The CX4 is a low wing, single-seat, conventional landing gear equipped aircraft, designed to be simple to build and safe to fly. The name of the plane, CX4, is taken from an old radio show featuring Hop Harrigan, whose plane was called CX4. The aircraft is all metal, 6061-T6 aluminium, except the cowling. The aluminum main gear legs are sourced from a Monnett Sonerai with hydraulic disc toe brakes. It has a heater and ventilation system for all season flying. The aircraft can be built with an optional 3 gal aux fuel tank. The CX4's standard specified powerplant is a Volkswagen air-cooled engine. The design load factor is 3.8 g, with an ultimate load of 5.7 g. The CX4 first flew in 2004. As of April, 2017, there were 55 flying CX4s in Australia, Brazil, Canada, New Zealand, South Africa, and the United States. The fleet had flown 3316.6 hours total. As of April 2017, 55 had been built.