The Lockheed C-130 Hercules is a four-engine turboprop military 
transport aircraft designed and built originally by Lockheed, now Lockheed Martin. Capable of using unprepared runways for takeoffs and landings, the C-130 Hercules was originally designed as a troop, medical evacuation, and cargo transport aircraft. The versatile airframe has found uses in a variety of other roles, including as a gunship (AC 130), for airborne assault, search and rescue, scientific research support, weather reconnaissance, aerial refueling, maritime patrol and aerial firefighting. It is the main tactical airlifter for many military forces worldwide. Over 40 models and variants of the Hercules serve with more than 50 nations.
During its years of service the Hercules family has participated in countless military, civilian and humanitarian aid operations. The family has the longest continuous production run of any military aircraft in history. In 2007, the C-130 Hercules became the fifth aircraft—after the English Electric Canberra, B-52 Stratofortress, Tupolev Tu-95, and KC-135 Stratotanker—to mark 50 years of continuous use with its original primary customer, in this case, the United States Air Force. The C-130 is also the only military aircraft to remain in continuous production for 50 years with its original customer, as the updated C-130J Super Hercules.
The Korean War, which began in June 1950, showed that World War II-era transports—C-119 Flying Boxcars, C-47 Skytrains and C-46 Commandos—were inadequate for modern warfare. Thus on 2 February 1951, the United States Air Force issued a General Operating Requirement (GOR) for a new transport to Boeing, Douglas, Fairchild, Lockheed, Martin, Chase Aircraft, North American, Northrop, and Airlifts Inc. The new transport would have a capacity for 92 passengers, 72 combat troops or 64 paratroopers in a cargo compartment that is approximately 41 feet long, 9 feet high, and 10 feet wide. Loading is from the rear of the fuselage with a range of 1,100&_160;nmi (1,300&_160;mi; 2,000&_160;km), takeoff capability from short and unprepared strips, and the ability to fly with one engine shut down.
Fairchild, North American, Martin and Northrop declined to participate. 
The remaining five companies tendered a total of ten designs Lockheed two, Boeing one, Chase three, Douglas three, and Airlifts Inc. one. The contest was a close affair between the lighter of the two Lockheed (preliminary project designation L-206) proposals and a four-turboprop Douglas design.
