Boeing 737
The Boeing 737 is a narrow-body aircraft produced by Boeing at its Everett and Renton factories in Washington. Developed to supplement the Boeing 727 on short and thin routes, the twinjet retains the 707 fuselage width and six abreast seating but with two underwing turbofans instead of four. Envisioned in 1964, the initial 737-100 made its first flight in April 1967 and entered service in February 1968 with Lufthansa. The lengthened 737-200 entered service in April 1968, and evolved through four generations, offering several variants for 85 to 215 passengers.
The 737-100/200 original variants were powered by Pratt & Whitney JT8D low-bypass engines and offered seating for 85 to 130 passengers. Launched in 1980 and introduced in 1984, the 737 Classic -300/400/500 variants were upgraded with CFM56-3 turbofans and offered 110 to 168 seats. Introduced in 1997, the 737 Next Generation (NG) -600/700/800/900 variants have updated CFM56-7 turbofans, a larger wing and an upgraded glass cockpit, and seat 108 to 215 passengers. The latest generation, the 737 MAX, 737-7/8/9/10 MAX, powered by improved CFM LEAP-1B high bypass turbofans and accommodating 138 to 204 people, entered service in 2017. Boeing Business Jet versions have been produced since the 737NG, as well as military models.
As of October 2023, 16,159 Boeing 737s have been ordered and 11,569 delivered. Initially, its main competitor was the McDonnell Douglas DC-9, followed by its MD-80/MD-90 derivatives. In 2013, the global 737 fleet had completed more than 184 million flights over 264 million block hours since its entry into service. It was the highest-selling commercial aircraft until being surpassed by the competing Airbus A320 family in October 2019, but maintains the record in total deliveries. The 737 MAX, designed to compete with the A320neo, was grounded worldwide between March 2019 and November 2020 following two fatal crashes.
The initial concept featured podded engines 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. The engine nacelles 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. 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. 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.
At the time, Boeing was far behind its competitors; the SE 210 Caravelle had been in service since 1955, and the BAC One-Eleven (BAC-111), Douglas DC-9, and Fokker F28 were already into flight certification. 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.
Development: Boeing (USA)
Assembly: Renton (Washington, USA)
First flight: 1967
Production: 10,586
Crew: 2
Capacity: 85—215 seats
Engine: 2 × CFM56-3
Max speed: 876 km/h
Range: 4,176 km
Ceiling: 12,400 m
Weight: 32 t
Price: +89,500,000 $