[1][2] Originally conceived to use a piston engine driving a five- or six-blade pusher propeller, brothers Scott and Dan Hanchette commenced work on the prototype, then known as the ViperFan,[3] in February 1996.
[4] However, concerns about the difficulty and cost associated with eliminating vibration from the drivetrain led the Hanchettes to choose turbojet propulsion instead, and they installed a Turbomeca Marboré engine in place of the Continental flat-6 they had originally envisaged as a powerplant.
[7] With this engine producing around four times the thrust of the previous powerplants tested in the Viper, the Hanchettes substantially redesigned the aircraft, dubbing the J85-powered version the MKII.
[7] The prototype was dismantled and rebuilt, with parts of the canopy and fuselage center section all that remained of the original design.
[7] The slightly larger MKII also features a pressurized cabin,[8] nearly three times the fuel tankage,[9] stronger undercarriage,[9] and optional tip tanks.