Tachometer, Helicopter, USSR 0-4000 RPM C-7 The glass is clear and

The glass is clear and intact

The round turret silhouette in the center of the dial rotated as the turret rotated relative to the forward direction of the aircraft

25in diameter and ~4in deep

such as the P-40

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

Tachometer, Helicopter, USSR 0-4000 RPM C-7 The glass is clear andHere 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