Schlüsselwort: Feasibility Study

Developments of the last decades, latest investigations, implementations and trend analysis show: the further increase in bypass ratios of jet engines is one key to persisting efficieny improvements. Most likely this is accompanied by increase in fan diameter and concatenated decrease of the rotational frequency, stability and level of fan efficiency. This challenge can be replied by introducing a variable area fan nozzle (VAFN). Such a system requires an actuation system. VAFN Systems are typically integrated into the nacelle of an aero engine. Analogous to a VAFN, a modern thrust reverser unit (TRU) is also integrated to the nacelle and also requires an actuation system. The thesis arouse, that reducing the number of actuation systems by combining two similar systems leads to a decrease of complexity, weight and required design space while at least maintaining the same level of safety. Starting with the idea to this research project up to the latest results, technical solutions and the process of creating the solutions are documented in this dissertation. One of the most important objectives was to work scientifically and footloose while creating a feasible concept. As a consequence, system safety assessments and type certification investigations were important parts along with the technical design. A comprehensive outline of potential benefits of a VAFN System, of airborne equipment development and safety analysis methods as well as selection of appropriate methods are part of the documentation. A type certificate programe enhances the technical requirements and is the foundation of the creative concept development. An innovative concept has been identified, preliminary designed and is actually part of a patenting process. The actuation systems complies with the safety and design space requirements. Although a system with an additional function is always more complex, it is less complex than two systems with one function each. The presented actuation system concept with enhanced functionality has only insignificantly more mass than a comparable TRU actuation system, and has less mass than a concept with separate actuation systems for TRU and VAFN, besides further benefits of a coupled system.