Which of the following is NOT an advantage of Horizontally Opposed Engines?

Horizontally opposed engines, commonly used in many small aircraft, have several key advantages that enhance their performance and usability. These engines are designed with cylinders arranged opposite one another, allowing for a lower center of gravity and more stable aircraft handling.

The option regarding improved fuel efficiency does not accurately represent a primary advantage of horizontally opposed engines. While they can offer good fuel efficiency, this characteristic is not exclusive to them and can vary significantly depending on engine design, aircraft type, and operational conditions. Other types of engines may achieve better fuel efficiency based on different design parameters and optimization strategies.

In contrast, the other advantages illustrate the distinct benefits of horizontally opposed engine configurations. Better visibility stems from the engine's design that allows for a more unobstructed pilot view. Ease of maintenance is due to the compact structure of horizontally opposed engines, which generally makes access to engine components simpler than in inline or V-type engines. Additionally, low vibration is a significant benefit of this design, as the opposing cylinder arrangement helps to cancel out the vibrations produced during operation, leading to a smoother flight experience.

Understanding these features helps to clarify the landscape of engine designs and their respective advantages in aviation.