Jet airliner

 ( Jet Airliners ) 

A jet airliner or jetliner is an airliner powered by (passenger jet aircraft). Airliners usually have twinjet or quadjet jet engines; trijet designs were popular in the 1970s but are less common today. Airliners are commonly classified as either the large wide-body aircraft, medium narrow-body aircraft and smaller regional jet.

Most airliners today are powered by jet engines, because they are capable of safely operating at high speeds and generate sufficient thrust to power large-capacity aircraft. The first jetliners, introduced in the 1950s, used the simpler turbojet engine; these were quickly supplanted by designs using , which are quieter and more fuel-efficient.

The early jet airliners had much lower interior levels of noise and vibration than contemporary piston-engined aircraft, so much so that in 1947, after piloting a jet powered aircraft for the first time, Wing Commander Maurice A. Smith, editor of Flight magazine, said, "Piloting a jet aircraft has confirmed one opinion I had formed after flying as a passenger in the Lancastrian jet test beds, that few, if any, having flown in a jet-propelled transport, will wish to revert to the noise, vibration and attendant fatigue of an airscrew-propelled piston-engined aircraft"

These first jet airliners were followed some years later by the Sud Aviation Caravelle from France, the Tupolev Tu-104 from the Soviet Union (2nd in service), and the Boeing 707, Douglas DC-8 and Convair 880 from the United States. National prestige was attached to developing prototypes and bringing these early designs into service. There was also a strong nationalism in purchasing policy, so that US Boeing and Douglas aircraft became closely associated with Pan Am, while BOAC ordered British Comets.

Pan Am and BOAC, with the help of advertising agencies and their strong nautical traditions of command hierarchy and chain of command (retained from their days of operating ), were quick to link the "speed of jets" with the safety and security of the "luxury of " in the General public's perception.

Aeroflot used Soviet , while Air France introduced French Caravelles. Commercial realities dictated exceptions, however, as few airlines could risk missing out on a superior product: American Airlines ordered the pioneering Comet (but later cancelled when the Comet ran into metal fatigue problems), Canadian, British and European airlines could not ignore the better operating economics of the Boeing 707 and the DC-8, while some American airlines ordered the Caravelle.

Boeing became the most successful of the early manufacturers. The KC-135 Stratotanker and military versions of the 707 remain operational, mostly as tankers or Freight aircraft. The basic configuration of the Boeing, Convair and Douglas aircraft jet airliner designs, with widely spaced podded engines underslung on pylons beneath a swept wing, proved to be the most common arrangement and was most easily compatible with the large-diameter high-bypass turbofan engines that subsequently prevailed for reasons of quietness and fuel efficiency.

The de Havilland and Tupolev designs had engines incorporated within the wings next to the fuselage, a concept that endured only within military designs while the Caravelle pioneered engines mounted either side of the rear fuselage.

15,591 Boeing 737s have been ordered and 11,395 delivered, and it remains the most produced jet aircraft.