FAA Powerplant Written Practice Test

What effect does a carburetor air scoop have on incoming air?

1. It decreases the air temperature

2. It filters the air

3. It increases the pressure on the incoming air by ram effect

4. It removes moisture from the air

The correct answer is: It increases the pressure on the incoming air by ram effect

A carburetor air scoop serves a specific purpose in directing air into the carburetor for the purpose of mixing with fuel before entering the engine. The correct answer highlights that the air scoop increases the pressure on the incoming air due to the ram effect. When the aircraft is in motion, the design of the scoop captures air more efficiently, allowing for a greater volume of air to enter the carburetor. As the aircraft moves forward, the air pressure is effectively increased because the scoop acts like a funnel, directing the oncoming airflow into a tighter space. This phenomenon can lead to more air being available for combustion, enhancing engine performance, especially under high-speed conditions. While a scoop may aid in filtering out some debris, its primary purpose is not air filtration, making that option less relevant. Similarly, the ability to cool or remove moisture from incoming air does not directly stem from the function of a carburetor air scoop, and therefore, those options do not accurately describe the primary effect of the scoop on airflow. The ram effect created by the design of the scoop itself is the key reason why it increases pressure on incoming air.