Douglas DC-3, N510NR, undergoing conversion to a Basler BT-67 turboprop on the north side of Oshkosh Airport in May 1989. The BT-67 conversion includes retrofitting the aircraft with new P&WC PT6A-67R turboprop engines, lengthening the fuselage (seen here underway), strengthening the airframe, upgrading the avionics, and modifying the leading edges and wingtips. This became the 12th BT-67. It was sold to the Guatemala Air Force in 1992. In January 1990, Basler Turbine Conversions opened a new 75,000 sq ft hangar at KOSH for BT-67 conversions.