Sikorsky S-55

Sikorsky S-55 / H-19 Chickasaw
Type:	Transport helicopter
Design country:	United States
Manufacturer:	Sikorsky Aircraft Corporation
First flight:	November 10, 1949
Commissioning:	March 25, 1952
Number of pieces:	1,067 and 547 under license

The Sikorsky S-55 or H-19 Chickasaw was an American transport helicopter . With a crew of two, ten passengers or six wounded in an ambulance could be carried on stretchers or 1300 kg of cargo over a very long distance of 300 km at the time of design.

history

On May 1, 1949, the Sikorsky design office received the order to develop a transport helicopter that could carry ten people in just seven months. Five prototypes were built within a very short time . These were sent to the United States Air Force (USAF) for testing and were given the military designation YH-19 . The first YH-19 (USAF serial number 49-2012) flew on November 10, 1949. The fuselage and tail rotor arm of the prototypes were given fairings during flight tests to increase lateral stability. These were used in Korea as early as 1950.

On April 28, 1950, the US Navy ordered ten HO4S-1 (H-19A), which were delivered to the HU-2 squadron from December 27, 1950.

On August 2, 1950, the US Marine Corps ordered 60 copies.

In 1951 the first 50 S-55A series models (H-19A) were ordered by the USAF, which were delivered to the 3rd Air Rescue Squadron from 1952. These hardly differed from the prototypes, only a triangular surface for stabilization was fitted between the tail unit support and the cabin.

The US Army then ordered 410 H-19C and D models in 1952.

The civil registration of the S-55 took place on March 25, 1952. For the US armed forces numerous variants were built, some of which were used in the Korean War; in addition there are the two civil series. The experience gained in Korea with the S-55 was to become part of a new military doctrine that envisaged helicopters as an integral part of the various roles of warfare. These findings and tactics were implemented later in the Vietnam War , where the direct successor to the S-55 , the S-58 , was to play a role.

A total of 1,067 copies were completed by Sikorsky, a further 547 by licensees. Westland Aircraft produced the S-55 in Great Britain as Westland Whirlwind , Mitsubishi in Japan and the SNCA du Sud-Est (later part of Aérospatiale ) in France .

Versions

Civil versions
S-55A S-55B
S-55T	Version of Aviation Specialties from 1969 that was equipped with a Garrett AiResearch TSE331 shaft turbine
Military versions
US Air Force	YH-19 (prototype) H-19A (corresponds to the S-55A) H-19B (corresponds to the S-55B) SH-19B H-19C
US Army	UH-19C Chickasaw (equivalent to the H-19C) UH-19D
US Navy	HO4S-1 (corresponds to the H-19A) HO4S-2 HO4S-3
US Marine Corps	HRS-1 (corresponds to HO4S-1) HRS-2 (corresponds to HO4S-2) HRS-3 (corresponds to HO4S-3)
US Coast Guard	HO4S-3G (upgraded Navy-HO4S-3)

commitment

As early as 1950, two of the YH-19 prototypes were used in Korea as rescue helicopters by the 3rd Air Rescue Squadron, which were equipped with a hydraulic winch with 30 m steel cable on the starboard side. From 1952 the series helicopters were used in search and rescue missions, but also in combat and secret service missions. On September 13, 1951, S-55s were deployed for the first time on a large scale in a combat area. On April 12, 1952, the flying ace Joseph McDonnel was rescued from behind enemy lines after he was shot down, and in the summer of 1952 the remains of a crashed MiG-15 were recovered. The first US Army H-19C and D were deployed on March 20, 1953. During the Korean War, the S-55 of the Marines unit HMR-161 carried more than 60,000 soldiers in 18,600 missions.

In addition to their military use, the S-55 were used at the beginning of the Mercury space program to rescue the return capsules and to support Antarctic expeditions.

Civil she was registered as a commercial transport helicopter by New York Airways and used from July 8, 1953 to transport passengers between Idlewild (now JFK), LaGuardia and Newark airports. In Europe it was used by the Belgian Sabena from September 1, 1953 for liner services between Brussels and Maastricht, Rotterdam and Lille.

From 1987 onwards, 15 Orlando Helicopters S-55s were converted for the US Army to simulate Soviet Mi-24 helicopters .

technology

The fuselage of the helicopter was made of all-metal half - shell construction, the planking consisted of aluminum and magnesium alloys . The engine, in all variants an air or fan-cooled , single-row nine-cylinder radial engine , was installed at an angle in the nose of the fuselage, in the round “nose” in front of the passenger cabin. It was accessible via two large side-opening maintenance hatches. The pilot's cockpit was located above the cabin, with the three-bladed main rotor above it . A drive shaft led under the cockpit from the engine to the main gearbox of the rotor mast behind the pilot's seats. This design was new up until then and should remain the distinguishing feature of the S-55 and S-58 series. This enabled a large cargo space under the main rotor and thus prevented the problematic shifting of the center of gravity with changing payloads. The rotor blades were made entirely of metal and passed endurance tests over 20,000 hours. Two tanks with a total capacity of 700 liters of AvGas were located below the cabin floor. The four-wheel chassis could be supplemented by inflatable floats or completely replaced by a wheel / float chassis . The two braked main landing gear wheels were arranged behind the center of gravity on broad-gauge struts, at the front at the height of the motor bulkhead there was a deflectable nose landing gear leg with smaller wheels on each side of the fuselage. The S-55A had a Pratt & Whitney R-1340-57 with 404.5 kW (550 hp). The S-55B got a Wright R-1300-3 with 514.8 kW (700 PS) along with a larger main rotor and a tail boom that was tilted three degrees down to increase the distance to the rotor blades. The HRS-1 machines had self-sealing tanks compared to the H-19A .

production

As part of the Mutual Defense Aid Program (MDAP), the S-55 was also delivered to allied countries.

Acceptance of the S-55 by the USAF and the US Navy / Marine-Corps / Coast Guard (only until 1957):

version	1950	1951	1952	1953	1954	1955	1956	1957	1958	1959	TOTAL
YH-19	3										3
H-19A		7th	43								50
H-19B				125	109						234
H-19C			72								72
H-19D				16	24	30th	62	46	61	16	255
H-19 MDAP			1					2			3
H-19B MDAP				12	9	9					30th
H-19D MDAP								12	15th	1	28
HO4S-1	6th	4th									10
HO4S-3				41	20th						61
HO4S-2 Coast Guard		7th									7th
HO4S-3 Coast Guard				9	4th						13
HRS-1		59	13			1					73
HRS-2			79								79
HRS-3				69			10	5			84
TOTAL	9	77	208	272	166	40	72	65	76	17th	1002

Military users

Greek H-19

A Sikorsky S-55 of the Força Aérea Portuguesa

Spanish Westland Whirlwind

Sikorsky H-19 users  Argentina  Belgium  Belgian Congo  Brazil  Chile  Denmark  Germany  Dominican Republic  France French Air Force  Greece  Guatemala  Haiti  Honduras  Israel  Italy  Japan Ground Self-Defense Forces 1954–1976 Marine Self- Defense Forces 1954–1970 Air Self Defense Forces 1957–1973 Coast Guard 1952–1974  Yugoslavia  Canada  Colombia  Kuwait  Nicaragua  Netherlands  Norway : 4 H-19D-4 v 1958-1967  Pakistan  Philippines  Portugal  Taiwan  South Vietnam  Spain  South Korea : v 1958–1976  Thailand  Turkey  Uruguay  United States United States Army United States Air Force United States Marine Corps United States Navy United States Coast Guard  United Kingdom Royal Navy  Venezuela

Westland Whirlwind users  Bahamas  Brazil  Brunei  France  Ghana  Iran  Jordan  Canada  Qatar  Cuba  Kuwait  Nigeria  Austria : 10 WS-55 Whirlwind Srs.2 v 1958–1965  Saudi Arabia  Spain  United Kingdom Royal Air Force Royal Navy

Technical specifications

Parameter	Data from the H-19C
Construction year	1952
Manufacturer	Sikorsky
Main rotor diameter	16.15 m
Tail rotor diameter	2.64 m
Hull length	12.88 m
Length over all	19.07 m
height	4.06 m
Preparation mass	2245 kg
Max. Takeoff weight	3266 kg (3407 kg HO4S-3)
payload	~ 1000 kg
crew	2
Top speed	162 km / h
Hovering altitude with ground effect	1950 m
Service ceiling	3218 m
Range	650 km
Engine	a radial engine Wright R- 1300-3 with 514.8 kW (700 PS)

See also

• List of helicopter types

Web links

Commons : H-19 Chickasaw  - album with pictures, videos and audio files

• Sikorsky S-55 (Aviastar) (English)
• H-19 (GlobalSecurity) (English)
• Helicopter Pilot Training: "Transition to the H-19" - 1956 US Army Training Film , contemporary US Army pilot instruction film on Youtube, in English, accessed on February 15, 2019

Individual evidence

1. ↑ FlugRevue November 2009, pp. 92–95, breakthrough for the helicopter - Sikorsky S-55
2. ↑ Statistical Digest of the USAF 1948, p. 16; 1949, p. 164 f .; 1951, p. 158; 1952, p. 158; 1953, p. 185 f .; 1954, pp. 70 f .; 1955, p. 80 f .; 1956, p. 91 f .; 1957, p. 97 f .; 1958, p. 72; 1959, p. 68
3. ↑ Doppeladler.com