Early jet airliners, such as the Boeing 707, were able to offer competitive operating costs and range, firstly because they were much larger than existing piston engine airliners and secondly, because the wing design and engine sizing were not compromised to allow operations from existing runways.

Different concepts of engine location. By the mid-1950s, three different engine layouts had flown, of which only two are now in current production. Sud Aviation set the trend in rear engine design with the world's first short-haul jet, the Caravelle, which entered service with Air France in May 1959.

Among the advantages of pod-mounted engines, such as those of the DC-8, are: high intake efficiency with least adverse effect at high angles of attack, fuel lines to engines do not pass through fuselage and there is more freedom for engine position (without the concern for CG position associated with fuselage-mounted engines).

Over 30 years separate the design of the Douglas DC-8 and the Airbus A340, but similarities endure. This figure, scaled for equal wing spans, shows some differences. For example, the A340 has lower wing sweep and its engine locations are different. Of course, the A340 shares a broadly common wing with the A330 twin which, for reasons of engine-out minimum control speed, requires its two engines to be located more inboard than optimum for a four engine design. In compensation to gain structural inertia relief, the A340’s outboard engines are about as far outboard as possible, consistent with flutter requirements, and required an increase in fin area.

When the Ilyushin Il-62 was first seen in the West, it was thought that the rear-engine configuration had been chosen simply because Russia did not have the wind tunnel data and the engineering sophistication to hang them from the wings.

Noise considerations. In promoting its VC10’s rear-engine configuration, Vickers Armstrong used the argument that not only was the aircraft’s tailplane well clear of wing downwash (at low AoA) but that the noise damage to it was reduced, compared with wing-mounted engines. That was until ‘screech’ (a noise component at 90° to an exhaust jet full of shock-waves) was discovered. That said, the proportion of airframe surface, in particular the passenger cabin, is greatly reduced. Moreover, the forward projected noise from rear-mounted engines can be blanked by the wing.

Two of the first turbine-powered civil aircraft to enter widespread service were the Viscount and Vanguard (foreground), seen here at London’s Heathrow Airport c.1964.

Although the Bristol Aero Engines Proteus was troublesome in its early stages, it settled down after intensive development and operated successfully in the Bristol Britannia with an overhaul life of 7,500hr.

Stretching rear-engine aircraft. As engines get bulkier and heavier, configuration problems become more difficult. This is particularly true when the engines are located long distances from the aircraft's centre of gravity. The forebody must be lengthened relative to the aftbody to balance the added weight at the back and, as a consequence, the spread between the centre of gravity at full payload and the centre of gravity of the empty aircraft increases rapidly. Nevertheless, Douglas found with its DC-9, even in its earliest days, that it could be stretched by 28% in length (DC-9-10 to DC-9-50) to carry 54% more passengers over increased range.