The H-19 was made by Sikorsky Aircraft and first flown in 1949. The H-19A had a straight tail with two fins running diagonally down from the tail. The "A" model was powered by a 600 horsepower Pratt and Whitney engine (same as the AT-6 airplane). The transmission was fitted with a centrifugal clutch to engage the rotors. It had an actuator to move the left foot pedal forward and back to allow for adjustment especially during hovering when more left pedal was required. Since the pedals were not hydraulic boosted, extended hovering was tiring.
The H-19B had a "drooped" tail to allow more clearance between the rotors and the tail cone and two small fins running horizontally on the tail. The "B" model had a Wright 1300-3B/C seven cylinder radial engine, which developed 700 horsepower. It had a hydraulic actuated clutch to engage the rotors, so you could idle the engine with the rotor brake on without the rotors turning. It had a max. gross operating weight of 7900 pounds with a maximum airspeed of 112 knots.
The H-19 was the first helicopter to be procured in quantity by the Air Force. It was also the world's first helicopter to have a nose-mounted engine. It was originally designed for rescue purposes but with a large main cabin it worked well for cargo, troops, or litters. The H-19 entered service in 1951 and saw extensive service in the Korean War.
Shortly after it entered service, Capts. Joseph D. Copper and Russell Winnegar, with some South Koreans, lowered an H-19 into a canyon 35 miles behind North Korean lines. The South Koreans fieldstripped a crashed MiG-15 and hooked the carcass on the H-19's external winch. Overloaded, the crew lifted off and, flying through heavy ground fire, returned safely to base. In April 1953, Capt. Joseph McConnell, Jr., who would go on to be the leading ace of the Korean War, was pulled out of the Yellow Sea by an SH-19B (as the dedicated rescue aircraft were designated) crew. H-19 crews were also heavily involved in Special Operations in Korea, including retrieving agents who had parachuted into North Korea. On January 15, 1953, Capt. Lawrence A. Barrett and Lt. R. F. Sullivan flew more than 100 miles behind North Korean lines to rescue a downed F-51 pilot.
On July 13–31, 1952, two Air Force crews, Capts. Vincent McGovern and Harry C. Jeffers and Capt. George O. Hembrick and Lt. Harold Moore, flying two H- 19s nicknamed “Hopalong”and “Whirl-o-Way”, made the first crossing of the Atlantic by helicopter. The crews flew from Westover AFB, Mass., to Prestwick, Scotland, in five stages, covering 3,535 miles in 42 hours, 25 minutes.
The H-19/S-55 series was also flown by the US Navy, Marine Corps, Coast Guard (as HRS and HO4S), and Army (H- 19D, which carried their official nickname of “Chickasaw”), as well as 35 other nations. License production took place in Britain, France, and Japan. The H-19s were re-designated UH/HH-19 in 1962 when the Department of Defense standardized the designation system. The last Air Force H-19s were believed to have been taken out of service in 1970.