The Vultee P-66 Vanguard was a fighter aircraft developed in the United States during the late 1930s. It was designed to meet a requirement from China for a modern fighter aircraft but ultimately proved to be unsuccessful, and only a small number were built.

The P-66 was a single-engine, single-seat aircraft with a low-wing design. It was powered by a Wright R-1820-53 radial engine and was armed with a combination of .50 caliber machine guns and 20mm cannon. The aircraft also featured a retractable landing gear.

One of the unique features of the P-66 was its design, which included a number of features intended to make the aircraft suitable for operation in China’s harsh environment. The aircraft had a large oil cooler and air filter to protect the engine from the dusty conditions, and the landing gear was reinforced to handle rough terrain.

Despite its unique features, the P-66 proved to be underpowered and had poor performance, especially at high altitudes. The aircraft was also plagued by a number of mechanical problems and was difficult to maintain.

The P-66 saw limited service during World War II, primarily with the Chinese Air Force. However, the aircraft proved to be unpopular with Chinese pilots, who preferred more advanced designs such as the Curtiss P-40. As a result, only a small number of P-66s were built and the type was quickly phased out of service.

Today, no P-66s are known to survive.