The Use of Manned Flight Simulation to Analyze All Weather Shipboard Operations of the Merlin Helicopter on the Future Type 45 Destroyer

Evaluation is presented concerning testing results from a realtime ship motion-based helicopter recovery monitoring system. The simulated flight test has 5 (five) essential objectives: assess the capabilities of the Cockpit Dynamic Simulator (CDS) to support or conduct SHOL limits; demonstrate HLA federation along with selected modules e.g. air wake; examine T45 airwakerelated issues; evaluate recovery safety improvements offered by LPD; and determine feasibility of running the simulation over a Wide Area Network (WAN). The method, which has been implemented at the Culdrose Test Centre, gives good performance and airloads correlation with apparent quiescent windows of deck motion. The T45 destroyer is being studied owing to hangar design which has indications of significant bluff body turbulent vortex shedding. These free-flow separations are associated with the presence of shear and turbulence greatly complicating the free-stream flow. Wake distortions are minimised when solid structures do not disturb the flow field. This correlates with lower ship motions. The theoretical approach is described. Results are presented for wake geometries and structures created over the T45 destroyer air deck in relation to the approach of a RN MERLIN helicopter. The monitoring system is based on the Landing Period Designator (LPD) energy index, which was integrated into the flight simulator at Culdrose. The system is a reliable means of recording ship motion parameters at the landing deck and in the hangar. A brief synopsis is presented summarising development, simulation and testing of the LPD helicopter recovery aid as applied during the simulator test. The energy index, an empirical relation, evaluates ship motion as a function of the air vehicle limits by a process of filters designed to determine the air vehicle responses at the instant of recovery. Measurements of instantaneous degree-offreedom velocity and acceleration are reported, and preliminary comparisons are made with the LPD energy index evaluation during recovery.