U.S. Centennial of Flight Commission home page
This Pitcairn PAA-1 autogiro was flown at Langley for the NACA investigation of an experimental cantalevered three-bladed roto

This Pitcairn PAA-1 autogiro was flown at Langley for the NACA investigation of an experimental cantalevered three-bladed rotor.  

Credits - NASA