The AeroVee 3.5 is a lightweight, air-cooled engine designed for use in small aircraft and experimental vehicles. It features a four-cylinder configuration and is known for its reliability and efficiency, making it a popular choice among aviation enthusiasts and builders of kit aircraft. This engine typically produces around 80 horsepower and operates on automotive fuel, which makes it cost-effective for pilots. The AeroVee 3.5 is often praised for its straightforward installation process and low maintenance requirements, appealing to both novice and experienced builders in the homebuilt aircraft community.