GE Aviation has successfully tested F414 turbofan demonstrator engine’s rotating low-pressure turbine blades that were made up of light-weight, ceramic matrix composite (CMC) components.
The test was undertaken at an undisclosed location. It was designed to further validate the heat-resistant material for high-stress operation in the company’s next-generation adaptive engine technology demonstrator (AETD) programme, currently in development with the US Air Force Research Laboratory.
The F414 CMC test comprised 500 gruelling cycles. It validated the temperature and durability capabilities of turbine blades made from heat-resistant CMCs, which resulted in record-breaking temperature and fuel burn achievements.
GE Aviation Advanced Combat Engine programme general manager Dan McCormick said: "One of the key challenges in transitioning CMC to rotating components from static components is the stress field in which they must live.
"The progression of F414 CMC testing has provided key learnings in making this transition happen for our adaptive cycle engine.
"The CMC low-pressure turbine blade is about one-third the weight of the metal blade it replaces, and at the second stage, the CMC doesn’t have to be air-cooled."
GE Aviation advanced polymer matrix composite research and CMC general manager Jonathan Blank said: "By reducing the need for cooling components, our engine becomes aerodynamically more efficient and also more fuel efficient."
The CMC is made of silicon carbide ceramic fibres and ceramic resin, and are manufactured by GE facilities in Delaware and North Carolina, US. It reduces the weight of rotating turbine blades compared to the high-stress turbine, which will enable GE to reduce the size and weight of the metal disks to which the CMCs system is connected.
GE’s adaptive cycle engine is expected to feature both static and rotating CMCs. It will have more durability than traditional engines as CMC’s material temperature capability is hundreds of degrees higher than nickel-based alloys currently in service in commercial and military engines.
The AETD programme will build on such enhanced propulsion capabilities to deliver a 25% reduction in specific fuel consumption, as well as more than 30% improvement in range and 10% higher maximum thrust compared to existing advanced fifth-generation aircraft.
GE tested the world’s only adaptive three-stream technology demonstrator, called the adaptive versatile engine technology (ADVENT) engine in 2014.
The ADVENT programme aims to develop an efficient variable cycle engine in the 20,000lbf thrust class beyond 2020, to provide a next-generation military aircraft with greater range and mission flexibility, as well as enhanced thermal management capabilities.