Production. A-31 ("Vengeance") dive bombers. Spark-plug installation. Women workers are shown installing spark plugs in the powerful Wright "double cyclone" engine used in the Vultee "Vengeance" dive bomber manufactured at Vultee's Nashville Division. The "Vengeance" (A-31) was originally designed for the French. It was later adopted by the RAF (Royal Air Force) and still later by the U.S. Army Air Forces. It is a single-engine, low-wing plane, carrying a crew of two men and having six machine guns of varying calibers