ADDRESSING noise, emissions, and fuel efficiency

In an interview with Aerospace Engineering, Rolls-Royce Engineering Director Mike Howse explains the technical challenges and tradeoffs in jet-engine design and development. This is the last installment of a three-part series on aircraft engine design.

It has been more than 60 years since Ernst von Ohain's radical new aircraft-engine concept took the little Heinkel He 178 into the air to signal the start of the jet age. With the onset of World War II, the pressure on both the Allied and Axis sides to develop the technology mounted. By 1945, with German and British gas-turbine-powered fighters in service, it was clear that the jet engine was viable and would be the powerplant of the future-not only for military, but for civil applications, too. In 1949, the British de Havilland Comet, the world's first jet airliner, made its maiden flight. It entered airline service in 1952, operating between London and Johannesburg. Two years later came the aircraft that was to do more than any other to point the way toward mass travel by a jet airliner: the Boeing 707. It had been only 15 years since the He 178's first cautious flight.

Now, almost half a century after the start of commercial jet services, the pace of development of the gas-turbine aircraft engine shows little sign of reducing its momentum. In his first interview since being appointed Engineering Director of Rolls-Royce, Mike Howse said, “You do eventually get to the point where components reach the limit of their efficiency. So there is a plateau-but the aero engine industry is certainly not there yet. There are many developments and improvements that can, and will, take place. For example, Rolls-Royce has improved specific fuel consumption (SFC) by about 1% per year over the last 20 years and will continue to maintain improvement. By 2006 or 2007 we will see a decrease of about 10% compared to the SFC of engines we produced in the mid-1990s. I believe it will be possible to make further improvements of 10 to 15%.”