Patent GB-452116-A (GB)
Title: Improvements in aeroplanes having a variable lifting surface
IPC: B64C3/54
Filed: 1935-02-14
Abstract: 452,116. Aircraft wings of variable area. GERIN, J., 24, Rue de la Tourelle, Boulogne-sur-Seine, France. Feb. 14, 1935, No. 4816. Convention date, Feb. 20, 1934. [Class 4] Planes, construction of.-In a variable-area wing such as described in Specification 399,048, Fig. 1, in which flexible surfaces comprising ribs 1 composed of a plurality of articulated elements, are moved along a fixed wing 2 to increase the chord thereof both in advance of the leading edge and aft of the trailing edge, the leading edge of the flexible surface assembly is constituted by the juxtaposition substantially edge to edge of rigid streamlined elements threaded on resilient bonds connecting the front ends of the ribs together so as to constitute a continuous strip and provided with covering material so arranged as to make the leading edge substantially indeformable under the action of air forces whilst permitting it to flex for winding on to the drum. The arrangement shown in Fig. 1 is generally that described in Specification 399,048 except that the after parts of the flexible surface comprise two pivoted rib elements 9, 10, and that the aerofoil supported by rib elements 9 is formed with a fixed slot. The foremost aerofoil carried by rib element 4, is provided with a journal 15, Figs. 4 and 6, on which two shells 16 are mounted and prevented from axial movement by cups 17, 18. Between the shells 16 associated with successive rib elements 4 is arranged a chain of streamlined wooden blocks 22 having plane side faces 23 with two semi-cylindrical recesses 24 thus providing between each pair of adjacent blocks a cylindrical recess in which is located a wooden spool member 25 serving as an articulation and as a locking member. Similar spools are arranged between shells 16 and the abutting elements 22. Resilient flexible bonds 27 pass through blocks 22, spools 25 and are anchored in shells 16, Fig. 6. Bonds 27 which may be of shock absorber cord are fitted with initial tension. The leading edge thus constituted is enclosed by a non-extensible canvas band 31, Fig. 5, glued to the outer surfaces of the blocks. A two-ply rubberized fabric 33 which constitutes the covering of the entire forward aerofoil element is glued to band 31. The two thicknesses of material 31, 33 are then slit at the ventral face of the leading edge at the abutting faces 23. A rubber strip 34 arranged as shown in Fig. 5 is glued to the fabric 33. Blocks 22 cannot move in vertical planes relatively to one another but flexure of the assembly for winding on the drum is permitted as shown in Fig. 7. Curvature of the leading edge in flight is prevented. by the un-slit fabric strips 31, 33 of the dorsal face of the leading edge. The leading edge of aerofoil element 38, Figs. 1 and 14, is constituted by a continuous steel ribbon 69 secured on the lower face of ribs 1 and on which a pull is exerted for spreading out the flexible surface. Hinged to ribbon 69 between each pair of ribs is a second ribbon 69a adapted to fold on the former when the surfaces are wound on the drum and to assume the position shown when the surface is extended and thus to form a rib bracing element. The covering of the aerofoil element comprises a double thickness of canvas reinforced by a cable 41, Fig. 1. The after aerofoil element 39 carried by rib element 9 comprises a double thickness of canvas reinforced by cables 48, 54, Fig. 1, and a leading edge built up from blocks 47 shaped as shown in Figs. 9, 10, 11. The covering of the leading edge is similar to that described with reference to Fig. 5, and comprises a rubber band 49. The aftermost aerofoil element 40 carried by rib element 10 is similarly constructed and is braced by cables 52, 53, Fig. 1.