USE OF MAXIMUM LIFT AND ANGLE-OF-ATTACK, A REVIEW OF EXPERIENCE WITHIN BAE MILITARY AIRCRAFT

Prior to the adoption of modern flybywire high authority flight contro l systems, the usable lift or angle of attack was usually dictated by the wing stall and subsequent loss of control of the aircraft. With th e advent of the high authority FCS, with high levels of integrity, the designer of modern combat aircraft faces the possibility of providing good levels of aircraft control up to and well beyond the AoA at whic h maximum lift or loss of control would have occurred in the past. Fur ther, the use of such control systems has allowed maximum advantage to be taken of control configured vehicle technology to enhance the perf ormance of the aircraft within the conventional angle of attack range. This paper provides a review of the experience which has been gathere d within BAe Military Aircraft, Warton, in the use and benefits of the se technologies with regard to the high AoA capability and impact on m aximum usable lift. Examples are drawn from the Tornado, Jaguar FEW an d EAP aircraft programmes, all of which have employed flybywire contro l, to some degree or other, combined with varying degrees of CCV techn ology, leading to their adoption on the Eurofighter 2000 programme. In doing this, some of the engineering compromises which the modern airc raft designer faces in achieving the customer required levels of aircr aft performance will be addressed, together with the outcome which has satisfied these purposes in the particular example considered. In par ticular, the power of the modern FCS places an increased reliance on t he knowledge of the aerodynamics of the aircraft, around which the FCS must be designed. This raises particular challenges in the increased AoA ranges which associate with the maximum lift of these high perform ance configurations. The paper concludes with an indication of the dev elopments in technology which are evolving and which will lead to furt her advances and increased capability combat aircraft in future years.