X-Plane 9.70+ T-28A Trojan. The North American Aviation T-28 Trojan was a piston-engined military trainer aircraft used by the United States Air Force and United States Navy beginning in the 1950s. Besides its use as a trainer, the T28 was successfully employed as a counter-insurgency (COIN) aircraft, primarily during the Vietnam War. The T-28A was the US Air Force version with an 800 hp (597 kW) Wright R-1300-7 radial engine. 1194 of this type were built. By David Austin.