The Sikorsky R-6 is an American light two-seat helicopter of the 1940s. In

Royal Air Force The Royal Air Force (RAF) is the United Kingdom's air and space force. It was formed towards the end of the First World War on 1 April 1918, becoming the first independent air force in the world, by regrouping the Royal Flying Corps (RFC) an ...

and

Royal Navy The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by Kingdom of England, English and Kingdom of Scotland, Scottish kings from the early medieval period, the first major maritime engagements were foug ...

service, it was named the Hoverfly II.

Development

The R-6/Hoverfly II was developed to improve on the successful

Sikorsky R-4 The Sikorsky R-4 is a two-seat helicopter that was designed by Igor Sikorsky with a single, three-bladed main rotor and powered by a radial engine. The R-4 was the world's first large-scale mass-produced helicopter and the first helicopter used ...

. In order to enhance performance, a completely new streamlined fuselage was designed and the boom carrying the tail rotor was lengthened and straightened. The main rotor and transmission system of the R-4 were retained. Sikorsky allotted their Model 49 designation to the new design. Later, dynamically-balanced modifications to the rotor were carried out by Doman Helicopters Inc. The new aircraft could attain compared with by the earlier design. Initial production was by Sikorsky, but most examples were built by

Nash-Kelvinator Nash-Kelvinator Corporation was the result of a merger in 1937 between Nash Motors and Kelvinator Appliance Company. The union of these two companies was brought about as a result of a condition made by George W. Mason prior to his appointment a ...

. Some of the later aircraft were fitted with more powerful engines.

Operational history

The first R-6s were delivered to the

United States Army Air Forces The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and ''de facto'' aerial warfare service branch of the United States during and immediately after World War II ...

(USAAF) in late 1944 and some were transferred to the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

(USN). It was initially intended to pass 150 R-6s to the

(RAF), but delays caused by the switch of production from Sikorsky's factory at Stratford, Connecticut, to Nash-Kelvinator at

Detroit Detroit ( , ; , ) is the largest city in the U.S. state of Michigan. It is also the largest U.S. city on the United States–Canada border, and the seat of government of Wayne County. The City of Detroit had a population of 639,111 at ...

Michigan Michigan () is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the List of U.S. states and ...

, meant that only 27 R-6As were actually delivered to the RAF as the Hoverfly II. Fifteen of these were passed on to the Royal Navy's Fleet Air Arm (FAA). Some of the RAF examples were allotted to 657 Squadron RAF for proving the use of helicopters in the Army Co-operation role, and two external stretchers could be fitted to the fuselage. 657 Squadron operated their Hoverfly IIs as Air Observation Posts, spotting for Army artillery units. The Hoverfly IIs remained in operation until April 1951, and one squadron example was displayed at the September 1950

Farnborough Air Show The Farnborough Airshow, officially the Farnborough International Airshow, is a trade exhibition for the aerospace and defence industries, where civilian and military aircraft are demonstrated to potential customers and investors. Since its fir ...

. The FAA used their Hoverfly IIs in the training and liaison roles. Naval units to use the type included 771 Squadron from December 1945, followed by 705 Squadron. The USAAF operated their R-6s in secondary roles and the survivors were redesignated H-6A in 1948. The USN examples were designated the HOS-1 and a further 64 were intended to be transferred from the USAAF, but this did not take place. Disposals of surplus military S-49s were made in the civil market in the late 1940s but none now remain in operation. Four are currently displayed in US museums.

Variants

US Navy Sikorsky HOS-1 in flight in January 1947

Sikorsky R-6A Hoverfly II N74176 NEAM BDL 09

;XR-6 : prototype powered by a Lycoming O-435-7 (one) ;XR-6A : as XR-6 but powered by the

Franklin O-405-9 The Franklin O-405 (company designation 6AC-403) was an American air-cooled aircraft engine of the 1940s. The engine was of six-cylinder, horizontally-opposed layout and displaced . The power output was between and depending on variant. The O ...

(five) of which three to the US Navy as XHOS-1 ;YR-6A : as XR-6A with small changes (26) built by Nash-Kelvinator ;R-6A : production model (193) built by Nash-Kelvinator of which 36 to US Navy as HOS-1 and 27 to the RAF as Hoverfly II ;R-6B : projected variant with Lycoming O-435-7, but not proceeded with ;XR-7 : projected development of the XR-6 with a Franklin O-405-9 engine, not built. ;Doman LZ-1 :One R-6A modified as a testbed ;Doman LZ-1A :One R-6A modified as a testbed with a Doman-designed hingeless rotor blades and self-lubricating rotor hub.

Operators

; *

162nd Liaison Squadron Sixteen or 16 may refer to: *16 (number), the natural number following 15 and preceding 17 *one of the years 16 BC, AD 16, 1916, 2016 Films * ''Pathinaaru'' or ''Sixteen'', a 2010 Tamil film * ''Sixteen'' (1943 film), a 1943 Argentine film dir ...

United States Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army S ...

72d Liaison Squadron The 72nd Helicopter Squadron is an inactive United States Air Force unit. It was last active as a flight, then as a squadron from 1991 to 1995 at Langley Air Force Base, Virginia, where it provided light transport and assisted with search and ...

United States Coast Guard The United States Coast Guard (USCG) is the maritime security, search and rescue, and law enforcement service branch of the United States Armed Forces and one of the country's eight uniformed services. The service is a maritime, military, mu ...

The mexican air force opered one ejemplar 1952 - 1970

Aircraft on display

* 43-45462 – R-6A on static display at the Museo Militar de Aviacion in Santa Lucía Air Force Base Num 1. * 43-45473 – R-6A on static display at the United States Army Aviation Museum at Fort Rucker near Ozark, Alabama. * 43-45379 – R-6A on static display at the National Museum of the United States Air Force in

Dayton, Ohio Dayton () is the sixth-largest city in the U.S. state of Ohio and the county seat of Montgomery County. A small part of the city extends into Greene County. The 2020 U.S. census estimate put the city population at 137,644, while Greater ...

. * 43-45480 – LZ-1A on static display at the New England Air Museum in

Windsor Locks, Connecticut Windsor Locks is a town in Hartford County, Connecticut, United States. As of the 2020 census, its population was 12,613. It is the site of Bradley International Airport, which serves the Greater Hartford-Springfield region and occupies approx ...

. It was converted by Doman from the R-6. * 43-45531 – R-6 under restoration at the American Helicopter Museum and Education Center in West Chester, Pennsylvania.

Specifications (R-6A)

References

Notes

Bibliography

* * * * *

External links

Sikorsky S-49/R-6A/HOS-1/Hoverfly Mk II page at the Sikorsky Archives

Sikorsky R-6A page at the National Museum of the United States Air Force

{{USN helicopters 1940s United States military utility aircraft United States military helicopters 1940s United States helicopters R-006 Single-engined piston helicopters Aircraft first flown in 1943