Future Directions In Helicopter Rotor Development

Although significant advances have been made in recent years, some of the fundamental problems limiting helicopter operation remain unresolved. Flight test and wind tunnel test have been the main source of progress, but the use of older and well established experimental methods may be approaching the point of diminishing returns. The level of understanding necessary to make further advances is i not achievable without a better insight into the physics of the problem. Several emerging technologies, such as new computers, Computational Fluid Dynamics (CFD), holographic interferometry, etc., we offer the means of quantifying detailed rotor phenomena which, until now, have defied a rigorous assessment. These details are the key to the definition of the next generation of improved helicopter rotors. This paper reviews the aerodynamic phenomena most critical to the definition of the next generation of advanced rotors. Recommendations are also made on the near term use of improved rotor analysis and testing methods.