The Sikorsky

Sikorsky Aircraft

The Sikorsky Aircraft Corporation is an American aircraft manufacturer based in Stratford, Connecticut. Its parent company is United Technologies Corporation.-History:...

 S-61L and S-61N are civil variants of the successful SH-3 Sea King helicopter

Helicopter

A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...

. They are two of the most widely used airliner and oil rig support helicopters built.
In September 1957, Sikorsky won a United States Navy

United States Navy

The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

 development contract for an amphibious anti-submarine warfare (ASW) helicopter capable of detecting and attacking submarines. The XHSS-2 Sea King prototype flew on 11 March 1959.