This Pitcairn PAA-1 <a href="https://en.wikipedia.org/wiki/autogiro" class="extiw" title="w:autogiro">autogiro</a> was flown at Langley for the NACA investigation of an experimental cantilevered three-bladed rotor. Photo date 6-19-1943.
Unknown author<span style="display: none;">Unknown author</span>
<a rel="nofollow" class="external free" href="https://crgis.ndc.nasa.gov/historic/File:EL-2003-00013.jpg">https://crgis.ndc.nasa.gov/historic/File:EL-2003-00013.jpg</a>