American Airlines Boeing 707 model. In August 1952, the company took the bold step of gambling some 16 million dollars to build the prototype of a completely new turbojet-powered civil transport. Boeing was sufficiently realistic to appreciate from the very beginning that its large private-venture investment, even in 1952 dollars, was nowhere near the amount that would be needed if large-scale production of a civil airliner was to become a reality. Shrewdly, they developed the initial design to serve as a high-speed military transport, or inflight-refueling tanker, banking upon gaining a military contract which would underwrite the tooling costs and provide finance for the development of a first-class civil airliner. The prototype, known as the Dash-80, flew for the first time on July 15, 1954, and on October 5, 1954, Boeing's gamble paid off, they were awarded an initial contract for 29 KC-135A tanker/transports (the military version of the 707). Then, on October 13, 1955, Boeing received the first contract for six civilian aircraft from Pan American, with the inaugural flight on October 26, 1958, on Pan Am's New Your-London route. However, it was not until the Model 707-320 intercontinental, that sustained scheduled transatlantic flights began on October 10, 1959. When production of the 707 came to an end in 1990, a total of 999 aircraft had been built, in several variations. The Boeing 707-320C had a maximum speed of 627 mph, maximum cruising speed of 605 mph, service ceiling of 39.000 feet, and a range with maximum fuel and 147 passengers of 5,755 miles.