GB664058A - Improvements in high-speed aircraft - Google Patents

Abstract

664,058. Propelling and controlling aircraft. BAYNES, L. E., and MUNTZ & CO., Ltd., A. March 1, 1950 [March 11, 1949], No. 6792/49. Class 4. An aircraft is provided with two wings hinged to the fuselage about axes which are approximately vertical when the aircraft is in level flight, a control member operable while the aircraft is in flight to move the wings about their hinge axes between a substantially fully spread position suitable for low speed flight and a position in which the wings have the pronounced sweepback desirable for transonic and supersonic flight and means operated by the said control means for varying the tail lift simultaneously with the said movement of the wings in such a manner and to such an extent as to maintain the longitudinal trim and stability within safe limits. The aircraft comprises a fuselage 10 of elliptical cross section enclosing two side-byside axial flow turbo-jet engines 11 supplied with air by two intake pipes 13 which pass on either side of the pilot's cockpit and are each divided vertically to pass above and below the wing centre section structure. The jet efflux pipes 14 are similarly divided vertically to clear the tail plane centre section structure. Each mainplane spar is mounted on pivots 17, the axes 18 of which are inclined rearwardly with respect to a vertical line 19 and the inner end of each auxiliary spar is supported in the fuselage by a guide and is connected to an irreversible screw jack 23. The horizontal tail surfaces 24 are mounted on pivots 25, the axes 26 of which are inclined in a similar manner to the mainplane axes 18. A tail fin 85 is mounted on a transverse hinge and all tail surfaces are pivoted rearwardly by a common screw jack coupled directly to the jack mechanism that alters the sweepback of the main planes. Such mechanism is driven by a continuously running electric motor operating through a hydraulic clutch and incorporates a differential gear controlled by a pilot's control member in such a manner that appropriate movements of the control member effect identical fore and aft movements of the main planes and related movements of the tail surfaces or differential movement of the main planes and identical fore and aft movement of the tail surfaces in the same sense. When the main planes are moved from the spread position shown in chain-dotted lines in Fig.. 2 to the swept-back position shown by full lines, corresponding movement of the tail surfaces ensures a correction of the longitudinal trim of the aircraft. To effect lateral control each main plane may be swept from a position slightly forward of the spread position to the fully swept-back position and forward movement of one wing is accompanied by rearward movement of the other wing. The variation between the spans of -the two wings and the difference in incidence resulting from the inclination of the pivots 17 causes a change in the downwash airflow over the whole span of the aircraft and in the wake of the wings with a consequent change in the effective incidence of the vertical fin 85 which creates a favourable yawing movement. In order to retain directional control at low flying speeds a rudder may be fitted. Wing flaps, Figs. 9, 10 (not shown), may be fitted and are arranged to be depressed automatically when the wings are spread. Such automatic operation may comprise hydraulic jacks controlled by a master cylinder located adjacent each hinge 17 and actuated by a cam formed on each wing or each flap may be pivoted at its root end to the fuselage and guided at its tip in a curved slot formed in the wing.