Flagellar oscillation: new vibes from beads

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The Legacy of the X-15

The X-15 established such widespread confidence in aerodynamic, thermal, and structural areas that new designs for operation aircraft for any speed regime could be expected to be successfully achieved if good use was made of all pertinent test facilities and analytical methods. This philosophy guided design of the space shuttle and is the real legacy of the X-15. The accomplishments and contributions attributable to the research and development work on the X-15 that influenced the formative years of the Space Shuttle Program are presented

Flagellar propulsion

In this JEB Classics paper, Sir James Gray and G. J. Hancock explained how spermatozoa are propelled by flagellar bending waves (Gray and Hancock, 1955). This paper was a lasting success because it provided an easy-to-understand solution to a complicated hydrodynamic problem, and because it provided a quantitative prediction of the swimming speed that was almost identical to the swimming speed measured in Gray's accompanying paper on the movement of sea urchin spermatozoa (Gray, 1955)