What split does a turboprop engine allocate between propeller thrust and exhaust thrust?

• A. 50% propeller, 50% exhaust
• B. 60% propeller, 40% exhaust
• C. 10% propeller, 90% exhaust
• D. 90% propeller, 10% exhaust

Answer: (D)

In a turboprop, the majority of thrust comes from the propeller. The gas turbine drives the propeller to accelerate a large mass of air, which produces thrust efficiently at typical turboprop operating speeds. The exhaust from the engine does contribute some thrust, but it’s a smaller portion, since the energy remaining in the exhaust after driving the propeller is less effective at producing forward push. As a rule of thumb, the propeller accounts for about 90% of thrust, with roughly 10% coming from the exhaust jet. This split can vary with design and operating conditions, but the key idea is that the propeller dominates propulsion in a turboprop.