Front view of U.S. experimental aircraft <a href="https://en.wikipedia.org/wiki/en:Douglas_D-558-1_Skystreak" class="extiw" title="w:en:Douglas D-558-1 Skystreak">Douglas D-558-1 Skystreak</a>.
<div class="fn value">
NASA</div>
Late 40s or early 50s
<a rel="nofollow" class="external free" href="http://www.nasa.gov/centers/dryden/pdf/88788main_D-558.pdf">http://www.nasa.gov/centers/dryden/pdf/88788main_D-558.pdf</a> J.D. Hunley, ed. <i>Toward Mach 2: the Douglas D-558 program</i>, p. 9.