The Belgian fired point-blank at the kite balloon for the fourth time. Instead of bursting into flame, the “sausage” shot up and collided with the little Hanriot H.D.1 scout. As he cut his engine, the balloon sagged and sank below him. The Hanriot then plunged over the side of the balloon, nose first. As the propeller began to spin, the pilot opened the throttle and gunned his ship for home. The gasbag, torn and leaking, fell to earth and exploded in fire.

It was May 15, 1918—Willy Coppens, Belgium’s greatest World War I ace, had just scored his fourth and most famous victory. Coppens flew almost exclusively in the French-designed Hanriot H.D.1—highly maneuverable but fitted with only one centrally located machine gun. At the beginning of his career, he had to hoard incendiary bullets. His May 15th downing of the recalcitrant sausage had cost him eight of those prized bullets.

The Belgian’s final victory in October 1918 resulted in a serious leg wound and crash landing. He spent months in the hospital, but the loss of his leg didn’t prevent him from returning to the skies. Coppens emerged from the war with a Distinguished Service Order, a Military Cross, and 37 kills, including 26 balloons. He was given the title of Baron and became a widely known figure in European postwar aviation. Coppens lived into his mid-nineties, becoming one of the last “knights of the air.”