It's more an engineer's dream than nightmare - to rapidly prototype and redesign aircraft using 3-D printed parts. That's just what a team of student interns and engineers at NASA's Ames Research Center in Moffett Field, California, got to do: custom-build aircraft by repurposing surplus Unmanned Aerial Vehicles (UAVs). Grafting fuSLUges side-by-side adds more motors, propellers and batteries to improve power and performance capacity.