Sikorsky R-4
Encyclopedia
The Sikorsky R-4 was a two-place helicopter designed by Igor Sikorsky
Igor Sikorsky
Igor Sikorsky , born Igor Ivanovich Sikorsky was a Russian American pioneer of aviation in both helicopters and fixed-wing aircraft...
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
Mass production
Mass production is the production of large amounts of standardized products, including and especially on assembly lines...
helicopter
Helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...
and the first helicopter to enter service with the United States Army Air Forces
United States Army Air Forces
The United States Army Air Forces was the military aviation arm of the United States of America during and immediately after World War II, and the direct predecessor of the United States Air Force....
, Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
, and Coast Guard
United States Coast Guard
The United States Coast Guard is a branch of the United States Armed Forces and one of the seven U.S. uniformed services. The Coast Guard is a maritime, military, multi-mission service unique among the military branches for having a maritime law enforcement mission and a federal regulatory agency...
, as well as for the United Kingdom's Royal Air Force
Royal Air Force
The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...
and Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
.
Development
The VS-316, was developed from the famous experimental VS-300 helicopter, invented by Igor SikorskyIgor Sikorsky
Igor Sikorsky , born Igor Ivanovich Sikorsky was a Russian American pioneer of aviation in both helicopters and fixed-wing aircraft...
and publicly demonstrated in 1940. The VS-316 was designated the XR-4, under the United States Army Air Forces
United States Army Air Forces
The United States Army Air Forces was the military aviation arm of the United States of America during and immediately after World War II, and the direct predecessor of the United States Air Force....
' series for "Rotorcraft". The XR-4 made its initial flight on 13 January 1942 and was accepted by the Army on 30 May 1942. The XR-4 exceeded all the previous helicopter endurance, altitude and airspeed records that had been set before it. The XR-4 completed a 761-mile (1,225 km) cross country flight from Connecticut to Wright Field, Ohio, set a service ceiling of 12,000 feet (3,700 m), 100 flight hours without a major incident, and an airspeed approaching 90 mph (140 km/h).
The British Admiralty
Admiralty
The Admiralty was formerly the authority in the Kingdom of England, and later in the United Kingdom, responsible for the command of the Royal Navy...
having learned of the VS-300, made a ship available that had been intended to show the USN their work with autogyro
Autogyro
An autogyro , also known as gyroplane, gyrocopter, or rotaplane, is a type of rotorcraft which uses an unpowered rotor in autorotation to develop lift, and an engine-powered propeller, similar to that of a fixed-wing aircraft, to provide thrust...
s and ship operations. The Empire Mersey
Empire ship
The Empire ships were a series of ships in the service of the British Government. Their names were all prefixed with "Empire". Mostly they were used during World War II by the Ministry of War Transport , who owned the ships but contracted out their management to various shipping lines. Some ships...
was fitted with a landing platform. After her loss in 1942 to a U-boat
U-boat
U-boat is the anglicized version of the German word U-Boot , itself an abbreviation of Unterseeboot , and refers to military submarines operated by Germany, particularly in World War I and World War II...
, she was replaced by the SS Daghestan. The British would receive two of the first eight helicopters built.
On 5 January 1943, the United States Army Air Forces ordered 29 prototypes. The first three prototypes were designated as the YR-4A and used for evaluation testing. The YR-4A benefited from a larger, 180 hp (130 kW) Warner Super Scarab
Warner Scarab
|-See also:-References:*-External links:*...
(R-550-1) engine, compared to the 165 hp (123 kW) R-500-3 engine in the prototype, and a rotor diameter increased by one foot (30 cm). Evaluation of the YR-4A demonstrated a need for further improvements, including moving the tailwheel further towards the rear of the tailboom, venting the exhaust to the side instead of downward, and increasing the fuel capacity by five gallons (19 liters). These and other design changes led to the designation of later prototypes as YR-4B, which were used for service testing and flight training.
Operational history
On 22–23 April 1944, U.S. Army Lieutenant Carter Harman of the 1st Air Commando Group1st Air Commando Group
The 1st Air Commando Group is an inactive United States Air Force unit. It was last assigned to the Army Service Forces, based at Camp Kilmer, New Jersey. It was inactivated on 3 November 1945....
conducted the first combat rescue by helicopter using a YR-4 in the China-Burma-India theater
China Burma India Theater of World War II
China Burma India Theater was the name used by the United States Army for its forces operating in conjunction with British and Chinese Allied air and land forces in China, Burma, and India during World War II...
. Despite the high altitude, humidity, and capacity for only a single passenger, Harman rescued a downed liaison aircraft pilot and his three British soldier passengers; two at a time. On 22–23 January 1945, another rescue by the R-4 involved several legs for refueling and navigating through passes between mountains nearly 10,000 feet (3,000 m) tall, to reach a weather station located at an elevation of 4,700 feet (1,400 m). The higher than normal altitude required a downhill run of 20 ft (6.1 m) to get airborne.
While the R-4 was being used for rescues in Burma and China, it was also being used to ferry parts between floating Aviation Repair Units in the South Pacific. On 23 May 1944, six ships set sail with two R-4s on board each vessel. The ships had been configured as floating repair depots for damaged Army Air Forces aircraft in the South Pacific. When the helicopters were not being used to fly the parts from one location to another, they were enlisted for medical evacuation and other mercy missions.
In Royal Air Force
Royal Air Force
The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...
service, the R-4 was called the Hoverfly. The Helicopter Training School, formed January 1945, at RAF Andover
RAF Andover
Andover Airfield is a former Royal Flying Corps and Royal Air Force station. The ICAO code for the airfield is EGWA and the IATA code is ADV...
, was the first British military unit to be equipped with the helicopter. Many of the RAF Hoverfly Is were transferred to the Royal Navy for training and one was used in 1945/46 by Fairey Aviation
Fairey Aviation
The Fairey Aviation Company Limited was a British aircraft manufacturer of the first half of the 20th century based in Hayes in Greater London and Heaton Chapel and RAF Ringway in Greater Manchester...
to develop rotor systems for their Gyrodyne helicopter.
Variants
XR-4
- One prototype Model VS-316A with a crew of two and dual controls, 165 hp R-500-3 engine, became XR-4C
YR-4A
- Version with larger rotor diameter and a 180 hp R-550-1 engine; three built.
YR-4B
- Version with detailed changes; 27 built for development testing followed by a further batch of 14, seven to US Navy as HNS-1s.
R-4B
- Production version with 200 hp R-550-3 engine; 100 built including 20 for the US Navy and 45 for the Royal Air Force.
XR-4C
- Prototype XR-4 re-engined with 180 hp R-550-1 engine with the larger YR-4A type rotor.
HNS-1
- Three YR-4Bs and 22 R-4Bs transferred to the US Navy; two diverted to the United States Coast Guard.
Hoverfly I
- UK military designation of the R-4 for the Royal Air Force and Royal Navy; 52 delivered and one later transferred to the Royal Canadian Air Force.
Sikorsky S-54
- An R-4B modified with an observers seat aft of the main rotor gearbox for trials.
Operators
- Royal Canadian Air ForceRoyal Canadian Air ForceThe history of the Royal Canadian Air Force begins in 1920, when the air force was created as the Canadian Air Force . In 1924 the CAF was renamed the Royal Canadian Air Force and granted royal sanction by King George V. The RCAF existed as an independent service until 1968...
- Royal Air ForceRoyal Air ForceThe Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...
- Helicopter Training Flight 43 OTU, Transport Command Development Unit, Kings Flight (mail flights between RAF Dyce and BalmoralBalmoral- Australia :* Balmoral, New South Wales, a locality of Sydney* Balmoral, New South Wales * Balmoral, New South Wales * Balmoral, Queensland* Balmoral, Victoria* Balmoral, Western Australia- Canada :...
) - Fleet Air ArmFleet Air ArmThe Fleet Air Arm is the branch of the British Royal Navy responsible for the operation of naval aircraft. The Fleet Air Arm currently operates the AgustaWestland Merlin, Westland Sea King and Westland Lynx helicopters...
- 705 NAS
United States
- United States Army Air ForcesUnited States Army Air ForcesThe United States Army Air Forces was the military aviation arm of the United States of America during and immediately after World War II, and the direct predecessor of the United States Air Force....
- United States NavyUnited States NavyThe United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
- United States Coast GuardUnited States Coast GuardThe United States Coast Guard is a branch of the United States Armed Forces and one of the seven U.S. uniformed services. The Coast Guard is a maritime, military, multi-mission service unique among the military branches for having a maritime law enforcement mission and a federal regulatory agency...
Aircraft on display
- XR-4C prototype, the Smithsonian Museum's Steven F. Udvar-Hazy CenterSteven F. Udvar-Hazy CenterThe Steven F. Udvar-Hazy Center is the Smithsonian National Air and Space Museum 's annex at Washington Dulles International Airport in the Chantilly area of Fairfax County, Virginia, United States....
- R-4B (s/n 43-46506) is on display at the National Museum of the United States Air ForceNational Museum of the United States Air ForceThe National Museum of the United States Air Force is the official museum of the United States Air Force located at Wright-Patterson Air Force Base northeast of Dayton, Ohio. The NMUSAF is the world's largest and oldest military aviation museum with more than 360 aircraft and missiles on display...
at Wright-Patterson AFB near Dayton, OhioDayton, OhioDayton is the 6th largest city in the U.S. state of Ohio and the county seat of Montgomery County, the fifth most populous county in the state. The population was 141,527 at the 2010 census. The Dayton Metropolitan Statistical Area had a population of 841,502 in the 2010 census...
. It was donated by the University of Illinois in 1967. - Hoverfly Mk.1, KL110/KL995, at the Royal Air Force Museum London. Supplied under lend-lease, it arrived in Britain in February 1945. It flew with the RAF, later the Royal Navy, until 1951. It was used by the College of Aeronautics, Cranfield until it was presented to the RAF museum in 1966.
- R-4B in the Storage Hangar of the Canada Aviation and Space Museum in Ottawa, Ontario
- National Museum of Naval AviationNational Museum of Naval AviationThe National Museum of Naval Aviation is a military and aerospace museum located at Naval Air Station Pensacola, Florida. The museum opened in 1962....
in Pensacola, FloridaPensacola, FloridaPensacola is the westernmost city in the Florida Panhandle and the county seat of Escambia County, Florida, United States of America. As of the 2000 census, the city had a total population of 56,255 and as of 2009, the estimated population was 53,752...
. Exhibit is an HNS-1 Hoverfly (Bureau Number 39047) - On indoor static display in US Coast Guard markings. - Army Aviation Museum at Fort RuckerFort RuckerFort Rucker is a U.S. Army post located mostly in Dale County, Alabama, United States. It was named for a Civil War officer, Confederate General Edmund Rucker. The post is the primary flight training base for Army Aviation and is home to the United States Army Aviation Center of Excellence and...
, Alabama. U.S. Army R-4B Hoverfly (Serial Number 43-46592) and R-6A Hoverfly II (Serial Number 43-45473) on indoor static display. - Yanks Air MuseumYanks Air MuseumThe Yanks Air Museum is a non-profit 501 organization dedicated to exhibiting, preserving and restoring American aircraft and artifacts.-Chino facility and exhibits:...
in Chino, CaliforniaChino, CaliforniaChino is a city in San Bernardino County, California, United States. It is located in the western end of the Riverside-San Bernardino Area and it is easily accessible via the Chino Valley and Pomona freeways....
has an R-4B (Serial Number 43-46534) in their restoration hangar.