As a pilot aid to manually synchronizing the propellers, some twins have a small gauge called a synchroscope mounted in or by the tachometer(s) with a propeller symbol on a disk that spins. The pilot manually fine tunes the engine r.p.m.
In certain aircraft models, a small gauge called a synchroscope serves as a pilot aid for manually synchronizing propeller speeds. This gauge is usually mounted in or by the tachometer(s) and includes a propeller icon on a spinning disk. Pilots then adjust the engine's r.p.m. to achieve synchronization.