On Jan 13, 1942, the XR-4 made its first flight. It was the world’s first production helicopter, the first helicopter designed specifically for the military, and the only US helicopter to see action in World War II. Sikorsky company pilot C. L. “Les” Morris flew the prototype 761 miles from the Stratford, Conn., factory to Wright Field, Ohio. Since the helicopter had a cruise speed of 70 miles per hour, the trip took five days and 16 flights. Igor Sikorsky was the passenger on the last hop from Springfield, Ohio, to Wright Field.
Orville Wright was present when the U.S Army Air Corps formally accepted the XR-4 on May 30, 1942. Three YR-4As and 27 YR-4Bs were ordered in 1943. These were sent to Burma (six), Alaska, Wright Field (six), and other places and other services (three in all to the Navy and designated HNS) to test the aircraft in various conditions. The first landing on a ship came on May 6, 1943, when USAAF Capt. H. Franklin Gregory touched down on the stern of the tanker SS Bunker Hill riding at anchor in Long Island Sound. The YR-4A was powered by a Warner seven-cylinder radial engine developing 180 hp at cruise and 190 hp at takeoff. Even with the increased horsepower, the helicopter could barely lift two crewmembers and a full load of fuel on hot days at high density altitudes. The R-4 had a maximum gross weight of 2540 pounds, maximum speed of 81 mph, range of 230 miles and a ceiling of 8000′.
The first combat rescue came on April 25 – 26, 1944, when AAF 2nd Lt. Carter Harman and his YR-4B lifted a downed L-1 pilot and the three injured British soldiers out of the jungle in Burma. Col. Philip Cochran, commander of the 1st Air Commando Group, later wrote, “Today, the ‘egg-beater’ went into action and the damn thing acted like it had good sense.”
One hundred R-4B’s were ordered, and the type was used by the AAF, US Navy and Coast Guard (as HNS-1s), and the British Royal Navy. Later, the R-4s were used for helicopter training. Some were in use as late as 1948.