Editing Boeing 707 (section)

===Model 367-80 origins===
{{main|Boeing 367-80}}
[[File:Boeing 367-80 in flight.jpg|thumb|The 707 was based on the [[Boeing 367-80|367-80]] "Dash&nbsp;80"]]
[[File:Washington National Airport Sept 1961 f.jpg|thumb|N708PA, the first Boeing 707 built (1957). This airplane would later crash as [[Pan Am Flight 292]].]]

During and after World War II, Boeing was known for its military aircraft. The company had produced innovative and important bombers, from the [[Boeing B-17 Flying Fortress|B-17 Flying Fortress]] and [[B-29 Superfortress]] to the jet-powered [[B-47 Stratojet]] and [[B-52 Stratofortress]], but its commercial aircraft were not as successful as those from [[Douglas Aircraft]] and other competitors. As Douglas and [[Lockheed Corporation|Lockheed]] dominated the postwar air transport boom, the demand for Boeing's offering, the [[Boeing 377 Stratocruiser|377 Stratocruiser]], quickly faded with only 56 examples sold and no new orders as the 1940s drew to a close. That venture had netted the company a $15 million loss.<ref>[https://web.archive.org/web/20061222070652/http://www.time.com/time/magazine/article/0,9171,857520,00.html "Gamble in the Sky."] ''[[Time (magazine)|Time]]'', July 19, 1954. Retrieved December 27, 2009.</ref> During 1949 and 1950, Boeing embarked on studies for a new jet transport and saw advantages with a design aimed at both military and civilian markets. [[Aerial refueling]] was becoming a standard technique for military aircraft, with over 800 [[KC-97 Stratofreighter]]s on order. The KC-97 was not ideally suited for operations with the USAF's new fleets of jet-powered fighters and bombers; this was where Boeing's new design would win military orders.<ref>{{Cite book |last=Wilson |first=Stewart |title=Boeing 707, Douglas DC-8, and Vickers VC-10 |location=Fyshwick, Australia |publisher=Aerospace Publications|isbn=978-1-875671-36-6 |year=1998|page=18}}</ref>

As the first of a new generation of American passenger jets, Boeing wanted the aircraft's model number to emphasize the difference from its previous propeller-driven aircraft, which bore 300-series numbers. The 400-, 500- and 600-series were already used by their missiles and other products, so Boeing decided that the jets would bear 700-series numbers, and the first would be the 707.<ref name="irving171">Irving 1994, p. 171.</ref>  The marketing personnel at Boeing chose 707 because they thought it was more appealing than 700.<ref name="why7">{{cite web|url=https://www.boeing.com/news/frontiers/archive/2004/february/i_history.html|archive-url=https://web.archive.org/web/20210416224312/https://www.boeing.com/news/frontiers/archive/2004/february/i_history.html|archive-date=April 16, 2021|title=Boeing Frontiers Online: Why 7's been a lucky number|first=Mike|last=Lombardi|website=www.boeing.com|url-status=live|access-date=June 13, 2021|date=March 2004}}</ref>

The project was enabled by the [[Pratt & Whitney JT3C]] [[turbojet]] engine, the civilian version of the [[Pratt & Whitney J57|J57]] that yielded much more power than the previous generation of jet engines and was proving itself with the B-52.  Freed from the design constraints imposed by limitations of late-1940s jet engines, developing a robust, safe, and high-capacity jet aircraft was within reach for Boeing.  Boeing studied numerous wing and engine layouts for its new transport/tanker, some of which were based on the B-47 and C-97, before settling on the [[Boeing 367-80|367-80]] "Dash 80" [[quadjet]] [[prototype]] aircraft. Less than two years elapsed from project launch in 1952 to rollout on May 14, 1954, with the first Dash 80 flying on July 15, 1954.<ref name="ar 2022-01-08">{{cite web |last1=Thomas |first1=Geoffrey |title=The birth of the Boeing 707 was no secret - everyone knew! |url=https://www.airlineratings.com/news/birth-boeing-707-no-secret-everyone-knew/ |website=Airline Ratings |access-date=June 3, 2023 |language=en-AU |date=January 8, 2022}}</ref> The prototype was a proof-of-concept aircraft for both military and civilian use.<ref name="ar 2022-01-08"/> The [[United States Air Force]] was the first customer, using it as the basis for the [[KC-135 Stratotanker]] aerial refueling and cargo aircraft.

Whether the passenger 707 would be profitable was far from certain. At the time, nearly all of Boeing's revenue came from military contracts.  In a demonstration flight over [[Lake Washington]] outside [[Seattle]], on August 7, 1955, test pilot [[Tex Johnston]] performed a [[barrel roll]] in the 367-80 prototype.<ref name="Ruffin">{{cite book|last=Ruffin|first=Steven A|title=Aviation's Most Wanted: The Top 10 book of Winged Wonders, Lucky Landings and Other Aerial Oddities|year=2005|publisher=Potomac Books|location=Washington D.C.|isbn=978-1574886740|page=320}}</ref> Although he justified his unauthorized action to [[William McPherson Allen|Bill Allen]], then president of Boeing, as selling the airplane with a 1 'g' maneuver he was told not to do it again.<ref>{{cite book |last=Johnston |first=A. M. |author-link=Alvin M. Johnston |title=Tex Johnston: Jet-Age Test Pilot |publisher=[[Smithsonian Books]] |date=December 2000 |page=[https://archive.org/details/texjohnstonjetag00john/page/204 204] |isbn=978-1-56098-931-8 |url=https://archive.org/details/texjohnstonjetag00john|url-access=registration}}</ref>

The {{cvt|132|in|mm}} wide fuselage of the Dash 80 was large enough for four-abreast (two-plus-two) seating like the Stratocruiser. Answering customers' demands and under Douglas competition, Boeing soon realized this would not provide a viable payload, so it widened the fuselage to {{cvt|144|in|sigfig=3}} to allow five-abreast seating and use of the KC-135's tooling.<ref>Francillon, René. ''Boeing 707: Pioneer Jetliner''. Shrewsbury, Shropshire, UK: Motor Books International, 1999. {{ISBN|978-0-7603-0675-8}}. p. 34</ref> Douglas Aircraft had launched its [[Douglas DC-8|DC-8]] with a fuselage width of {{cvt|147|in|sigfig=3}}. The airlines liked the extra space and six-abreast seating, so Boeing increased the 707's width again to compete, this time to {{cvt|148|in|sigfig=3}}.<ref name="irving194">{{harvnb|Irving|1994|pp=194–197}}</ref>