In 1968 the Cavalier Aircraft Corporation modified two P-51 Mustangs with Dart engines in an attempt to interest the USAF in a lightweight counter-insurgency aircraft but having failed to do so, sold the design to Piper in 1979 who instead used the YT-55 turboprop in the two Enforcers they built. Despite looking like the Mustang, there was less than 10% commonality. First flown in 1983, the concept was successfully demonstrated but again no orders were forthcoming.