Patent GB-561835-A (GB)
Title: Improvements in or relating to trainers for instructing aviation pupils on the ground
IPC: G09B9/16
Filed: 1942-07-29
Abstract: 561,835. Training aviators. LINK AVIATION DEVICES, Inc. July 29, 1942, No. 10617. Convention date, Aug. 8, 1941. [Class 4] A " Link " trainer coupled to a recorder has means for influencing the movement of the recorder in accordance with the direction and speed of an assumed wind, this means comprising a deformable triangle having one side fixed in direction but variable in length in proportion to the assumed air speed of the trainer as controlled by the throttle setting, and a second side having its length varied in accordance with the assumed wind speed and its direction adjusted jointly in accordance with the direction of the assumed wind and the position in azimuth of the trainer fuselage. The direction of movement of the recorder is finally determined jointly by the direction of the third side of the triangle and the position in azimuth of the trainer fuselage, and the speed of movement by the length of the third side of the triangle. The trainer is of the kind described in Specifications 481,375 and 370,128, and the recorder is described in Specification 484,243. The instructor's desk on which the-recorder moves to indicate the track of the supported flight has means for simulating radio signals to the trainer as described in Specification 476,816, and means for communicating the direction and strength of a supposed wind to the wind drift instrument which is shown in sectional elevation and plan respectively in Figs. 2 and 3. The cockpit heading is continuously transmitted to a shaft 32 in the intrument and the supposed wind speed and direction are respectively communicated to shafts 34 and 36. The deformable triangle ABC has a fixed corner B, the corner A being movable towards and away from the corner B in a fixed vertical plane containing the latter in accordance with the throttle setting. The corner C is carried by a slide 138 movable radially in a guide 140 turnable about a vertical axis at the corner B. A carriage 58 is movable along guides 56, 74 by means of a rack 64 engaged by a pinion 66 driven by a reversible motor 60 under control of a follow-up switch carried by a pulley 54 which is urged in one direction by a,spring and in the other direction by a cable 52 connected to the throttle lever in the trainer. The carriage 58 has a housing 230 supporting a vertical shaft 232 having its axis at the corner A. This shaft has a toothed portion 228, Fig. 4, engaged by teeth on a rack bar 224 connected at one end to a pivot at the corner C so that if either the carriage 58 or the corner C be moved the shaft will be rotated by the rack bar and its motion will be transmitted to a bevel wheel 78 rotatable in an extension 76 of the housing 230. The bevel wheel 78 can slide on a splined shaft 80 by which its motion is transmitted to the left-hand pinion of a differential gear 84. The rack bar 224 slides through a sleeve 240 on a member 242, Fig. 4, rotatable about the axis of the shaft 232. The member 242 is connected to a bevel wheel 260 by which angular movements of the member and therefore of the rack bar 224 are transmitted to a bevel wheel 270 slidable on a splined shaft 264. Rotation of the shaft 264 is transmitted through idle gears 272, 276 to a gear 280 on the frame of the differential 84 to neutralize the effect of any angular movement of the rack bar so that the output shaft 86 of the differential gear moves solely in proportion to the linear displacement of the rack bar 224. The shaft 86 has a pinion 90 gearing with a rack 91 by which a cylinder 94 is moved along a splined shaft 96 continuously rotated by a motor 98. The cylinder 94 has a raised cam portion 104 which completely surrounds the cylinder at one end and stops short of the other end of the cylinder. The cam portion engages a follower 106 to close a switch 114 for a greater or shorter time per revolution according to the axial displacement of the cylinder 94 and the impulses are transmitted to the recorder through a cable 122 to determine its speed of movement. The shaft 264 has an extension carrying a gear 282 in mesh with a gear 284 connected to the frame of a differential 42, the left pinion of which is connected to the shaft 32. Consequently the output shaft 44 of the gear moves in accordance with the coinbined angular motions of the rack bar 224 and of the trainer fuselage. This motion is transmitted through a detachable coupling 46 to an autosyn 48, connected to the recorder through a cable 50, by which the direction of movement of the recorder is controlled. The shaft 32 carries a gear 214 in mesh with a gear 216 connected to the righthand pinion of a differential gear 220, the frame of which is adjusted by the shaft 36 through a worm 148 and worm wheel 150, consequently the output shaft 152 of the differential gear moves in accordance with both the wind direction and the orientation of the trainer fuselage. This motion is transmitted through a worm 156 and worm wheel 158, Fig. 5, to a vertical shaft 160 which drives through two equal gears 166, 168 a sleeve 170 keyed to the guide 140. A gear 192 at the lower end of the shaft 160 drives through a reversing idler 194 a gear 198 connected to the pinion 206 of a differential gear 130, the frame 204 of which can be turned by a worm wheel 128 and worm 124 from the shaft 34. The opposite pinion 212 of the differential gear is connected to a shaft 132 having a pinion 136 in mesh with the slide 138 which has a pin 142 for connection to the rack bar 224. The drive from the shaft 160 ensures that the pinion 136 turns at the same rate as the sleeve 170 when the latter is turned, so that there is no resultant axial displacement of the slide 138 from this cause, such sliding only being effected by turning the shaft 34 which introduces the wind speed factor. The corner C of the triangle ABC is coincident with the axis of the pin 142, the rack bar 224 being offset equally from the axis of the pin 142 and the axis passing through point A.