Grand challenges push aero innovation

One of the UK's leading innovators reveals his thinking and details of some past and current aerospace projects. Tom Shelley reports

Innovation is best driven by challenges, according to Christopher Clarkson, Future Air Systems Technical Director of BAE Systems Air Systems. Giving the annual Lanchester Lecture at the Royal Aeronautical Society, Clarkson revealed innovations developed in response to past challenges and some of the challenges remaining to be met. A challenge posed some years ago was to find ways of doing away with aircraft undercarriages. These he explained, are heavy, complex and require maintenance, yet are only required for takeoff and landing. One solution investigated was to catch a hovering Harrier with a grab on a crane. The idea, given the name 'Skyhook' got as far as live aircraft tests at Dunsfold. The Harrier was never actually hooked up, although the tests showed the idea to be perfectly feasible. This, apparently, is a challenge that has been looked at repeatedly from time to time. Past solutions seriously considered have included landing on jets of air and landing on flexible rubber. Harrier and its successor, the Joint Strike Fighter show the feasibility of landing on jets of air whilst some 200 test landings were apparently made by Vampires on a flexible rubber deck on an aircraft carrier in the 1940s and 1950s. Landing vertically on a cradle or being grabbed by a crane could still become commonplace thanks to advances in flight control systems. Another challenge, to find a way to land a fast jet on an aircraft carrier was addressed by the idea of generating an artificial headwind from six Spey engines beneath louvers on the end of a flight deck. This idea was mocked up using vacuum cleaners, and progressed to wind tunnel trials and computer simulation. It failed to be implemented because of the abandonment of the Navalised Eurofighter it was to help land, but could still see the light of day to meet some future requirement. A more recent challenge that the company has been making major efforts to address is the need to do something drastic to reduce the increasingly long and costly development and maturation process for major aerospace projects. This led to the establishment of the BAE Systems Advanced Technologies Demonstration Centre at Warton in 1996. Successes achieved there have included a generic test system to test anything, and a laser projection system to help manufacturing engineers position holes and parts. This in turn has led to the laser alignment system to be used for Eurofighter assembly. In this method, fuselage sections are mounted on computer controlled jacks. Laser scanning is used to exactly locate each section after which the sections can be moved to exact marry up positions. Once the undercarriage has been installed, it can be lowered, after which the jacks are fully retracted and moved away. He concluded by posing what he considered to be, "A grand challenge": to develop a maintenance free unmanned air combat vehicle, without conventional control surfaces, with no performance or cost penalty. Ideas already mooted include a self-repairing structure, perhaps using carbon nanotubes filled with resin, which would leak out and harden in the event of fracture. Other ideas around include plasma fluidic control and intelligent flight control systems which could land an aircraft by varying engine speeds in the event of control surface failure. BAE Systems