Editing Boeing 737 (section)

=== Initial design ===
[[File:1964 Boeing 737 concept.png|thumb|1964 concept with tail mounted engines]]

Boeing had been studying short-haul jet aircraft designs, and saw a need for a new aircraft to supplement the [[Boeing 727|727]] on short and thin routes.<ref name="nyt transport news">"[https://www.nytimes.com/1964/07/17/transport-news-boeing-plans-jet.html Transport News: Boeing Plans Jet.] {{Webarchive|url=https://web.archive.org/web/20170821213438/http://www.nytimes.com/1964/07/17/transport-news-boeing-plans-jet.html |date=August 21, 2017}}" ''[[The New York Times]]'', July 17, 1964. Retrieved: February 26, 2008.</ref> Preliminary design work began on May 11, 1964,{{sfn|Endres|2001|p=122|ps=}} based on research that indicated a market for a fifty to sixty passenger airliner flying routes of {{Convert|50|to|1000|mi|-2}}.<ref name="nyt transport news" />{{sfn|Sharpe|Shaw|2001|p=12|ps=}}

The initial concept featured [[podded engine]]s on the aft fuselage, a [[T-tail]] as with the 727, and five-abreast seating. Engineer [[Joe Sutter]] relocated the engines to the wings which lightened the structure and simplified the accommodation of six-abreast seating in the fuselage.<ref name=FG170406 /> The engine [[nacelle]]s were mounted directly to the underside of the wings, without pylons, allowing the [[landing gear]] to be shortened, thus lowering the fuselage to improve baggage and passenger access.{{sfn|Sutter|2006|pp=76–78}} Relocating the engines from the aft fuselage also allowed the [[horizontal stabilizer]] to be attached to the aft fuselage instead of as a T-tail.{{sfn|Sharpe |Shaw|2001|p=17|ps=}} Many designs for the engine attachment strut were tested in the wind tunnel and the optimal shape for high speed was found to be one which was relatively thick, filling the narrow channels formed between the wing and the top of the nacelle, particularly on the outboard side.[[File:Boeing 737 patent USD206035S.jpg|thumb|October 18, 1966, Jet aircraft patent, filed June 22, 1965, by John Steiner and [[Joe Sutter]] for Boeing]]

At the time, Boeing was far behind its competitors; the [[Sud Aviation Caravelle|SE 210 Caravelle]] had been in service since 1955, and the [[BAC One-Eleven]] (BAC-111), [[McDonnell Douglas DC-9|Douglas DC-9]], and [[Fokker F28]] were already into flight certification.<ref name="german order" /> To expedite development, Boeing used 60% of the structure and systems of the existing 727, particularly the fuselage, which differs in length only. This 148-inch (3.76 m) wide fuselage cross-section permitted six-abreast seating compared to the rivals' five-abreast. The 727's fuselage was derived from the 707.{{sfn|Sharpe|Shaw|2001|p=13|ps=}}

The proposed wing [[airfoil]] sections were based on those of the 707 and 727, but somewhat thicker; altering these sections near the nacelles achieved a substantial drag reduction at high Mach numbers.<ref>Olason, M.L. and Norton, D.A. "Aerodynamic Philosophy of the Boeing 737", AIAA paper 65-739, presented at the AIAA/RAeS/JSASS Aircraft Design and Technology Meeting, Los Angeles California, November 1965. Reprinted in the AIAA Journal of Aircraft, Vol. 3 No. 6, November/December 1966, pp. 524–528.</ref> The engine chosen was the [[Pratt & Whitney JT8D]]-1 low-bypass ratio turbofan engine, delivering {{Convert|14500|lbf|kN|lk=on}} of thrust.{{sfn|Shaw|1999|p=6|ps=}}

The concept design was presented in October 1964 at the [[Air Transport Association]] maintenance and engineering conference by chief project engineer Jack Steiner, where its elaborate [[high-lift device]]s raised concerns about [[aircraft maintenance|maintenance]] costs and dispatch reliability.<ref name=FG170406>{{cite news |url= https://www.flightglobal.com/news/articles/analysis-half-century-milestone-marks-737s-endurin-435787/ |title= Half-century milestone marks 737's enduring appeal |date= April 7, 2017 |author= Stephen Trimble |work= FlightGlobal}}</ref>