Allison Engines recently acquired by Rolls-Royce, became a commercial turbofan manufacturer for the first time earlier this year, when the Indianapolis Company gained US Federal Aviation Administration certification, for its 33.5kN AE3007 engine.
The power plant is manufactured in two de-rated versions, for Cessna's Citation X business jet (28kN) and the Embraer EMB-145 regional jet (32kN).
In late January, Allison revealed details of a new variant of its 250 turbo-shaft for the Bell 407 helicopter. The -C47M is based on the -C40, which powers the recently launched Bell 430 helicopter. The -C47M's compressor includes a high-flow impeller, with a brush seal to reduce leakage, which increases airflow by 7%.
The turbine includes an air-cooled first-stage nozzle for operation at higher temperatures, improved first-stage turbine-blade clearance control, and optimised first- and third-stage turbine-nozzle flow areas.
Meanwhile, Polish manufacturer PZL-Swidnik has selected Allison's 250-C20R/2 turbo-shaft for its PZL-SW4 utility helicopter, now under development.
Source: Flight International
