A very ‘Chained Lightning’

In 1940, while World War II raged and the United States watched from the sidelines, the British Royal Air Force was anxious to buy high quality military aircraft and American manufacturers were anxious to sell them.

One of these American companies was Lockheed, whose new P-38 was viewed by the RAF as one of the few American fighters with real combat potential.

The U.S. Army Air Corps, which had ordered a number of P-38s, was not excited about having the RAF butt into the production line, but senior Air Corps leaders saw an opportunity. They would allow Lockheed to sell modified P-38s, the Model 322, to the RAF if Lockheed would built two larger and improved P-38s with new, very powerful Continental IV-1440 engines and longer range – at no cost to the Air Corps.

The idea behind the new aircraft was that, in the event Britain fell, the United States would need very long range fighters to attack the new German empire or to fight off waves of Axis bombers attacking the United States.

Lockheed agreed and developed two variations of the P-38 – the single-seat XP-49 and the two-seat XP-58, dubbed the “Chain Lightning.” Even though the RAF later found the 322’s performance so unsatisfactory it only took three of the modified Lightnings, Lockheed remained “on the hook” for developing the XP-49 and XP-58 at its own expense.

The XP-49 was dropped in May 1940 when the prototype showed poor handling, and development focused on the two seat XP-58. While the XP-58 had P-38’s twin booms where the engines were mounted and a center fuselage pod for crew and armament, it was really an entirely different aircraft.

For one thing, it was huge – almost 50 feet long, with a 70-foot wingspan (nearly twice that of the normal Lightning) and a takeoff weight of more than 35,000 pounds. This was bigger and heavier than the B-25 medium bomber.

The center crew/armament pod was also significantly larger than the P38’s. It carried a pair of remotely controlled turrets, each with two .50 machine guns, on the top and bottom of the pod for rear defense and a second crew member to operate them. To get fighter performance out of this large aircraft required very powerful engines, so the Air Corps changed the power plants from the Continentals to the (theoretically) more powerful Pratt & Whitney XH-2600. Shortly thereafter, the XH-2600 engine was cancelled.

Lockheed wanted to replace the XH-2600s with the excellent Pratt & Whitney R-2800 radial, probably the best radial ever designed, which powered the P-47 and Grumman Hellcat. But in March 1941, USAAC foisted the Wright XR-2160 Tornado engine, which promised 2,350 horsepower, on Lockheed for the XP-58. Along with the new engine, the Air Corps had new requirements that added more weight to the aircraft.

With the changes, progress on the aircraft was very slow, but the design changes were nothing compared to the tooing-and-froing over the mission of the aircraft. The RAF victory in the Battle of Britain showed that a large, two seat escort fighter was an invalid concept, so attention was focused on the long range bomber destroyer role while attempts to solve the engine problems continued.

The huge center pod proved to be a “tabula rasa” for armament personnel who were enamored of large aircraft cannon. Their first proposal was for a quadruple mount of four 37 millimeter M4 cannon in the nose, followed by a proposal to develop a nose turret for the four cannon to they could be elevated to lob shells into a bomber formation.

Not surprisingly, this was too heavy and complex, so the engineers moved to a single, automatic loading 75 millimeter cannon supplemented by two .50 machine guns and proposed using the aircraft as a tank killer.

However, this proved to be like rearranging the chairs of the Titanic. By 1943, the war had taken shape to the point where it was clear standard American fighters could both shoot down enemy fighters and, as fighter bombers, operate effectively against enemy armor.

The XP-58’s power plant was changed yet again to another new engine, the Allison V-3420, but since the prototype not even flown its days were clearly numbered. Lockheed was focused on its new jet fighter, the P-80 Shooting Star, and was in no hurry to spend time on the clearly obsolete XP-58.

The Chain Lightning finally made its first test flight on June 6, 1944, but when it was turned over to the military it had continuous engine and maintenance problems and it only flew a few flights before being discarded. It become a maintenance trainer, a role where, given its problems, it probably excelled.

Interestingly, one role that never seems to have been considered was using the XP-58 as a night fighter, where its large size would have allowed it to easily carry the bulky early airborne radars and the required heavy armament. But that was a road not taken, and the Chain Lighting certainly qualifies as a finalist in the most ill-conceived and poorly executed American aircraft programs of World War II.

(Dr. Michel is currently deployed downrange)