The WR-21 is an advanced marine gas turbine designed to power the latest naval surface combatants of the partner nations (e.g the UK's Type 45 AAW Destroyer.) Developed under a US Navy contract, with support from the UK and France the WR-21 is designed and manufactured by an international consortium which includes Rolls-Royce and Northrop Grumman and DCN.

The WR-21 is the first aeroderivative gas turbine to incorporate compressor intercooling and exhaust heat recuperation (ICR) technologies that deliver low specific fuel consumption across the engines' operating range.

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

A reduction in fuel burn of 27% is predicted.

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

In its role of powering naval warships, it is a candidate to replace the current market leader, the General Electric LM2500, which, however, has been receiving periodic updates.

It is also 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 through-life cost reductions to operators.