PW901A
The two-shaft PW901A is fitted as standard to the Boeing 747-400, and is now Pratt & Whitney Canada's (P&WC)only APU product. A development of this model is expected to be offered for the new-generation airliners being planned by Airbus and Boeing, the A3XX and 747-500/600X respectively. This variant may include single-crystal turbine-blade technology, and feature a redesigned compressor. The company is, however, reluctant to make substantial changes that could compromise the PW901A's high reliability rates.
The unit's high-pressure spool consists of a single-stage centrifugal compressor and annular combustion chamber, driving a single-stage high-pressure turbine.
The low-pressure spool consists of a single-stage power turbine, driving an inlet guide vane-modulated single-stage centrifugal compressor, and a load gearbox. There are also drives for two generators and a cooling fan.
Source: Flight International
