Patent GB-673816-A (GB)
Title: Computer for aviation trainers
IPC: G09B9/16
Filed: 1948-03-30
Abstract: 673,816. Indicating- apparatus. LINK AVIATION, Inc. March 30, 1948 [March 27, 1947], No. 8993/48. Class 106 (iv). [Also in Group XXXIII] A computer comprises a master member adapted to be positioned, relatively to two sets of graphical curves on a geometrical surface, by at least two independent inputs represented graphically by one of the sets of curves, in which its movements relatively to the other set of curves are transmitted to at least two output members to position them in accordance with outpute represented graphically by the other set of curves, so that each output is dependent on variations in either or both of the independent inputs. The invention is described as applied to a ground trainer for teaching aircraft pilots, of the type described in Specifications 370,128 and 481,375, [both in Group XXXIII], a number of computers in the form of interconnected mechanical linkages operating the dummy flying instruments in accordance with movements of the dummy controls. Three computers are described, viz: (a) an engine computer, the inputs being throttle lever setting, engine speed lever setting and assumed altitude, the outputs being manifold pressure and brake horse-power; (b) a flight computer, the inputs being aircraft attitude and either airspeed or horsepower available, and the outputs vertical speed and either airspeed or horsepower required; (c) a rate-of-turn computer in which the inputs are air-speed and engine power, the output being rate-of-turn. Engine computer (Figs. 3 and 4).-The mechanism consists essentially of a rhombus formed by a " manifold pressure arm" (MPA), "horse power arm" (HPA) connected by a fixed master pivot 112 (FMP), and links 100, 102 connected by an "altitude master pivot " (AMP), the latter point moving over a manifold pressurebrake horsepower chart consisting of a series of intersecting arcs in accordance with the positioning of the manifold pressure and horsepower arms as determined by engine speed lever setting, throttle setting and assumed altitude. Engine speed (or propeller governor) setting. The engine speed lever 120, Fig. 6 (not shown), is connected by a link 130 and members 132, 134, 142, 146 to an arm 148 having a fixed pivot 150, the arm 148 being connected to an arm 156 the end of which forms a " sea level master pivot " (SLMP). Under assumed sea level conditions the points SLMP and AMP coincide, the latter being displaced as the assumed altitude varies. Movement of the engine speed lever determines on which engine speed arc the point SLMP will be positioned. Throttle setting. The throttle lever 160, Fig. 6 (not shown), is connected by a link 190 which, through a shaft 196, rotates a sector 200 meshing with a pinion 208 fixed to a shaft 210 which carries a link 216 fixed to a second link 218 whose other end is connected to the point SLMP. The latter is connected by a link 230 with a short arm 230a, and a link 244 to a block 252 slidable along a rod 250, to position the point AMP. Altitude setting. The altitude unit is connected by a cable 268 to a sector 259 operating a linkage 258, 254, 244, 230, the end of the latter being connected to the point SLMP. Link 244 is connected to the block 248 movable along the rod 250, to adjust the position of the point AMP, the sector 259 being carried on a link 234 which rotates about a fixed pivot 236. As the result of the adjustment of the controls the arms of the rhombus take up their appropriate positions and the point AMP its position on the manifold pressure-horsepower chart, the arms MPA and HPA giving visual indications of their associated quantities. In the case of manifold pressure, a pinion 110, Fig. 4, is coupled to the arm MPA and meshes with a second pinion 270 which, through a Selsyn transmission 274, 286, operates a dummy manifold pressure gauge 288. Flight computer (Fig. 8).-The computer comprises links 348, 360 carried by a fixed pivot 340 and links 352, 356 pivoted to a block 368 slidable along a rod 371, one end of which is mounted on a fixed pivot 372. The horsepower input is fed into the computer from the arm HPA of the engine computer (Fig. 4) through links 322, 324, 364, the latter being connected to an arm 361 integral with the member 360. A link 370 connected to the sliding block 368 and the members 361, 364 is adjusted in accordance with the attitude of the trainer by a bell-crank lever 374, 376 connected to the attitude control member 380, Fig. 4. In this case the airspeed and vertical speed are recorded on dummy instruments, the former by means of a toothed sector 430 integral with the arm 348 and meshing with a pinion 432 operating the indicator 460 through a Selsyn transmission. The rod 371 carries at its free end a member 529 movable between electric contacts 536, 538 to control a follow-up motor connected through a Selsyn system to a dummy vertical speed indicator 588, Fig. 12 (not shown), the reading of which may be integrated with time to operate a dummy altimeter 623, Fig. 12 (not shown). Rate-of-turn computer (Fig. 15).-The rudder centring valve 684 in addition to its control by the dummy pedals 676, 677, is controlled by a linkage 687, 673, 668, 667, 652, 653, 654, 656, 660, the latter member being connected by a link 662 to the throttle control lever, while the lever 654 is connected through a link 665 to the air-speed control, so that any variations in throttle setting or air-speed operate the valve 684 to cause turning of the fuselage. The trainer described is also arranged to simulate the effect of air-speed and engine power output on fuselage attitude, and vertical hunting effect, by appropriate adjustment of the elevator control valve, the effect on air-speed and altitude of flap adjustment, " mush effect," i.e. loss of height when the air-speed falls to a critical value without alteration of fuselage attitude, and also rough air effects. Specification 623,573, [Group XXXIII], also is referred to.