Aircraft

In the next six to 12 months the US Air Force Research Laboratory is to establish the goals for its proposed AD-HEETE project, a follow-on from its ongoing Highly Efficient Embedded Turbine Engine (HEETE) and Adaptive Versatile Engine Technology (Advent) research studies.

A 2017 engine demonstration is one target for AD-HEETE that will merge the adaptive and high-performance core technologies from its predecessor studies. The 2017 engine will use "second generation" adaptive technology that the AFRL wants to enable precise control of air temperature and its delivery to different parts of the engine.

Thermal management systems are another target as the heat at maximum thrust during take-off is known to play a major part in reducing the life of an engine, despite the fact that aircraft spend up to 90% of their operational time at cruise, when lower engine temperatures translate to relatively little ageing of the powerplant.

"We want an adaptive engine that reduces the temperature at thrust for take-off," AFRL propulsion directorate turbine division chief engineer Jeff Stricker told at the American Institute of Aeronautics and Astronautics' 44th Joint Propulsion Conference in Hartford, Connecticut on 21 July.

Another technology goal is expected to be the move from the use of nickel in the engine core components to intermetallics, which are combinations of metals that have radically different crystalline structures to their constituent materials.

General Electric and Rolls-Royce were selected for HEETE and Advent. HEETE is for engines in the 20,000-35,000lb thrust class (89-156kN) and Advent will see a demonstration engine in 2012.