The Remote Tach can be used to remotely measure the rotor speed of a RC helicopter in flight.Taching is accomplished by viewing the helicopter though the viewing shutter and adjusting the speed of the shutter until the main blades of the Helicopter appear to stop.
The shutter speed can be increased or decreased using the buttons at the back of the tach. The shutter speed range corresponds to 1000 to 3190 rpm of the helicopter head speed.The tach automatically shuts off after 30 seconds of inactivity. It will remember the last set RPM. After wakeup, allow 3 seconds for the shutter RPM to stabilize.