GB648645A - Improvements in ground based night-flying visual aids for aircraft - Google Patents

Abstract

648,645. Visual landing aids for aircraft. McCLEMENTS, A. July 16, 1948, No. 19107. [Class 118 (ii)] [Also in Group XI] To indicate at night the direction of the wind to the pilot of an aircraft a wind-operated screen is arranged to cast an elongated shadow on an illuminated patch of the landing ground. Light from a lamp 7 mounted on a wheeled tripod 3 is directed by a lens 8 and a conical reflector 11 to give all-round illumination of the ground below the lamp and a screen 18 on the end of a boom 14 rotatably mounted on a vertical tube 12 and carrying at its other end a wind vane 15 intercepts the light over a narrow angle in azimuth to cast a shadow in the up-wind direction. An approach path indicator comprising a lamp 20 and a box-like structure of vertically arranged filters 25 ... 27 and opaque screens 29 ... 32 adapted to emit non-overlapping coloured beams extending over predetermined angular ranges in elevation may be mounted above the wind indicator with the box-like structure attached to the rotatable boom 14 so that the coloured beams are only visible from the down-wind direction and from a small angle on either side thereof. Downwardly directed light from the lamp 20 is intercepted by a cylindrical screen 23. Mechanism may be provided to give the lamp 20 a flashing characteristic so that it may also serve as an identification beacon for the landing ground ; alternatively the lamp 20 may be distinctively coloured. In an alternative form of construction the whole installation including the lamp 7, the reflector 11, screen 18, the wind vane 15 and the approach path indicator is constructed as a unit the parts of which are relatively immovable and is mounted for rotation as a whole about a vertical pivot axis.