The Development of the Total Vibration Reduction (TVR) System

The TVR system is designed to reduce most of the major harmonic vibration caused by a main rotor system. It consists of the AAPL and AVR system. The AAPL system reduces 1/rev vibration by adjusting the length of pitch links automatically in all flight conditions. The AVR system reduces higher harmonic vibrations such as 4/rev and 8/rev by hydraulic actuators those are installed in main gear box mounts. As a result of the flight test on BK117 C-1 helicopter, the vibration level was very low in every flight speed, so the development of the TVR system was successful. The series production model of the TVR system is being designed now.