Helicopter rotors present an even more difficult modeling challenge. Wings, after all, are firmly fixed to the plane, and there are generally just two of them. Helicopter rotors, on the other hand, are essentially a bunch of wings whirling hundreds of times a minute, amplifying the vibrations, bends, and twists that occur in flight. When studying aerodynamics, the interplay between the vibrating aircraft and the air around it makes for a complex mathematical tangle. Partly because of the inherent complexities, partly because they didn't receive much attention until the Vietnam War, helicopters lag far behind airplanes in terms of performance and reliability.
Helicopters are noisier, more difficult to fly, and give a bumpier ride than conventional aircraft.
Gaonkar is taking advantage of the IBM SP2 supercomputer at the Maui High Performance Computing Center , a member of the Alliance's Partnership for Advanced Computational Services, to improve the design of helicopters using Floquet analysis, the primary mathematical tool for helicopter stability investigations. But, like other aerodynamics calculations, it takes a heap of memory and computation time, making it impractical for all but the simplest designs.