DE HAVILLAND DH.106 COMET

The Comet was world's first commercial airliner powered by jet engines. Designed by a team led by Ronald Bishop (of Mosquito fame), it first flew on 27 July 1949 and began its service in 1952. The plane was powered by four engines buried in wings near the wing roots, a solution dropped in subsequent jet airliner designs in favor of external engine nacelles attached under wings due to easier maintenance and security reasons.

Jet propulsion made the Comet unrivalled in terms of flight comfort, significantly reducing noise and vibration that plagued passengers of piston-engined aircraft. The prospects seemed promising and former reservations about jet airliners were dropped, as De Havilland was approached by several airlines that intended to purchase the aircraft.

However, the Comet was soon to face dire problems. In 1952 a Comet crashed at takeoff, followed by another accident in 1953. Also in 1953 and in the followig year two Comets fell to the ground for no obvious reasons. Subsequent examination determined metal fatigue to be the main cause of disasters. Because of unprecedented operating speeds and cabin pressurization, the fuselage design employed new materials and construction features. Some of the alloys used were discovered to be prone to metal fatigue, resulting in disintegration of several planes in mid-air.

The design was improved to answer the problems and afterwards the Comet flew passengers until 1981, although it was quickly outclassed by newer designs.

Specifications (Comet 1)

wingspan: 115 ft (35 m)
length: 93 ft (28 m)
max. takeoff weight: 110,000 lb (50,000 kg)
cruising speed: 740 km/h (400 kn; 460 mph)
cruise altitude: 42,000 ft (13,000 m)
range: 1,500 mi (1,300 nmi; 2,400 km)
powerplant: four de Havilland Ghost 50 Mk1 turbojets, 5,050 lbf (22.5 kN)