Calculator, Ballistic Correction No1, MK I, metal, made by CM Co, place of manufacture unknown, c. 1940
This mechanical calculator is mounted on a heavy metal plate. The plate has four holes which were used to mount the calculator inside an aircraft. At the top right side is a dial with two selectors and two numbered plates for setting the selectors. There are two metal information plates riveted to the large plate the array is mounted on. extending out the bottom and the right side of the dial are actuator arms that connect to five further actuators.
'Calculator, ballistic', 'No I. MK.I', 'CM Co', 'Reg No 154'