P-38 Lightning

The Lockheed P-38 Lightning was a single-seat, twin-engine fighter used by the United States during World War II. Built by Lockheed for the Army Air Corps, it had a distinctive twin-boom layout with a central pod for the pilot and weapons. The P-38 served in many roles beyond standard fighter duty, including fighter-bomber, night fighter, and long-range escort fighter when fitted with drop tanks. It also acted as a pathfinder, guiding bomber formations or bomb-carrying P-38s to their targets. Though not officially classed as a heavy fighter or bomber destroyer, it performed those jobs effectively. Unlike German heavy fighters that required two or three crew, the P-38’s single pilot allowed it to maneuver well enough to match single-engine fighters.

About 1,200 Lightnings—roughly one in nine—were converted into F-4 or F-5 reconnaissance variants by replacing weapons with cameras, making it one of the war’s most prolific reconnaissance aircraft. The P-38 saw its greatest success in the Pacific, China-Burma-India, and Southwest Pacific theaters, where it was flown by America’s top aces: Richard Bong (40 victories), Thomas McGuire (38 victories), and Charles H. MacDonald (27 victories). In the Southwest Pacific, it was the primary long-range fighter for the US Army Air Forces until the P-51D Mustang became widely available late in the war. Unusually for an early-war design, both engines were turbocharged, giving it strong high-altitude performance and muffling the exhaust for quieter operation. The Lightning was forgiving in flight and could handle rough use, but early versions had a slow roll rate compared to contemporaries; later models fixed this with hydraulically boosted ailerons. The smaller, sleeker P-51 was faster in a dive, leading to its replacement of the P-38 in most European fighter groups by mid-1944. The P-38 was the only American fighter produced in large numbers throughout the entire US involvement in the war, from Pearl Harbor to Victory over Japan Day.

**Design and development** Lockheed designed the P-38 in response to a February 1937 Army Air Corps specification. Circular Proposal X-608, drafted by First Lieutenants Benjamin S. Kelsey and Gordon P. Saville, called for a twin-engine, high-altitude “interceptor” capable of intercepting and attacking enemy aircraft at altitude. Kelsey later explained that they used the word “interceptor” to bypass rules limiting pursuit aircraft to 500 pounds of armament and single-engine fighters to one engine. They wanted at least 1,000 pounds of armament and a fighter better suited for dogfighting and high-altitude combat. The specification demanded a top speed of at least 360 mph at altitude and a climb to 20,000 feet in six minutes—the toughest set of requirements the Army Air Corps had ever issued. The unbuilt Vultee XP1015 was considered but deemed too immature. A single-engine proposal, Circular Proposal X-609, led to the Bell P-39 Airacobra. Both required liquid-cooled Allison V-1710 engines with turbosuperchargers, and tricycle landing gear earned extra points.

Lockheed set up a secret engineering team separate from the main factory—an approach later called Skunk Works. Under Hall Hibbard and Clarence “Kelly” Johnson, the team explored twin-engine layouts, including both engines in a central fuselage with push-pull propellers. The final design—twin booms for the tail, engines, and turbosuperchargers, with a central nacelle for the pilot and armament—was rare among contemporary fighters, though the Dutch Fokker G.I, Northrop P-61 Black Widow, and Swedish SAAB 21 used a similar planform. The XP-38 mockup mounted two .50-caliber M2 machine guns (200 rounds each), two .30-caliber Brownings (500 rounds each), and a prototype T1 23 mm autocannon with a rotary magazine, substituting for the nonexistent 25 mm Hotchkiss cannon specified by Kelsey and Saville. In the YP-38 prototypes, a T9 37 mm autocannon (later the M4) with 15 rounds replaced the 23 mm gun. The 15 rounds came in three five-round clips, which Kelsey found unsatisfactory, and the T9/M4 was unreliable in flight. Armament experiments from March to June 1941 led to the P-38E’s final combat loadout: four M2 machine guns and one Hispano 20 mm autocannon with 150 rounds. Clustering all weapons in the nose was unusual for US aircraft, which typically used wing-mounted guns with converging trajectories. The P-38’s 20 mm rounds were heavier than standard.