This is a decent example, but it's not quite comparable to developing general AI. We can build helicopters without a full conceptual understanding of aerodynamics, but we can't produce a physical simulation which will accurately determine which helicopter designs will and will not fly for any given design without a full understanding of aerodynamics under the conditions in which helicopters operate.

Creating aerodynamics simulation is creating an aerodynamic system. Creating a general intelligence is creating an intelligent system. A better analog to creating a helicopter using incomplete understanding of aerodynamics is something like creating a system that can discriminate between what is and isn't a general intelligence. We don't have such a system, but it at least doesn't seem like the sort of thing that would require a full understanding of intelligence.