After programming a basic version of the CFDs model, Blackley used several programs to examine the simulated currents of air that flowed across a model of a flat plate. He adjusted the code until the plate fell realistically, and then constructed test models for a plane wing and fuselage. He eventually built a complete but dysfunctional plane by using data from "pinhead books". By reading aircraft design manuals, he discovered that the problems were caused by his plane's incorrect tail and center of gravity. Following this, he created an exact three-dimensional model of the Extra 300S over roughly three days. As he had not yet simulated the physical attributes of its propeller, Blackley programmed the plane to be propelled from the rear. However, the accurate model performed properly in the simulated atmosphere.