Patent GB-366965-A (GB)
Title: Improvements in or relating to metal truss structures particularly for use in aircraft
IPC: B64C1/08
Filed: 1930-09-12
Abstract: 366,965. Aircraft structures. BUDD MANUFACTURING CO., E. G., 2500, Hunting Park Avenue, Philadelphia, U.S.A. -(Assignees of Ragsdale, E. J. W. ; Curren Terrace, Norristown, Pennsylvania, U.S.A.) Sept. 12, 1930, No. 27302. Convention date, Sept. 13, 1929. [Class 4.] In a metal truss structure of the type comprising chord members of closed cross section formed by complemental inner and outer elements, the inner elements are formed with substantially flat and relatively wide angularly related faces to which corresponding faces of or extending from the struts of the structure are secured. An application to an aeroplane fuselage is described which comprises longitudinal main members 14, Fig. 1, interconnected by transverse and diagonal struts 15, 16, respectively. The longerons 14 each consist of an inner channel section part 21, Fig. 2, flattened at 25 and spot welded along outwardly turned flanges 23 to an angle section closing member 22. Vertical and transverse struts 15, Fig. 1, and diagonal struts 17 are built up from channel members 27 and longitudinally corrugated closing members 28 to give the cross section shown in Fig. 6, edges 30 of parts 28 and flanges 29 of the channels 27 being spot welded together. Fig. 8 illustrates the method of attachment of the struts to the longeron. U-shaped pieces 32 are welded to the channel sides 27 of the struts 15 to provide a face for welding to the sides 21 of the longerons and the flanges and bottoms of channel portions 27 of struts 16 are cut away and the sides bent inwardly at the end to fit in the angle formed between the transverse struts and longeron to which they are welded. A gusset member 34, Fig. 2, of a section similar to that of parts 21 but reversed is welded by its flattened apex 35 to the corresponding part 25 of the longer on and to the undersides of the struts with which it contacts. A similar gusset 36 is placed on the outer side of the joint over the flanges 23 of the longeron part 21 and is welded to these and to the end parts of the flanges of the struts with which it makes contact. The assembly of the joint is completed by welding on the closing parts 22, 28. This method of assembly is illustrated in Figs. 10, 12, and 14. The longeron parts 21 are first mounted on a jig 39, the U-shaped parts 32 are welded in their correct positions to receive the channel portions of the transverse and vertical struts, and the transverse and diagonal struts 15, 16 successively placed in position and welded to each other and to parts 32. The body structure with or without the engine bearer portion shown in Fig. 1 and the tail portion is then removed from the jig and the gussets 34, 36 welded in position in turn, Fig. 12. Next cross braces 17 of similar construction to the diagonal struts are attached as shown in Fig. 14 but in cases where the structure is insufficiently rigid these may be attached before removal of the structure from the jig. Finally the closing members 28 are applied then the members 22. The engine bearer portion is similarly constructed; the construction of the sternpost portion is shown in Figs. 15, 16, and 18. The inner flanges of top and bottom longerons are cut away at an angle to permit of the side walls abutting at their ends where they are received in a channel section strut 40, as are also the ends of the rearmost diagonal struts 16. The order of assembly is as follows, first the abutting ends of the longerons are welded together at 43, Fig. 16, then the extended side walls of the channel portions of the struts are welded to each other at 44 and to the longeron parts 21 at 45. The joint is then reinforced by gussets 41. A rudder hinge tube 42 is welded to the strut 40, Fig. 18, and this strut is then placed in position and spot welded as indicated in Fig. 15. The side walls of strut 40 extend over the longerons and are wrapped over these members and welded in place, Fig. 16. The structure is completed by attachment of the closing members 28 to struts 16 and of a closing member 48 to strut 40. The method of construction used throughout is stated to be electric spot welding and the material light gauge high tensile rustless steel sheet.