Which engine type is best at high speeds like fighter jets?

• A. Turboprop
• B. Turbojet
• C. Turbofan
• D. Accessory section

Answer: (B)

At the highest flight speeds, the propulsion goal is to maximize thrust without carrying a lot of heavy bypass air. A turbojet achieves this by pushing most of the combustion gases directly out the exhaust with little to no bypass flow, giving high specific thrust and strong performance at high Mach numbers. That high jet velocity makes turbojets well suited for interceptors and fighters that need rapid acceleration and top-end speed.

Turboprops are built around a propeller, so their efficiency drops as speed climbs because propeller drag and tip speeds become limiting factors; they’re ideal for slower, fuel-efficient flight, not maximal speed. Turbofans prioritize fuel efficiency and smoothness by using a large amount of bypass air, which makes them excellent for subsonic airliners and general aviation but reduces the maximum achievable speed due to the heavier, slower exhaust. The accessory section isn’t a propulsion type at all and doesn’t produce thrust.

So for high-speed, fighter-jet-like performance, the turbojet stands out because of its high thrust-to-weight and high exhaust velocity at speed.