GB703239A - Improvements in or relating to the manufacture of complex structures of sheet material - Google Patents

Abstract

703,239. Making aircraft wings. FAIREY AVIATION CO., Ltd. March 28, 1950 [Dec. 6, 1949 No. 31272/49. Classes 83 (2), 83 (3) and 83 (4). [Also in Groups XXIII and XXXIII] In a method of making a complex structure of sheet material, such as an aircraft wing, the component parts of the skin of the structure are brought to their finished shapes, mounted in a lofting apparatus relatively to a datum line and marked out relatively to said datum line. The lofting apparatus comprises a datum beam 28, Figs. 1 and 6, on a sprung carriage 29, with screw adjustment for levelling purposes. A carriage 33, slidably mounted on the machined and surfaced top of the beam 28 and which may be clamped in any position thereon by a clamp 36, comprises an upper part 37 which may be set angularly relatively to a lower part 38 through a range of 360 degrees and clamped in position by a screw 39. Fine setting of the carriage longitudinally on the beam is achieved by a threaded shaft 54 operated by hand wheel 55. The part 37 carries a tower 41 mounted at one side on a spindle 42 and having at the other side clamps 43 on a rod 44 whose ends pass through quadrants 45, allowing the tower to be set at any angle between 0 degrees and 90 degrees to the beam. The quadrants are mounted eccentrically on a bar 57 rotatable by a tommy bar 57a and clamped' by clamps 59, to provide a fine adjustment of the angular position of the tower. For positions of the tower away from the vertical its free end may be supported by a jack. The beam 28 is positioned from a support beam 20 for the curved skin structure 21 by fixed and movable spacing blocks 49, 50, respectively, having locating pins, the beams being then bolted together. The side edges 48 of the tower are machined and surfaced to constitute a surfaceplate for scribing means. Drilling; jigs; riveting.-In a modification, Figs. 14 and 15, a backing plate 70 for a jig is held on the beam 20 and is marked out and drilled with holes 71, all of the same size irrespective of the size of the rivets to be employed in the structure. Curved skin panels 74 are then located and clamped within the jig and the internal members such as spars and ribs 75 are similarly set up and clamped. Drilling is then performed by a combined drill and countersink 79, 80 guided by a sleeve 77 which engages with a hole 71. Rivets are then inserted and set and the heads faced off by a small milling cutter also operating within the sleeve 77. Stamping.-Shallow curvatures may be imparted to the skin panels by. forcing them into the curved jig template, and leading edge and like deeply curved sections may be curved prior to their insertion into the jig by a punch 87, Fig. 11, having a body of laminated paper impregnated with a synthetic resin and a nose 88 of laminated impregnated fabric, forcing sheet metal 83 into a channel-shaped structure against a rubber sheet 84. Specifications 703,305 and 703,306 are referred to.