Harman wasn't sure his sub-200-horsepower engine would make the trip. He also knew how vulnerable his craft was to enemy fire, being made of plywood ribs atop a steel tube frame. Virtually everything, including the fuselage, was covered only in fabric. The 500-mile trip demanded a climb over a 5000-foot mountain range—the YR-4B was rated only to 4000 feet and its recommended range was a mere 100 miles at a cruising speed of 65 MPH. He would have to stop every hundred miles to refuel and navigate visually since there were no maps available. And the Lieutenant would make the journey solo, without on-board medical staff. The helicopter only had room for one other person, and he needed that space to transport the wounded Soldiers. Harman used a jerking movement, over and over again, to coax the aircraft off the ground. The Sikorsky struggled in the tropical heat and humidity. When the stranded men saw Harman's craft wobble into view they were stunned. Like many people at the time, they had never seen a helicopter before.
A Sikorsky YR-4B hovers above an airstrip at Langley Air Force, Langley Virginia, in 1949.
Lieutenant Carter Harman at the controls of the Sikorsky YR-4B Hoverfly that would complete the Army's first air evacuation.