Which rotor configuration best describes the engine?

• A. Dual rotor, single high bypass
• B. Twin rotor, low bypass
• C. Single rotor, high bypass
• D. Triple rotor, bypassed

Answer: (A)

Two rotors on separate shafts with a large bypass flow describe the engine configuration you’ll see on modern commercial turbofans. This means there’s a low‑pressure spool driving the fan and booster, and a high‑pressure spool driving the core compressor and turbine. Having two independent spools lets each part run at its own optimal speed, boosting efficiency and throttle responsiveness across different flight conditions. A high bypass ratio means most of the air bypasses the core, which improves propulsive efficiency, reduces fuel burn, and lowers noise. This combination—two spools with a high bypass flow—is the standard for contemporary turbofan engines, making it the best description of the engine configuration. The other options imply configurations that aren’t typical for modern jets, such as fewer or more spools or a low bypass path.