Sikorsky R-4

Sikorsky R-4B at National Museum of the United States Air Force

The Sikorsky R-4 was "The R-4 was the world's first production helicopter and the Air Force's first service helicopter"[1]

History

It was the United States Air Force's first service helicopter. The original military model, the XR-4, was developed from the famous experimental VS-300 helicopter, invented by Igor Sikorsky and publicly demonstrated in 1940. The XR-4 made its initial flight on January 13, 1942 and as a result of its successful flight tests, the United States Army Air Forces ordered 3 YR-4As and 27 YR-4Bs for service testing and flight training.

Combat service

The R-4 was first used in combat in May 1944. In a letter to a friend, Col. Philip G. Cochran, commanding officer of the 1st Air Commando Group, wrote "Today the 'egg-beater' went into action and the damn thing acted like it had good sense." [2]

Of these 30, one went to Burma and one to Alaska, while several others were assigned to the United States Navy, United States Coast Guard and British Royal Navy who named it the Gadfly. In Royal Air Force service it was called the Hoverfly. The R4 equipped the first British military unit to be equipped with helicopters, the Helicopter Training School, formed in January 1945 at RAF Andover.

It was first used in combat in May 1944. In a letter to a friend, Col. Philip G. Cochran, Commanding Officer (CO) of the 1st Air Commando Group, wrote "Today the 'egg-beater' went into action and the damn thing acted like it had good sense."

Igor Sikorsky and Orville Wright with Sikorsky XR-4 in 1942

The R4 showed such promise that the AAF ordered 100 R-4Bs.

Versions

External differences noted in photos: Some R-4's had the tail wheel located at the extreme aft end of the boom near the tail rotor while others had it positioned at the mid-point of the boom. Additionally, some had short "stub" exhaust pipes from the engine while others had a much longer one which extended vertically and then aft above the main landing gear struts.

Designation

The R-4 was designated under the United States Army Air Force, a series starting with R-1 and proceeded up to about R-16. In 1947 with the start of the United States Air Force, there was a new system, and many aircraft, but not all, were redesignated. The R-4 became the H-4, but this was the first in H-, there was no H-1. The United States Army broke off with its own designation system in the 1950s, resulting in new designations for its helicopter projects (such as HO-6). In 1962 under the new tri-service system (see 1962 United States Tri-Service aircraft designation system), Navy and Army aircraft were given the low numbers. Under the 1962 system, H-4 was given to the HO-4, which was later developed into the OH-58 (after it lost to the OH-6 during the 1960s Army LOH competition).

Survivors

• Smithsonian Museum's Steven F. Udvar-Hazy Center has the XR-4C prototype
• National Museum of the United States Air Force at Wright-Patterson AFB near Dayton, Ohio
• RAF Museum at Hendon in north London
• Canada Aviation Museum in Ottawa, Ontario
• National Museum of Naval Aviation in Pensacola, FL. Exhibit is a HNS-1 Hoverfly (Bureau Number 39047) - On indoor static display in US Coast Guard markings.

Quotes

"Today the 'egg-beater' went into action and the damn thing acted like it had good sense."

– Philip G. Cochran, Commanding Officer (CO) of the 1st Air Commando Group. May 1944

Operators

• Template:UK: RAF, Royal Navy
• Template:USA: USAAF, USAF US Navy, US Coast Guard

Controversy

The Focke-Wulf Fw 61 is sometimes confused as the first production helicopter, but it was only the technology demonstrator and did not enter serial production. It was however, the first fully controllable helicopter (but not first helicopter) to take flight (in 1936). Other claims are that the R-4 was the third or 2nd production helicopter, after the German Focke-Achgelis FA 223 Drache and the Flettner Fl 282 but sources conflict.

Specifications (R-4B)

• Rotor diameter: 38 ft (11.5 m)
• Length: 33 ft 7 3/4 in (10.2 m)
• Height: 12 ft 5 in (3.8 m)
• Weight: 2,581 lb (1170 kg) loaded
• Armament: None
• Engine: Warner R-550 - 200 hp. (149 kW)

• Maximum speed: 75 mph (120 km/h)
• Cruising speed: 65 mph (105 km/h)
  • Service Ceiling: 8,000 ft (2400 m)

External links

• Sikorsky R-4 page at the National Museum of the United States Air Force
• RAF Museum Sikorsky R4 Hoverfly webpage
• Photo gallery of Sikorsky R-4B Hoverfly I
• See the National Museum of Naval Aviation's web page for the HNS-1.

See also

• Sikorsky R-5

Related development
Vought-Sikorsky 300

Designation sequence

• Pre-1948 USAAC/F:
  • Helicopter: R-1 - R-2 - R-3 - R-4 - R-5 - R-6 - R-7 - R-8
• Post-1948 USAF:
  • H-4 - H-5 - H-6 - R-7 - R-8 - H-9 - H-10
• 1922-1962 Navy :
  • HNS - HOE - HOK - HOS - HO2S, HO3S - HO4S - HO5S