Patent GB-834661-A (GB)
Title: Improvements in or relating to grounded flight trainers
IPC: G09B9/32
Filed: 1956-04-06
Abstract: 834,661. Grounded aircraft trainers. LINK AVIATION Inc. April 6, 1956 [April 14, 1955], No. 10578/56. Class 4. A grounded aircraft trainer comprises two projectors, one projecting a moving picture simulating a ground surface terrain as it would appear to a pilot, and the other projecting a moving pattern composed of a number of discrete light sources simulating a pattern of ground lights as they would appear to the same pilot. In Fig. 1, a cockpit is situated within a light proof enclosure 19, and an inclined screen 14 receives images of ground terrain from a projector 16, and images of ground lights from a projector 17. The projector 16 is shown in Fig. 6, and comprises a fixed support 118 mounting a tube 110 containing a light source 111 and a condenser 112. A cylindrical member 30 is mounted for rotation on member 118. A carrier 130 is slidably mounted in member 30, and is formed with a rack 137 engaged by a pinion 136 driven by motor 134 rigidly mounted on member 30. Member 130 supports two film spools carrying a transparency 113, and connected by a belt drive 141. One spool is driven by a motor 144. Member 30 is formed with a bevel ring gear 119 engaged by a bevel pinion 120 driven by motor 28. The motors 28, 134 and 144 are driven by the outputs derived from conventional heading, North South speed, and East- West speed computors, so that the terrain image projected from the transparency 113 moves as the trainee manipulates the controls. The optical projecting system comprises a variable magnification element 126 controlled by a motor 29, so that the size of the image varies according to computed altitude. A further optical element 26 introduces a given amount of distortion so as to reproduce perspective on the screen 14. Fig. 7 shows the projector 17. A shaft 70 rotatable by a motor 71 is secured to a platform 74 in which a bed 79 is slidable by a motor 76 through a rack and pinion. A platform 84 is rigid with bed 79, and a bed 89 therein is slidable by a motor 85 through a rack and pinion. A platform 94 is rigid with bed 89, and pillars 95 depending therefrom support the apparatus forming the discrete light sources. Motors 71, 76 and 85 are driven by the outputs derived from the heading, North-South speed, and East-West speed computers, so that the light source images move as the trainee manipulates his controls. The light source apparatus comprises an opaque platform 50 in which are formed a series of wedge shaped transparent or cut out portions 51, radiating from a point 52, and cooperating with two boxes 55, each having a slit 61. The optical projecting system (of constant magnification) is beneath platform 50, and thus projects two rows of discrete points of light onto the screen 14. The two boxes 55 are mounted on pillars 56 threaded to receive shafts 57 each threaded in two oppositely handed parts, and journalled in the pillars 95. The shafts 57 can be rotated by a motor 60 controlled by the altitude computer, so that a decrease in altitude moves the boxes 55 further apart, increasing the size of the projected image, and vice-versa. At the same time, cams 65 moving on surfaces 66 see also Fig. 4 (not shown), widen the slits 61, which lie over wider parts of the wedge shaped portions 51, so that the projected image of each light source grows larger as computed altitude decreases, and vice versa. In the flight computer, the simulated ground speeds are divided by the altitude by conventional methods, and the resulting potentials actuate the motors 134, 144, 76 and 85. For night landing practice, the projector 17 alone operates at high altitude, and as altitude decreases, the light source 111 of the projector 16 is gradually brightened by the flight computer as the ground details would become visible to an actual pilot. Roll and pitch may be simulated by tilting either the cockpit or the projectors and screen. Specifications 807,233,822,336 and 834,662 are referred to.