This paper covers the problems met with in pod design and installation of the three-shaft, high by-pass ratio turbofan engines RB.207 and RB.211.
The three-quarter length cowl configuration was chosen for the nacelle since this arrangement gave the best all-round performance particularly when considering low noise levels. The accessory gearbox was fan mounted rather than on the core of the engine as this resulted in greater reliability and ease of access. New concepts in engine mounting design were evolved to conserve space and reduce fan duct blockage to a minimum.
The pod comprises the air intake, bolted directly on to the engine, behind which are a series of hinged, detachable alloy panels, together with the fan reverser shrouds. Behind these the rest of the pod comprises assemblies carried directly from the core engine.
Reverse thrust in the engine is achieved by a combination of fan reverser and pivoted spoilers at the rear of the engine. Engine noise is significantly reduced by a variable nozzle arrangement in the jet pipe at the rear of the engine.
Maintenance is facilitated, in addition to the detachable panels, by the accessibility of thermocouples, borescope holes burners and igniter plugs.