Editing Boeing 757 (section)

===Design effort===
The 757 was intended to be more capable and more efficient than the preceding 727.<ref name="b12">{{harvnb|Birtles|2001|p=12.}}</ref> The focus on [[fuel efficiency]] reflected airline concerns over [[operating cost]]s, which had grown amid rising oil prices during the [[Yom Kippur War]] of 1973.<ref name=norris20/><ref name="norris145">{{harvnb|Norris|Wagner|1998|p=145.}}</ref> Design targets included a 20&nbsp;percent reduction in fuel consumption from new engines, plus 10&nbsp;percent from aerodynamic improvements, versus preceding aircraft.<ref name=norris145/> Lighter materials and new wings were also expected to improve efficiency.<ref name=norris20/> The [[maximum take-off weight]] (MTOW) was set at {{convert|220000|lb|kg|sigfig=3}},<ref name=b16/> which was {{convert|10000|lb|kg|sigfig=3}} more than the 727.<ref name=727tech/> The 757's higher [[thrust-to-weight ratio]] allowed it to take off from short runways and serve airports in [[hot and high]] conditions with higher ambient temperatures and thinner air, offering better [[takeoff]] performance than that offered by competing aircraft. Competitors needed longer takeoff runs for these hot and high conditions. Boeing also offered options for higher [[Payload (air and space craft)|payload capability]].<ref name="b16">{{harvnb|Birtles|2001|pp=16–17.}}</ref><ref name="ostrowerwall">Ostrower, Jon, and Wall, Robert, "Boeing weighs options to reprise aging 757s", ''Wall Street Journal'', February 11, 2015, pp. B1–2.</ref>

[[File:Transavia Airlines Boeing 757-2K2 Wedelstaedt.jpg|thumb|Forward view of a [[Transavia|Transavia Airlines]] 757-200, showing fuselage profile, [[Dihedral (aircraft)|wing dihedral]], and [[Rolls-Royce RB211|RB211]] engines|alt=Forward view of aircraft, showing fuselage profile, two circular engines.]]
The twin-engine configuration was chosen for greater fuel efficiency versus three- and four-engine designs.<ref name="intro12">{{Cite web |last=Velupillai |first=David |date=January 2, 1982 |title=Boeing 757: introducing the big-fan narrowbody |url=http://www.flightglobal.com/pdfarchive/view/1982/1982%20-%200014.html |url-status=live |archive-url=https://web.archive.org/web/20190212130856/https://www.flightglobal.com/pdfarchive/view/1982/1982%20-%200014.html |archive-date=February 12, 2019 |access-date=February 2, 2011 |website=Flight International |pages=12, 15}}</ref> Launch customers Eastern Air Lines and British Airways selected the {{nowrap|[[Rolls-Royce RB211|RB211-535C]]}} turbofan built by [[Rolls-Royce plc|Rolls-Royce]], which was capable of {{convert|37400|lbf|kN|}} of [[Jet engine#Thrust|thrust]].<ref name="intro19">{{harvnb|Velupillai|1982|p=19.}}</ref> This marked the first time that a Boeing airliner was launched with engines produced outside the U.S.<ref name=norris20/> Domestic manufacturer [[Pratt & Whitney]] subsequently offered the {{convert|38200|lbf|kN|}} thrust [[Pratt & Whitney PW2000|PW2037]],<ref name=intro19/> which Delta Air Lines launched with an order for 60 aircraft in November 1980.<ref name=norris20/><ref>{{harvnb|Davies|1990|p=102.}}</ref> [[General Electric Aviation|General Electric]] also offered its {{nowrap|CF6-32}} engine early in the program, but eventually abandoned its involvement due to insufficient demand.<ref name="eden98-9">{{harvnb|Eden|2008|pp=98–99.}}</ref>

As development progressed, the 757 increasingly departed from its 727 origins and adopted elements from the 767,<ref name=norris20/> which was several months ahead in development.<ref>{{harvnb|Birtles|2001|pp=12–13.}}</ref> To reduce risk and cost, Boeing combined design work on both twinjets,<ref name=norris143/><ref name=intro12/> resulting in shared features such as interior fittings and handling characteristics.<ref name=norris23/> [[Computer-aided design]], first applied on the 767, was used for over one-third of the 757's design drawings.<ref name="intro15">{{harvnb|Velupillai|1982|p=15.}}</ref> In early 1979, a common two-crew member glass cockpit was adopted for the two aircraft, including shared instrumentation, [[avionics]], and [[flight management system]]s.<ref name="norris23">{{harvnb|Norris|Wagner|1999|p=23.}}</ref> In October 1979 the nose was widened and dropped to reduce aerodynamic noise by six dB, to improve the flight deck view and to give more working area for the crew and for greater commonality with the 767.<ref>{{Cite magazine |date=October 6, 1979 |title=Boeing refine 757 flight deck |url=https://www.flightglobal.com/pdfarchive/view/1979/1979%20-%203639.html |url-status=live |archive-url=https://web.archive.org/web/20180110054511/https://www.flightglobal.com/pdfarchive/view/1979/1979%20-%203639.html |archive-date=January 10, 2018 |access-date=January 9, 2018 |magazine=Flight International |page=1098}}</ref> [[Cathode-ray tube]] (CRT) color displays replaced conventional [[electromechanics|electromechanical]] instruments,<ref name=norris23/> with increased automation eliminating the [[flight engineer]] position common to three-person cockpits.<ref name=norris23/> After completing a short conversion course, pilots rated on the 757 could be qualified to fly the 767 and vice versa, due to their design similarities.<ref name=norris23/>

[[File:Boeing 757-236 G-BNSF Air Europe Newcastle Airport.jpg|thumb|Predecessor and successor: an [[Air Atlantis]] [[Boeing 727|727-200]] and an [[Air Europe]] 757-200 <!-- at [[Newcastle Airport]] -->|alt=Side view of twin-engine jet on tarmac, with attached airstairs and support vehicle, along with a trijet aircraft in the background.]]
A new [[Supercritical airfoil|aft-loaded]] shape which produced [[Lift (force)|lift]] across most of the upper wing surface, instead of a narrow band as in previous [[airfoil]] designs, was used for the 757's wings.<ref name=norris20/> The more efficient wings had less drag and greater fuel capacity,<ref name=norris20/> and were similar in configuration to those on the 767.<ref name=intro15/> A wider [[wingspan]] than the 727's produced less [[lift-induced drag]], while larger [[wing root]]s increased [[Landing gear|undercarriage]] storage space and provided room for future stretched versions of the aircraft.<ref name=intro15/>

One of the last 727 vestiges, the T-tail, was dropped in mid-1979 in favor of a conventional tail.<ref name=norris20/> This avoided the risk of an aerodynamic condition known as a [[Deep stall#Deep stall|deep stall]], and allowed for more passengers to be carried in a less tapered rear fuselage.<ref name="norris151">{{harvnb|Norris|Wagner|1998|pp=151–53.}}</ref> At {{convert|155.3|ft|sigfig=3}} in length,<ref name=757tech/> the {{nowrap|757-200}} was {{convert|2.1|ft|sigfig=3}} longer than the {{nowrap|727-200}}, and with a greater proportion of its internal volume devoted to cabin space, seating was available for 239 passengers, or 50 more than its predecessor.<ref name="727tech">{{Cite web |title=Boeing 727 Specifications |url=http://www.boeing.com/boeing/commercial/727family/product.page |url-status=live |archive-url=https://web.archive.org/web/20141027024649/http://www.boeing.com/boeing/commercial/727family/product.page |archive-date=October 27, 2014 |access-date=October 26, 2014 |publisher=Boeing}}</ref><ref name=757plan/> The fuselage cross-section, whose upper lobe was common to the [[Boeing 707|707]] and 737,<ref>{{harvnb|Sharpe|Shaw|2001|pp=9, 17.}}</ref><ref>{{harvnb|Davies|2003|p=96.}}</ref> was the only major structural feature to be retained from the 727.<ref>{{harvnb|Birtles|2001|p=15.}}</ref> This was mainly to reduce drag,<ref name=norris145/> and while a wider fuselage had been considered, Boeing's market research found low cargo capacity needs and reduced passenger preference for wide-body aircraft on short-haul routes.<ref name=norris147/><ref name=intro12/>