GB395806A - Improvements relating to calculating apparatus for solving vector triangles - Google Patents

Abstract

395,806. Calculating- apparatus. LEVKOVITSCH, P. GOUDIME-, La Maion Longa, La Napoule, France. March 1, 1932, No. 6238. [Class 106 (i).] Plane-trigonometry calculators.-A device for solving vector triangles for use on aircraft or surface vessels comprises three spaced arms or equivalents associated with scale and pointer indicators whereby the magnitude and direction of the observed vectors may be set. The ends of the outer arms are operatively connected with the mid arm or so disposed with respect thereto that the ends of the three arms lie in a straight line, the ends of the outer arms being equidistant from the end of the mid arm. The principle underlying the invention is shown in Fig. 1, the sides AB, DA of the triangle ABD represent the direction and magnitude of the velocity of the wind and the course and air speed and the resultant DB represents the ground speed and track. By completing the parallelogram the vectors can be represented by DA, DC, and DE by maintaining AE equal to EC, the scale on DE being half the scale on DA, DC. A constructional form of apparatus is shown in Figs. 3, 4, and 5. A panel 1 has mounted thereon three units 2, 3, 4 each unit comprising an arm 5 with rack teeth 15 engaging a pinion 14 on a setting knob 13 and guided for radial movement in guides 16. The guides are secured to a graduated dial 12 formed with a central aperture to expose scale markings on the arm 5. The dial 12 carries a scale bearing member 19 viewable through an aperture 20 in the panel and is formed with a knurled projection 23 to effect its angular adjustment. The arm 5 and dial 12 are adapted to be held in set position by a locking device 24. The ends of the arms of the outer units 2, 4 carry pivots 9 on which are mounted oppositely disposed rack elements 6, 7 that are engaged by a pinion 8 on the end of the arm of the mid unit 3. To ascertain the course to steer and the ground speed the outer units would be set to the air speed and compass course and wind velocity and direction whereupon the result would be read directly on the mid unit. The panel may be provided with a slide rule 25 graduated to make corrections for height of aircraft. A modified form of the apparatus is shown in Fig. 6, the panel being transparent so that it can be used directly on a chart. The air speed is adapted to be set on a graduated arm 28 carried by a rotatable disc 19, the ground speed and wind velocity are marked off on diametrical scales on the discs 19 of the units 3, 4, the scale ratio being 2 : 1. To the arm 28 is pivoted a graduated ruler 27 with two sets of markings bearing a ratio similar to that of the co-operating disc scales.