Maneuvering Rotorcraft Aeromechanics

The Civil Tiltrotor (CTR) offers a unique opportunity to create a new aircraft market while off-loading a portion of the short-haul traffic. (Ref. NASA?s civil tiltrotor web page). Rotary-wing vehicles proposed for improved system capacity must meet global civil aviation requirements for safety, efficiency, and affordability. Many advances have been made in measuring characteristics of rotary-wing vehicles; however, measurements of dynamic, unsteady, and cross-coupling effects are still challenges posing impediments to rapid design cycles. An innovative method, accurately collecting such measurements, utilizes water as a medium for dynamic testing. This testing technique circumvents many of the problems presented by testing in air and provides better insight into the fluid mechanics, interactions and interferences. The method allows testing in slow motion, separates model and test support frequencies, greatly improves signal-to-noise ratios, and provides unparalleled flow visualization. Water tunnel testing will predict maneuvering aerodynamics and stability parameters early in the design cycle, reducing the development time, risk, and cost of new rotorcraft. The method also applies to high performance aircraft development.