Tachometer, Helicopter, USSR 0-4000 RPM C-7 The N-1 system was commonly

The N-1 system was commonly used in early models of the US Air Force bomber B-52 Stratofortress

type AChS-1

The star chart for the intended course of the aircraft was selected from among the 7 canisters stored in the wooden case

The glass is clear and intact

Tachometer, Helicopter, USSR 0-4000 RPM C-7 The N-1 system was commonlyHere is a Cold War era electronic dual Tachometer, 0 4000 RPM, as used in military helicopters of the USSR and Poland such as the MIL MI 1 (see cockpit photo, the tachometer is in the middle of the second column of instruments from the right) and MIL MI 4 (see cockpit photo, the tach is in the bottom row 3rd instrument from left). The pointer labeled "P" indicates RPMs of the Rotor, while the pointer labeled "M" indicates RPMs of the Engine. It is in