Lockheed P-38 Lightning P-38E

By the time Lockheed began delivering production Lightnings, the P-38D had mainly served to work out teething troubles. The next step, the P-38E (company Model 222-62-09), was the first to be built in significant numbers and the first the Army regarded as fully combat ready. Beneath an almost unchanged outline sat more than 2000 changes compared with the earlier aircraft. Most were minor and invisible from outside: the electrical system, the control panels, improved radio equipment, new instruments and a revised hydraulic circuit. The most obvious external difference was that the large air scoop on top of each tail boom gave way to two smaller ones.

Another change arrived part-way through production, when the Hamilton Standard Hydromatic hollow-steel propellers of the first machines were replaced by Curtiss Electric duralumin propellers. Power came from handed Allison V-1710-27 and -29 engines of about 1,150hp each, according to John Rickard's entry on History of War, which credits the type with a top speed of 395 mph at 20,000 ft and a cruise of 300 mph.

The P-38E is the version in which the gun package that made the fighter famous was fixed. For the first time the four .50-calibre nose guns were joined by a 20 mm Hispano-Suiza cannon, built under licence by Bendix as the M-1, which replaced the 37 mm cannon intended for the earlier versions. That big gun carried only 15 rounds; the new one had 150. A redesign of the nose wheel freed space for ammunition as well, so each machine gun went from 200 to 500 rounds.

The layout changed too. On the P-38D the machine guns had been mounted symmetrically, which forced the ammunition belts to bend and caused jamming. On the P-38E they were staggered, the muzzles protruding from the nose in relative lengths of roughly 1:4:6:2, so that each belt ran straight into its weapon. The arrangement was kept on every later version.

The first P-38E rolled out of the factory in October 1941, while the Battle of Moscow dominated the world's headlines. A total of 210 were built, and early in 1942 the line moved on to the P-38F, with racks inboard of the engines for drop tanks or bombs. The sources disagree on the month of the changeover: English Wikipedia gives February, Spanish Wikipedia April. The Anglo-French order of 1940, the Model 322, was itself defined as a variant of the P-38E without turbosuperchargers, because of the American ban on exporting that equipment.

Italian Wikipedia notes that the first P-38Es went to home defence and that they were also the first Lightnings to fight in the air, if only on a limited scale. From 1943 they were withdrawn from all front-line use.

The theatre where the P-38E made its mark was the far North Pacific. On 29 May 1942, 25 P-38s began operating in the Aleutian Islands of Alaska. There the Lightning became the standard American fighter: single-engined types had neither the range nor the reliability for an island chain almost 1,900 km long, with few airstrips and brutal weather. Conditions were so harsh that more aircraft were lost to the weather than to the enemy, and some pilots, after hours over grey seas under grey skies, simply flew into the water.

On 9 August 1942, at the end of a long-range patrol of some 1,600 km, two P-38Es came across a pair of Japanese Kawanishi H6K "Mavis" flying boats and destroyed them: they were the first Japanese aircraft shot down by Lightnings. The US National Park Service credits the victory to Lieutenants Kenneth Ambrose and Stanley Long of the 54th Fighter Squadron, Eleventh Air Force; English Wikipedia assigns the two aircraft to the 343rd Fighter Group, to which the squadron came to belong.

The recollections gathered by the same service give a sense of squadron life: missions of nine or ten hours over water with no landmarks, ground crew leaving gum and candy in the cockpit for the long hauls, strafing runs over Kiska, sorties from Amchitka in 1943 during the battle of Attu, and losses such as Lieutenant Warren Banks, who ran out of fuel and went into the sea at the age of 22.

Speed, working altitude and the redundancy of two engines made the P-38E a natural platform for photographic reconnaissance. More than a hundred were completed in the factory or converted in the field as F-4s, with the nose guns replaced by cameras. The variant list of English Wikipedia puts F-4 production at 99, and History of War describes the F-4-1 with two fixed vertical K-17 cameras, while other sources speak of four cameras. Most stayed in the United States for training, yet the F-4 was the first Lightning to see action: it joined the 8th Photographic Squadron in Australia on 4 April 1942, and three flew briefly with the Royal Australian Air Force in September 1942.

Very early in the Pacific War it was proposed to fit Lightnings with droppable floats so they could ferry themselves across the ocean and shed them before combat. Because salt spray was feared to corrode the tailplane, in March 1942 P-38E 41-1986 received a tail raised by 16 to 18 in, booms lengthened by 2 ft and a rear-facing second seat for an observer. A second version on the same airframe gave the booms more side area to help the rudders; a third returned the booms to normal length but raised the tail by 33 in. All three tails were designed by George H. "Bert" Estabrook, and photographs of this scorpion-tailed aircraft are among the oddest of the family.

The final version was used on 7 December 1942 for a quick series of dive tests, with Milo Burcham flying and Kelly Johnson watching from the rear seat. Johnson concluded that the raised tail did nothing to cure compressibility. The aircraft never carried floats: according to English Wikipedia, because the Navy proved to have enough sealift to keep up with P-38 deliveries to the South Pacific; according to History of War, because after the Battle of Midway such long-range fighters no longer seemed needed.

The P-38E airframe served other experiments as well. One received an extended central nacelle with tandem seats and dual controls, and later a laminar-flow wing. Another towed a Waco troop glider in 1942 as a demonstration, but there were plenty of other aircraft for that job, such as the C-47, and the Lightning was spared it. A battered RP-38E, the "piggyback" mule Lockheed had used to test the P-38J chin intercooler installation, ended up as one of the two P-38Ks with paddle-bladed Hamilton Standard propellers, and a further P-38E was given the same propellers.