By Lieutenant Colonel Ronald J. Brown
U.S. Marine Corps Reserve, Retired
The first U.S. Navy experience with rotary-wing aircraft was not a good one. The Pitcarin OP-1 autogiro, an airplane not a true helicopter, had been tested and found wanting during the era between the World Wars. It was not until Igor Sikorsky introduced his VS-316 model helicopter on 13 January 1942 that vertical takeoff and landing aircraft became feasible. Sikorsky had earlier flown the first practical American helicopter, the VS-300, but that machine was only a test bed. The follow-on VS-316, designated the XR-4 by the U.S. Army, had a two-seat side-by-side enclosed cabin. A 200 horsepower Warner R-550-3 engine that ran a single overhead main rotor and a smaller anti-torque rotor on the tail powered the aircraft. The XR-4 prototype could hit a top speed of around 85 miles per hour, cruised at about 70 miles per hour, and had a range of about 130. In July 1942, the Navy tested its first one; an R-4 transferred from the Army and then promptly re-designated HNS-1 by the Bureau of Aeronautics. Two more were requisitioned from Army stocks in March 1943. The new helicopter was a success, and 22 more were procured for use as trainers beginning on 16 October 1943. The HNS-1 served as the primary naval aviation helicopter trainer until the Bell HTL-series replaced it.
Several other early helicopters (the Platt LePage R-1 and the Kellet R-2 and R-3) produced by other manufacturers were considered but not selected. All was not lost, however, because a bright young Kellet engineer, Frank Piasecki, would later develop tandem-rotor helicopters that would become a mainstay of naval aviation. The Bell Aircraft Company was too busy turning out jets to enter the initial helicopter competition, but that corporation’s mathematician and engineer Arthur M. Young would soon revolutionize light helicopter design.
Sikorsky Aircraft produced 133 HNS helicopters; the Navy accepted 23, the Army kept 58, and the British Royal Air Force got 52. The first shipboard helicopter trials were conducted by America’s first certified military helicopter pilot, Army Captain Hollingworth “Frank” Gregory. He put his HNS through its paces by repeatedly landing and taking off from the tanker Bunker Hill operating in Long Island Sound on 7 May 1943. Coast Guard Lieutenant Commander Frank A. Erickson flew the initial naval service helicopter mercy mission when he delivered two cases of blood plasma to a hospital at Sandy Hook on the New Jersey shore. Doctors credited Erickson’s timely arrival with saving several lives. Other rescue missions aiding both civilian and military personnel in the New York area soon followed. The U.S. Army and the Office of Strategic Services both used helicopters for special combat missions in Asia during World War II.
The Navy was satisfied enough with the HNS to order an additional 150 helicopters from Sikorsky, 100 HOS-1s (designated R-6A by the USAAF) and 50 HO2S-1s (Army designation R-5A) before the end of the war. The HOS-1 was more compact, more powerful, and more maneuverable than its HNS predecessor. It mounted a single overhead main rotor, and was powered by a 240 hp Franklin O-405-9 engine. Three XHOS-1s were requested for testing from Army R-6A stocks in late 1942 and were accepted by the U.S. Coast Guard, which was by then running Navy helicopter training at New York’s Floyd Bennett Field in March 1944. After the war a second batch of 36 HOS-1s were assigned to the Navy helicopter development squadron (VX-3) after passing acceptance tests. The Navy also took two HO2S-1 (Army R-5A) test models in December 1945, but opted to place an order for slightly modified S-51 commercial models (designated HO3S-1) which became the standard Navy, Marine, and Coast Guard light utility helicopters in 1947.
When the Coast Guard returned to the Treasury Department from the Navy Department on 28 December 1945, the U.S. Navy took over helicopter training and development. Marine helicopter pilots learned their trade with VX-3 before moving on to HMX-1 at Quantico, Virginia, prior to the Korean War.