GE tests AM demonstrator turboprop engine


General Electric has completed testing a 35%-additive manufactured (AM) demonstrator engine which is designed to validate additive parts in its clean-sheet-design Advanced Turboprop (ATP). The AM demonstrator engine will power the all-new 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).

The additive CT7-2E1 technology demonstrator engine, dubbed the ‘a-CT7’, was designed, built and tested in 18 months, reducing more than 900 subtractive manufactured parts down to 16 additive-manufactured parts.

The new ATP engine architecture is derived from the CT7, allowing for part commonality between the two additive test programs. The ATP will utilize more additive parts than any production engine in aviation history – 855 subtractive manufactured parts will be reduced to 12 additive parts, with AM components constituting 35% of the ATP’s total part count.

The 12 additive ATP parts include: sumps, bearing housings, frames, exhaust case, combustor liner, heat exchangers and stationary flowpath components. By comparison, the CFM LEAP engine includes one additive part category, the fuel nozzle tip.

The same team of eight engineers responsible for designing the CFM LEAP additive fuel nozzle tip led the design effort for the 16 additive parts tested in the a-CT7. GE is building more additive hardware for additional a-CT7 tests (which will include an even greater number of additive parts than the first a-CT7) in Lynn, Massachusetts. The additive components for a-CT7 and ATP tests are built at GE Aviation’s Additive Development Center (ADC) in Cincinnati, Ohio. GE expects to run its first full ATP engine test by the end of 2017.

An additional benefit to the ATP is an expedited engine certification schedule. GE recently completed ATP combustor rig tests six months ahead of schedule due to the faster part production speeds allowed by additive manufacturing. For example, the combustor liners were printed in merely two days.

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 1,000-1,600shp range.

November 9, 2016

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