Later testing involved the use of an exhaust turbine which was a half-scale version of that used in the Whittle W.1 turbojet, the first British jet engine to fly. Unlike a conventional turbocharger the turbine was coupled to the engine's accessory driveshaft and acted as a power recovery device. It was thought that using the turbine would lower fuel consumption allowing the engine to be used in larger transport aircraft. This was confirmed during testing, but failures due to severe overheating and drive shaft fractures were experienced.