GB384838A - Improvements in aircraft structures - Google Patents

Abstract

384,838. Aircraft framework. A.T.S. CO., Ltd., WYLIE, H. N., and SANDERS, S., 5, Clement's Inn, Strand, London. Feb. 8, 1932, No. 3624. [Class 4.] Tapering tubular metal spars comprise booms which are either corrugated or of generally arched or tubular cross section ; when corrugated booms are employed these are of considerable width and are interconnected by side members free from lightening holes each comprising a single flat surface strengthened by stiff metal transverse members, and when booms of generally arched or tubular cross section are employed these side members are bent outwardly to form two or more flat portions interconnected by flanges and also stiffened by transverse members. Fig. 1 shows a rectangular spar comprising corrugated booms 4 and flat thin sheet side members 1 riveted at flanged edges 2 to similar flanges 5 on the booms 4. The sheets 1 are reinforced by members 3 placed at intervals between upper and lower flanges 28. The spar may be placed at the deepest part of the aerofoil and according to modification be of generally trapezoidal form to fit in a tapering part of the aerofoil section. In a further modification, Fig. 2, arched booms 4 are riveted to outwardly splayed side members 1 which have their abutting edge flanges 9 riveted together, Fig. 5, and to a transverse tie member 10 which may be continuous or may comprise a number of spaced tie members. Stiffening posts 3 may be upwardly extended to support rib booms 6. In a modified form, Fig. 4, tubular booms have inwardly extending flanges 11 between which are nested the outer edges of the side-plates 1. The features of the spars described above may be combined to form a triangular spar having a corrugated boom forming one side of the triangle and an apical boom of tubular or arched form.