USNI News – In the jungles, plains and mountains of Luzon, the U.S. Army is experimenting with 3D-printed drones, missile launchers and new operational maneuvers in a test of their ability to defend the Philippines’ largest island. The drills come amid Manila’s concerns of potential spillover from a cross-strait conflict between Beijing and Taipei reaching Northern Luzon, located just 155 miles south of Taiwan.