MERC Contributions:

• 737 fuselage stress analysis
• 777 nacelle stress analysis
• Structural response & flutter analysis of 777 fuselage fin

The Boeing 737 is a short- to medium-range twinjet narrow-body airliner developed and manufactured by Boeing Commercial Airplanes in the United States. Originally developed as a shorter, lower-cost twin-engine airliner derived from the 707 and 727, the 737 has developed into a family of ten passenger models with capacities from 85 to 215 passengers. The 737 is Boeing’s only narrow-body airliner in production, with the 737 Next Generation (-700, -800, and -900ER) and the re-engined and redesigned 737 MAX variants currently being built.

Originally envisioned in 1964, the initial 737-100 made its first flight in April 1967 and entered airline service in February 1968 at Lufthansa. Next, the lengthened 737-200 entered service in April 1968. In the 1980s, Boeing launched the longer −300, −400, and −500 models, subsequently referred to as the Boeing 737 Classic series and featuring CFM56 turbofan engines along with wing improvements.

The 737 Next Generation was introduced in the 1990s, with a redesigned, increased span laminar flow wing, upgraded “glass” cockpit, and new interior. The 737 Next Generation comprises the four −600, −700, −800, and −900 models, with lengths ranging from 102 to 138 ft (31.09 to 42.06 m). Boeing Business Jet versions of the 737 Next Generation are also produced. The 737 was revised again in the 2010s for greater efficiency with the 737 MAX series featuring CFM International LEAP-1B engines and improved winglets. The 737 MAX entered service in 2017.

The 737 series is the best-selling jet commercial airliner in history. The 737 has been continuously manufactured by Boeing since 1967 with 9,571 aircraft delivered and 4,478 orders yet to be fulfilled as of June 2017. Assembly of the 737 is performed at the Boeing Renton Factory in Renton, Washington. Many 737s serve markets previously filled by 707, 727, 757, DC-9, and MD-80/MD-90 airliners, and the aircraft currently competes primarily with the Airbus A320 family. As of 2006, there were an average of 1,250 Boeing 737s airborne at any given time, with two departing or landing somewhere every five seconds.

The Boeing 777 is a family of long-range wide-body twin-engine jet airliners developed and manufactured by Boeing Commercial Airplanes. It is the world’s largest twinjet and has a typical seating capacity of 314 to 396 passengers, with a range of 5,240 to 8,555 nautical miles (9,704 to 15,844 km). Commonly referred to as the “Triple Seven”, its distinguishing features include the largest-diameter turbofan engines of any aircraft, six wheels on each main landing gear, fully circular fuselage cross-section, and a blade-shaped tail cone. Developed in consultation with eight major airlines, the 777 was designed to replace older wide-body airliners and bridge the capacity difference between Boeing’s 767 and 747. As Boeing’s first fly-by-wire airliner, it has computer-mediated controls. It was also the first commercial aircraft to be designed entirely with computer-aided design.

The 777 is produced in two fuselage lengths as of 2017. The original 777-200 variant entered commercial service in 1995, followed by the extended-range 777-200ER in 1997. The stretched 777-300, which is 33.25 ft (10.1 m) longer, followed in 1998. The initial 777-200, -200ER and -300 versions are equipped with General Electric GE90, Pratt & Whitney PW4000, or Rolls-Royce Trent 800 engines. The extended-range 777-300ER and ultra-long-range 777-200LR variants entered service in 2004 and 2006 respectively, while the 777F, a freighter version, debuted in February 2009; these variants all feature high-output GE90 engines and extended raked wingtips. The 777-200LR is the world’s longest-range airliner, able to fly more than halfway around the globe, and holds the record for the longest distance flown non-stop by a commercial aircraft.

The 777 first entered commercial service with United Airlines on June 7, 1995. It has received more orders than any other wide-body airliner; as of June 2017, 60 customers had placed orders for 1,935 aircraft of all variants, with 1,502 delivered. The most common and successful variant is the 777-300ERwith 743 delivered and 819 orders; Emirates operates the largest 777 fleet, with 157 passenger and freighter aircraft as of July 2016. The 777 has been involved in six hull losses as of October 2016; the Asiana Airlines Flight 214 accident in July 2013 was its first fatal crash in 18 years of service.

The 777 ranks as one of Boeing’s best-selling models. Airlines have acquired the type as a comparatively fuel-efficient alternative to other wide-body jets and have increasingly deployed the aircraft on long-haul transoceanic routes. Direct market competitors include the Airbus A330-300, the Airbus A350 XWB, and the out-of-production A340 and McDonnell Douglas MD-11. The 787 Dreamliner, which entered service in 2011, shares design features and a common type rating for pilots with the 777. In November 2013, Boeing announced the development of upgraded 777-8 and 777-9 variants, collectively named 777X, featuring composite wings and GE9X engines and further technologies developed for the 787. The new 777X series is planned to enter service by 2020.