Sikorsky H-19 Chickasaw

The Sikorsky H-19 Chickasaw (company model number S-55) is a multi-purpose piston-engined helicopter that was used by the United States Army and United States Air Force. It was also license-built by Westland Aircraft as the Westland Whirlwind in the United Kingdom. United States Navy and United States Coast Guard models were designated HO4S, while those of the U.S. Marine Corps were designated HRS. In 1962, the U.S. Navy, U.S. Coast Guard and U.S. Marine Corps versions were all redesignated as H-19s like their U.S. Army and U.S. Air Force counterparts.

The H-19 pioneered the use of a nose-mounted radial engine powering a single fully articulated main rotor located above the cabin, which helped maintain a proper center of gravity under varying loading conditions without requiring ballast to maintain longitudinal stability as with prior Sikorsky designs. This layout gave the H-19 series a characteristic bulbous-nosed appearance and made it one of the first truly successful single-rotor utility helicopters, leading to a number of derivative designs including the Sikorsky H-34, which was produced in even greater numbers. The H-19 had a long military career worldwide in the late 20th century, and proved popular with civil operators.

Development

thumb|left|HRS-1 of the USMC, on display at a museum, 2014

Development of the H-19 was initiated privately by Sikorsky without government sponsorship. The helicopter was initially designed as a testbed for several novel design concepts intended to provide greater load-carrying ability in combination with easy maintenance. Under the leadership of designer Edward F. Katzenberger, a mockup was designed and fabricated in less than one year. Although tests of the system were considered successful, it was never adopted operationally.

Another benefit of this engine location was ease of maintenance, as the engine could be readily accessed at ground level through dual clamshell-style doors; the entire engine could be changed in only two hours, and the radial engine was oriented backwards relative to a typical airplane installation, allowing more convenient access to engine accessories.

thumb|right|UH-19B rotor head, with main rotors folded

The offset flapping hinges and hydraulic servos gave more positive flight control under differing loading conditions, isolated the flight controls from vibration, and lessened control forces; the H-19 could be flown with only two fingers on the cyclic control.

The success of helicopter operations with the USMC prompted the service to seek a military light utility vehicle that the HRS could lift, leading to the development of the aluminum-bodied, M422 Mighty Mite in the early 1950s. However, developmental issues delayed deployment of the M422 until 1959, by which time the HRS was being replaced by utility helicopters capable of lifting standard U.S. light utility vehicles, rendering the M422 unnecessary anddue to its unique designa supply chain liability. The Mighty Mite was only produced in small numbers and was mostly withdrawn from service by the late 1960s.

The U.S. Air Force (USAF) ordered 50 H-19A's for rescue duties in 1951. These aircraft were the primary rescue and medical evacuation helicopters for the USAF during the Korean War. The Air Force continued to use the H-19 through the 1960s, ultimately acquiring 270 of the H-19B model.

thumb|left|USAF HH-19 in a publicity photo purported to show the rescue of U.S. [[North American F-86 Sabre|F-86 ace Joseph C. McConnell; the actual rescue was conducted using a different H-19.

On 1 September 1953, Sabena used the S-55 to inaugurate the first commercial helicopter service in Europe, with routes between Rotterdam and Maastricht in the Netherlands and Cologne and Bonn in West Germany.

Pakistan ordered eight S-55s in 1956 to equip search and rescue squadrons of the Pakistan Air Force. They saw service during the 1965 Indo-Pakistani War, flying various missions including counterintelligence operations at Karachi in co-operation with the Army. They were retired from service in 1971.

The H-19 left U.S. military service when the CH-19E was retired by U.S. Navy squadron HC-5 on 26 February 1969. Surplus H-19s were sold on the open market, and civil interest was sufficient that Sikorsky (and later Orlando Helicopter Airways or OHA) offered conversion kits allowing a military surplus H-19 to be commercially operated under a standard Federal Aviation Administration type certificate as an S-55B. Turboshaft conversions were also offered by aftermarket modification companies.

In the mid-1980s, the U.S. Army sought an economical helicopter to simulate the sound and radar signature of the Soviet Mil Mi-24 during exercises. OHA sold the Army fifteen modified S-55/Mi-24s with a new five-bladed rotor system, which was quieter than the original three-bladed rotor and made the aircraft sound similar to an Mi-24. The piston engines and original Sikorsky tail rotors were retained.

OHA also produced the S-55QT Whisper Jet, an extra-quiet civil conversion based on the five-bladed S-55/Mi-24, but using an Garrett TPE331 derated to from the S-55T, which lowered the aircraft's empty weight by . The aircraft were also outfitted with special intake and exhaust silencers, carbon fiber noise-absorbing engine compartment doors, and a transparent Plexiglas floor. Five aircraft were built in 1999 to comply with strict National Park Service noise limits for Grand Canyon aerial tours; however, the aircraft were only used in this role for two years because it was difficult for pilots in the high-mounted cockpit to communicate with tourists in the main cabin. After being retired from sightseeing, the helicopters were used in utility and lift roles. derated to , three built for Royal Canadian Navy (RCN), both surviving aircraft subsequently converted to HO4S-3.

;HO4S-2G

:US Coast Guard version of HO4S-2, seven built.

;HRS-2

:HRS-1 with equipment changes, 101 built.

;HRS-3

:HRS-2 with R-1300-3 engine, 105 built and conversions from HRS-2.

;HRS-4

:Project for HRS-3 with a R-1820 radial engine, not built.

Post-1962 Tri-Service designations

;UH-19A

:H-19A redesignated in 1962.

;HH-19A

:SH-19A redesignated in 1962.

;UH-19B

:H-19B redesignated in 1962.

;HH-19B

:SH-19B redesignated in 1962.

;CH-19E

:HRS-3 redesignated in 1962.

;UH-19F

:US HO4S-3 redesignated in 1962. (RCN/CAF aircraft retained HO4S-3 designation.)

Civil variants

;S-55: Commercial version with R-1340 engine.

;S-55A: Commercial version with R-1300-3 engine.

;S-55B: New designation given to civilian kit conversions of military surplus H-19s with R-1300-3 engine.

Aircraft on display

See Westland Whirlwind museum examples for examples of the British license-built S-55.

thumb|Sikorsky HRS-3, later renamed the CH-19E, of the US Marine Corps at museum

thumb|S-55 of Spain

;Argentina

H-04 – S-55 on display at the Museo Nacional de Aeronáutica de Argentina in Morón, Buenos Aires.
0371/55-633 – S-55 on display at the Museo de la Aviacion Naval in Bahia Blanca, Buenos Aires.

;Guatemala

S-55 on display in the traffic circle at the main gate of Air Force Headquarters, Aeropuerto Internacional La Aurora, Guatemala City.

;Canada

55822 – S-55 on static display at The Hangar Flight Museum in Calgary, Alberta. It was operated by Associated Airways in Canada's north and is fitted with a 550 hp Pratt & Whitney Wasp R-1340-S1H2 engine.
55885 – HO4S-3 on static display at the Shearwater Aviation Museum in Shearwater, Nova Scotia. It is painted in Royal Canadian Navy Sqn. No. 7 colors as used by Anti-Submarine Squadron HS-50 and Utility Squadron HU-21.

;Denmark

S-883 - S-55C C/N 55-1031, on static display at Danmarks Tekniske Museum in Helsingør
S-884 – S-55C C/N 55-1032, on static display at the Danmarks Flymuseum in Skjern, Ringkøbing-Skjern.

;Germany

53-4458 – H-19B on static display at the Deutsches Museum in Munich, Bavaria.

;India

IZ1590 – S-55C C/N 55-1077, on static display at the Indian Air Force Museum in Palam, Delhi.

;Israel

03 – H-19 on static display at the Israeli Air Force Museum in Hatzerim, South District.

;Japan

JG-0001 – H-19C on static display at the Tokorozawa Aviation Museum in Tokorozawa, Saitama.
40012 – H-19C in storage at the Kawaguchiko Motor Museum in Narusawa, Yamanashi.

;Norway

56-4279 – H-19 D-4 on static display at the Norwegian Armed Forces Aircraft Collection in Gardermoen, Akershus.

;Portugal

9101 – UH-19 at the Museu do Ar on Sintra Air Base near Lisbon.

;Serbia

11714 – S-55 on static display at the Museum of Aviation in Surčin, Belgrade.

;Thailand

H3-3/97 – Type 3 on display at the Royal Thai Air Force Museum in Bangkok, Bangkok.

;Turkey

52-7577 – UH-19B on static display at the Istanbul Aviation Museum in Istanbul, Istanbul.

thumb|Sikorsky HO4S-1 on display at the [[Historic Aviation Memorial Museum]]

;United States

Unknown ID – UH-19F on static display at Kirtland Air Force Base in Albuquerque, New Mexico.
130151 – CH-19E on static display at the National Museum of Naval Aviation in Pensacola, Florida. It is displayed in a US Coast Guard paint scheme.
130252 – HRS-3 on static display at the Flying Leatherneck Aviation Museum in San Diego, California. It is painted with the unit markings of HMR-161.
thumb|Sikorsky YH-19A as shown at the [[Steven F. Udvar-Hazy Center]]49-2012 – YH-19 on static display at the Udvar-Hazy Center of the National Air and Space Museum in Chantilly, Virginia. This airframe was the first S-55 built.
52-7537 – UH-19B on static display at the Pima Air and Space Museum in Tucson, Arizona. It is painted as a rescue helicopter with the 534th Air Defense Group.
52-7573 - H-19B on static display at the Connecticut Air & Space Center in Stratford, Connecticut.
52-7587 – UH-19 on static display at the National Museum of the United States Air Force in Dayton, Ohio. It is painted as Hopalong, one of the helicopters to make the first transatlantic flight.
52-7602 – H-19D on static display at the Evergreen Aviation & Space Museum in McMinnville, Oregon. It is painted in U.S. Army scheme.
53-4426 – H-19B on static display at the Strategic Air Command & Aerospace Museum in Ashland, Nebraska.
55-0433 – H-19D in storage at Fantasy of Flight in Polk City, Florida.
55-3221 – H-19D Chickasaw on static display at the United States Army Aviation Museum at Fort Novosel, Alabama.
55-4943 – UH-19D on static display at the Estrella Warbird Museum in Paso Robles, California. This airframe had previously been on display at the Museum of Flight in Seattle, Washington.
57-5937 – UH-19D on static display at the Valiant Air Command Warbird Museum in Titusville, Florida. It is painted in a USAF rescue scheme. It was previously on display at the EAA AirVenture Museum in Oshkosh, Wisconsin. This aircraft is a former Winnebago Heli-Home.

Specifications (UH-19C)

frameless|right|3-view line drawing of the Sikorsky HO4S-2

thumb|A 3-view line drawing of a Sikorsky H-19A Chickasaw on floats

Notable appearances in media

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References

Notes

Citations

Bibliography

Duke, R.A., Helicopter Operations in Algeria [Trans. French], Dept. of the Army (1959)
France, Operations Research Group, Report of the Operations Research Mission on H-21 Helicopter Dept. of the Army (1957)
Harding, Stephen. U.S. Army Aircraft Since 1947, Shrewsbury, UK: Airlife Publishing (1990). .
Riley, David, French Helicopter Operations in Algeria, Marine Corps Gazette, February 1958, pp. 21–26.
Shrader, Charles R., The First Helicopter War: Logistics and Mobility in Algeria, 1954–1962, Westport, Connecticut: Praeger Publishers (1999)
Spenser, Jay P., Whirlybirds: A History of the U.S. Helicopter Pioneers, Seattle, Washington: University of Washington Press (1998)

External links

H-19 US Army Aviation history fact sheet
USMC Sikorsky HRS (H-19) Database
HELIS.com Sikorsky S-55 (H-19/HRS/HO4S) Database