Boeing and Rolls-Royce will conduct the next phase of Quiet Technology Demonstrator (QTD) tests in the second quarter, after which Boeing will start looking for applications. QTD is part of wider environmental technology programmes being conducted by the manufacturer, which account for a $20-30 million annual investment, says Billy Glover, director environmental performance strategy.

QTD has been testing a "cookie cutter" installation on the exhaust nozzles and a new engine inlet on a Trent 800-powered Boeing 777-200ER. The "cookie cutter" or chevron feature reduces jet noise, particularly low-frequency noise, by mixing ambient air with the jet flow, while the engine inlet provides 30% more acoustic absorbing area.

The first application for the new inlet will probably be on the 777 within two years, while the chevron exhaust is expected to be in service within five years.

Meanwhile, Boeing was expecting proposals last week from companies seeking to participate in an electric aircraft demonstration programme, investigating environmentally friendly fuel cell technology.

Boeing intends to develop a demonstrator based on a motorised glider, replacing the engine with a fuel cell system powered by a hydrogen-based fuel. First flight is set for 2003.

The goal is to replace a gas turbine auxiliary power unit with fuel cells. Glover concedes that this is 10 to 15 years away, but fuel cell technology could eventually be used to power any onboard electrical system.

Glover says a hydrogen-based fuel cell system would provide increased flexibility, would be quieter on the ground, more efficient, provide fuel savings and produce lower emissions. The downside is increased weight, however.

Source: Flight International