March 1918, 700 qualified mechanics were graduated. Six squadrons from Kelly Field, Texas, were sent to Selfridge for study in the shops. The training center suffered an early setback in March 1918, as the Clinton River flooded the entire site and all personnel were evacuated to schools and churches in nearby Mount Clemens. On 1 April 1, 1918, preparations got underway for the opening of a new gunnery school. Instructors were borrowed from the French, British and Canadian flying corps. By July 1918, Selfridge had reached its peak performance in gunnery training. Over 250 students were enrolled at one time, and on one occasion 52 planes were in the air over the field simultaneously. Classes were so filled that 150 Lewis air guns, 60 Lewis ground guns, 80 Marlin air guns, 90 camera guns and 10 aerial cameras were in use daily. By the end of World War I, the young base had 1,028 enlisted men and 200 officers. It had trained 72 pilots and 700 mechanics, and 1,002 men had attended gunnery school. The 1918 Armistice with Germany ended World War I. The end of the war, however, produced some major changes. From a training field producing mechanics and gunners, Selfridge became a pursuit (fighter) field, but men who had enlisted for the duration of the war were being discharged, and no new students were being trained. Inter-war period Beginning 27 June 1919, Selfridge became the home of the 1st Pursuit Group, currently the oldest combat group in the Air Force. The group was organized in France during World War I and like many others, was demobilized after the war then re-created in 1919. It remained based at Selfridge for approximately 20 years. Many notable names are included in the group's roster including George H. Brett, James "Jimmy" Doolittle, Carl A. Spaatz, Curtis LeMay, Frank O. Hunter, Emmett "Rosie" O'Donnell, Earle E. Partridge, Paul Wurtsmith and over 100 men who rose to the rank of Air Force general ("Home of Generals"). (Lieutenant LeMay was fined $50 for flying a biplane through Selfridge Hangar #6.) The uncertain future of Selfridge Field, however, caused the 1st Pursuit Group to be moved to Kelly Field, Texas, shortly after its return. On 28 August 1919, following an order from Washington, all but 40 men left for Texas airfields. Finally reduced to a staff of only 14 civilians, Selfridge Field for all practical purposes