Which component ultimately drives the N2 compressor?

Which component ultimately drives the N2 compressor?

• A. The high pressure turbine
• B. The low pressure turbine
• C. The FADEC
• D. The accessory gear box

Answer: (A)

In a two-spool turbofan, the N2 compressor is the high‑pressure compressor and is driven by the high‑pressure turbine on the same high‑pressure shaft. The hot gases expanding through the high‑pressure turbine transfer energy to spin the turbine, and that rotation is transmitted to the N2 compressor, keeping the high‑pressure flow moving. The low‑pressure turbine, by contrast, powers the N1 (low‑pressure) compressor. The FADEC controls engine operation, not the mechanical drive, and the accessory gearbox is driven by the high‑pressure spool to provide accessories, but it’s not the direct source that drives the N2 compressor.

In a two-spool turbofan, the N2 compressor is the high‑pressure compressor and is driven by the high‑pressure turbine on the same high‑pressure shaft. The hot gases expanding through the high‑pressure turbine transfer energy to spin the turbine, and that rotation is transmitted to the N2 compressor, keeping the high‑pressure flow moving. The low‑pressure turbine, by contrast, powers the N1 (low‑pressure) compressor. The FADEC controls engine operation, not the mechanical drive, and the accessory gearbox is driven by the high‑pressure spool to provide accessories, but it’s not the direct source that drives the N2 compressor.