Vibration Aspects of Small Turbine Engines in Aircraft Installations

Vibrations experienced in PT6 and JT15D installations are reviewed. The JT15D turbojet vibrations are due primarily to rotor unbalances which may produce significant responses at some of the critical speeds. The PT6 turboprop vibrations are mainly caused by the propeller and, therefore, occur at low frequencies. PT6 gearbox vibrations at very high frequencies are of interest in the production process. Typical vibration problems are discussed.