The term Maximum Engine Overtorque applies to which engine types?

The term Maximum Engine Overtorque applies to which engine types?

• A. Turbopropeller and turboshaft engines incorporating free power turbines
• B. Piston engines
• C. Turbojet engines without free power turbines
• D. Electric propulsion systems

Answer: (A)

Maximum engine overt torque is a short-duration torque limit that applies to turboprop and turboshaft engines that use a free power turbine. In these engines, the power turbine that drives the output (propeller or shaft) is not directly coupled to the gas generator. Because of this decoupling, the turbine can respond differently to sudden throttle changes or load surges, potentially producing a momentary overload on the drivetrain. The overtorque limit exists to protect the reduction gears and turbine components during those transient conditions. Piston engines and turbojets without a free power turbine don’t have this separate transient-torque limit because their power delivery and drivetrain dynamics differ; electric propulsion also uses a different control approach. So the specific term and limit are used for turbopropeller and turboshaft engines with a free power turbine.

Maximum engine overt torque is a short-duration torque limit that applies to turboprop and turboshaft engines that use a free power turbine. In these engines, the power turbine that drives the output (propeller or shaft) is not directly coupled to the gas generator. Because of this decoupling, the turbine can respond differently to sudden throttle changes or load surges, potentially producing a momentary overload on the drivetrain. The overtorque limit exists to protect the reduction gears and turbine components during those transient conditions.

Piston engines and turbojets without a free power turbine don’t have this separate transient-torque limit because their power delivery and drivetrain dynamics differ; electric propulsion also uses a different control approach. So the specific term and limit are used for turbopropeller and turboshaft engines with a free power turbine.