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.
Design and development
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 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 gun at the end of each tail boom.
By July 1940, when use of the Pratt & Whitney XH-2600 was entertained, it was decided that the aircraft would have two seats, and the aircraft was designated XP-58. However, soon Lockheed was advised the development of the XH-2600 engine was terminated. After consideration of the engine alternatives, the design was changed to use two Wright R-2160 Tornado engines, as well as a change of the rear facing armament to two turrets, one upper and the other lower on the fuselage, each turret containing two .50 in machine guns. As support equipment for the two crewmen was added the estimated weight of the XP-58 grew to by August 1941.
As vacillation continued over the engine and role of the XP-58, the USAAF agreed to a Lockheed proposal for a second XP-58 that would incorporate features to obtain a range of 3,000 miles (4,800 km). In September 1942, a decision was made to convert the aircraft for a role as a low-altitude tank-killer, which introduced complications as the Beechcraft XA-38 Grizzly was being developed for this role. As a result, the second XP-58 was canceled and the role of the design reverted to that of a high-altitude fighter, but one using 75 mm cannon to break up bomber formations.
In February 1943, use of another engine, the Allison V-3420, was necessary due to poor progress with the Tornado engine development. With this change, the second XP-58 was resurrected. The XP-58 finally flew on 6 June 1944
, but flight test work on the XP-58 took second place to other higher priority developments. Eventually 25 test flights were completed. The XP-58 was then flown to Wright Field for USAAF acceptance tests, even though the turbo-superchargers were experiencing torching and a number of systems were not installed including provision for cockpit pressurization and armament with its fire-control equipment. Although the prototype arrived at Wright Field on 22 October 1944
the aircraft was a maintenance headache and no further trials were conducted. The construction of the second prototype was abandoned.