In 1946 the US Navy released acquirements for a helicopter to be used aboard cruisers and battleships. Both Piaseckie and Sikorsky received a contract for the development of two prototypes based upon these requirements.
Sikorsky developed the Sikorsky S.53, or XHJS-1, which was based upon the HO3S-1, the naval version of the S-51.
The S.53 was equipped with the more powerful Continental R-975-34 rated 525 hp and was capable to carry five passengers. The type made its maiden-flight in September 1947.
After evaluation and comparison with the Piaseckie XHJP-1, this last type was chosen. One of the main reasons was the necessity to change the ballast of the Sikorsky when the load was changed.
Sikorsky developed a modified version, but this model was not selected.
In 1949 the Helicopter Divisional Office of the USAAF requested proposals for a new helicopter.
Sikorsky built a mock-up, which was based upon the successor of the XHJS-1.
This proposal was accepted and the USAF ordered to built five YH-19 pre-production examples, registered 49-201 till49-2916. Th first made its first flight on November 10, 1949. These machines differed from the later production-versions lacking the triangular fin between the tail and the fuselage. Also these machines had a horizontal stabilizer.
An order for 51 H-19A followed in 1951, soon succeeded by an order for the H-19B, which was equipped with a more powerful engine and an enlarged main rotor with a diameter of 16,16 m.
The engine was mounted in the nose of the fuselage and the cabin was positioned in the centre of gravity. Because of this construction the load hardly influenced the stability of the helicopter. Much attention was paid to the maintenance of the machine, an engine change, for example, could be done in two hours.
In March 1952 the S-55 received it civil certifications and was the first commercial helicopter available in Europe.
Over 1000 examples of the military version were built plus an additional 550 examples license built by Westland as Westland Whirlwind. Also Sud-Est in France built several example.
- pre-production version, five examples built.
- the USAF-version of the YH-19 with a Pratt & Whitney R-1340-57 engine rated 600 hp and a rotor diameter of 16.15 m. Fifty examples built. From 1962 designated as UH-19A.
- SH-19A: Modified H-19A for rescue duties; From 1962 designated as HH-19A.
- H-19C: US Army version of the H-19A; From 1962 and on designated as UH-19C. 72 examples built.
- As H-19A, but with more powerful R-1300-3 engine rated 700 hp and a rotor diameter of 16,16 m. 264 examples built . From 1962 and on designated as UH-19B.
- SH-19B: Modified H-19B for rescue duties; From 1962 and on designated as HH-19B.
- H-19D: US Army version of the H-19B; From 1962 and on designated as UH-19D. 301 examples built.
- US Navy version of the H-19A, ten examples built.
- never built rescue version for the US Coast Guard.
- Version with new Wright R-1300 engine rated 700 hp, built for US Navy and Canada. From 1962 and on designated as UH-19F. 79 examples built.
- HO4S-3G: Version of the HO4S-3 for US Coast Guard, 30 examples built. From 1962 and on designated as HH-19G.
- HRS-1: Version of the HO4S for US Marine Corps for transport of eight marines. 60 examples built.
- HRS-2: HRS-1 with modified equipment: 101 examples built.
- HRS-3: HRS-2 with Wright ER-1300-3 engine rated 700 hp. From 1962 and on designated as CH-19E. 105 examples built plus several uprated HRS-2s.
- HRS-4: never built version of HRS-3 with a Wright R-1820 rated 1025 hp.
- Civil version with Pratt & Whitney R-1340 rated 600 hp and a straight tail.
- Commercial version with Wright R-1300-3 engine rated 800 hp and inclined tail .
- Version of the S-55A with a Wright R-1340 engine rated 600 hp and inclined tail.
- version converted by Aviation Specialties S-55 with modified equipment and a Garrette Airesearch TPE-331-3U-303 turbojet rated 650 hp.
- Very quiet version for flight across the Grand Canyon.
- Whirlwind HAR21:
- Westland built version of the HRS-2; ten examples built for the Royal Navy.
- Whirlwind HAS22:
- Fifteen examples Westland built version of the HO4S-3.
|Length with rotor||12,85 m||Rotor diameter:||16,15 m|
|Height:||4,06 m||Tail Rotor diameter:||- m|
|Empty weight:||2079 kg||Full weight:||3578 kg|
|Max. speed:||190 km/u||Climbing speed:||213 m/min|
|Cruising speed:||155 km/u|
|Range:||595 km||Service ceiling:||3200 m|
|Engine type:||One Wright R-1300-3 rated 700 hp|