GE tests advanced turboprop engine
GE Aviation has completed testing a 35% additive manufactured demonstrator engine to validate 12 additive parts in its Advanced Turboprop (ATP) engine. Once certificated the engine will power the Cessna Denali single-engine turboprop aircraft.
Additive components reduce the ATP’s weight by 5% while contributing a 1% improvement in specific fuel consumption (SFC).
An additive CT7 technology demonstrator engine, dubbed the “a-CT7,” was designed, built and tested in 18 months, reducing more than 900 conventionally manufactured parts to 16 additive manufactured parts. The ATP engine architecture is derived from the in-service CT7 engine, allowing for additive part commonality between the two engine programs.
The ATP will include more printed components than any production engine in aviation history with 35% of the turboprop’s parts built via additive manufacturing. 855 conventionally manufactured parts will be reduced to 12 additive parts on the ATP, including: sumps, bearing housings, frames, exhaust case, combustor liner, heat exchangers and stationary flowpath components.
In the coming months, GE will run a second a-CT7 test with even more additive parts to expand the technology to additional structures and assemblies. The additive components for a-CT7 and ATP tests are built at GE Aviation’s Additive Development Centre (ADC) in Cincinnati, Ohio.
The a-CT7 tests are conducted at GE Aviation’s facility in Lynn, Massachusetts. GE expects to run its first full ATP engine test by the end of 2017 in Europe.
Additive manufacturing (also called 3D printing) involves taking digital designs from computer aided design (CAD) software, and laying horizontal cross-sections to manufacture the part. Additive components are typically lighter and more durable than traditionally-manufactured parts because they require less welding and machining. Additive manufacturing allows GE to build parts at lower weight with better performance and durability.
“With subtractive manufactured parts and assemblies, you traditionally use bolts, welds or other interfaces to attach the parts together, which adds weight to the engine. On the ATP, additive reduces weight by eliminating those attaching features while also optimizing design of the parts.”
Gordon Follin, ATP Engineering GM at GE Aviation said: “With subtractive manufactured parts and assemblies, you traditionally use bolts, welds or other interfaces to attach the parts together, which adds weight to the engine. On the ATP, additive reduces weight by eliminating those attaching features while also optimizing design of the parts.”
Because additive parts are essentially “grown” from the ground up, they generate far less scrap material. Freed of traditional manufacturing restrictions, additive manufacturing dramatically expands the design possibilities for engineers.
“A huge benefit of additive is expedited test schedules,” said Follin. “For a program like ATP, one of our big philosophical points of emphasis is getting hardware to test faster instead of spending too much time with models on a computer. By putting real hardware on test as quickly as we can, we can use the resultant data to help us design the next iteration for a better product, and we get that product much faster than if we were to use conventional manufacturing methods.”
GE has invested approximately $1.5 billion in manufacturing and additive technologies since 2010.
The new 1,240SHP-rated ATP is the first entry in GE’s new family of turboprop engines aimed at business and general aviation aircraft in the 1,000-1,600 SHP range.
