A U.S. Navy Piper HE-1 (BuNo 30197) flying ambulance, circa 1943. The HE-1 was a hospital variant for the United States Navy with a hinged fuselage top for stretcher access. 100 were built and later re-designated AE-1.
U.S. Navy
<a rel="nofollow" class="external text" href="http://www.navy.mil/ah_online/department_arch.html">U.S. Navy All Hands magazine</a> <a rel="nofollow" class="external text" href="http://www.navy.mil/ah_online/archpdf/ah194306.pdf">June 1943</a>, p. 13.