This 1/4 scale aircraft tachometer was designed and built by Pat Loop of Washington in 1995. Tachometers display the speed of an engine in revolutions per minute (rpm), and this is one of the smallest mechanical tachometers in the world. Pat Loop created this miniature tach to confirm that it could function and display rpm as accurately as a full-size tach. Extensive testing proved that it could. It displayed accurate readings from 0 to 7,000 rpm.
Tachometers are usually driven by a flexible shaft or cable attached to the engine’s camshaft. Within its mechanism, the rotating shaft generates a magnetic field that creates needle movement as the engine’s speed changes. This mechanism can be calibrated so the needle accurately displays the engine’s exact running speed.