In a turboshaft engine, what percentage of energy is absorbed by the turbine wheel to turn the propeller?

In a turboshaft engine, a significant portion of the energy generated in the engine is used by the turbine wheel to produce a mechanical output, such as turning a propeller or driving an accessory. The correct response indicates that up to 80% of the energy can be harnessed by the turbine wheel for this purpose.

This efficiency level can be attributed to the design and function of turboshaft engines, which are optimized to convert thermal energy from combustion into mechanical energy. Turboshaft engines primarily focus on maximizing the usable energy output for propulsion rather than speed, which is the focus in a turbojet. Therefore, they can operate with greater thermal efficiency and better energy transfer to the turbine.

In contrast, lower percentages such as 20%, 50%, or 70% would not accurately reflect the capabilities of a well-designed turboshaft engine. These figures could correspond to other engine types, or they simply underestimate the turbine's capacity to convert engine-generated energy into work effectively. Thus, the best representation of a turboshaft engine's performance is that it absorbs up to 80% of the energy produced.