Reduction of torque pulsation in ultralight helicopter transmission

Abstract

Usually, 1–2 seats helicopters use piston engines. One of their disadvantages is a significant torque pulsation on the engine shaft. The main reason for such fluctuations is the change in parameters during the engine’s operating cycle. The purpose of the investigation was to define the pulsation on the helicopter rotor shaft. An additional elastic clutch was used on a single-seat ultralight helicopter Rotorschmiede VA-115 of German firm RS Helikopter GmbH for pulsation dampening. Several flights were performed to assess the pulsation on the shafts. The results of the tests showed that the torque pulsation on the shaft in all modes does not exceed 30 %. This is 10 times less than the pulsation value of 300% specified by the airworthiness standards for this helicopter class.