FS2004 Beech Duke And Merlin Flight Models. Paul Craig has designed excellent aircraft models. This file contains revised flight models for three aircraft: Beechcraft BE60 Duke, the original piston powered model; Beechcraft Turbine Duke, repowered by Royal Turbine with PW PT6 turbines; Swearingen SA227 Merlin. The flight have been revised with Gerry Beckwith's Air Wrench. By Michael Verlin.