GB707881A - Improvements in or relating to aircraft - Google Patents

Abstract

707,881. Pivoted closures for aircraft. ROLLSROYCE, Ltd. Jan. 11, 1952 [Oct: 12, 1950], No. 24983/50. Class 4 [Also in Group XXV] A door for closing an aperture in the outer skin of an aircraft is pivoted about an axis so located that its orthogonal projection in the plane of the door passes through the centre of area of the door, and is spring loaded into an open position, the outer surface of the door or the outer skin of the aircraft in the region of the door, or both the outer surface of the door and the outer skin, being shaped so that when the aircraft is airborne the airflow in the region of the door creates a closing torque on the door opposing the spring load. The door comprises a sheet metal pressing 57 formed with a part aerofoil raised portion 57a and a forwardly extending lip 57b which abuts rubber pads 56 secured to the undersurface of the leading edge member 52 of the door frame so as to leave an air passage between the door and the frame. The door has depending side walls 58 fitted with bushes through which extends a hollow spindle 60 and the door also has a mass balance weight 61 carried thereon by brackets 62 riveted to the spindle and the door. The ends of the spindle 60 engage part spherical collars received in bearing blocks 64 riveted to the side members 50 of the door frame. The door frame members are. interconnected and riveted to the aircraft skin 51 the leading edge member 52 being extended rearwardly to overlap the flange 57b of the door and being provided with a shaped member 55 which completes the part-aerofoil section of the portion 57a. The trailing edge member 53 of the frame underlies the door at 53a with an air gap therebetween. When the aircraft is stationary the door is urged by springs (not shown) to the open position indicated by dotted lines and when airborne the door is closed by the suction created by the relative airflow over the part aerofoil section leading edge portion. The airflow through the gaps formed at the leading and trailing edges of the door reduce flutter. Alternative arrangements of part aerofoil sections and air gaps are described and an alternative hinge arrangement may be used comprising a small diameter spindle having low frictional resistance which deflects under load when the door is closed so that the hinge loads may be carried by a stiffer hollow spindle co-axial with the smaller spindle, (see Group XXV).