Keywords: XHRP-1 Piasecki NAN4 47.jpg The prototype of the U S Navy's Piasecki XHRP-1 helicopter ca 1946 U S Navy Naval Aviation News April 1947 http //www history navy mil/nan/backissues/1940s/1947/Apr47 pdf 1946 USN PD-USGov-Military-Navy Piasecki HRP Rescuer |