Flight Envelope Opening Of A VTOL UAS

Abstract

Beside its major activity in the development of piloted helicopters, Airbus Helicopters has been developing for a decade now VTOL UAS systems. Regarding flight testing, opening the envelop of an UAS is a complete change of paradigm: when, on a manned helicopter, the flight envelop can be opened step by step and always relies on the capability of the on board pilot to recover and to come back to a safe envelop, on a UAS, the level of automation, the complexity of the overall system, the reduced awareness due to remote control and monitoring and the site and airworthiness constraints are new challenges adding to the standard problems of flight testing a VTOL. This paper describes the methods used to open the flight envelope of the VSR700 Unmanned Aircraft System (UAS). The VSR700 is the leading UAS program in Airbus Helicopters which enabled to grow competencies in VTOL UAS development. A focus will be made on two specific flight testing phases: the initial speed/altitude domain opening coupled with the tuning of the autopilot and the Ship-Helicopter Operating Limits (SHOL) opening. When dealing with heavy UAS, the flight test logics can be either to minimize the development time, whatever the risks. It can also be to minimize the risk, leading to long development time. The flight test technique that was adopted is a compromise between these two strategies.