Patent GB-581462-A (GB)
Title: Improvements in ground aviation trainers
IPC: G09B9/24
Filed: 1944-06-29
Abstract: 581,462. Radio navigation. LINK AVIATION DEVICES, Inc. June 29, 1944, No. 12418. Convention date, July 30, 1943. [Class 40 (v)] [Also in Group XXXIII] A ground aviation trainer, in which the pupil is accommodated in a rotatable fuselage 10 (see Group XXXIII), is furnished with means under the control of an operator for forming about a transmitting antenna a signal field in accordance with the direction of the assumed geographical position of the trainer from the assumed geographical position of the transmitting antenna, and with a receiving antenna responsive to variations in the form of the signal field, the receiving antenna being connected to the fuselage so as to move with respect to the signal field in response to changes in the direction of the fuselage. As shown, a transmitter 156 (of the form described in Specification 577,242) provides radio frequency waves modulated by any desired audiofrequency waves and is located in an operator's desk 35. The transmitter is connected by a lead 158 to a transmitting antenna 160 in the form of a coil of wire fixed to a rotatable shaft 162, which carries a knob and index 164 by means of which it may be set in relation to a scale 166. The coil 160 is positioned between a pair of perpendicularly disposed coils 168, 170 connected in series to similar coils 72, 174. Mounted on a shaft 184 is a rotatable 'coil 180 connected through slip rings 182, brushes 186, cable 188, brushes 190, slip rings 192, terminals 194 and cable 196 to a radio receiver 198, which is connected to earphones 200 worn by the pupil and may be tuned to the frequency of transmission 156. The shaft 184 carries a gear 208 rotatable by means of a synchronous transmission system comprising a transmitter teletorque 222 and receiver teletorque 216 interconnected by cables, slip rings and brushes as shown. The input shaft of teletorque 222 is rotated by a gear 68 through a differential gear 230 when the fuselage is rotated, and causes a corresponding rotation of the coil 180. The latter may also be rotated by the pupil by means of a handle 246 geared to an azimuth scale 258 and to the frame of the differential gear. In operation, the knob 164 and shaft 184 are set to the appropriate bearing of the assumed position of the trainer from the assumed position of the transmitter. To determine the bearing of the transmitter with respect to the fuselage axis, the pupil rotates the handle 246 until " no signal " is heard in the earphones ; the bearing is then indicated by the scale 258. If the trainer changes course, the gear 68 will rotate the coil 180 through the differential gear and transmission system and a signal will again be heard. The pupil then rotates handle 246 to determine the new bearing. As the trainer proceeds on the course indicated by a recorder 37 (of the form described in Specification 484,243, [Group XXXIII]) on a map 36, the operator alters the setting of the knob 164 to the new bearing of the assumed position of the trainer from the assumed position of the station. The method of zeroing the system is described. A further transmitter 262 working on a different frequency to the transmitter 156 is provided to enable the determination of a radio " fix " to be simulated. Specification 561,835, [Group XXXIII], also is referred to.