The Rolls-Royce RB.37 Derwent is a 1940s British centrifugal compressor turbojet engine, the second Rolls-Royce jet engine to enter production. Essentially an improved version of the Rolls-Royce Welland, itself a renamed version of Frank Whittle's Power Jets W.2B, Rolls inherited the Derwent design from Rover when they took over their jet engine development in 1943. Performance over the Welland was somewhat improved, reliability dramatically, making the Derwent the chosen engine for the Gloster Meteor and many other post-World War II British jet designs.