Boeing celebrated the 50th anniversary of the first flight of the 707 jetliner on Thursday, Dec. 20.
The 707 is not to be confused with the earlier Model 367-80, the "Dash 80" that Boeing intended as a prototype for a U.S. military program competition and which ultimately was the aircraft from which the KC-135 series of military tankers and transport aircraft was derived.
Three and a half years before the 707 first flew, the Dash 80 made its first flight on July 15, 1954. During an early demonstration flight, its pilots famously threw the huge Dash 80 into a barrel roll in front of many industry witnesses. The event was caught on film.
However, the Dash 80 directly led to the development of the 707 and the two aircraft are very similar in configuration, both having swept-back, low-mounted wings and horizontal stabilizers, and four under-wing jet engines.
Dec. 20, 1957, the day of the 707's first flight, was a cold and rainy Friday in the U.S. Northwest. As noon passed, Boeing's chief of flight test Tex Johnston, his co-pilot Jim Gannet and flight engineer Tom Layne sat on the drenched runway at Renton Municipal Airport in the first production 707, checked weather reports and waited for the chance to take off.
At 12:30 p.m., the decision was made to take off and the 707-120 powered into the sky. But as it climbed over the city of Renton, the unpredictable weather immediately closed in around the airliner and forced a landing at nearby Boeing Field after just seven minutes in the air.
However, later in the day, the sky cleared enough for the crew to take the 707 up for a 71-minute flight. The day was the culmination of five years of hard work and momentous decisions. With the 707, Boeing's president William Allen and his management team had pinned the company?s future firmly to the vision that jets represented the future of commercial aviation.
707 not the first jet airliner
The Boeing 707 was not the first jet airliner to see service, or even the first to fly the Atlantic. The de Havilland Comet was the world's first production jet airliner to fly (in 1949), the first to enter service (in 1952) and the first to operate transatlantic flights (also in 1952).
But early fatal break-ups of Comets at high altitude -- which investigators found were caused by cabin-pressurization-induced metal fatigue -- led to the larger Boeing 707 and its rival, the Douglas DC-8, quickly becoming the standard Western aircraft for long-haul air travel.
Since the 707 was the first of the two big U.S. jets to fly, the first flight of the prototype 707 effectively represented the point in commercial aviation history when propeller-driven aircraft (whether piston- or turboprop-powered) gave way to the jet age on transatlantic and U.S. transcontinental routes.
Allen and his managers had made the right decision. Production of commercial 707s ended in 1978 after 878 had been built. However, production of 707s as for military uses as E-3A AWACS airborne early warning and control aircraft and E-6s -- which the U.S. Navy used for communications with submarines -- continued at low levels until 1994, and the total number of 707s manufactured was 1,010.
Most civil 707s left in service today have been converted to freighters, while a number are used as corporate transports. Approximately 130 remain in commercial service.
Various Boeing 707 models produced
The first commercial 707s, labeled the 707-120 series, had a longer, wider cabin and other improvements compared to the prototype Dash 80. Powered by early Pratt & Whitney JT3C turbojet engines that were based on military J57s, these initial 707s had range capability that was barely sufficient to cross the Atlantic Ocean.
Boeing soon introduced the long-range 707-320 Intercontinental that in May 1959 flew 5,382 miles nonstop from Seattle to Rome in 11 hours and 6 minutes. A number of variants were developed for special use, including shorter-bodied airplanes and the 720 series (originally called the 707-020), which was lighter and faster and had better runway performance than the basic 707-120.
Pan American World Airways was the first 707 customer, signing up for 20 Boeing 707-120s in October 1955. In 1962, Pan Am also took delivery of the last 707-120 series airplane, an improved 707-120B.
Other early 707 variants included the JT4A-powered 707-220, only five of which were manufactured, for long-haul flights to hot-and-high South American airports by Braniff; and the 707-138, a short-fuselage, long-haul version for Australia's Qantas, one of which is now flown by John Travolta as a personal airliner. Both variants were made obsolete by the 707-120B, which flew for the first time in June 1960.
The 707-320, 707-320B and 707-320C, all of which had a 100-inch longer fuselage than the 707-120, were the most-produced 707s. Production of the basic 707-320 Intercontinental began in 1958 and the final, improved 707-320C was completed in 1978.
Another relatively late-model 707 variant was the 707-420, a version specially produced for British Overseas Airways Corporation (a state-owned precursor, along with British European Airways, of today's British Airways) with Rolls-Royce Conway 508 turbofan engines. Lufthansa and Air-India also operated this version of the 707.
Boeing's jet transport success
If one considers the Dash 80 as the forebear of all Boeing jet transports, it was easily the most far-sighted innovation in which the company ever invested. Not including Douglas-heritage jet transports (Boeing bought McDonnell Douglas in 1997), the company has won orders for more than 17,000 large transport jets, from the 707 to the 787, in the last 53 years. In that time, Boeing has become by far the world's largest producer of commercial and military jet transport aircraft.
More than 730 KC-135s, directly developed from the Dash 80 prototype along with the 707, were produced for the U.S. Air Force and France's Arm?e de l'Air. The KC-135 was actually the original Boeing 717, a model number which was soon forgotten as a result of its more widely used military designation.
In the late 1990s, Boeing applied the 717 model number retroactively to the MD-95 t-tail twinjet design, based on the MD-90, that it had inherited in its takeover of McDonnell Douglas.