Initial Investigation of the Acoustics of a Counter-Rotating Open Rotor Model with Historical Baseline Blades in a Low-Speed Wind Tunnel

New (perfect condition)

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Like new (excellent condition)

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Very good (good condition)

Pages are intact and may have minimal notes and/or highlighting or folds.

Good (clean condition)

All pages and the cover is intact. The spine may show signs of wear. Pages include notes and/or highlighting.

Acceptable (readable condition)

All pages and the cover is intact. Pages include considerable notes in pen or highlighter, but the text is not obscured.