Rolls Royce Nene Jet Engine

Second generation centrifugal flow turbo-jet engine. This engine has nine combustion chambers, and a single stage centrifugal compressor with a double sided impeller. The compresser is directly coupled to a single stage axial turbine, with the main rotating assembly being carried on three bearings. Air is drawn into the compressor through both front and rear intakes and is accelerated and compressed through the impeller and a diffuser vane ring to be delivered to the combustion chambers. There it is mixed with fuel, the gases are ignited and flow rapidly rearwards to the nozzle guide vanes. The turbine extracts some of the energy from the gases to drive the compresser and decreases the gas velocity. The reduced exit area of the propelling nozzle again accelerates the exhaust gases to an extremely high speed to produce the propulsive jet.

The prototype Nene engine was designed and built in six months in 1944. It produced 5000 lb thrust for a weight of 1580 lb.

This was a massive step improvement from the early model Welland engine of 1600 lb thrust and the Derwent Mark 1 engine of 2000 lb thrust. At the time of its development, however, there were no suitable airframes capable of taking the engine. Subsequent developments of the Nene, the first of which was renamed as the Derwent Mark 5, saw it reduced in size and able to be accomodated in the nacelles of Gloster Meteor fighters. The unchanged Nene was subsequently fitted to a number of foreign airframes, and later also powered the RAAF's Vampire jet fighters.

As with all Rolls Royce turbojets, it was named after a British river, echoing the idea of continuous flow.