The S-58 (aka H-34 Choctaw) is a military helicopter produced by the Sikorsky helicopter company that first flew on March 8 1945.
The S-58 was conceived, designed and produced as an anti-submarine helicopter. It’s essentially a longer and more powerful version of the S-55, upon which it was based.
The nose is similar to that model, but the tail-dragger rear fuselage and landing gear make it impossible to confuse it with the S-55’s high tail, four post pattern.
The S-58 represents the last of the piston-powered military helicopters which were replaced by turbine helicopters such as the UH-1 Huey and CH-46 Sea Knight.
The engine (there is only one) in question here is the Wright R-1820-84 Cyclone. This radial piston engine provided 1525 horsepower which gave the S58 a maximum speed of 138 miles per hour and a range of 280 miles.
The S-58 had a role in several theaters of war. It was active in the Algerian and Vietnam wars. The US armed forces continued to use the S-58 into the late 1960s. By the early 1970s the armed forces had terminated the service of all S-58/H-34 helicopters.
In total, 1868 of these helicopters were produced with at least 22 operators worldwide. It was also put into use by the United States Army, Navy and Marines.
About 50 variants of this helicopter exists. While production of the S-58 ran between 1954-1970 it is still in civilian use today. Production under license also continued after Sikorsky stopped making the S-58.