GB565988A - Improved computing device - Google Patents

Abstract

565,988. Calculating-apparatus. MIRSKY, A. Feb. 10, 1943, No. 2236. [Class 106 (i)] A device for computing the essential data apertaining to the control and performance estimation of an aircraft comprises relatively movable members bearing groups of graphs and scales. Graphs a, Fig. 1, define the relationship between true air speed and indicated airspeed with variations in height, scales b permit corrections to be made to altitude for pressure and temperature deviations, graphs c associated with sets of engine control data in spaces d, and graphs e to allow for changes in the gross weight of the aircraft and /or changes in altitude and associated with a gross weight scale f. A cylindrical form of apparatus is shown in Fig. 3. The charts a, c and d are arranged in the space 1 and the charts e in the space 2 of the cylinder 5. A cursor 6 mounted for rotary movement bears the altitude scale b, density height scale g and gross weight scale f. In the space 4 on the cursor is arranged a table of sets of coordinated values of the best indicated air-speed for range and the respective air miles per gallon with variations of height and loading. A range scale k on the cursor co-operates with graphs j for ascertaining the remaining range of the aircraft according to the fuel left in the tank. The top of the cylindrical body is provided with relatively movable scales for assessing changes in the gross weight due to the consumption of fuel and the ballast loaded or jettisoned. The arrangement shown in Figs. 2 and 3 comprises an adjustable annular ring 7 with scales representing gallons of fuel in the tank GT and gross weight GW, a fixed disc with a scale graduated in gallons per hour GPH, a rotatable arm 9 and a slotted sector 12 to co-operate with ballast scales BC, BJ.