This is a North American T-28C Trojan. Designed as a replacement for the T-6 trainer, the Trojan went into production in 1950. The USAF version (T-28A) was powered by an 800 hp Wright R-1300 engine whereas later US Navy versions (T-28B and C) were powered by the more powerful 1,425 hp Wright R-1820 engine. When production ceased in 1957, a total of 1,948 Trojans had been built.
In 1962, the USAF began a program to modify more than 200 T-28's as tactical fighter-bombers for counterinsurgency warfare in Vietnam. Equipped with 1,425 hp engines, these airplanes (designated the T-28D "Nomad") proved to be an effective weapon in close air support missions against enemy troops inside South Vietnam.