GB560706A - Improved target locating and course steering means for use in the navigation of bomber and like aircraft - Google Patents

Abstract

560,706. Course-recording apparatus ; setting-out instruments for angles. MAY, W. J. Dec. 3, 1942, No. 17178. [Class 97 (ii)] [Also in Group XXI] Relates to course - recording apparatus for aircraft to enable a course to a target to be steered and to alter such course when about to make an approach for dropping bombs, flares, parachutists, &c. as well as to predetermine accurately points over the ground for releasing the bombs; flares, &c. when the target is obscured. The device comprising the invention consists of a transparent scale ruled by a number of lines representing altitudes and intersected by lines representing wind or ground speeds and having compass graduations to enable the scale to be set against a chart or course marked disc in a predetermined direction. As shown in Fig. 2, the transparent scale 17 is marked with longitudinal lines 18 representing altitudes, transverse lines 19 representing distances as indicated on part 10 of a course marked disc 7a, Fig. 1, such as is described in Specification 542,792. The scale is also provided with inclined lines 22 representing ground speeds. The end of the scale is provided with an aperture to enable it to be clamped between two rings, one of which, 28, is provided with compass graduations. Within the rings' a disc having an aperture 27 is provided. The course marked disc 7a is rotated in unison with a vector triangle apparatus and is provided with a direction pointer 9 which remains parallel to the direction bar of the vector triangle apparatus embodying vectors representing air, wind and ground speeds. In use, the scale is placed on the course marked disc 7a with the aperture over the target and the scale along the run-up course, as shown in Fig. 4. The bomb release point would then be that point on the chart indicated by the point on the mid-line x which is on the transverse plane of the point where the altitude line crosses the ground speed line on the scale. Fig. 5 shows a modification in which the scale is intended for dropping parachutists or flares, wind speed lines 34 replace the ground speed lines, and the scale is placed on the chart in the direction of the wind, as shown in Fig. 7. The point of dropping is determined as before, but a compensation for varying ground speeds is introduced in the shape of a disc 37 having concentric lines 38 representing ground speeds. Travelling with the wind the point of release is the part of the appropriate circle 38 most remote from the target. Against a head wind the point of release would be that part nearest the target and for other wind directions the release point will be where the appropriate circle 38 intersects a radial line parallel with the bearing of the course of the aircraft.