Patent GB-507973-A (GB)
Title: Improvements in or relating to aircraft wing construction
IPC: B64C3/00
Filed: 1938-07-06
Abstract: 507,973. Aircraft wing structures. ROHRBACH, A. K., and WESER FLUGZEUGBAU GES. July 6, 1938, Nos. 20070 and 20071. Convention dates, July 7, 1937 and June 20, 1938. [Class 4] An aircraft wing comprises a closed hollow spar on which are mounted separate front and rear parts which completely enclose the spar, the wing parts each comprise ribs covered with a skin and mounted on the spar by devices facilitating ready detachment, the joint between the wing parts running longitudinally of the wing and being located near the spar. The box-section spar 1, consists of a U-shaped member and a closure plate 22, connected thereto by flanges. Diaphragms 23 may be riveted inside the box, and may be apertured for lightness. Transverse and /or longitudinal internal stiffeners 24 and external stiffeners-20 may be fitted. According to modifications the upper and lower walls may be corrugated or may comprise separate elements which facilitate manufacture. Large spars may be constituted by channels lap-jointed together. The diaphragms 23 may have laterally extending lugs gripped between the flanges connecting the spar parts. The spars may be other than square. The front and rear wing sections 2, 3, Fig. 2, comprise ribs 6 covered with a skin 7 and are divided spanwise into a number of separable components. Each section comprises locating and securing means which may be separate or combined. In one form, Fig. 3, a bolt 8 carried by a rib 6 of the section 2 engages a bush 9 secured to the spar. At the rear end of the rib a screwed bolt 11, Fig. 6, is provided which engages a nut 12 passing through a lug 13 and formed with a flange engaging the lug. The rear section 3 is provided with a lug 15 which engages the nut 12 and is secured by a nut 16 screwed on to the shank of the nut 12 which is externally threaded. Access to the nut 16 is by an opening 17 in skin 7. The front and rear skin panels overlap and are secured together for instance by wood screws passing through the panels into wooden stringers screwed to a flange formed on the rear panel. According to modifications the bolt 8 may be carried by the spar and the bush 9 by the rib 6, or the lugs through which the nuts 12 pass, or to which bolt 8 is secured, are secured in extensions of the reinforcing members 20. In one such arrangement a bolt, 11 has two screwed ends projecting on either side of the lug to receive the bored lugs carried by the sections 2 and 3 which are retained by nuts. Connection between the parts may be by vertical bolts and in one arrangement, Fig. 13, section 3 carries bolts 19 engaging in housings secured to spar 1 and lugs secured to sections 2 and 3 are registered by a sleeve 21a which is slidden upwardly from a bracket secured to the spar and is retained by a screwed bolt 21. The chordwise joints between the several sections may be covered by glued strips of tape.. Instead of connecting the skin panels of front and rear sections by lap joints and providing inspection apertures these panels may be arranged to leave a slot between them on assembly which slot is afterwards covered by a separate covering strip in order to facilitate assembly. The covering strip may be formed to engage the skin at one edge, the other edge being secured by quick-release fasteners.