What type of propulsion system uses jet fuel?

• A. Piston engines
• B. Turboshaft engines
• C. Turbojet and turbofan engines
• D. Electric engines

Answer: (C)

Turbojet and turbofan engines are specific types of gas turbine engines that utilize jet fuel as their primary source of energy. Jet fuel, such as Jet A or JP-8, is designed to provide efficient combustion at high temperatures and pressures, which is essential for the operation of these engines.

Turbojet engines work by drawing in air, compressing it, mixing it with fuel, and igniting the mixture to produce thrust. Similarly, turbofan engines also utilize jet fuel, but they have a large fan at the front that provides additional thrust by bypassing some of the air around the engine core. This results in greater efficiency and reduced noise.

Piston engines generally operate using aviation gasoline (AvGas) rather than jet fuel. Turboshaft engines, while related to turbojet and turbofan engines, are primarily used for helicopter propulsion and can sometimes use jet fuel, but they are not as commonly referred to in the context of propulsion systems that predominantly use jet fuel for fixed-wing aircraft. Electric engines operate on batteries and do not use jet fuel at all. Thus, turbojet and turbofan engines are clearly the correct answers as they directly relate to the use of jet fuel for propulsion.