AFOQT Practice Test

What is one primary characteristic of turbojet engines?

1. They utilize a variable pitch propeller

2. They accelerate air through the engine to produce thrust

3. They rely on reciprocating motion

4. They burn solid fuel

The correct answer is: They accelerate air through the engine to produce thrust

Turbojet engines are characterized primarily by their method of propulsion, which involves accelerating air through the engine to produce thrust. This process occurs through intake, compression, combustion, and exhaust stages. As air enters the engine, it is compressed and mixed with fuel, which is then ignited. The high-temperature, high-pressure exhaust gases are expelled at high speed, resulting in thrust according to Newton's third law of motion. This thrust is what propels the aircraft forward. The other choices refer to characteristics found in different types of engines or propulsion systems. For instance, the variable pitch propeller is associated with propeller-driven aircraft and is not applicable to turbojet engines. Similarly, relying on reciprocating motion is a characteristic of piston engines (such as those found in general aviation aircraft), which is distinct from the continuous flow of air in turbojet engines. Lastly, burning solid fuel is not a feature of turbojet engines; they typically use liquid fuels for combustion, which is again a fundamental aspect separating them from other propulsion systems.