Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Lockheed XP-58 Chain Lightning was an American long-range fighter developed during World War II. Although derived from the successful P-38 Lightning, the XP-58 was plagued by technical problems with its engines that eventually led to the cancellation of the project. The XP-58 was a Lockheed Aircraft Company funded initiative to develop an improved Lightning as a long-range fighter following the release by the U.S. Army Air Corps of the Lightning for sale to Britain on 20 April 1940. Initially, two designs were formulated, both using the Continental IV-1440 engines. One would be a single seat aircraft with one 20 mm (.79 in) cannon and four .50 in (12.7 mm) machine guns. The second would be a two-seat aircraft with the addition of a flexible .50 in (12.7 mm) gun at the end of each tail boom.