Which statement describes the PW127 engine compressor arrangement?

Which statement describes the PW127 engine compressor arrangement?

• A. It uses a 2-spool, free-turbine compressor with reverse flow
• B. It uses a 1-spool, fixed-turbine compressor
• C. It uses a 3-spool, free-turbine compressor
• D. It uses a 2-spool, fixed-turbine compressor

Answer: (A)

The PW127 uses a two-spool arrangement with a free-turbine driving the propeller and a reverse-flow core. That means there are two concentric shafts for the compressor stages (low-pressure and high-pressure spools), and the turbine that powers the propeller is not fixed to the same shaft as the compressor—it's a separate, free turbine connected to the reduction gearbox. The reverse-flow design shortens the engine length by routing the air path in a back-and-forth fashion inside the core. This combination fits turboprop practice: two spools for efficient operation, a power turbine (free-turbine) to drive the propeller, and a compact, reverse-flow core to save space. The other options would imply a single-spool or fixed-turbine layout, or a three-spool arrangement, which does not match how the PW127 is built.

The PW127 uses a two-spool arrangement with a free-turbine driving the propeller and a reverse-flow core. That means there are two concentric shafts for the compressor stages (low-pressure and high-pressure spools), and the turbine that powers the propeller is not fixed to the same shaft as the compressor—it's a separate, free turbine connected to the reduction gearbox. The reverse-flow design shortens the engine length by routing the air path in a back-and-forth fashion inside the core.

This combination fits turboprop practice: two spools for efficient operation, a power turbine (free-turbine) to drive the propeller, and a compact, reverse-flow core to save space. The other options would imply a single-spool or fixed-turbine layout, or a three-spool arrangement, which does not match how the PW127 is built.