synchronizer

synchronizing systems automatically matches the revolutions of one or several propellers to the RPM of the master engine.

synchronizer

calculates the propeller revolutions with the aid of inductive RPM sensors on the propeller shafts or with pickups on the governors.

central position

When the system is switched off, the actuator of the slave engine is automatically set to what position?

master motor synchronization

used on WWII four-engine aircraft consisted of a synchronizer master unit, four alternators, a master tachometer, a tachometer generator and contactor unit for each engine, an rpm master control lever, switches, and wiring. When activated, these components automatically control the speed of each engine and synchronize all engines at a selected rpm.

One Engine Master Control System

These newer synchronizer systems typically consist of a control box that includes a comparative circuit, a special master governor on the left engine, slave governor on the right engine, and an activator in the right engine nacelle. Both governors incorporate a frequency generator that produces a frequency proportional to the engine's rotational speed.

Synchrophasing

systems are a refinement of propeller synchronization systems in that they allow a pilot to control the angular difference in the plane of rotation between the propeller blades. This angular difference is known as the phase angle and can be adjusted by the pilot to achieve minimum noise and vibration levels.

pulse generator

magnetic pick-up device keyed to the main blade of its respective propeller

propeller manual phase control

allows the pilot to manually select the phase angle which produces the minimum vibration and noise

Synchrophaser with Mechanical Governing System

Through a synchrophaser the system receives a phase signal from the propellers in addition to the RPM signal through the RPM pickup or additional pickups. The system then sets the slave propeller to the determined phase position. The phase position of the slave propeller is some degrees off that of the master propeller. This offsetting is programmed in such a way that vibrations in the cabin are kept to a minimum. Thus the synchrophaser sets the slave propeller to a constant phase displacement.

Synchrophaser with Electronic Governing System

The left propeller is the master for synchophasing. By connecting the two PECs the left PEC can transmit a signal to the right one. In this way the latter can adjust revolutions to master RPM. As the PECs control propeller RPM very exactly (+/- 0.2%), the difference in RPM is very small when synchrophasing. The synchrophasing function is automatically activated if the power lever is at CLIMB or CRUISE and the difference in RPM is less than 1 min-1.