, Fig. 2. The horizontal arm 9 of the bell-crank lever has a projecting lug 18 upon which rests a lever 17 freely pivoted on the shaft 10 at one end and connected by a link 22 with a tail skid 23 at the other, thus rocking of the tail skid on landing causes rocking of the bell-crank lever to open out the brake surfaces. The lever 17 is in two parts joined by a vertical hinge and normally maintained in line by a spring. A cable 20 is attached to the outer part of the lever to allow of this being pulled out of contact with the lug 18 thus preventing actuation of the brake. A chamfer on the underside of lug 18 permits return of the lever 17 to its operative position. A pawl formed on the end of lever 9 engages in a ratchet 13 pivotally mounted at 4 to the fuselage and maintained in its effective position by a spring 15. A cable 16 permits withdrawal of the ratchet from the pawl to release the air brake. According to modifications vertical surfaces pivotally mounted at the sides of the fuselage or embracing the fin may be employed, or horizontal surfaces disposed between the main planes, the method of actuation being the same in each case. According to another form of the invention a tail wheel 26, Fig. 7, is carried in a fork 28 and the rotation of the wheel on landing is arranged to operate vertical brake surfaces 1 pivotally mounted on the sides of the fuselage. Mounted on the axle 27 of the wheel 26 is a drum 29 to which is secured one end of a cable 30 corresponding to the link 22 of Fig. 1. This drum is driven by the wheel hub through a clutch 31 which may be disengaged when necessary by a fork 32 mounted on a shaft 36 adapted to be rotated by a cable 33 passing round a pulley 35 secured to the shaft. In the case of horizontally disposed brake surfaces the upper surface may be caused to move through a greater distance than the lower surface.