A 'Tolerant' Wing Design for UCAV

摘要

UCAV wing design is a major research activity. Many manufacturers throughout the World are displaying examples (X47B, X-45 and Neuron etc.). For a given flight envelope, the UCAV needs to be as light and small as possible. The design is a compromise between efficient high-speed flight, loiter and good stability and handling at low speeds. This work programme is concerned with fundamental understanding the complex flow separations arising on modern combat aircraft wings including UCAV's, An aspect of interest is the selection and adaptation of a suitable model for further research and development. An early UCAV research model from 1990's, extensively studied (theory & experiment) is the (planar - uncambered wing) Model 1303. Although it may lack some of the modern attributes (e.g. stealth properties), the high quality data-set available provided a valuable platform / opportunity for further work towards a "tolerant" wing design and CFD, experimental validations. We have analysed the existing data-set and shown good agreement with the predictive methods. This provided the confidence for deriving realistic designs with appropriate camber and twist in fulfilling the typical flight envelope. The effects of longitudinal static stability margins on design geometry have been assessed. One of the designs was aimed at modifying, with camber and twist, the LE area, but this did not give an adequate control of stability margins without an additional balancing design in the TE area. As expected, a designed wing has a completely different flow Separation characteristics c.f. a Planar wing. In a wider perspective, an understanding has evolved for either exploitation or avoidance of the complex flows. This will continue to motivate future work.