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A STATUS OF NASA ROTORCRAFT RESEARCH

In 2006, NASA rotorcraft research was refocused to emphasize high-fidelity "first-principles" predictive tool development and validation. As part of this new emphasis, documenting the status of NASA rotorcraft research and defining the state-of-the-art in rotorcraft predictive capability were undertaken. This report is the result of this two-year effort. Contributors to this work encompass a wide range of expertise covering the technical disciplines of aeromechanics, acoustics, computational fluid dynamics (CFD), flight dynamics and control, experimental capabilities, propulsion, structures and materials, and multi-disciplinary analysis.

The document below highlights technical areas in which NASA has invested resources and therefore the document does not provide a comprehensive review of all areas of rotorcraft research, nor is there an attempt made to exhaustively review and reference the works of other organizations. Within the last 10 years, excellent surveys have been written on different disciplines and topics of rotorcraft research, they are referenced in the chapters to follow. Collectively, these surveys provide a comprehensive review of the progress and current state of rotorcraft research, and this document serves as a complementary assessment strictly from a NASA perspective. This document will serve as a reference against which NASA research progress beyond 2007 can be measured. In order to measure progress, however, metrics must be established, and that is not a straightforward exercise. Often, a predictive capability is mature for certain flight conditions or configurations, but not for others. For example, much effort has been expended in predicting rotor-blade airloads for hover and steady, level flight but not for unsteady, maneuvering flight conditions. A key challenge in preparing this document was to present measurements and predictions in a format that can be used for multiple conditions, configurations, and parameters so that in the future, improvements in predictive capability can be easily tracked.

In any research area, monitoring progress against established goals and frequently assessing the path ahead are critical for the research to remain relevant. For NASA, where the research is typically long-term and high-risk, this self-assessment process can be especially challenging. This document is hopefully the first of a series of periodic assessments of rotorcraft research within NASA.

"A Status of NASA Rotorcraft Research," NASA NASA_TP_2009_215369. Download