Planes which have made History, Part I

Lockheed P-38 Lightning

The Lockheed P-38 Lightning was a World War II American fighter aircraft built by Lockheed. Developed to a United States Army Air Corps requirement, the P-38 had distinctive twin booms and a single, central nacelle containing the cockpit and armament. Named "fork-tailed devil" by the Luftwaffe and "two planes, one pilot" by the Japanese, the P-38 was used in a number of roles, including dive bombing, level bombing, ground-attack, photo reconnaissance missions, and extensively as a long-range escort fighter when equipped with drop tanks under its wings.

The P-38 was used most successfully in the Pacific Theater of Operations and the China-Burma-India Theater of Operations as the mount of America's top aces, Richard Bong (40 victories) and Thomas McGuire (38 victories). In the South West Pacific theater, the P-38 was the primary long-range fighter of United States Army Air Forces until the appearance of large numbers of P-51D Mustangs toward the end of the war. The P-38 was unusually quiet for a fighter, the exhaust muffled by the turbo-superchargers. It was extremely forgiving, and could be mishandled in many ways, but the rate of roll was too slow for it to excel as a dogfighter. The P-38 was the only American fighter aircraft in production throughout American involvement in the war, from Pearl Harbor to Victory over Japan Day.

Lockheed designed the P-38 in response to a February 1937 specification from the United States Army Air Corps. Circular Proposal X-608 was a set of aircraft performance goals authored by First Lieutenant Benjamin S. Kelsey (later Brigadier General) and First Lieutenant Gordon P. Saville (later General) for a twin-engine, high-altitude "interceptor" having "the tactical mission of interception and attack of hostile aircraft at high altitude." Kelsey recalled in 1977 that he and Saville drew up the specification using the word interceptor as a way to bypass the inflexible Army Air Corps requirement for pursuit aircraft to carry no more than 500 lb (227 kg) of armament including ammunition, as well as the restriction of single-seat aircraft to one engine. Kelsey was looking for a minimum of 1,000 lb (454 kg) of armament. Kelsey and Saville aimed to get a more capable fighter; better at dog-fighting and at high-altitude combat. Specifications called for a maximum airspeed of at least 360 mph (580 km/h) at altitude, and a climb to 20,000 ft (6,100 m) within six minutes; the toughest set of specifications USAAC had presented to that date. The unbuilt Vultee XP1015 was designed to the same requirement, but was not advanced enough to merit further investigation. A similar single-engine proposal was issued at the same time: Circular Proposal X-609, in response to which the Bell P-39 Airacobra was designed. Both proposals required liquid-cooled Allison V-1710 engines with turbo-superchargers and both gave extra points for tricycle landing gear.

The Lockheed design team, under the direction of Hall Hibbard and Clarence "Kelly" Johnson, considered a range of twin-engine configurations including both engines in a central fuselage with push-pull propellers.

The eventual configuration was rare in terms of contemporary fighter aircraft design, with only the preceding Fokker G.1 and later Northrop P-61 Black Widow having a similar planform. The Lockheed team chose twin booms to accommodate the tail assembly, engines, and turbo-superchargers, with a central nacelle for the pilot and armament. The XP-38 gondola mock-up was designed to mount two .50 in (12.7 mm) M2 Browning machine guns, with 200 rpg, two .30 in (7.62 mm) Brownings, with 500 rpg, and a T1 Army Ordnance .90 in (23 mm) autocannon with a rotary magazine as a substitute for the non-existent 25 mm Hotchkiss aircraft autocannon specified by Kelsey and Saville. In the YP-38s, a larger John Browning-designed, Colt-made M9 37 mm (1.46 in) autocannon with 15 rounds replaced the T1. The 15 rounds were in three 5-round clips, an unsatisfactory arrangement according to Kelsey, and the M9 did not perform reliably in flight. Further armament experiments from March to June 1941 resulted in the P-38E combat configuration of four M2 Browning machine guns, and one Hispano 20 mm (.79 in) autocannon with 150 rounds.

Clustering all the armament in the nose was unlike most other U.S. aircraft which used wing-mounted guns with trajectories set up to crisscross at one or more points in a "convergence zone." Guns mounted in the nose did not suffer from having their useful ranges limited by pattern convergence, meaning good pilots could shoot much farther. A Lightning could reliably hit targets at any range up to 1,000 yd (910 m), whereas other fighters had to pick a single convergence range between 100 and 250 yd (230 m). The clustered weapons had a "buzz saw" effect on any target at the receiving end, making the aircraft effective for strafing as well. The rate of fire on the guns was about 650 rounds per minute for the 20×110 mm cannon round (130 gram shell) at a muzzle velocity of about 2,887 ft/s (880 m/s), and for the .50 inch machine guns (43–48 gram rounds), about 850 rpm at 2,756 ft/s (840 m/s) velocity. Combined rate of fire was over 4,000 rpm with roughly every sixth projectile a 20 mm. Time of firing for the 20 mm cannon and .50 caliber machine guns were approximately 14 seconds and 35 seconds respectively.

The Lockheed design incorporated tricycle undercarriage and a bubble canopy, and featured two 1,000 hp (746 kW) turbo-supercharged 12-cylinder Allison V-1710 engines fitted with counter-rotating propellers to eliminate the effect of engine torque, with the superchargers positioned behind the engines in the booms. Counter-rotation was achieved with the use of "handed" engines, which meant that the crankshaft of each engine turned in the opposite direction of its counterpart. The V-12 engines only required that the spark plug firing order be changed in order for the direction of the crank shaft to be reversed, according to the General Motors Allison V1710 Service School Handbook.

It was the first American fighter to make extensive use of stainless steel and smooth, flush-riveted butt-jointed aluminum skin panels. It was also the first fighter to fly faster than 400 mph (640 km/h).

Lockheed won the competition on 23 June 1937 with its Model 22 and was contracted to build a prototype XP-38 for US$163,000, though Lockheed's own costs on the prototype would add up to US$761,000. Construction began in July 1938 and the XP-38 first flew on 27 January 1939 at the hands of Ben Kelsey.

Kelsey then proposed a speed dash to Wright Field on 11 February 1939 to relocate the aircraft for further testing. General Henry "Hap" Arnold, commander of the USAAC, approved of the record attempt, and recommended a cross-country flight to New York. The flight set a speed record by flying from California to New York in seven hours and two minutes, not counting two refueling stops, but the aircraft was downed by carburetor icing short of the Mitchel Field runway in Hempstead, New York, and was wrecked. However, on the basis of the record flight, the Air Corps ordered 13 YP-38s on 27 April 1939 for US$134,284 apiece. (The initial "Y" in "YP" was the USAAC's designation for a prototype while the "X" in "XP" was for experimental.) Lockheed's Chief test pilot Tony LeVier angrily characterized the accident as an unnecessary publicity stunt, but according to Kelsey the loss of the prototype, instead of hampering the program, speeded the process by cutting short the initial test series. The success of the aircraft design contributed to Kelsey's promotion to captain in May, 1939.

Manufacture of the YP-38s fell behind schedule, at least partly due to the need for mass-production suitability making them substantially different in construction than the prototype. Another factor was the sudden required facility expansion of Lockheed in Burbank, taking it from a specialized civilian firm dealing with small orders to a large government defense contractor making Venturas, Harpoons, Lodestars, Hudsons, and designing the Constellation airliner for TWA. The first YP-38 was not completed until September 1940, with its maiden flight on 17 September. The 13th and final YP-38 was delivered to the Air Corps in June 1941; 12 aircraft were retained for flight testing and one for destructive stress testing. The YPs were substantially redesigned and differed greatly in detail from the hand-built XP-38. They were lighter, included changes in engine fit, and the propeller rotation was reversed, with the blades rotating outwards (away) from the cockpit at the top of their arc rather than inwards as before. This improved the aircraft's stability as a gunnery platform.

Test flights revealed problems initially believed to be tail flutter. During high-speed flight approaching Mach 0.68, especially during dives, the aircraft's tail would begin to shake violently and the nose would tuck under, steepening the dive. Once caught in this dive, the fighter would enter a high-speed compressibility stall and the controls would lock up, leaving the pilot no option but to bail out (if possible) or remain with the aircraft until it got down to denser air, where he might have a chance to pull out. During a test flight in May 1941, USAAC Major Signa Gilkey managed to stay with a YP-38 in a compressibility lockup, riding it out until he recovered gradually using elevator trim. Lockheed engineers were very concerned at this limitation, but first they had to concentrate on filling the current order of aircraft. In June 1941, the Army Air Corps was renamed the U.S. Army Air Forces (USAAF) and a total of 65 Lightnings were finished for the service by September 1941 with more on the way for the USAAF, the Royal Air Force (RAF) and the Free French Air Force operating from England.

By November 1941, many of the initial assembly line challenges had been met and there was some breathing room for the engineering team to tackle the problem of frozen controls in a dive. Lockheed had a few ideas for tests that would help them find an answer. The first solution tried was the fitting of spring-loaded servo tabs on the elevator trailing edge; tabs that were designed to aid the pilot when control yoke forces rose over 30 lb (14 kg), as would be expected in a high-speed dive. At that point, the tabs would begin to multiply the effort of the pilot's actions. The expert test pilot, 43-year-old Ralph Virden, was given a specific high-altitude test sequence to follow, and was told to restrict his speed and fast maneuvering in denser air at low altitudes since the new mechanism could exert tremendous leverage under those conditions. A note was taped to the instrument panel of the test craft, underscoring this instruction. On 4 November 1941, Virden climbed into YP-38 #1 and completed the test sequence successfully, but 15 minutes later was seen in a steep dive followed by a high-G pullout. The tail unit of the aircraft failed at about 3,000 ft (910 m) during the high-speed dive recovery; Virden was killed in the subsequent crash. The Lockheed design office was justifiably upset, but their design engineers could only conclude that servo tabs were not the solution for loss of control in a dive. Lockheed still had to find the problem; the Army Air Forces personnel were sure it was flutter, and ordered Lockheed to look more closely at the tail.

Although the P-38's empennage was completely skinned in aluminum (not fabric) and was quite rigid, in 1941, flutter was a familiar engineering problem related to a too-flexible tail. At no time did the P-38 suffer from true flutter. To prove a point, one elevator and its vertical stabilizers were skinned with metal 63% thicker than standard, but the increase in rigidity made no difference in vibration. Army Lieutenant Colonel Kenneth B. Wolfe (head of Army Production Engineering) asked Lockheed to try external mass balances above and below the elevator, though the P-38 already had large mass balances elegantly placed within each vertical stabilizer. Various configurations of external mass balances were equipped and dangerously steep test flights flown to document their performance. Explaining to Wolfe in Report No. 2414, Kelly Johnson wrote "... the violence of the vibration was unchanged and the diving tendency was naturally the same for all conditions." The external mass balances did not help at all. Nonetheless, at Wolfe's insistence, the additional external balances were a feature of every P-38 built from then on.

After months of pushing NACA to provide Mach 0.75 wind tunnel speeds (and finally succeeding), the compressibility problem was revealed to be the center of lift moving back toward the tail when in high-speed airflow. The compressibility problem was solved by changing the geometry of the wing's underside when diving so as to keep lift within bounds of the top of the wing. In February 1943, quick-acting dive flaps were tried and proven by Lockheed test pilots. The dive flaps were installed outboard of the engine nacelles and in action they extended downward 35° in 1½ seconds. The flaps did not act as a speed brake, they affected the center of pressure distribution so that the wing would not lose its lift.

Late in 1943, a few hundred dive flap field modification kits were assembled to give North African, European and Pacific P-38s a chance to withstand compressibility and expand their combat tactics. Unfortunately, these crucial flaps did not always reach their destination. In March 1944, 200 dive flap kits intended for European Theater of Operations (ETO) P-38Js were destroyed in a mistaken identification incident in which a RAF fighter shot down the Douglas C-54 Skymaster taking the shipment to England. Back in Burbank, P-38Js coming off the assembly line in spring 1944 were towed out to the tarmac and modified in the open air. The flaps were finally incorporated into the production line in June 1944 on the last 210 P-38Js. Despite testing having proved the dive flaps were effective in improving tactical maneuvers, a 14-month delay in production limited their implementation with only the final 50% of all Lightnings built having the dive flaps installed as an assembly line sequence.

Buffeting was another early aerodynamic problem, difficult to sort out from compressibility as both were reported by test pilots as "tail shake". Buffeting came about from airflow disturbances ahead of the tail; the airplane would shake at high speed. Leading edge wing slots were tried as were combinations of filleting between the wing, cockpit and engine nacelles. Air tunnel test number 15 solved the buffeting completely and its fillet solution was fitted to every subsequent P-38 airframe. Fillet kits were sent out to every squadron flying Lightnings. The problem was traced to a 40% increase in air speed at the wing-fuselage junction where the chord/thickness ratio was highest. An airspeed of 500 mph (800 km/h) at 25,000 ft (7,600 m) could push airflow at the wing-fuselage junction close to the speed of sound. Filleting forever solved the buffeting problem for the P-38E and later models.

Another issue with the P-38 arose from its unique design feature of outwardly rotating counter-rotating propellers. Losing one of two engines in any twin engine non-centerline thrust aircraft on takeoff creates sudden drag, yawing the nose toward the dead engine and rolling the wingtip down on the side of the dead engine. Normal training in flying twin-engine aircraft when losing an engine on takeoff would be to push the remaining engine to full throttle; if a pilot did that in the P-38, regardless of which engine had failed, the resulting engine torque and p-factor force produced a sudden uncontrollable yawing roll and the aircraft would flip over and slam into the ground. Eventually, procedures were taught to allow a pilot to deal with the situation by reducing power on the running engine, feathering the prop on the dead engine, and then increasing power gradually until the aircraft was in stable flight. Single-engine takeoffs were possible, though not with a full fuel and ammunition load.

The engines were unusually quiet because the exhausts were muffled by the General Electric turbo-superchargers on the twin Allison V12s. There were early problems with cockpit temperature regulation; pilots were often too hot in the tropical sun as the canopy could not be fully opened without severe buffeting, and were often too cold in northern Europe and at high altitude, as the distance of the engines from the cockpit prevented easy heat transfer. Later variants received modifications (such as electrically-heated flight suits) to solve these problems.

On 20 September 1939, before the YP-38s had been built and flight tested, the USAAF ordered 66 initial production P-38 Lightnings, 30 of which were delivered to the USAAF in mid-1941, but not all these aircraft were armed. The unarmed aircraft were subsequently fitted with four .50 in (12.7 mm) machine guns (instead of the two .50 in/12.7 mm and two .30 in/7.62 mm of their predecessors) and a 37 mm (1.46 in) cannon. They also had armor glass, cockpit armor and fluorescent cockpit controls. One was completed with a pressurized cabin on an experimental basis and designated XP-38A. Due to reports the USAAF was receiving from Europe, the remaining 36 in the batch were upgraded with small improvements such as self-sealing fuel tanks and enhanced armor protection to make them combat-capable. The USAAF specified that these 36 aircraft were to be designated P-38D. As a result, there never were any P-38Bs or P-38Cs. The P-38D's main role was to work out bugs and give the USAAF experience with handling the type.

In March 1940, the French and the British ordered a total of 667 P-38s for US$100M, designated Model 322F for the French and Model 322B for the British. The aircraft would be a variant of the P-38E. The overseas Allies wished for complete commonality of Allison engines with the large numbers of Curtiss P-40 Tomahawks both nations had on order, and thus ordered for the Model 322 twin right-handed engines instead of counter-rotating ones, and without turbo-superchargers. After the fall of France in June 1940, the British took over the entire order and christened the aircraft "Lightning". By June 1941, the War Ministry had cause to reconsider their earlier aircraft specifications, based on experience gathered in the Battle of Britain and The Blitz. British displeasure with the Lockheed order came to the fore in July, and on 5 August 1941 they modified the contract such that 143 aircraft would be delivered as previously ordered, to be known as "Lightning (Mark) I", and 524 would be upgraded to US-standard P-38E specifications, to be called "Lightning II" for British service. Later that summer, an RAF test pilot reported back from Burbank with a poor assessment of the 'tail flutter' situation, bringing the British to cancel all but three of the 143 Lightning Is. Because a loss of approximately US$15M was involved, Lockheed reviewed their contracts and decided to hold the British to the original order. Negotiations grew bitter and stalled. Everything changed after December 7, 1941 when the United States government seized some 40 of the Model 322s for West Coast defense, subsequently all British Lightnings were delivered to the USAAF starting in January 1942. The USAAF lent the RAF three of the aircraft which were delivered by sea in March 1942 and were test flown no earlier than May at Swaythling, Boscombe Down and Farnborough. These three were subsequently returned to the USAAF; one in December 1942 and the others in July 1943. Of the remaining 140 Lightning Is, 19 were not modified and were designated the USAAF as RP-322-I ('R' for 'Restricted', because non-counter-rotating props were considered more dangerous at takeoff), while 121 were converted to non-turbo-supercharged counter-rotating V-1710F-2 engines and were designated P-322-II. All 121 were used as advanced trainers; a few were still serving that role in 1945. A few RP-322s were later used as test modification platforms such as for smoke-laying canisters. The RP-322 was a fairly fast aircraft under 16,000 ft (4,900 m) and well-behaved as a trainer.

One positive result of the failed British/French order was to give the aircraft its name. Lockheed had originally dubbed the aircraft Atalanta in the company tradition of naming planes after mythological and celestial figures, but the RAF name won out.

The first unit to receive P-38s was the 1st Fighter Group. After the attack on Pearl Harbor, the unit joined the 14th Pursuit Group in San Diego to provide West Coast defense.

The first Lightning to see active service was the F-4 version, a P-38E in which the guns were replaced by four K17 cameras. They joined the 8th Photographic Squadron out of Australia on 4 April 1942. Three F-4s were operated by the Royal Australian Air Force in this theater for a short period beginning in September 1942.

On 29 May 1942, 25 P-38s began operating in the Aleutian Islands in Alaska. The fighter's long range made it well-suited to the campaign over the almost 1,200 mi (2,000 km)–long island chain, and it would be flown there for the rest of the war. The Aleutians were one of the most rugged environments available for testing the new aircraft under combat conditions. More Lightnings were lost due to severe weather and other conditions than enemy action, and there were cases where Lightning pilots, mesmerized by flying for hours over gray seas under gray skies, simply flew into the water. On 9 August 1942, two P-38Es of the 343rd Fighter Group, 11th Air Force, at the end of a 1,000 mi (1,609 km) long-range patrol, happened upon a pair of Japanese Kawanishi H6K "Mavis" flying boats and destroyed them, making them the first Japanese aircraft to be shot down by Lightnings.

After the Battle of Midway, the USAAF began redeploying fighter groups to Britain as part of Operation Bolero, and Lightnings of the 1st Fighter Group were flown across the Atlantic via Iceland. On 14 August, Second Lieutenant Elza Shahan of the 27th Fighter Squadron, and Second Lieutenant Joseph Shaffer of the 33rd Squadron operating out of Iceland shot down a Focke-Wulf Fw 200 Condor over the Atlantic. Shahan in his P-38F downed the Condor; Shaffer, flying either a P-40C or a P-39, had already set an engine on fire. This was the first Luftwaffe aircraft destroyed by the USAAF.

P-38 Lightnings had a number of lucky escapes, exemplified by the arrival of the 78th fighter Group at RAF Goxhill (Lincolnshire, England) in July 1942. The official handover ceremony was scheduled for mid-August, but on the day before the ceremony, Goxhill experienced its only air raid of the war. A single German bomber flew overhead and dropped a very well aimed bomb right on the intersection between the two newly concreted runways, but it didn’t explode and the aircraft were able to continue their mission. (As it turned out, the bomb could not be removed and, for the duration of the war, aircraft had to pass over it every time they took off.)

After 347 sorties with no enemy contact, the 1st, 14th and 82nd Fighter Groups were transferred to the 12th Air Force in North Africa as part of the force being built up for Operation Torch. On 19 November 1942, Lightnings escorted a group of B-17 Flying Fortress bombers on a raid over Tunis. On 5 April 1943, 26 P-38Fs of the 82nd destroyed 31 enemy aircraft, helping to establish air superiority in the area, and earning it the German nickname "der Gabelschwanzteufel" – the Fork-Tailed Devil. The P-38 remained active in the Mediterranean for the rest of the war. It was in this theatre that the P-38 suffered its heaviest losses in the air. On 25 August 1943, 13 P-38s were shot down in a single sortie by Jagdgeschwader 53 Bf 109s without achieving a single kill. On 2 September, 10 P-38s were shot down, in return for a single kill, the 67-victory ace Franz Schiess (who was also the leading "Lightning" killer in the Luftwaffe with 17 destroyed). Kurt Bühligen, third highest scoring German pilot on Western front with 112 victories, recalled later: “The P-38 fighter (and the B-24) were easy to burn. Once in Africa we were six and met eight P-38s and shot down seven. One sees a great distance in Africa and our observers and flak people called in sightings and we could get altitude first and they were low and slow.”  General der Jagdflieger Adolf Galland was unimpressed with the P-38, declaring, "it had similar shortcomings in combat to our ME-110, our fighters were clearly superior to it." Experiences over Germany had shown a need for long-range escort fighters to protect the Eighth Air Force's heavy bomber operations. The P-38Hs of the 55th Fighter Group were transferred to the Eighth in England in September 1943, and were joined by the 20th, 364th and 479th Fighter Groups soon after. P-38s soon joined Spitfires in escorting the early Fortress raids over Europe.

Because its distinctive shape was less prone to cases of mistaken identity and friendly fire, Lieutenant General Jimmy Doolittle, Commander 8th Air Force, chose to pilot a P-38 during the Invasion of Normandy so that he could personally assess the progress of the air offensive over France. At one point in the mission, Doolittle flick-rolled through a hole in the cloud cover but his wingman, Earle E. "Pat" Partridge (later General), was looking elsewhere and failed to notice Doolittle's quick maneuver, leaving Doolittle to continue alone on his survey of the crucial battle. Of the P-38, Doolittle said that it was "the sweetest-flying plane in the sky".

A little-known role of the P-38 in the European theater was that of fighter-bomber during the invasion of Normandy and the Allied advance across France into Germany. Assigned to the IX Tactical Air Command, the 370th Fighter Group and its P-38s initially flew missions from England, dive-bombing radar installations, enemy armor, troop concentrations, and flak towers. The 370th's group commander Howard F. Nichols and a squadron of his P-38 Lightnings attacked Field Marshal Günther von Kluge's headquarters in July 1944; Nichols himself skipped a 500 lb (227 kg) bomb through the front door. The 370th later operated from Cardonville France, flying ground attack missions against gun emplacements, troops, supply dumps and tanks near Saint-Lô in July and in the Falaise-Argentan area in August 1944. The 370th participated in ground attack missions across Europe until February 1945 when the unit changed over to the P-51 Mustang.

Italian pilots in the Mediterranean theatre started to face P-38s from late 1942 and considered it a formidable foe compared to other fighters, including the Supermarine Spitfire. A small number of P-38s fell into the hands of German and Italian units and were subsequently tested and used in combat.

On 12 June 1943, a P-38G, while flying a special mission between Gibraltar and Malta, landed on the airfield of Capoterra (Cagliari) , in Sardinia, for navigation error due to a compass failure. Regia Aeronautica chief test pilot colonnello Lieutenant Colonel Angelo Tondi flew the aircraft to Guidonia airfield where the P-38G was evaluated. On 11 August 1943, Tondi took off to intercept a formation of about 50 B-24s, returning from the bombing of Terni (Umbria). Tondi attacked a bomber that fell off the shore of Torvaianica, near Rome, while six airmen were parachuting. That was the first and last war mission for the plane, as the Italian petrol was too corrosive for the Lockheed tanks. The Lightning was eventually acquired by Italy for postwar service.

If faced by more agile fighters at low altitudes in a constricted valley, Lightnings could suffer heavy losses. On the morning of 10 June 1944, 96 P-38Js of the 1st and 82nd Fighter Groups took off from Italy for Ploesti, the third-most heavily defended target in Europe, after Berlin and Vienna. Instead of bombing from high altitude as had been tried by the Fifteenth Air Force, USAAF planning had determined that a dive-bombing surprise attack, beginning at about 7,000 feet (2,100 m) with bomb release at or below 3,000 feet (900 m), performed by 46 82nd Fighter Group P-38s, each carrying one 1,000-pound (500 kg) bomb, would yield more accurate results. All of 1st Fighter Group and a few aircraft in 82nd Fighter Group were to fly cover, and all fighters were to strafe targets of opportunity on the return trip; a distance of some 1,255 miles (2,020 km), including a circuitous outward route made in an attempt to achieve surprise.

Some 85–86 fighters arrived in Romania to find enemy airfields alerted, with a wide assortment of aircraft scrambling for safety. P-38s shot down several enemy including heavy fighters, transports and observation aircraft. At Ploieti, defense forces were fully alert, the target was concealed by smoke screen, and anti-aircraft fire was very heavy—seven Lightnings were lost to it at the target, and two more during strafing attacks on the return flight. German Bf 109 fighters from I./JG 53 and 2./JG 77 fought the Americans. One flight of 16, the 71st Fighter Squadron, was challenged by a large formation of Romanian single-seater IAR.81C fighters. The fight took place at and below 300 feet (100 m) in a narrow valley. Herbert Hatch saw two IAR 81Cs that he misidentified as Focke-Wulf Fw 190s hit the ground after taking fire from his guns, and his fellow pilots confirmed three more of his kills. However, the outnumbered 71st Fighter Squadron took more damage than it dished out, losing nine aircraft. In all, the USAAF lost 22 aircraft on the mission. The Americans claimed 23 aerial victories, though Romanian and German fighter units admitted losing only one aircraft each. Eleven enemy locomotives were strafed and left burning, and flak emplacements were destroyed, along with fuel trucks and other targets. Results of the bombing were not observed by the USAAF pilots because of the smoke. The dive-bombing mission profile was not repeated, though the 82nd Fighter Group was awarded the Presidential Unit Citation for their part.

After some disastrous raids in 1944 with B-17s escorted by P-38s and Republic P-47 Thunderbolts, Jimmy Doolittle, then head of the U.S. Eighth Air Force, went to Farnborough asking for an evaluation of the various American fighters. RAF Captain Eric Brown recalled:

"We had found out that the Bf 109 and the Fw 190 could fight up to a Mach of 0.75, three-quarters the speed of sound. We checked the Lightning and it couldn't fly in combat faster than 0.68. So it was useless. We told Doolittle that all it was good for was photo-reconnaissance and had to be withdrawn from escort duties. And the funny thing is that the Americans had great difficulty understanding this because the Lightning had the two top aces in the Far East."

After evaluation tests at Farnborough, the P-38 was kept in fighting service in Europe for a while longer. However, even if many of the aircraft's problems were fixed with the introduction of the P-38J, by September 1944, all but one of the Lightning groups in the Eighth Air Force had converted to the P-51 Mustang. The Eighth Air Force continued to conduct reconnaissance missions using the F-5 variant.

The P-38 was used most extensively and successfully in the Pacific theater, where it proved ideally suited, combining excellent performance with very long range. The P-38 was used in a variety of roles, especially escorting bombers at altitudes between 18-25,000 ft (5,500-7,600 m). The P-38 was credited with destroying more Japanese aircraft than any other USAAF fighter. Freezing cockpits were not a problem at low altitude in the tropics. In fact, since there was no way to open a window while in flight as it caused buffeting by setting up turbulence through the tailplane, it was often too hot; pilots taking low altitude assignments would often fly stripped down to shorts, tennis shoes, and parachute. While the P-38 could not out-maneuver the A6M Zero and most other Japanese fighters, its speed and rate of climb gave American pilots the option of choosing to fight or run, and its focused firepower was even more deadly to lightly armored Japanese warplanes than to the Germans'. The concentrated, parallel stream of bullets allowed aerial victory at much longer distances than fighters carrying wing guns. It is therefore ironic that Dick Bong, the United States' highest-scoring World War II air ace (40 victories solely in P-38s), would fly directly at his targets to make sure he hit them (as he himself acknowledged his poor shooting ability), in some cases flying through the debris of his target (and on one occasion colliding with an enemy aircraft which was claimed as a "probable" victory). The twin Allison engines performed admirably in the Pacific.

On 2–4 March 1943, P-38s flew top cover for 5th Air Force and Australian bombers and attack-planes during the Battle of the Bismarck Sea, a crushing defeat for the Japanese. Two P-38 aces from the 39th Fighter Squadron were killed on the second day of the battle: Bob Faurot and Hoyt "Curley" Eason (a veteran with five victories who had trained hundreds of pilots, including Dick Bong).

General George C. Kenney, commander of the USAAF Fifth Air Force operating in New Guinea, could not get enough P-38s, though since they were replacing serviceable but inadequate P-39s and P-40s, this might seem like guarded praise. Lightning pilots began to compete in racking up scores against Japanese aircraft.

The Lightning figured in one of the most significant operations in the Pacific theater: the interception, on 18 April 1943, of Admiral Isoroku Yamamoto, the architect of Japan's naval strategy in the Pacific including the attack on Pearl Harbor. When American codebreakers found out that he was flying to Bougainville Island to conduct a front-line inspection, 16 P-38G Lightnings were sent on a long-range fighter-intercept mission, flying 435 miles (700 km) from Guadalcanal at heights from 10–50 ft (3–15 m) above the ocean to avoid detection. The Lightnings met Yamamoto's two Mitsubishi G4M "Betty" fast bomber transports and six escorting Zeros just as they arrived. The first Betty crashed in the jungle and the second ditched near the coast. Two Zeros were also claimed by the American fighters with the loss of one P-38. Japanese searchers found Yamamoto's body at the jungle crash site the next day.

The P-38's service record shows mixed results, but usually because of misinformation. P-38s have been described as being harder to fly than single-engined planes, but this was because of inadequate training in the first few months of the war. The P-38's engine troubles at high altitudes only occurred with the Eighth Air Force. One reason for this was the inadequate cooling systems of the G and H models; the improved P-38 J and L had tremendous success flying out of Italy into Germany at all altitudes. Up until the -J-25 variant, P-38s were easily avoided by German fighters because of the lack of dive flaps to counter compressibility in dives. German fighter pilots not wishing to fight would perform the first half of a Split S and continue into steep dives because they knew the Lightnings would be reluctant to follow.

On the positive side, having two engines was a built-in insurance policy. Many pilots made it safely back to base after having an engine fail en route or in combat. On 3 March 1944, the first Allied fighters reached Berlin on a frustrated escort mission. Lieutenant Colonel Jack Jenkins of 55FG led the group of P-38H pilots, arriving with only half his force after flak damage and engine trouble took their toll. On the way in to Berlin, Jenkins reported one rough-running engine and one good one, causing him to wonder if he'd ever make it back. The B-17s he was supposed to escort never showed up, having turned back at Hamburg. Jenkins and his wingman were able to drop tanks and outrun enemy fighters to return home with three good engines between them.

In the ETO, P-38s made 130,000 sorties with a loss of 1.3% overall, comparing favorably with ETO P-51s which posted a 1.1% loss, considering that the P-38s were vastly outnumbered and suffered from poorly thought-out tactics. The majority of the P-38 sorties were made in the period prior to Allied air superiority in Europe when pilots fought against a very determined and skilled enemy. Lieutenant Colonel Mark Hubbard, a vocal critic of the aircraft, rated it third best Allied fighter in Europe. The Lightning's greatest virtues were long range, heavy payload, high speed, fast climb, and concentrated firepower. The P-38 was a formidable fighter, interceptor and attack aircraft.

In the Pacific theater, the P-38 downed over 1,800 Japanese aircraft, with more than 100 pilots becoming aces by downing five or more enemy aircraft. American fuel supplies contributed to a better engine performance and maintenance record, and range was increased with leaner mixtures. In the second half of 1944, the P-38L pilots out of Dutch New Guinea were flying 950 mi (1,530 km), fighting for 15 minutes and returning to base. Such long legs were invaluable until the P-47N and P-51D entered service.

The end of the war left the USAAF with thousands of P-38s rendered obsolete by the jet age. The last P-38s in service with the United States Air Force were retired in 1949. A total of 100 late-model P-38L and F-5 Lightnings were acquired by Italy through an agreement dated April 1946. Delivered, after refurbishing, at the rate of one per month, they finally were all sent to the AMI by 1952. The Lightnings served in 4 Stormo and other units including 3 Stormo, flying reconnaissance over the Balkans, ground attack, naval cooperation and air superiority missions. Due to unfamiliarity in operating heavy fighters, old engines, and pilot errors, a large number of P-38s were lost in at least 30 accidents, many of them fatal. Despite this, many Italian pilots liked the P-38 because of its excellent visibility on the ground and stability at takeoff. The Italian P-38s were phased out in 1956; none survived the inevitable scrapyard.

Surplus P-38s were also used by other foreign air forces with 12 sold to Honduras and fifteen retained by China. Six F-5s and two unarmed black two-seater P-38s were operated by the Dominican Air Force based in San Isidro Airbase, Dominican Republic in 1947. The majority of wartime Lightnings present in the continental U.S. at the end of the war were put up for sale for US$1,200 apiece; the rest were scrapped. P-38s in distant theaters of war were bulldozed into piles and abandoned or scrapped; very few avoided that fate.

A single P-38M was used by the CIA during the 1954 Guatemalan coup d'etat. During the conflict this aircraft bombed and sank the British cargo ship SS Springfjord, carrying Czech armaments. The Guatemalan conflict was the last known combat seen by the P-38.

P-38s were popular contenders in the air races from 1946 through 1949, with brightly colored Lightnings making screaming turns around the pylons at Reno and Cleveland. Lockheed test pilot Tony LeVier was among those who bought a Lightning, choosing a P-38J model and painting it red to make it stand out as an air racer and stunt flyer. Lefty Gardner, former B-24 and B-17 pilot and associate of the Confederate Air Force, bought a mid-1944 P-38L-1-LO that had been modified into an F-5G. Gardner painted it white with red and blue trim and named it White Lightnin'; he reworked its turbo systems and intercoolers for optimum low-altitude performance and gave it P-38F style air intakes for better streamlining. White Lightnin' was severely damaged in a crash landing during an air show demonstration, and has since been bought, restored, and repainted with a brilliant chrome finish by the company that owns Red Bull. The plane is now located in Austria.

F-5s were bought by aerial survey companies and employed for mapping. From the 1950s on, the use of the Lightning steadily declined, and only a little more than two dozen still exist, with few still flying. One example is a P-38L owned by the Lone Star Flight Museum in Galveston, Texas, painted in the colors of Charles H. MacDonald's Putt Putt Maru. Two other examples are F-5Gs which were owned and operated by Kargl Aerial Surveys in 1946, and are now located in Chino, California at Yanks Air Museum, and in McMinnville, Oregon at Evergreen Aviation Museum.

Over 10,000 Lightnings were manufactured in all; becoming the only U.S. combat aircraft that remained in continuous production throughout the duration of American participation in World War II. The Lightning had a major effect on other aircraft; its wing, in a scaled-up form, was used on the L-049 Constellation.

Delivered and accepted Lightning production variants began with the P38-D model. The few "hand made" YP-38s initially contracted were used as trainers and test aircraft. There were no Bs or Cs delivered to the government as the USAAF allocated the 'D' suffix to all aircraft with self-sealing fuel tanks and armor. Many secondary but still initial teething tests were conducted utilizing the earliest D variants.

The first combat-capable Lightning was the P-38E (and its photo-recon variant the F-4) which featured improved instruments, electrical, and hydraulic systems. Part-way through production, the older Hamilton Standard Hydromatic hollow steel propellers were replaced by new Curtiss Electric duraluminum propellers. The definitive (and now famous) armament configuration was settled upon, featuring four .50 in (12.7 mm) machine guns with 500 rpg, and a 20 mm (.79 in) Hispano autocannon with 150 rounds.

While the machine guns had been arranged symmetrically in the nose on the P-38D, they were "staggered" in the P-38E and later versions, with the muzzles protruding from the nose in the relative lengths of roughly 1:4:6:2. This was done to ensure a straight ammunition-belt feed into the weapons, as the earlier arrangement led to jamming.

The first P-38E rolled out of the factory in October 1941 as the Battle of Moscow in the Eastern Front Campaign of World War II filled the news wires of the world. Because of the versatility, redundant engines, and especially high speed and high altitude characteristics of the aircraft, as with later variants over a hundred P-38Es were completed in the factory or converted in the field to a photo-reconnaissance variant, the F-4, in which the guns were replaced by four cameras. Most of these early reconnaissance Lightnings were retained stateside for training, but the F-4 was the first Lightning to be used in action in April 1942.

After 210 P-38Es were built, they were followed, starting in April 1942, by the P-38F, which incorporated racks inboard of the engines for fuel tanks or a total of 2,000 lb (907 kg) of bombs. Early variants did not enjoy a high reputation for maneuverability, though they could be agile at low altitudes if flown by a capable pilot, using the P-38's forgiving stall characteristics to their best advantage. From the P-38F-15 model onwards, a "combat maneuver" setting was added to the P-38's Fowler flaps. When deployed at the 8° maneuver setting, the flaps allowed the P-38 to out-turn many contemporary single-engined fighters at the cost of some added drag. However, early variants were hampered by high aileron control forces and a low initial rate of roll, and all such features required a pilot to gain experience with the aircraft, which in part was an additional reason Lockheed sent its representative to England, and later to the Pacific Theater. The aircraft was still experiencing extensive teething troubles as well as being victimized by "urban legends", mostly involving inapplicable twin engine factors which had been designed out of the aircraft by Lockheed. In addition to these, the early versions had a reputation as a "widow maker" as it could enter an unrecoverable dive due to a sonic surface effect at high sub-sonic speeds. The 527 P-38Fs were heavier, with more powerful engines that used more fuel, and were unpopular in the air war in Northern Europe. Since the heavier engines were having reliability problems and with them, without external fuel tanks, the range of the P-38F was reduced, and since drop tanks themselves were in short supply as the fortunes in the Battle of the Atlantic had not yet swung the Allies' way, the aircraft became relatively unpopular in minds of the bomber command planning staffs despite being the longest ranged fighter first available to the 8th Air Force in sufficient numbers for long range escort duties. Nonetheless, General Spaatz, then commander of the 8th Air Force in the UK, said of the P-38F: "I'd rather have an airplane that goes like hell and has a few things wrong with it, than one that won't go like hell and has a few things wrong with it."

The P-38F was followed in early 1943 by the P-38G, utilizing more powerful Allisons of 1,400 hp (1,040 kW) each and equipped with a better radio. A dozen of the planned P-38G production was set aside to serve as prototypes for what would become the P-38J with further uprated Allison V-1710F-17 engines (1,425 hp/1,060 kW each) in redesigned booms which featured chin-mounted intercoolers in place of the original system in the leading edge of the wings and more efficient radiators. Lockheed subcontractors, however, were initially unable to supply both of Burbank's twin production lines with a sufficient quantity of new core intercoolers and radiators. War Production Board planners were unwilling to sacrifice production, and one of the two remaining prototypes received the new engines but retained the old leading edge intercoolers and radiators. As the P-38H, 600 of these stop-gap Lightnings with an improved 20 mm cannon and a bomb capacity of 3,200 lb (1,450 kg).were produced on one line while the near-definitive P-38J began production on the second line. The Eighth Air Force was experiencing high altitude and cold weather issues which while not unique to the plane, were perhaps more severe as the turbo-superchargers upgrading the Allisons were having their own reliability issues making the planes more unpopular with senior officers out of the line. This was a situation unduplicated on all other fronts where the commands were clamoring for as many P-38s as they could get. Both the P-38G and P-38H models' performance was restricted by an intercooler system integral to the wing's leading edge which had been designed for the YP-38's less powerful engines. At the higher boost levels, the new engine's charge air temperature would increase above the limits recommended by Allison and would be subject to detonation if operate at high power for extended periods of time. Reliability was not the only issue, either. For example, the reduced power settings required by the P-38H did not allow the maneuvering flap to be used to good advantage at high altitude. All these problems really came to a head in the unplanned P-38H and sped the Lightning's eventual replacement in the Eighth Air Force; fortunately the Fifteenth Air Force were glad to get them.

Some P-38G and H production was diverted on the assembly line to F-5A and F-5B reconnaissance aircraft. An F-5A was modified to an experimental two-seat reconnaissance configuration as the XF-5D, with a plexiglas nose , two machine guns and additional cameras in the tail booms.

The P-38J was introduced in August 1943. The turbo-supercharger intercooler system on previous variants had been housed in the leading edges of the wings and had proven vulnerable to combat damage and could burst if the wrong series of controls were mistakenly activated. In the P-38J model, the streamlined engine nacelles of previous Lightnings were changed to fit the intercooler radiator between the oil coolers, forming a "chin" that visually distinguished the J model from its predecessors. While the P-38J used the same V-1710-89/91 engines as the H model, the new core-type intercooler more efficiently lowered intake manifold temperatures and permitted a substantial increase in rated power. The leading edge of the outer wing was fitted with 55 gal (208 l) fuel tanks, filling the space formerly occupied by intercooler tunnels, but these were omitted on early P-38J blocks due to limited availability.

The final 210 J models, designated P-38J-25-LO, alleviated the compressibility problem through the addition of a set of electrically-actuated dive recovery flaps just outboard of the engines on the bottom centerline of the wings. With these improvements, a USAAF pilot reported a dive speed of almost 600 mph (970 km/h), although the indicated air speed was later corrected for compressibility error, and the actual dive speed was lower. Lockheed manufactured over 200 retrofit modification kits to be installed on P-38J-10-LO and J-20-LO already in Europe, but the USAAF C-54 carrying them was shot down by an RAF pilot who mistook the Douglas transport for a German Focke-Wulf Condor. Unfortunately the loss of the kits came during Lockheed test pilot Tony LeVier's four-month morale-boosting tour of P-38 bases. Flying a new Lightning named "Snafuperman" modified to full P-38J-25-LO specs at Lockheed's modification center near Belfast, LeVier captured the pilots' full attention by routinely performing maneuvers during March 1944 that common Eighth Air Force wisdom held to be suicidal. It proved too little too late because the decision had already been made to re-equip with Mustangs.

The P-38J-25-LO production block also introduced hydraulically-boosted ailerons, one of the first times such a system was fitted to a fighter. This significantly improved the Lightning's rate of roll and reduced control forces for the pilot. This production block and the following P-38L model are considered the definitive Lightnings, and Lockheed ramped up production, working with subcontractors across the country to produce hundreds of Lightnings each month.

References

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Aversa, R., D. Parcesepe, R.V.V. Petrescu, F. Berto and G. Chen et al., 2017d. Process ability of bulk metallic glasses. Am. J. Applied Sci., 14: 294-301.

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Aversa, R., D. Parcesepe, R.V. Petrescu, G. Chen and F.I.T. Petrescu et al., 2016b. Glassy amorphous metal injection molded induced morphological defects. Am. J. Applied Sci., 13: 1476-1482.

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Aversa, R., V. Perrotta, R.V. Petrescu, C. Misiano and F.I.T. Petrescu et al., 2016g. From structural colors to super-hydrophobicity and achromatic transparent protective coatings: Ion plating plasma assisted TiO2 and SiO2 Nano-film deposition. Am. J. Eng. Applied Sci., 9: 1037-1045.

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Petrescu, F.I., Petrescu, R.V., 2014e Machine Equations to the Classical Distribution, International Review of Mechanical Engineering 8(2):309-316.

Petrescu, F.I., Petrescu, R.V., 2014f Forces of Internal Combustion Heat Engines, International Review on Modelling and Simulations 7(1):206-212.

Petrescu, F.I., Petrescu, R.V., 2014g Determination of the Yield of Internal Combustion Thermal Engines, International Review of Mechanical Engineering 8(1):62-67.

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Petrescu, FIT.; Calautit, JK.; Mirsayar, M.; Marinkovic, D.; 2015 Structural Dynamics of the Distribution Mechanism with Rocking Tappet with Roll, American Journal of Engineering and Applied Sciences, 8(4):589-601. DOI: 10.3844/ajeassp.2015.589.601

Petrescu, FIT.; Calautit, JK.; 2016 About Nano Fusion and Dynamic Fusion, American Journal of Applied Sciences, 13(3):261-266.

Petrescu, R.V.V., R. Aversa, A. Apicella, F. Berto and S. Li et al., 2016a. Ecosphere protection through green energy. Am. J. Applied Sci., 13: 1027-1032. DOI: 10.3844/ajassp.2016.1027.1032

Petrescu, F.I.T., A. Apicella, R.V.V. Petrescu, S.P. Kozaitis and R.B. Bucinell et al., 2016b. Environmental protection through nuclear energy. Am. J. Applied Sci., 13: 941-946.

Petrescu, Relly Victoria; Aversa, Raffaella; Akash, Bilal; Bucinell, Ronald; Corchado, Juan; Berto, Filippo; Mirsayar, MirMilad; Apicella, Antonio; Petrescu, Florian Ion Tiberiu; 2017a Modern Propulsions for Aerospace-A Review, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, Relly Victoria; Aversa, Raffaella; Akash, Bilal; Bucinell, Ronald; Corchado, Juan; Berto, Filippo; Mirsayar, MirMilad; Apicella, Antonio; Petrescu, Florian Ion Tiberiu; 2017b Modern Propulsions for Aerospace-Part II, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, Relly Victoria; Aversa, Raffaella; Akash, Bilal; Bucinell, Ronald; Corchado, Juan; Berto, Filippo; Mirsayar, MirMilad; Apicella, Antonio; Petrescu, Florian Ion Tiberiu; 2017c History of Aviation-A Short Review, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, Relly Victoria; Aversa, Raffaella; Akash, Bilal; Bucinell, Ronald; Corchado, Juan; Berto, Filippo; Mirsayar, MirMilad; Apicella, Antonio; Petrescu, Florian Ion Tiberiu; 2017d Lockheed Martin-A Short Review, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, Relly Victoria; Aversa, Raffaella; Akash, Bilal; Corchado, Juan; Berto, Filippo; Mirsayar, MirMilad; Apicella, Antonio; Petrescu, Florian Ion Tiberiu; 2017e Our Universe, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, Relly Victoria; Aversa, Raffaella; Akash, Bilal; Corchado, Juan; Berto, Filippo; Mirsayar, MirMilad; Apicella, Antonio; Petrescu, Florian Ion Tiberiu; 2017f What is a UFO?, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, RV., Aversa, R., Akash, B., Corchado, J., Berto, F., Mirsayar, MM., Apicella, A., Petrescu, FIT., 2017 About Bell Helicopter FCX-001 Concept Aircraft-A Short Review, Journal of Aircraft and Spacecraft Technology, 1(1).

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Petrescu, RV., Aversa, R., Akash, B., Corchado, J., Berto, F., Mirsayar, MM., Kozaitis, S., Abu-Lebdeh, T., Apicella, A., Petrescu, FIT., 2017 Airlander, Journal of Aircraft and Spacecraft Technology, 1(1).

Petrescu, RV., Aversa, R., Akash, B., Corchado, J., Berto, F., Apicella, A., Petrescu, FIT., 2017 When Boeing is Dreaming – a Review, Journal of Aircraft and Spacecraft Technology, 1(1).