Mission Performance and Cost Calculation for variable Rotor Speed Drivetrain

Abstract

The research presented in this paper is part of the international research project VARI-SPEED, which aims to invent a mass optimized speed variable drivetrain comprising a main gearbox with variable transmission ratio and a rotor suitable for rotor speed variation. A performance and cost simulation model was set up for the Sikorsky UH-60A. Three different types of drivetrains were investigated: The Standard drivetrain, a 2 Speed gearbox and a continuously variable transmission (CVT). Flight missions of 3 industry sectors- Oil and Gas, Construction and Search and Rescue with a total of 33 different missions were simulated. The simulation was performed to evaluate the effects of the variable rotor speed technologies on performance and costs in the context of missions. It could be shown that rotor speed variation in a range of 50% can lead to less fuel consumption and mission costs in every industry sector and the performance of the helicopter can be increased. The CVT seems to be the better solution for multi purpose helicopters. In single missions the results can be different, therefore it is important to have a look on more different missions in an industry sector. The mass of the transmission system has an significant impact on the results. The results of the investigation can give an idea about the boundary conditions for the usage of rotor speed variation and show the critical points of rotor speed variation. The technology increases the efficiency, decreases fuel consumption and CO2emission and reduces noise and environmental impact of rotorcraft. Furthermore it can have also economic advantages for the operator.