Overall Systems Design Method for Evaluation of Electro-Hydraulic Power Supply Concepts for Modern Mid-Range Aircraft

It is an important task during conceptual design of aircraft on-board systems to identify tipping points, at which novel system technology concepts become superior to a state-of-the-art solution. Such a tipping point can occur, inter alia, at a specific size of an aircraft. For instance, zonal hydraulic power supply concepts, which generate the hydraulic power in the vicinity of the respective hydraulic actuation systems, reduce the amount of hydraulic pipe installations. While it has already been shown, that for a short-medium range aircraft the associated mass savings are outweighed by the additional electro-hydraulic power supply modules, the result might be different for a larger aircraft size. To answer such “what if” questions during the early design phases, system design methods are required, which balance fidelity and flexibility of analysis models on an overall systems level. In this paper, overall systems design (OSD) methods for an evaluation of electro-hydraulic (eH) power supply concepts are presented. They are exemplified by a system trade study comparing two eH power supply architectures for a modern mid-range aircraft – i.e. a centralized and a zonal arrangement. The results underline the importance of OSD methods, because the calculated mass savings on system-level which can be achieved with both eH supply concepts do not translate to savings in mission fuel mass and direct operating costs. Instead, a preliminary analysis of direct operating cost (DOC) indicates, that the system acquisition costs need to be lower for both eH power supply concepts compared to the conventional architecture to achieve the same total net present value (NPV) as a conventional systems architecture over an assumed product lifespan of 25 years.

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Overall Systems Design Method for Evaluation of Electro-Hydraulic Power Supply Concepts for Modern Mid-Range Aircraft