Jet airliner

A jet airliner, sometimes contracted to jetliner, is a passenger airplane (passenger aeroplane) that is powered by jet engines.

In contrast to today's long-distance quiet, fuel-efficient, and modern turbofan powered air travel, first generation jet airliner travel was noisy and fuel inefficient. These inefficiencies were addressed by the jetprop, also known as the turboprop.

Although the fleets of many modern airlines may include a number of smaller but just as modern turboprop and seemingly ancient propeller propelled and reciprocating piston driven types, these appearances can be deceiving. These types of gas turbine, propjet airliners are just as modern as turbofan driven aircraft, and are typically used for shorter flights to provincial towns, island communities, or airports where topography or adjoining development limits the runway length.

Introduction and early history

The first airliners with turbojet propulsion were experimental conversions of the Avro Lancastrian piston engined airliner, which were flown with several types of early jet engine, including the de Havilland Ghost and the Rolls-Royce Nene, however these retained the two inboard piston engines, the jets being housed in the outboard nacelles and these aircraft were therefore of 'mixed' propulsion. The first airliner with full jet power was the Nene-powered Vickers VC.1 Viking "G-AJPH", which first flew on the 6 April 1948.

First commercially successful jet airliner

The first purpose-built jet airliner was the de Havilland Comet which first flew in 1949 and entered service in 1952. Also developed in 1949 was the Avro Jetliner, and although it never reached production, the term jetliner caught on as a generic term for all passenger jet aircraft.

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

These two airlines with strong nautical traditions of command hierarchy rank and chain of command, retained from their days of operations with flying boats, undoubtably were quick to capitalize upon, with the help of advertising agencies, the linkings of the "speed of jets" with the safety and secure "luxury of ocean liners" among public perception.

Aeroflot used Russian Tupolevs, 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 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 freighters. The basic configuration of the Boeing, Convair and Douglas aircraft jet airliner designs, with widely spaced podded engines under slung 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.

econd generation jet airliner developments

In the 1960s, when jet airliners were powered by slim, low-bypass engines, many aircraft used the rear-engined, T-tail configuration, such as the BAC One-Eleven, Douglas DC-9 twinjets ; Boeing 727, Hawker Siddeley Trident, Tupolev Tu-154 trijets; and the paired multi-engined Ilyushin Il-62, and Vickers VC-10 whose engines were mounted upon the aft fuselage. This engine arrangement survives into the 21st century on numerous twin engined Douglas DC-9 derivatives plus newer short haul and range regional aircraft "jet airliners" built by Bombardier, Embraer and, until recently, Fokker. However other "jetliner" developments, such as the concept of rocket assisted takeoffs RATO, and the briefly mentioned water-injection as used and tested upon first generation passenger jets, as well as trailing edge mounted powerplants, afterburners also known as reheat used upon supersonic jetliners SSTs such as the Concorde and Tupolev Tu-144, likewise have been relegated to the past.

For business jets, the rear-engined universal configuration pioneered by the turbojet powered early Learjet 23, North American Sabreliner , and Lockheed JetStar is common practice on smaller bizjet aircraft as the wing is too close to the ground to accommodate underslung engines. This is as opposed to early generation jet airliners, whose design engineers slung jet engines on the rear to increase wing lift performance and at the same time reduce cabin noise of the lower bypass "turbojet" engines.

Present day jet airliners

Airliners descriptions are commonly broken down into the distinction of "jumbo" and,"wide-body" jets, "narrow-body" jets, and "regional jets" with the terms "jets" and "liners" dropped from all but the "regional" and "jumbo jets."

ee also

* Airliner
* Aviation
* Business jet
* Freight aircraft
* Jet aircraft