Abstract
In recent years, the UK Ministry of Defence (MOD) has funded development, by QinetiQ and its predecessor organisations, of processes and tools to assess the performance of air vehicles, with the objective of maintaining status as an intelligent customer for a variety of air vehicle types. During this period, Operational Requirements have been evolving, requiring increased flexibility and the capability to produce accurate performance data for novel air vehicle concepts, including those which are not adequately represented by existing semi-empirical methods and databases. In order to explain the assessment process that has been developed, an example manned aircraft application is described. The component parts of the assessment process, and the underlying techniques and technologies are also described. Finally, indications are given of possible future directions.