 According to Lt Baine A. Hawthorne, who was a pilot of A/C 42-40003, "Ol' Gappy" was the name of just the chin turret.The name was painted on the chin turret as a joke toward a crew chief with a space between his front teeth (reference the space between the two machine guns in the chin turret).The aircraft was actually named "Topper" after a then-famous movie character.