Patent GB-956531-A (GB)
Title: Improvements in or relating to flight training or simulating apparatus
Inventor: BRIDGES BERNARD ARTHUR
IPC: G09B9/20
Filed: 1962-08-20
Abstract: 956,531. Grounded aircraft trainers. COMMUNICATIONS PATENTS Ltd. Aug. 20, 1962, No. 31854/62. Heading B7W. Means for simulating ambient temperature variation in a flight trainer computer, comprises first means computing a mean standard temperature as a function of height, from a rate of climb input signal, second means computing the difference between the mean standard temperature and a temperature varying with height according to a desired temperature lapse rate, from rate of climb and desired lapse rate input signals, and means for combining the mean standard temperature and difference temperature. In the Figure, a simulated rate of climb signal available at terminal 25<SP>1</SP> from part of a flight computer not described, energizes a potentiometer 30 having a grounded centre tap and driven by an instructor's knob 24, a dial 31 indicating the international standard atmosphere lapse rate of 1.98  C. per 1000 feet when the potentiometer wiper is at the top. The instructor can set knob 24 to select a lapse rate of between  3 C. per 1000 feet. The signal or the potentiometer wiper represents the product of rate of climb and departure of the lapse rate from the standard, which is the time rate of change of the difference between the standard temperature at the simulated altitude and the simulated ambient temperature, i.e. the temperature deviation rate. This is an A.C. signal, representing the magnitude of the temperature deviation rate by its amplitude, and the sign by its phase of 0 degrees or 180 degrees relative to a reference A.C. signal, and is fed through amplifier 35, and transformer 37, 38, 39, to a demodulator comprising diodes 40, 41 biased to the non-conducting condition during alternate half cycles by a reference A.C. voltage across terminals 47, 48, of amplitude greater than the maximum output of winding 39. The magnitude and sign of the total D.C. potential across capacitors 44, 45, thus corresponds to the amplitude and phase of the input. The D.C. signal is fed to a motor 49 which rotates at a speed and in a sense corresponding to the magnitude and sign of its energizing voltage. The shaft position of the motor thus represents the temperature deviation, which is available as an A.C. signal at the wiper of potentiometer 52 driven by the motor. The motor is de-energized by cam operated switches 61, 62, when the temperature deviation exceeds  30 C., the switches leaving the motor energizing circuit only that one of diodes 63, 64, which blocks further current flow in the sense to increase the temperature deviation. A clutch 51 enables the instructor to set an initial temperature deviation by knob 23, scale 58 showing the selected deviation from the standard sea level temperature of 15 C. The scale is subsequently rotated by motor 49 to show the computed deviation in flight. A potentiometer driven by an altitude servo (not shown) produces a standard temperature signal as a function of altitude in accordance with the international standard atmosphere, to which the deviation signal from potentiometer 62 is added to produce simulated temperature.