GB589338A - Improvements in and relating to aircraft navigation apparatus - Google Patents

Abstract

589,338. Course steering apparatus for aircraft. MAY, W. J. Jan. 30, 1944, No. 16081/43. [Class 97 (ii)] A device to be used on course-steering and bombsighting apparatus so that wind velocity and direction may be ascertained without altering course and compensations may be made for height of ground above sea level and variations in altitude of flight. The device comprising a supplementary foresight, 43a carried on a rearward extension 42 of the track bar 34 and a disc 51 graduated in compass degrees and inscribed with concentric. wind velocity circles may be added to the apparatus described in Specifications 145,810, [Class 97 (ii)], and 542,792, [Group XIX]. The supplementary foresight 43a which allows sights to be taken on an object away from which the aircraft is travelling and the foresight 35 at the point of intersection of the wind bar 32 and the track bar 34 are equidistant from the guide 36 and mutually adjustable by the knob 50. In use, the navigator pivotally connects the wind bar 32 to the track bar 34 so that the foresight 35 will not move relatively to the track bar but will rotate over the disc 51 as the length of the extension bar 42 is altered. A ground object directly beneath the aircraft is selected and at the end of a predetermined period of time the selected object is observed through the sights 39 and 43a. Adjustment of the sight 43a results in relative movement of the sight 35 and consequently the wind bar 32 to indicate the wind direction and velocity. The dials 15 and 18 can now be set for the new wind direction and velocity. In order that the apparatus itself will not impede correct sighting, an auxiliary back-sight 39c is used with a laterally placed supplementary fore-sight 43a and when vertical sights are required with the depending fore-sight 39a. Since the time over which an observation should be made is affected by altitude, the rack 38a with altitude graduations 38b allows the back-sight 39c to be adjusted to correspond with altitude readings from the altimeter and the graduations 38b used in conjunction with an adjustable index corrects for time lag in the dropping of bombs. Further corrections for the height above sea level of the ground over which the navigator is flying and in the observation of objects dropped into the sea or on land are made by use of the timing device shown in Fig. 6 which may be set for altitude or arranged to compensate for height of ground above-sea level and shows by the intersection of hair lines 74, 80 with the time graduations 75, 79 the periods of time for making observations on fixed ground and sea objects and objects dropped into the sea.