WWII German Luftwaffe Fl.20222-1 Tachometer Drehzahlmesser - 85aff - - Origina, RARE, NEW WWII German Luftwaffe Fl.20222-1 Tachometer Drehzahlmesser. Designation: mechanical. Tachometer Requirement characters: Fl. 20222-1 Measuring range: 500-2400 rpm M
Origina, RARE, NEW WWII German Luftwaffe Fl.20222-1 Tachometer Drehzahlmesser.
Designation: mechanical. Tachometer
Requirement characters: Fl. 20222-1
Measuring range: 500-2400 rpm
Manufacturer: Bruhn-Werke GmbH, Berlin
Year of construction: approx. 1941 (late model)
functionality: Flywheel tachometers are most commonly installed as short-range tachometers. The speed is recorded by a flexible shaft (on the camshaft for an in-line engine, on a special drive with half the crankshaft speed for a radial engine) and transferred to the display device (tachometer). This arrangement had to be made in order to reduce wear on the flexible shafts. Therefore, the flexible transmission shaft should not be longer than 3.5 m.
The flexible shaft causes 2 (sometimes 4) centrifugal pendulums sitting on a common axis to rotate in the display device. Under the influence of the centrifugal forces that occur, the weights strive outwards against the force of a return spring and thus move the pointer of the tachometer via a movable bushing.