Boeingcelebrated the 50th anniversary of the first flight of the 707 jetliner onThursday, Dec. 20.
The 707 isnot to be confused with the earlier Model 367-80, the "Dash 80" thatBoeing intended as a prototype for a U.S. military program competition andwhich ultimately was the aircraft from which the KC-135 series of militarytankers and transport aircraft was derived.
Three and ahalf years before the 707 first flew, the Dash 80 made its first flight on July15, 1954. During an early demonstration flight, its pilots famously threw thehuge Dash 80 into a barrel roll in front of many industry witnesses. The eventwas caught on film.
However,the Dash 80 directly led to the development of the 707 and the two aircraft arevery similar in configuration, both having swept-back, low-mounted wings andhorizontal 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 theU.S. Northwest. As noon passed, Boeing's chief of flight test Tex Johnston, hisco-pilot Jim Gannet and flight engineer Tom Layne sat on the drenched runway atRenton Municipal Airport in the first production 707, checked weather reportsand waited for the chance to take off.
At 12:30p.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 weatherimmediately closed in around the airliner and forced a landing at nearby BoeingField 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 a71-minute flight. The day was the culmination of five years of hard work andmomentous decisions. With the 707, Boeing's president William Allen and hismanagement team had pinned the company?s future firmly to the vision that jetsrepresented the future of commercial aviation.
707 notthe first jet airliner
The Boeing707 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 airlinerto fly (in 1949), the first to enter service (in 1952) and the first to operatetransatlantic flights (also in 1952).
But earlyfatal break-ups of Comets at high altitude -- which investigators found werecaused by cabin-pressurization-induced metal fatigue -- led to the largerBoeing 707 and its rival, the Douglas DC-8, quickly becoming the standardWestern aircraft for long-haul air travel.
Since the707 was the first of the two big U.S. jets to fly, the first flight of theprototype 707 effectively represented the point in commercial aviation historywhen propeller-driven aircraft (whether piston- or turboprop-powered) gave wayto the jet age on transatlantic and U.S. transcontinental routes.
Allen andhis managers had made the right decision. Production of commercial 707s endedin 1978 after 878 had been built. However, production of 707s as for militaryuses 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 lowlevels until 1994, and the total number of 707s manufactured was 1,010.
Most civil707s left in service today have been converted to freighters, while a numberare used as corporate transports. Approximately 130 remain in commercialservice.
VariousBoeing 707 models produced
The firstcommercial 707s, labeled the 707-120 series, had a longer, wider cabin andother improvements compared to the prototype Dash 80. Powered by early Pratt& Whitney JT3C turbojet engines that were based on military J57s, theseinitial 707s had range capability that was barely sufficient to cross the Atlantic Ocean.
Boeing soonintroduced the long-range 707-320 Intercontinental that in May 1959 flew 5,382miles nonstop from Seattle to Rome in 11 hours and 6 minutes. A number ofvariants were developed for special use, including shorter-bodied airplanes andthe 720 series (originally called the 707-020), which was lighter and fasterand had better runway performance than the basic 707-120.
Pan AmericanWorld Airways was the first 707 customer, signing up for 20 Boeing 707-120sin October 1955. In 1962, Pan Am also took delivery of the last 707-120 seriesairplane, an improved 707-120B.
Other early707 variants included the JT4A-powered 707-220, only five of which weremanufactured, for long-haul flights to hot-and-high South American airports byBraniff; 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 forthe first time in June 1960.
The707-320, 707-320B and 707-320C, all of which had a 100-inch longer fuselagethan the 707-120, were the most-produced 707s. Production of the basic 707-320Intercontinental began in 1958 and the final, improved 707-320C was completedin 1978.
Anotherrelatively late-model 707 variant was the 707-420, a version specially producedfor British Overseas Airways Corporation (a state-owned precursor, along withBritish European Airways, of today's British Airways) with Rolls-Royce Conway508 turbofan engines. Lufthansa and Air-India also operated this version of the707.
Boeing'sjet transport success
If oneconsiders the Dash 80 as the forebear of all Boeing jet transports, it waseasily the most far-sighted innovation in which the company ever invested. Notincluding Douglas-heritage jet transports (Boeing bought McDonnell Douglas in1997), 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 becomeby far the world's largest producer of commercial and military jet transportaircraft.
More than730 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-135was actually the original Boeing 717, a model number which was soon forgottenas a result of its more widely used military designation.
In the late1990s, Boeing applied the 717 model number retroactively to the MD-95 t-tailtwinjet design, based on the MD-90, that it had inherited in its takeover ofMcDonnell Douglas.