FAA Powerplant Written Practice Test

Which characteristic is typical of the cooling system in two-stroke light sport aircraft engines?

1. Oil-cooled cylinders

2. Liquid cooling with pumps

3. Air cooling with fans

4. Hybrid cooling systems

The correct answer is: Liquid cooling with pumps

In two-stroke light sport aircraft engines, a typical characteristic of the cooling system is that they often utilize liquid cooling with pumps. Two-stroke engines tend to operate at higher temperatures due to their design and the combustion process. Liquid cooling systems efficiently manage these temperatures by circulating coolant through the engine, allowing for effective heat dissipation. This method also helps maintain optimal operating conditions, which is crucial for the performance and longevity of the engine. In contrast, the other cooling methods present certain limitations in this context. Oil-cooled cylinders are not the primary method for cooling in two-stroke engines. While air cooling can be found in various aircraft engines, it tends to be less effective for two-stroke designs that demand more robust thermal management, particularly under higher power outputs. Hybrid cooling systems, which might combine elements of both air and liquid cooling, are more complex and are less commonly seen in straightforward light sport aircraft engines centered around simplicity and reliability.