Which engine module reduces the power turbine RPM and transfers power forward to the power output flange?

Which engine module reduces the power turbine RPM and transfers power forward to the power output flange?

• A. Reduction gearbox
• B. Accessory gearbox
• C. Fuel pump
• D. Hydraulic pump

Answer: (A)

The key idea is that to use the energy from the power turbine, the engine needs to deliver it at a usable speed. The power turbine spins extremely fast, so a reduction gearbox is placed in the drive path to lower the RPM while increasing the torque delivered to the external shaft. This gearbox takes the rotational energy from the power turbine and reduces its speed, with the output flange serving as the connection point to the load, such as a propeller or generator. The accessory gearbox, by contrast, is a separate unit driven from the engine to power things like the fuel pump and hydraulic pump; it isn’t meant to carry the main power take-off to the output flange. Fuel and hydraulic pumps are typical loads on that gearbox, not the primary power transfer to the output shaft.

The key idea is that to use the energy from the power turbine, the engine needs to deliver it at a usable speed. The power turbine spins extremely fast, so a reduction gearbox is placed in the drive path to lower the RPM while increasing the torque delivered to the external shaft. This gearbox takes the rotational energy from the power turbine and reduces its speed, with the output flange serving as the connection point to the load, such as a propeller or generator.

The accessory gearbox, by contrast, is a separate unit driven from the engine to power things like the fuel pump and hydraulic pump; it isn’t meant to carry the main power take-off to the output flange. Fuel and hydraulic pumps are typical loads on that gearbox, not the primary power transfer to the output shaft.