It's been nearly a year since Johns last flew one of Selby's finished models, at the Top Gun competition in Lakeland, Florida, and the memory haunts them both. Top Gun, held each April, is the de facto world championship of radio-controlled scale-model aeronautics, an invitation-only event that hosts some 130 entries, jets and prop-planes alike, from around the world. Selby had spent the two years before the event building and tweaking his Embraer Tucano 312 (a Brazilian turboprop fighter trainer), and the plane had a grip on first place going into its final competition flight. But suddenly, as it went into a tight turn, the plane stopped responding to Johns's control inputs. "We saw it jink to one side, and then it just keeled over and dove into the forest," Selby says. "We had to rent a helicopter to recover the pieces."