Simulation of a compound-split transmission for the UH-60

Abstract

Recent studies showed that the variation of the main rotor speed of the Sikorsky UH-60 (Black Hawk) offers the opportunity to reduce the propulsive power demand significantly in some flight states. A possibility to achieve this goal without changing the speed of the two turboshaft engines is the use of a Continuously Variable Transmission (CVT). One possible implementation is a so-called Compound-Split (CS), a special type of power-split transmission. The aim of this study is to present a drivetrain architecture of this type for the UH-60 helicopter and to show the feasibility by performing simulations in the time-domain. The results show that the transmission system is able to transmit the power in all searched flight conditions and the main rotor speed is kept within narrow limits around the target values.