Big Daddy was a D model Huey armed with a M39 20mm cannon. The cannon came off a wrecked F-100 fighter and was first mounted as a door gun. Later it was hung under the belly as in the photo. Note the flash protector on the barrel. The first time it fired the blast blew out the chin bubbles so a generator shipping container was cut in half and used to protect the bottom of the aircraft. The ship had a short life as the shock from firing the cannon broke the aircraft hard points. - Photo provided by Pat Ronan, Stinger 99