Telling a Harbin Z-20 and a Sikorsky UH-60 “Black Hawk” apart can be challenging – the two helicopters look almost identical and their dimensions are very similar. The striking resemblance underscores China’s decades-long effort to close the technological gap with the United States and Russia in the important aviation sector of helicopters. Yet, there are differences: the Z-20 has five main rotor blades compared with the UH-60’s four, and its cabin features two front windows instead of the...