Dynamic Interface Analysis of the Embarked Operation of the CL-327 ‘Guardian’ Unmanned Air Vehicle

The production Bombardier CL-327 ‘Guardian’ unmanned air vehicle (UAV) system has been developed to provide improved mission capabilities over its predecessor, the CL-227. A detailed dynamic interface study was undertaken to investigate securing requirements during embarked operation of the air vehicle. The first step in the analysis was a ship motion simulation study to characterise the flight deck motion of an FFG 7 class frigate and a WMEC Coast Guard Cutter -typical small ships. Using information describing the physical characteristics of the CL-327, a 16 degree-of-freedom mathematical model of the air vehicle/ship system was developed. The model incorporated the relevant on-deck dynamics of the UAV including various thrust levels and the associated induced rotor loads. Using the verified UAV model and the results of the ship motion analysis, two dynamic interface studies were performed. The first was aimed at defining apparent wind speed limits that would allow the vehicle to remain stable without vertical securing at the landing gear probes (LGPs). These wind speed envelopes were defined as a function of sea state, ship heading relative to the principal sea direction, and apparent wind direction. The second study was aimed at confirming that the vehicle is secure under severe conditions when vertical restraint is present at the LGPs and defining maximum securing loads that can occur in service. Results from the dynamic interface studies were used to support the design of air vehicle securing equipment and promote safety during a sea demonstration programme. The paper includes a description of the CL-327 and its capabilities; an overview of the mathematical model; the methodology and results of flight deck motion simulation; a summary of dynamic interface analysis results; and a description of the sea demonstration programme.