Should Airbus and Boeing put upgraded engines on their single-aisle airliners while waiting for the crop of next-gen turbofans with their promise of much better fuel, emissions and noise numbers?

Robert Nuttal, Rolls-Royce head of strategic marketing, thinks not. “The numbers do not stack up” for re-engining either the Airbus A320 or Boeing 737, he told AIN at the Farnborough airshow. “First, we don’t think re-engining offers any significant net financial benefit to the industry. Second, at the manufacturing level the program will be only half as long as a new engine program, so the returns are far less. And third,” he said, “if re-engining occurs, it delays an all-new aircraft, which will bring real benefits in terms of fuel economy and emissions.”

Nuttal said offering all-new engines for new airframes has been Rolls-Royce’s philosophy all along. “We believe in the relentless pursuit of advanced technology to bring new engines to market.” With the potential to deliver at least 10-percent lower fuel burn than any advanced turbofan under consideration, the open-rotor design is the only “game-changing” technology around, he said. This puts the UK company fundamentally at odds with Pratt & Whitney, which told AIN developments of its PW1000G engine will have fuel economy similar to that of an open rotor.

Nuttal said the four open-rotor rig tests carried out by Rolls-Royce to date showed that the concept will comfortably meet Stage 4 noise requirements and produce a 30-percent fuel saving over today’s engines. “We’ve cracked the physics. Now it’s an engineering problem,” he concluded.