Willy Coppens Belgium Fighter Ace Balloon Buster WWI Military Photo. Willy Omer François Jean baron Coppens d'Houthulst, DSO MC was Belgium's leading fighter ace and the champion "balloon buster" of World War I. He was credited with 37 confirmed victories and six probables. Not sure if this is a very old photo from the time it was taken but is at least vintage.  Managed ebay accepted. buyer pays shipping and handling of $5.00 in the US more for international shipping.