Handling qualities evaluation of an automatic slung load stabilisation system for the ACT/FHS

Abstract

The Handling Qualities (HQs) of a helicopter can be adversely affected through the presence of an externally slung load. Helicopter stability margins may be reduced, due to the additional dynamics of the load system, which can subsequently increase pilot workload, and reduce the operational envelope. An automatic slung load stabilisation system has been designed and has been successfully tested in flight. This system, alongside slung load scenarios, has been implemented within DLRs Air Vehicle Simulator (AVES). In this paper, the results from a simulated test campaign to observe the influence of the stabilisation system on the vehicle HQs are presented. The system is assessed using three Mission Task Elements (MTEs), designed for externally slung load operations. Results show that the conflict between pilot and stabilisation can cause degradation in HQs. However, it is shown that when the stabilisation system is used only "when required", both the HQs of the helicopter are conserved, and load oscillations are reduced. The results in this paper are intended to motivate future flights tests using DLR's Active Control Technology / Flying Helicopter Simulator (ACT/FHS).