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The P-38 Lightning

The Lightning was designed in 1937 as a high-altitude interceptor. The first one built, the XP-38, made its public debut on 11th February, 1939 by flying from California to New York in seven hours. Because of its unorthodox design, the aeroplane experienced "growing pains" and it required several years to perfect it for combat. Late in 1942, it went into large-scale operations during the North African campaign where the German Luftwaffe named it "Der Gabelschwanz Teufel"--"The Forked-Tail Devil."

Equipped with droppable fuel tanks under its wings, the P-38 was used extensively as a long-range escort fighter and saw action in practically every major combat area of the world. A very versatile aircraft, the Lightning was also used for dive bombing, level bombing, ground strafing and photo reconnaissance missions.

The Early Days

The P-38 Lightning history begins with an idea from Lockheed engineer Kelly Johnson who also designed the SR-71 Blackbird. Johnson's idea was far ahead of its time, and was more advanced than any other fighter/interceptor design during this time period. Many of the components that were incorporated into the designs were not yet invented, which would be a common theme in Johnson's designs after the war. The P-38 laid down the groundwork for other advanced fighters in the early 1940s. If not for the phenomena encountered during extensive testing, later fighters such as the P-51 would have taken much longer to reach operational status. The P-38 was used for logical purposes such as various attacking techniques, and was also put through radical design concepts such as a float-plane version for long distance ferrying in the Pacific. No other aircraft in the war was used for so many roles. It must be known that the P-38 was very capable in its main role as a fighter, but also equally successful in many other roles. The P-38 would begin its life in a spectacular and dramatic fashion with a record flight attempt, and would serve with valour and distinction throughout the war.

Just as the development of the North American P-51 Mustang, Republic P-47 Thunderbolt, and the Vought F4U Corsair pushed the limits of aircraft performance into unexplored territory, so to did P-38 development. The type of aircraft envisioned by the Lockheed design team and Air Corps strategists in 1937 did not appear until June 1944. This protracted shakedown period mirrors the tribulations suffered by Vought in sorting out the many technical problems that kept F4U Corsairs off U.S. Navy carrier decks until the end of 1944.

Johnson's team made numerous minor improvements to the basic P-38 design as they strove to give Lightning pilots every possible combat advantage. To ease control and improve stability, particularly at low speeds, Lockheed equipped all Lightnings, except a batch ordered by Britain, with propellers that counter-rotated. The propeller to the pilot's left turned counter-clockwise and the propeller to his right turned clockwise, so that one propeller countered the torque and airflow effects generated by the other. The aeroplane also performed well at high speeds and the definitive P-38L model could make better than 676 km/h (420 mph) between 7,600 and 9,120 m (25,000 and 30,000 ft). The design was versatile enough to carry various combinations of bombs, air-to-ground rockets, and external fuel tanks. The multi-engine configuration reduced the Lightning loss-rate to anti-aircraft gunfire during ground attack missions. Single-engine aeroplanes equipped with power plants cooled by pressurised liquid, such as the North American P-51 Mustang,were particularly vulnerable. Even a small nick in one coolant line could cause the engine to seize in a matter of minutes.

Lockheed's efforts to trouble-shoot various problems with the design also delayed high-rate, mass production. When Japan attacked Pearl Harbour, the company had delivered only 69 Lightning's to the Army. Production steadily increased and at its peak in 1944, 22 sub-contractors built various Lightning components and shipped them to Burbank, California, for final assembly. Consolidated-Vultee (Convair) subcontracted to build the wing centre section and the firm later became prime manufacturer for 2,000 P-38Ls but that company's Nashville plant completed only 113 examples of this Lightning model before war's end. Lockheed and Convair finished 10,038 P-38 aircraft including 500 photo-reconnaissance models. They built more L models, 3,923, than any other version.

The First of a New Breed

The Lightning designed by Lockheed engineer Clarence "Kelly" Johnson and his team of designers represented one of the most radical departures from tradition in American fighter development. The Lightning was a complete breakaway from conventional airframe design, power, and at long last, armament. Not only did it have twice the power and almost twice the size of its predecessors, but with no less than four .50 cal. machine guns plus a 20-mm cannon, the P-38 had enough firepower to sink a ship--and sometimes did. Concentrated in the central fuselage pod, the guns fired parallel which eliminated a need for a propeller synchroniser.

The Lightning tricycle landing gear and twin-boom configuration completed the list of major deviations from what might he considered conventional Army fighters. In this respect, it was very unusual that the Lightning design progressed beyond the testing stage; such radical concepts seldom achieved production status. But the simple fact was that the P-38 design worked and the Army seemed to have found its dream plane in this 400-mph (644-km/h) fighter.

The XP-38, 37-457, was built under tight secrecy and made its maiden flight on 27th January, 1939, with Air Corps test pilot and P-38 project officer, Lt. Benjamin S. Kelsey, at the controls. The P-38's performance justified Lockheed's investment of nearly $6,000,000 of its own funds to complete the prototype. The Army was so delighted with the big new fighter, it lifted the wraps of secrecy from the plane for a transcontinental speed dash on February 11, 1939. This event was marred by a crash when Kelsey undershot the runway at Mitchell Field, NY. Kelsey survived the crash and remained an important part of the Lightning programme. The aeroplane was written off, but Lockheed received a contract for thirteen YP-38s along with the usual list of improvements.

The XP-38 had been powered by two liquid cooled, Allison V-1710 engines turning 11½ foot (4m) Curtiss Electric, inward turning, counter-rotating propellers. With the YP-38s and all subsequent Lightings, the propellers rotated outward negating torque when both engines were operating. A batch of 600 ordered by Britain in 1940 & named the Lightning, distinguishing them from the American name Atlanta, did not have counter-rotating propellers or superchargers. The British felt as the aircraft was intended for medium altitude combat, the supercharges would not be needed. The requirement for only the use of right handed engines was for commonality with the large number of Curtiss Tomahawks they had on order. Lockheed engineers protested strongly against this decision & privately labeled the variant "The castrated Lightning". When the first three of the order were delivered the performance was so poor the rest of the order was cancelled, however the name P-38 Lightning had gone down in aeronautical history.

One XP-38A was built with a pressurised cabin. Armament on the YPs was altered by replacement of two of the .50s with .30s, and the 20-mm cannon gave way to a 37 mm. But even before the YP-38s were completed, the original machine gun arrangement was standardised for production types. The first production order was 35 P-38Ds, followed by 210 P-3XEs, which reverted back to the 20-mm cannon. These planes began to arrive in October 1941, just before America entered World War II. With the P-38D came self sealing fuel tanks and armour protection for the pilot. The Lightning was ready for war!

A major problem surfaced with the loss of control in a dive caused by aerodynamic compressibility. During late spring 1941, Air Corps Major Signa A. Gilke encountered serious trouble while diving his Lightning at high-speed from an altitude of 30,000 ft (9,120 m). When he reached an indicated airspeed of about 320-mph (515 kph), the aeroplane's tail began to shake violently and the nose dropped until the dive was almost vertical. Signa recovered and landed safely and the tail buffet problem was soon resolved after Lockheed installed new fillets to improve airflow where the cockpit gondola joined the wing centre section. Seventeen months passed before engineers began to determine what caused the Lightning's nose to drop. They tested a scale model P-38 in the Ames Laboratory wind tunnel operated by the NACA (National Advisory Committee for Aeronautics) and found that shock waves formed when airflow over the wing reached transonic speeds and became turbulent. Lockheed never remedied this problem but the firm did install dive recovery flaps under each wing in 1944 to restore lift and smooth the airflow enough to maintain control when diving at high-speed.

The fastest of the Lightning's was the P-38J with a top speed of 420 mph (676km/h), and the version produced in the greatest quantity was the "L", of which 3,810 were built by Lockheed and 113 by Vultee. The P-38L was powered by two 1,475 hp Allison V1710-111 engines. As with any long-term production aircraft, the P-38 underwent many modifications. The P-38J intakes under the engines were enlarged to house core-type intercoolers. The curved windscreen was replaced by a flat panel, and the boom mounted radiators were enlarged. Some were fitted with bombardier type noses, and were used to lead formations of bomb-laden P-38s to their targets. The P-38M was a two-seat radar-equipped night fighter, a few of which had become operational before the war ended. One interesting variation had an elevated tail assembly on upswept booms; another one had an elongated centre pod and was used for airfoil evaluation.

The dimensions of the P-38 remained the same throughout production, its wing spanning 52 feet (16m) with an area of 328 square feet (30 sq. meters). Overall length was 37 feet 10 inches (12m); height was 12 feet 10 inches (4m). The P-38L weighed 12,800 pounds (5806 kilos) empty and 17,500 pounds gross (7938 kilos). Thus, the P-38 was the largest, heaviest, and fastest "P" type to date. An internal fuel capacity of 410 gallons (1861 litres) could be increased to 1,010 gallons (4585 litres) with two external drop tanks and gave the Lightning a range of 450 miles (724km), making it the first fighter suitable as a long-range bomber escort. In addition to its devastating nose armament, the P-38 could carry up to 4,000 pounds (1814.4 kilos) of external weapons including bombs and rockets.

The Pacific Theatre

The first P-38s to reach the Pacific combat theatre arrived on 4th April, 1942, when a version of the Lightning that carried reconnaissance cameras (designated the F-4), joined the 8th Photographic Squadron based in Australia. This unit launched the first P-38 combat missions over New Guinea and New Britain during April. By 29th May, the first 25 P-38s had arrived in Anchorage, Alaska. On 9th August, pilots of the 343rd Fighter Group, Eleventh Air Force, flying the P-38E, shot down a pair of Japanese flying boats.

In the war against Japan, the P-38 truly excelled. Combat rarely occurred above 6,080 m (20,000 ft) and the engine and cockpit comfort problems common in Europe never plagued pilots in the Pacific Theatre. The Lightning's excellent range was used to full advantage above the vast expanses of water. In early 1945, Lightning pilots of the 12th Fighter Squadron, 18th Fighter Group, flew a mission that lasted 10 ½ hours and covered more than 3,220 km (2,000 miles). In August, P-38 pilots established the world's long-distance record for a World War II combat fighter when they flew from the Philippines to the Dutch East Indies, a distance of 3,703 km (2,300 miles). During early 1944, Lightning pilots in the 475th Fighter Group began the 'race of aces.' By March, Lieutenant Colonel Thomas J. Lynch had scored 21 victories before he fell to anti-aircraft fire while strafing enemy ships. Major Thomas B. McGuire downed 38 Japanese aircraft before he was killed when his P-38 crashed at low altitude in early January 1945. Major Richard I. Bong became America's highest scoring fighter ace (40 victories) but died in the crash of a Lockheed P-80 on 6th August, 1945.This was the same day the atomic bomb was dropped on Japan. The P-80 Lockheed Shooting Star was the first operational jet fighter in the US military. It went into service in 1945.

Lindbergh Connection

Charles Lindbergh was given permission by Colonel Robert Morrissey to travel to Nadzah, New Guinea, and become familiar with the P-38. On the 15th of June, 1944 Lindbergh arrived and was soon spending time behind a P-38. His first flight was rather interesting because once he landed, a brake malfunction resulted in a blown tyre, but there was no damage. Soon Lindbergh felt comfortable with the aircraft, and on the 26th of June he took off to join up with the 475th Fighter Group. He flew on combat missions as an observer, and quickly calculated that the combat radius could be extended by 30%. A standard technique at the time was cruising at 2200 - 2400 rpm's in auto-rich at low manifold pressure. Lindbergh called for only 1600 rpm in an auto-lean mixture with a high manifold pressure. This reduced fuel consumption to 70 U.S. gallons (265 liters) per hour, and resulted in a cruising speed of 185 mph (298 km/h). By comparison in July 1944, P-38s would fly a five-hour mission and come back on fumes, but after taking Lindbergh's advice they completed long missions with fuel to spare.

The European Theatre

In Europe, the first Americans to down a Luftwaffe aircraft were Lt. Elza E. Shahan flying a 27th Fighter Squadron P-38E, and Lt. J. K. Shaffer flying a Curtiss P-40 in the 33rd Fighter Squadron. The two flyers shared the destruction of a Focke-Wulf Fw 200C-3 Condor maritime strike aircraft over Iceland on 14thAugust, 1942. Later that month, the 1st fighter group accepted Lightning's and began combat operations from bases in England but this unit soon moved to fight in North Africa. More than a year passed before the P-38 reappeared over Western Europe. While the Lightning was absent, U. S. Army Air Forces strategists had relearned a painful lesson: unescorted bombers cannot operate successfully in the face of determined opposition from enemy fighters. When P-38s returned to England, the primary mission had become long-range bomber escort at ranges of about 805 km (500 miles) and at altitudes above 6,080 m (20,000 ft).

On 15th October, 1943, P-38H pilots in the 55th Fighter Group flew their first combat mission over Europe at a time when the need for long-range escorts was acute. Just the day before, German fighter pilots had destroyed 60 of 291 Eighth Air Force B-17 Flying Fortresses during a mission to bomb five ball-bearing plants at Schweinfurt, Germany. No air force could sustain a loss-rate of nearly 20 percent for more than a few missions but these targets lay well beyond the range of available escort fighters (Republic P-47 Thunderbolts). American war planners hoped the long-range capabilities of the P-38 Lightning could halt this deadly trend, but the very high and very cold environment peculiar to the European air war caused severe power plant and cockpit heating difficulties for the Lightning pilots. The long-range escort problem was not completely solved until the North American P-51 Mustang began to arrive in large numbers early in 1944.

Poor cockpit heating in the H and J model Lightning's made flying and fighting at altitudes that frequently approached 12,320 m (40,000 ft) nearly impossible. This was a fundamental design flaw that Kelly Johnson and his team never anticipated when they designed the aeroplane six years earlier. In his seminal work on the Allison V-1710 engine, Daniel Whitney analysed in detail other factors that made the P-38 a disappointing aeroplane in combat over Western Europe.

- Many new and inexperienced pilots arrived in England during December 1943, along with the new J model P-38 Lightning.
- J model rated at 1,600 horsepower vs. 1,425 for earlier H model Lightning's. This power setting required better maintenance between flights. It appears this work was not done in many cases.
- During stateside training, Lightning pilots were taught to fly at high rpm settings and low engine manifold pressure during cruise flight. This was very hard on the engines, and not in keeping with technical directives issued by Allison and Lockheed.
- The quality of fuel in England may have been poor, TEL (tetraethyl lead) fuel additive appeared to condense inside engine induction manifolds, causing detonation (destructive explosion of fuel mixture rather than controlled burning).
- Improved turbo supercharger intercoolers appeared on the J model P-38. These devices greatly reduced manifold temperatures but this encouraged TEL condensation in manifolds during cruise flight and increased spark plug fouling.

Using water injection to minimise detonation might have reduced these engine problems. Both the Republic P-47 Thunderbolt and the North American P-51 Mustang were fitted with water injection systems but not the P-38. Lightning pilots continued to fly, despite these handicaps.

Back in the United States, Army Air Forces leaders tried to control a rumour that Lightning's killed their own pilots. On 10th August 1942, Col. Arthur I. Ennis, Chief of U. S. Army Air Forces Public Relations in Washington, told a fellow officer "… Here's what the 4th Fighter [training] Command is up against… common rumour out there that the whole West Coast was filled with headless bodies of men who jumped out of P-38s and had their heads cut off by the propellers." Novice Lightning pilots unfamiliar with the correct bailout procedures actually had more to fear from the twin-boom tail, if an emergency dictated taking to the parachute but properly executed, Lightning bailouts were as safe as parachuting from any other high-performance fighter of the day. Misinformation and wild speculation about many new aircraft was rampant during the early War period.

P-38M Night Fighter

To meet the Army's need for a night interceptor aircraft, several types such as the British Bristol Beaufighter and the deHaviland Mosquito (both were acquired through the "reverse Lend Lease" programme), and the Douglas P-70 (variation from the A-20 Havoc light bomber) were tried. In the Pacific there some P-38s were converted into night fighter roles. The 6th Night Fighter Squadron on New Guinea mounted two SCR-540 Airborne Intercept (AI) radar units which were mounted into two P-38 drop tanks. These aircraft were also able to carry a passenger located directly behind the pilot under a small bubble canopy. There were other field converted P-38s but none were produced with the night fighter role in mind. During 1944, Lockheed began the development of the P-38 night fighter which involved the conversion of the P-38J with an AN/APS-4 AI radar pod mounted under the nose on a modified bomb pylon. In October 1944, Lockheed began production of the P-38M with all the modifications mentioned previously and it made it's maiden flight on 5th January, 1945. The P-38M crews trained at Hammer Field, California early in 1945, but did not finish training until early in the summer of 1945 and were not deployed because of the end of the war. By March of 1946, the P-38M was phased out of service.

By the end of production in 1945, 10,151 P-38s had been built. The Lightning was the only American fighter that saw action throughout out the entire war.

The P-38 Power Plant: The Allison V-1710 Engine

The V-1710 engine was the first product of an extensive U.S. Army programme to develop a high-power, liquid-cooled engine. Derived from a model designed in 1930 for airship use, the V-1710 was first used by the Air Corps in 1932. Rated at 1,000 horsepower, it was installed in the Consolidated XA-11A, an experimental attack version of the Consolidated P-25. By 1938, the engine's output had been increased to 1,150 horsepower and was used to power the Bell X/YFM-1 multiplace fighters. The V-1710 was continually improved and during World War II its output was increased to 1,475 horsepower in some series engines. During the war it was used primarily in the Curtiss P-40 "Warhawk", the Bell P-39 "Airacobra", and the twin-engine Lockheed P-38 "Lightning". It was also used in early versions of the North American P51"Mustang".

A right-hand drive V-1710-51, series was used primarily in the P-38G. When installed in a twin-engine P-38, it was paired with a left-hand drive V-1710-55 engine to counteract the effect of torque. The only difference between the two engines was the direction of propeller-shaft rotation.

Model: V-1710-51 (right-hand drive)
Model: V-1710-55 (left-hand drive)
Type: 12 cylinder, supercharged
Displacement: 1,710 (0.03 cu meters)
Weight: 1,345 lbs. (610.1 kg)
Maximum RPM: 3,000
Maximum Horsepower: 1,325
Cost: $19,000 (In 1940s Dollars)

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