In a turboprop engine, the total dynamic power delivered to the propeller is best described as

• A. SHP
• B. Propeller power
• C. ESHP
• D. BHP

Answer: (C)

In a turboprop, the energy from the engine ends up as mechanical power at the propeller shaft, but the actual propulsion effect is the power the propeller puts into the air (thrust power). To express that propulsion effect in the same horsepower units used for the engine shaft, we use Equivalent Shaft Horsepower. ESHP converts the propeller’s dynamic power into a shaft-horsepower-like value, accounting for the propeller’s efficiency and the way power is delivered through the gearbox. That makes ESHP the best descriptor for the total dynamic power delivered to the propeller, because it ties the actual propulsion effect to a familiar horsepower metric.

SHP and BHP refer to other ways of measuring power at the engine or shaft but don’t directly represent the propulsion power delivered to the air. “Propeller power” is a descriptive term for the power going into the propeller, but ESHP specifically expresses that dynamic power in equivalent shaft horsepower, which is the standard way to compare propulsion contributions.