Sikorsky Aircraft Corp.
First Flight: February 16, 1946
Four seats
Restored by Keystone Helicopter Corporation
Sikorsky followed the production R‑4 with the bigger R‑5, first flown on August 18, 1943. Powered by a 450‑hp Wasp Junior radial, it was ordered as the R‑5A for the US Army and as the H02S‑1 for the US Navy. Both were two‑seat tandem observation machines with twin front wheels and a stilted rear wheel at the root of the long tail boom. The 48‑ft. rotor was a notable advance over the R‑4 and gross weight was 5,000 lb., just twice as great. Instead of steel tube and fabric, the R‑5 was made chiefly of light‑alloy monocoque. Eventually about 300 were delivered, plus 139 built in England as the Westland Dragonfly with modified airframe and Alvis Leonides engine. Small batches were sold for commercial purposes.
While production of the R‑5A was getting underway, five pre‑series aircraft were converted into the R-5E, which had dual controls. At least 20 modified R-5As were later given new, 600 hp Wasp Junior engines and redesignated R‑5D. The USAAF ordered 4 XR‑5 prototypes in early 1943, shortly after the first flight of the R‑4, and a fifth later in the year. These were followed by 26 YR‑5A helicopters for service trials and a production order for 100 R‑5A aircraft, of which only 34 were completed.
The S‑51, the first commercial helicopter designed by Sikorsky, was a modification of the R‑5. Using basically the same rotor system as the R‑5, it had a slightly enlarged four‑seat cabin. The primary configuration difference is the reversal of the landing gear; the S‑51 has a nose gear instead of the tail gear of the R‑5. It first flew on February 16, 1946, and received CAA certification a month later. Deliveries began in August 1946. Helicopter Air Transport (HAT) purchased the first three S‑51’s for $48,500 each. In 1947, Los Angeles Airways initiated the world’s first scheduled helicopter service with five S‑51’s.
In 1947, the U.S.A.F. received 11 military S‑51’s designated R‑5F. These were followed in 1948‑49 by 38 H‑5G’s, with rescue hoists and maximum take‑off weight increased from 6,200 lb. (2,812 kg.) to 6,500 lb. (2,948 kg.), and 17 similar H‑5H’s with amphibious wheel/pontoon landing gear.
Sikorsky ended production of the R‑5/S‑51 series in 1951 after delivering some 300 aircraft to military and civilian customers. The US Air Force, Air Rescue Service outfitted the aircraft with an enclosed stretcher mounted externally on each side of cabin for medical evacuation during the Korean War. The Navy also used the aircraft for plane guard and general observation duties. Of the Navy procurement, the Coast Guard flew 2 H02S‑1G and 9 H03S‑1G helicopters from 1946‑1950. Nine of the H03S‑1 helicopters were used by the US Marine Corps from 1948‑1955, the first helicopters to be flown by that service. In Britain, Westland produced 133 of the S‑51 design under license for military and civil use. The RAF flew the helicopter as the Dragonfly in combat in Malaya from 1950‑1956.
| Aircraft Specifications | |
|---|---|
| Rotor Diameter | 49 ft |
| Fuselage Length | 41 ft 2 in |
| Maximum Speed | 103 mph |
| Cruise Speed | 85 mph |
| Height | 13 ft |
| Empty Weight | 4,050 lbs |
| Gross Weight | 5,500 lbs |
| Engine | 450 HP Pratt & Whitney R 985 AN5 |
| Acquisition Source | Peter Wright Donation |