[kach22i]

April 22, 2016
NASA Moves to Begin Historic New Era of X-Plane Research
https://www.nasa.gov/aero/nasa-moves-to-begin-historic-new-era-of-x-plane-research

The first leg of the stool – computational capabilities that, in this case,
show sound produced by air around jet engine rotors that would turn in opposite directions.
Credits: NASA / Tim Sandstrom