Left wing engine nacelles on Avro Shackleton MR.3 XF708, viewed from behind. This shows the outer (i.e. on left) engine nacelle with exhaust opening for auxiliary Armstrong Siddeley Viper turbojet, housed behind the Rolls-Royce Griffon piston engine. Compare to the inboard (i.e. on right) nacelle which does not carry the Viper.