Among the listed engine components, which one is a gearbox rather than a turbine?

• A. Axial Compressor
• B. Gas Generator
• C. Power Turbine
• D. Reduction Gearbox

Answer: (D)

The important idea is how power is transmitted versus how it’s produced. A turbine turns hot gas energy into mechanical power, spinning a shaft at very high speed to drive a load. A gearbox, by contrast, is not about producing power; it changes the speed and torque of that shaft to suit the load it drives. In many engines, the turbine’s high-speed output is too fast for a generator or propeller, so a reduction gearbox is used to lower the speed and increase torque, making the power usable. Among the options, the one whose primary role is to transmit power with speed reduction is the Reduction Gearbox. The other components are a compressor, the core gas generator, and a turbine, none of which function as gear systems.