Patent GB-569440-A (GB)
Title: Improvements relating to apparatus for instruction and training in flying on radio beam courses and for other navigation purposes
IPC: G09B9/26
Filed: 1943-09-10
Abstract: 569,440. Training aircraft pilots. JENSEN, P. W. W. Sept. 10, 1943, No. 14898. Convention date, Nov. 20, 1942. [Class 40 (v)] Training apparatus comprising a recorder arranged to execute upon a table movements simulating those of a moving craft such as an aroplane, is provided with means for producing an electro-magnetic field about a point on the table representing the position of a radio beacon so as to simulate upon a reduced scale the radiating field of the direction and marker beacons &c., the recorder having a pick-up coil which transmits to the pupil signals simulating those which would be received by an actual moving craft. A trainer of the " Link " type is described connected to a recorder 13 which moves over a table 12 in accordance with the supposed. track of an aircraft. Mounted beneath the table 12 at the point representing the position. of a radio beacon are two flat crossed coils 19, 20, in vertical planes, supplied with current at 1020 # from an oscillator 25, an automatic keying device 30 transmitting through a double pole relay 29 dot-dash A signals and dash-dot N signals to the respective coils so that where the fields overlap there will be four narrow radiating bands over which the note picked up by a coil 16 on the recorder will be continuous. The coil 16 has a vertical axis so that immediately over the point representing the beacon there will be silence. Additional coils 191, 201 similar to but larger than the coils 19, 20 are placed vertically beneath the coils 19, 20 to give a more close approximation to the variation of the intensity of field which occurs as an aircraft moves towards or away from a beacon. Fig. 5 shows one form of crossed coils with interlaced turns in planes at right angles. The signals are passed through a filter 41, amplifiers 42, 43, and pupils' volume control 44 to earphones 17. A '' background noise " generator 45 feeds into the circuit and a " pack limiter " 48 gives the effect produced by excessive signal strength so as to induce the pupil to use his volume control. A relay 28 on the automatic keying device enables the A and N signals to be interrupted at intervals and a station-identification signal sent out. A Z-' marker signal and fan marked signals at 3000# are simulated by separate coils at the centre and at equal distances from the centre along the simulated " beams." These signals, picked up by the coil 16 are filtered out by a band pass filter 50 and light up a signal lamp 18. In a modified form the crossed coils are carried on the recorder and the field beneath the table is provided by a conical coil on a vertical axis supplied with current at 1020#. The induced currents in the crossed coils are interrupted to give the A and N signals by apparatus on the trainer. Iron or other magnetic shields or baffles may be so placed as to distort or improve the fields of the coils 16, 19, 191, 20<1>, or the coils in the modified form of the apparatus, so as to obtain effects such as " course bending," " course-squeezing," orientation or for improving the simulated intensity gradient along the " beams." The crossed coils may be rotatable to vary the direction of the fields produced.