Rolls-Royce WR-21

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The WR-21 powers Royal Navy Type 45 destroyers.

The Rolls-Royce WR-21 is an advanced marine gas turbine engine, designed with a view to powering the latest naval surface combatants of the partner nations, and currently fitted to the Type 45 destroyer of the Royal Navy. Developed with some government funding input from the UK, France and the United States, the WR-21 was designed and manufactured by an international consortium primed by Northrop Grumman. The turbine itself was designed primarily by Rolls-Royce with significant marine engineering and test facility input from DCN.[1]


The WR-21 is the first aeroderivative gas turbine to incorporate Gas compressor intercooler and Exhaust heat recovery system (ICR) technologies that deliver low specific fuel consumption across the engine's operating range.[2] It offers a reduction in fuel burn of 30% across the typical ship operating profile.[3]

  • The intercooler cools air entering the high pressure compressor, reducing the amount of energy required to compress the air.[2]
  • The recuperator preheats the combustion air by recovering Waste-to-energy from the exhaust, improving cycle efficiency and reducing fuel consumption.[2]

WR-21 development draws heavily on the technology of the successful Rolls-Royce RB211 and Trent families of gas turbines.[2]


It is a candidate power plant for propulsion of cruise ships and other large commercial vessels, where fuel efficiency and its small size mean improved operational flexibility and significant lifetime cost reductions to operators.

The only current use of the WR-21 is in the Type 45 destroyer.


  • Rated power: 25.2 MW
  • Specific fuel consumption: ~190 g/kWh
  • Main module wet weight: 45974 kg
  • Twin-spool design + free rotating power Turbine
  • Six-stage IP compressor
  • Intercooler
  • Six-stage HP compressor
  • Exhaust heat recuperator
  • Nine radial combustors
  • Single-stage HP turbine: 8,100 rpm (135 Hz)
  • Single-stage IP turbine 6,200 rpm (103.33 Hz)
  • Five-stage power turbine 3,600 rpm (60 Hz)


  1. ^ "WR-21 gamble pays off". Jane's Navy International. 2000. Retrieved 2009-11-16. 
  2. ^ a b c d "WR-21 Marine gas turbine". Rolls-Royce plc. Retrieved 2009-11-16. 
  3. ^ "WR-21 engine selected for Royal Navy type 45 destroyers". Retrieved 2009-11-16. 

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