The first rotorcraft to serve with the Indian Air Force, the Sikorsky S-55 was obtained in April 1954, six examples being purchased from the United States and equipping No. 104 Helicopter Unit at Palam. A second batch of two S-55Cs was received by mid-April 1957.
The S-55s served general purpose and utility needs and were employed in a variety of roles, from VIP transportation to flood rescue and earthquake relief in Assam, Bengal, Bihar, Punjab and Delhi. In 1959, the S-55 was operationally used in NEFA when the Chinese intruded in the Longju area and it was on the S-55 that I.A.F. pilots first worked out the special techniques required for operations in hilly and inaccessible terrain. The S-55 assisted security forces in the Naga hills.
One S-55 (IZ 650) together with crew was loaned to the Indian Navy in November 1961 and remained on air-sea rescue and plane-guard duties with I.N.S. “Vikrant” till the Navy received its Alouette IIIs.
The S-55s were withdrawn from service in 1966.
Notes :
The Sikorsky S-55 (Whirlwind) prototype first flew on on November 7th 1949 and a total of 1290 helicopters of the type were manufactured by the parent company, some numbers also being assembled in France and Japan. The S-55 was built under licence by Westland Aircraft in England as the Whirlwind and the U.S.A.F. version was designated the H-19. The S-55, powered by one Wright R-1300-3 radial of 800 h.p. was employed by some 35 air arms.
| Country of origin | U.S.A. |
| Performance | Max. speed 112 m.p.h. (180 km./hr.) |
| Normal range 360 miles (579 km.) | |
| Hovering ceiling (i.g.e.) 5,800 feet (1,768 m.) | |
| Service ceiling 15,500 feet (4,724 m.) | |
| Weights | Empty 5,250 lb. (2,384 kg.) |
| Max. loaded 7,900 lb. (3,587 kg.) | |
| Dimensions | Rotor diameter 53 ft. (16.15 m.) |
| Fuselage length 42 ft. 3 in. (12.87 m.) | |
| Overall height 13 ft. 4 in. (4.06 m.) |
