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Sikorsky R-4

The Sikorsky R-4, or VS-316A, was a definitive development of Igor Sikorsky's successful pre-war VS-300, and in 1944 became the first helicopter in the world to be placed in series production. Like the VS-300, it had a framework of heavy-gauge steel tube, and all but the extreme rear end of the fuselage was fabric-covered, as were the 10.97m diameter main rotor blades. A completely new feature was the fully-enclosed cabin, with side-by-side seating and dual controls for the 2-man crew. Powered by a 165hp Warner R-500-3 engine, the prototype VS-316A flew for the first time on 13 January 1942; later, with the military designation XR-4 and serial number 41-18874, the aircraft was handed over to the USAAF for evaluation. It arrived at Wright Field, Ohio, on 18 May 1942, having completed, in stages, the 1225km trip from Bridgeport, Connecticut, in 16 hr. 10 min. flying time. Later in 1942 an order was placed for three service test YR-4A's with 180hp R-550-1 engines and main rotors of 11.58m diameter, and similar changes were made to the XR-4 in 1943, after which it was redesignated XR-4C. Other 1943 developments included the first-ever landing by a helicopter on a ship at sea (the tanker Bunker Hill) and the production of twenty-seven pre-series YR-4B's for further evaluation by the USAAF, the U.S. Navy (three), U.S. Coast Guard (three) and the RAF (seven). These were generally similar to the YR-4A's except for an enlarged cabin, and were used inter alia for winterisation and tropical trials in Alaska and Burma. In the latter theatre one of the YR-4B's carried out the first recorded casualty evacuation operation by helicopter.

One hundred production R-4B's were built, similar to the YR-4B except for a more powerful engine; thirty-five were delivered to the USAAF for observation and liaison duties, and twenty to the U.S. Navy as HNS-1 reconnaissance and air/sea rescue aircraft. The remaining forty-five were supplied to Great Britain under Lend-Lease, most of them going to the Royal Navy. The R-4B was known in British service as the Hoverfly I. In the RAF the Hoverfly I replaced the Rota (Cierva C.30A) autogiros of No.529 Squadron from August 1944, and some were supplied to the Helicopter Training School at Andover early in 1945. By the end of the year the type had passed out of RAF service, some aircraft being allocated for radar calibration work with the Telecommunications Research Establishment; others undertook snow and flood reporting duties, and one was allocated to the King's Flight to carry mail and freight. The Joint Experimental Helicopter Unit, established in 1954, was equipped initially with R-4B and R-6A helicopters handed on from the Royal Air Force and Fleet Air Arm. The R-4 did not enjoy a long service career, either in Britain or the United States, being supplanted in the early post-war years by the Sikorsky S-51 and its British-built equivalent, the Westland Dragonfly. Those still in American service were redesignated H-4B in 1948.

K.Munson "Helicopters And Other Rotorcraft Since 1907", 1968

Sikorsky R-4


- The first flight of the XR-4 was on 14 January 1942. On 21 April 1945 a single Canadian R-4 became the first helicopter to rescue a downed crew in the Arctic.

- Thirty production machines (YR-4As and YR-4Bs) were ordered in total.

- US Army Air Force R-4s were used to rescue downed crews in the Pacific.

- By the time production switched to the improved R-5/S-51 series, a total of 130 Sikorsky R-4s had been built.

- A Sikorsky R-4 was the first true helicopter to make a landing at sea.

- On 17 May 1942, the XR-4 flew a distance of 1224km.

- Colonel Frank Gregory made the first helicopter landing aboard ship, on 7 May 1943 in Long Island Sound, USA.

- Early XR-4s had a metal and fabric-covered fuselage.

- The US Navy established its first helicopter squadron, VX-3, at Floyd Bennett Field NAS.

- R-4Bs became the first production helicopters in the world.

Photo Gallery 

The first prototype XR-4 (VS-316; S-47)

An R-4B in flight. The resemblance to the VS-300 can be seen in this view. Sikorsky R-4s were the only U.S. military helicopter to be used operationally during World War II.

A U.S. Navy HNS-1 being flown by the Coast Guard, which was given responsibility for Navy helicopter development and operations during World War II. This float-equipped HNS-1 is shown over the icebreaker Northwind (AG-89) during Rear Admiral Richard E. Byrd's 1947 expedition to the Antarctic.

A Navy-Coast Guard HNS-1 is "stuffed" into a C-54 transport of the Air Transport Command at the Coast Guard air station in Brooklyn, N.Y. The helicopter was flown 1,000 miles on 29 April 1945, to Goose Bay, Labrador. It was then reassembled and rescued 11 Canadian airmen from two separate crashes in rugged territory, carrying them to safety one man per flight.

The first of a long line of Sikorsky military helicopters was the XR-4, shown here while assigned to the USAAF research and test facility at Wright Field in Ohio (now Wright-Patterson Air Force Base)

An experimental R-4 with a tilting tail rotor

Sikorsky R-4

Technical data for R-4

Crew: 1, passengers: 1, engine: 1 x Warner R-550 rated at 134kW, main rotor diameter: 11.6m, length: 14.7m, height: 3.8m, take-off weight: 1152kg, empty weight: 952kg, max speed: 132km/h, cruising speed: 105km/h, rate of climb: 3.3m/s, service ceiling: 2340m, range: 370km

Sikorsky R-4

Sikorsky R-4B

daniel j denton, e-mail, 10.08.2020reply

I like it too. I especially like how it had cables rather than a drive shaft connecting to the tail rotor. I have noticed that Kobe Bryant made a comment on here as well. How strange is that?

Kobe Bryant, 23.02.2016reply

its cool

Howard Frink, e-mail, 20.02.2016reply

We had 2 Sikorsky R-4's flying from a small flight deck on our ship -- 2nd Aircraft Repair Unit (Floating), which supported B-29 bombers flying from Saipan and Iwo Jima. All of the high tech shops to support the B-29's were installed on the Liberty ship -- parts and men were ferried to the air strips at Saipan and later at Iwo Jima.

Zac Yates, e-mail, 03.11.2010reply

Long shot, does anyone know where I can obtain a DVD of a 1980s doco called "The Chopper"? I have no idea who produced it, exact year, or who the English-sounding narrator is. It includes interviews with Hanna Reitsch and Bart Kelly (coworker of Arthur Young at Bell), and other techs and pilots, as well as footage of the prototype NOTAR, Apache, Sikorsky ABC and the XV-15, as well as the R-4.

Daniel Brewer, e-mail, 04.12.2010reply

I have some pictures of the HNS-1 at Goose Bay that my father took.

Leslie James Chatfield, e-mail, 30.09.2013reply

A surprisingly mature looking design for a first off like this aircraft. All modern single rotor helicopters look like this

Clarence Davis, e-mail, 07.12.2009reply

In 1947,I was instructor at the R-4 Helicopter Maintenance School at Shepard AFB in Texas. I went on some test flights of the R-4. For the times, it was quite amazing.

kiran, e-mail, 20.04.2009reply

will u send me model sketch of your project let me know something about your project please

(unidentified), e-mail, 24.04.2008reply

it sucks /the chinook rules

Butch Johnsn, e-mail, 05.01.2008reply

How was the helicopter used to attack a submarine with no war material.

Nate Strauss, e-mail, 12.05.2021 Butch Johnsn

I have no idea, Butch.

Sorry for the late reply.

-The Author


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