Patent GB-971543-A (GB)
Title: Aircraft navigation instruments
Inventor: CYPSER GUSTAVE JOHN
IPC: G01S1/02
Filed: 1961-03-03
Abstract: 971,543. Aircraft instruments. SPERRY RAND CORPORATION. March 3, 1961, No. 7826/61. Heading B7W. [Also in Division H4] Relates to an aircraft navigation instrument of the type disclosed in Specification 807,512 in which the heading of the craft relative to the direction of a ground track defined by a V.O.R. or I.L.S. localiser beacon, i.e. the track heading error, and the deviation of the craft from the track are indicated respectively by the angular rotation and lateral displacement of a pointer 30 relative to a fixed mimic aircraft index 15, the deviation of the craft from a glide slope defined by an I.L.S. glide slope beacon being indicated by the vertical displacement of a horizontal pointer 70 against a glide slope scale 77. According to the present invention the face of the instrument comprises a rotatable annular compass scale 16 surrounding a disc 33 carrying a raised convex plate 37, the disc 33 being set back from the plane of the annular scale 16 as shown in Fig. 2 (vertical section) and Fig. 3 (horizontal section) and two triangular indicators 61 and 62 being pivotally mounted so that they may be positioned out of sight between the disc 33 and plate 37 as indicated by the dashed lines in Fig. 1, the appropriate one of the indicators 61, 62 being moved out automatically from behind the plate 37 to a visible position, e.g. as shown by the full line drawing of the indicator 61 in Fig. 1, to indicate movement of the craft to or from the V.O.R. beacon when the receiver 38, Fig. 3, is set for V.O.R. operation; in this mode of operation the glide slope pointer 70 and scale 77 are both automatically moved behind the compass scale 16. When the receiver 38 is set for I.L.S. operation the To- From indicators 61, 62 are retained out of sight behind the plate 37, the horizontal pointer 70 is moved to a central datum position from which it is displaced by the glide slope error signal from the glide slope receiver 75, Fig. 3, and the glide slope scale 77 is automatically moved out/from behind the compass scale 16 to the visible position shown in full lines in Fig. 1 only when the received glide slope signal is reliable. As shown in Fig. 3 the annular compass scale 16 is controlled by the compass 24 via peripheral gears 19, the magnetic heading of the craft being read off the scale 16 against a fixed marker 26, Fig. 1, aligned with the aircraft index 15. The disc 33 is mounted on the end of a yoke 31 which is rotated about an axis perpendicular to the disc 33 by means of gears 41, 42 in accordance with the track heading error output from a differential gear 43 coupled to the compass 24 and a manual course selector 40, Figs. 1 and 3, and the vertical pointer 30 is attached to a horizontal arm 35 extending through slits 35 in the disc 33 and plate 37 from a meter movement 34 which rotates the arm 35 in the plane of the yoke 31 in accordance with deviation of the craft from the track. The heading error is also indicated by the angular displacement relative to the fixed marker 26, Fig. 1, of a marker 45, Figs. 1 and 2, controlled by peripheral gears 46, Fig. 3, and the heading error relative to another datum direction as set in by another manual selector 51, Figs. 1 and 3, is indicated in a similar manner by another marker 55, Figs. 1 and 2, controlled by peripheral gears 56, Fig. 3. The setting of the course selector 40 is indicated on the instrument by a course counter and the distance-todestination as determined by a known form of D.M.E. is indicated by a distance counter. Electrical heading error signals from synchros 50 and 57 may also be applied to an automatic pilot and/or flight director. The To-From indicator elements 61, 62 are attached by L- shaped arms 63, 64, Fig. 1, to corresponding meter movements 61<SP>1</SP>, 62<SP>1</SP>, Fig. 3, mounted on the yoke 31 and actuated by a known form of To-From circuit in the V.O.R. receiver 38 so that when the aircraft is correctly orientated on the desired V.O.R. track the visible indicator element 61 or 62 will form an arrowhead to the vertical pointer 30. Glide slope indication. The horizontal pointer 70 is attached to an arm 73, Figs. 2 and 3, which is rotated by the glide slope meter movement 71 and when the glide slope receiver 75, Fig. 3, is not in use the meter 71 is biased to move the pointer 70 upwards behind the compass scale 16. The glide slope scale 77, Fig. 1, is formed on a member 85, Fig. 3, attached to the arm 86 of a meter movement 87 which is biased so that the member 85 is normally located behind the compass scale 16 as indicated by the dotted lines in Fig. 3 and is only moved out by a " flag " signal from the glide-slope receiver 75 when the received glide slope signals are reliable. When the scale member 85 is moved behind the compass scale 16 it uncovers a fixed brightlycoloured warning " flag " element 91, Figs. 1 and 3. Specifications 638,971 and 807,512 are referred to.