Chapter 9
Development
In the late 1930s the Wright Field Pursuit Projects Office was the center for testing aviation technology and developing new military aircraft. In February 1937, with the crisis in Europe deepening, it issued requests for proposals for a single-engine fighter and a twin-engine fighter. Seven aircraft manufacturers were invited to participate, including Bell, Boeing, Curtiss, and Douglas.
The requirements for the new aircraft were clearly specified: minimum top speed of 360 mph; an operating ceiling of at least 20,000 feet, and a climb rate that would allow the aircraft to reach its ceiling in less than six minutes. Cannon armament was also specified, since the primary function of these new airplanes was high-altitude interception of hostile aircraft, specifically bombers. The aircraft had to be equipped with tricycle-type landing gear to facilitate ground handling, and the aircraft engines had to be able to operate at full throttle for at least one hour.
An airframe with these advanced specifications was needed by the Army Air Forces in order to keep pace with the rapidly advancing combat aircraft capabilities of Germany and Japan. To put these requirements into perspective, two fighters previously evaluated by the army in 1937 had maximum speeds of 313 mph. The new aircraft would represent a quantum leap forward in airplane design and performance.
The proposals submitted by Bell for the single-engine aircraft, and that of Lockheed for the twin-engine aircraft, were accepted.1 Bell’s design led to the P-39 Airacobra. Operating most effectively below 12,000 feet, the P-39 proved to be a useful ground-attack aircraft that was used widely by the Allied air forces.
Lockheed’s design led to the P-38 Lightning. Developed by noted aviation designers Hall Hubbard and Kelly Johnson, the proposed aircraft was so well received that an army contract was issued in June 1937. Although the amount of the army contract was just $163,000, Lockheed actually spent $761,000 to fulfill it—a testimony to their faith in the design and their commitment to get the aircraft into testing. Lockheed’s prototype was one of the world’s fastest aircraft when it first flew in early 1939, and became the first fighter to fly faster than 400 mph. It was destined to be the only U.S. fighter to remain in production throughout World War II.
Lockheed had originally dubbed the aircraft Atalanta, from Greek mythology, in keeping with the company tradition of naming planes after mythological and celestial figures: Atalanta—Greek goddess of the hunt. But initial orders for the P-38 went to Britain, whose RAF dubbed it the “Lightning,” and the name stuck. In his technical report “Assessing the Lockheed P-38 Lightning,” Dr. Carlo Kopp noted a further extraordinary feature of the Lockheed aircraft:
The P-38 excelled in that design parameter which is pivotal to fighting a strategic air war, its combat radius in excess of 700 NM [nautical miles] had no equivalent in either camp. The Lightning’s combat radius was exploited repeatedly and surprisingly, the Lightning repeatedly succeeded in catching its opponents off guard. Both in the Pacific and the Mediterranean, the P-38 provided long-range escort for heavy bombers, long-range fighter sweeps deep into hostile airspace and interdiction of surface targets.2
Design
The muscle of the twin-engine P-38 was provided by the new Allison V-12 engines mated to a new GE-developed turbocharger that provided enhanced performance at higher altitudes. This power plant enabled the Lightning to easily meet the army specifications. Among many innovations, the engines were “counter-rotating,” meaning the left engine rotated in the opposite direction from the right. This had the effect of negating torque—a troublesome attribute of single-engine aircraft or multi-engine aircraft that did not counter-rotate.
The cockpit, nosewheel, guns, and ammunition were all contained in a central pod (nacelle), and the engines were mounted in mid-wing nacelles extending back into tail booms joined by a horizontal tail and twin rudders. The cockpit was equipped with a jettisonable top cover and crank-down side windows. The windshield was a single slab of armored glass, and the pilot was protected by a steel plate forward and multiple rear plates. Responding to the army requirement for heavy armament, the P-38 was fitted with one 37mm cannon (later downgraded to a 20mm caliber) and a battery of four 12.7mm Browning machine guns, all mounted in the nose.
The Lightning was a heavy machine, categorized as a fighter but achieving the same weight class as lighter bombing platforms of her time. Yet even with its impressive size, it met the army’s specification of 400 mph top speed, and remained one of the fastest fighters through the mid-war period. Its long flight duration allowed it to outrange any single-seat fighter during the early war years.
A P-38 test pilot summed up the war bird’s legacy: “[T]his comfortable old cluck would fly like hell, fight like a wasp upstairs, and land like a butterfly.”3
Production, Delivery, and Variants
The army’s initial order for P-38 aircraft in September 1939 was intended to allow the army and Lockheed to refine the design and give the Army Air Forces experience with handling this new type of aircraft.
In the spring of 1940, President Roosevelt issued his call for fifty thousand new aircraft. At that time, the P-38 was already far along the development curve and the most readily available design. It was formally accepted into service in August of 1940, with serial production of the initial model—the P-38E—beginning in September.
Deliveries of the P-38G model—the first fully combat-capable version, commenced in August 1942, and by November Lightnings were operating from bases in North Africa and in the Southwest Pacific. It was this variant that was flown by the 14th Fighter Group in the summer of 1943, although it was also common for each squadron to hold two or three of the older F models in their arsenal.
Development of other highly performant aircraft continued, ultimately leading to the P-47 Thunderbolt and the P-51 Mustang, but by the time these new aircraft were introduced, the P-38 had already been in combat service for two and a half years.
By war’s end, just over ten thousand P-38s, in all variants, were produced. Roughly one out of eight P-38s initially produced were either used for photo reconnaissance or were modified for that purpose after delivery to the army. These photo reconnaissance variants, termed F-4s or F-5s, saw widespread service throughout the war, commencing in late 1942.
P-38G Specifications4
Maximum speed: 345 mph at 5,000 feet—400 mph at 25,000 feet.
Range on internal tanks: 850 miles (at 219 mph cruising speed and at 10,000 feet).
Range using drop tanks: 1,750 miles (using two 125-gallon drop tanks).
Time to climb to 10,000 feet (combat load): 3 minutes, 42 seconds.
Time to climb to 20,000 feet (combat load): 8 minutes, 30 seconds.
Service ceiling: 39,000 feet.
Weight empty: 12,200 pounds.
Weight with normal load: 15,800 pounds.
Wingspan: 52 feet.
Length: 37 feet, 10 inches.
Height: 9 feet, 10 inches.
Armament: One 20-mm Hispano M1 cannon with 150 rounds; four 0.50 Colt-Browning MG 53-2 machine guns with 500 rounds per gun.
Bomb load: Two 325-, 500-, or 1,000-pound bombs.
Features and Description
Unlike other fighters of the era, the P-38 did not use a central “joystick” for flight controls. Rather, it used a control wheel, called a yoke. This design innovation was required because the wing taper of the P-38 necessitated the use of small ailerons; in addition, the large movement of the aileron needed to initiate roll in the aircraft required more muscle at the controls than could be achieved with a stick. Radio and gun buttons were also located on the yoke, as was the drop-tank/bomb-drop button.
Clustering all the armament in the nose was unlike the typical style of most other U.S. aircraft, which used monocoque fuselage design and wing-mounted guns. Wing-mounted guns required that the trajectories be set up to crisscross at one or more points in a “convergence zone.” This was a limitation for these types of aircraft, since they could only bring their maximum firepower to bear on a single point, Typically 100–250 yards ahead of the aircraft.
Pattern convergence was not an issue for the nose-mounted guns of the P-38, permitting pilots to commence firing earlier, reliably hitting targets up to 1,000 yards ahead of the aircraft.
The guns and cannon were set to fire concurrently: The rate of fire for the cannon was about 650 rounds per minute, and 850 rounds per minute for each of the four .50-inch machine guns. This gave the P-38 a ferocious combined rate of fire of over 4,000 rounds per minute, with one out of six rounds a 20mm cannon shell. The magazine sizes limited the duration of fire: The cannons had a sustained duration of fire of about fourteen seconds, and the machine guns, about thirty-five seconds. It should be noted that pilots fired in bursts, rather than sustained firing, because the buildup of heat in the guns could cause malfunction and contributed to early gun-barrel wear.
Nose armament of the Lockheed P-38 Lightning.
NATIONAL ARCHIVES
The P-38 in Flight
The P-38 was an exceptionally aerobatic aircraft. With the exception of dives, mentioned below, there were no restrictions on maneuvers: Immelmanns, high-speed Split S turns, and a variety of high-performance loops, rolls, and figure eight aerobatics could all be executed easily. It was a very able aircraft “in the vertical,” both ascending and descending very quickly, making it an excellent platform for dive-bombing and strafing, and then climbing back up. It had an excellent rate of climb, and an exceptional “zoom rate”—a brief steep upward movement following horizontal acceleration. It could easily change direction while executing vertical maneuvers, and it was a very stable gun platform. The Lightning was also very maneuverable at low altitudes, due in part to the counter-rotating props and the elimination of engine torque.
Operational Advantages
The P-38 offered many exceptional operational advantages over other aircraft of the era—both Allied and Axis:
- The P-38 was unusually quiet for a fighter, the exhaust muffled by the turbo-superchargers.
- The P-38 was the only multi-engine fighter in operation during the war, and this new dimension gave the Lightning a great advantage during ground-attack missions. Single-engine airplanes equipped with liquid-cooled engines were quite vulnerable to ground fire; even a small nick in the coolant lines could cause the engine to seize in just a few minutes. And in flight, single-engine pilots had to be on high alert for any sign of engine failure—every ping, miss, or stutter could have severe consequences. The added insurance of a second engine made it possible for many P-38 pilots to safely return to base after losing an engine.
During the first eighteen months after America’s entry in the war, the P-38 was the fastest and most performant aircraft in wide usage. No World War II fighter had as much available horsepower at altitudes of 25,000 feet and above as the P-38.
The strategic air war in the Mediterranean Theater depended on the P-38’s exceptionally long range—up to 1,750 miles—in order to provide fighter protection deep into enemy territory. And it was capable of long-distance independent fighter sweeps to conduct dive-bombing and strafing missions. It was also possible for the P-38 to trade range for payload, carrying a bomber’s load of armaments on shorter missions. It had no equivalent among other Allied aircraft, or in the Luftwaffe.
The P-38 handled well both on the ground and in the air, making it less fatiguing for the pilot. And with the engines placed to the side and the cockpit placed forward, visibility was excellent.
It was an excellent fighter/interceptor whose versatility and ruggedness were legendary. Properly equipped, it could be used in any theater of the war and could be applied to a wide range of missions: it could sink a ship, dive-bomb tanks, radar installations, or gun positions, strafe troop concentrations or tanks, and destroy even hardened ground emplacements.
Finally, the P-38 could take a lot of punishment and still stay in the air. In one noteworthy example in the 49th squadron, Capt. William Hoelle’s P-38 clipped a telephone pole at 300 miles per hour. Flipped on its back by the impact, Hoelle was able to right his plane and return to base.
Capt. William Hoelle inspecting damage to his P-38, sustained when he hit a telephone pole on a low-level pass.
NATIONAL ARCHIVES
The aircraft that would later be assigned to Lieutenant Knepper in North Africa came off the assembly line at the Lockheed plant in Burbank just as Knepper was entering the halfway point of his Basic flight training, on November 6, 1942. It was originally destined for the 8th Air Force operating out of England, but when Operation Roundup was canceled and Operation Torch decided upon, the aircraft was redirected to the 12th Air Force in North Africa. It was flown to the port of Newark, disassembled, and packed for shipment to Europe.
It was a P-38G model, serial number 42-12961. With one exception, Lieutenant Knepper would fly this aircraft on all of his future combat missions, although as the aircraft was being test-hopped in Burbank, Knepper still didn’t know whether he would complete the flight program and receive his wings or wash out and return to the enlisted ranks.
Operational Disadvantages
For all of its outstanding design and operational features, the P-38 was not without its flaws:
- The Lightning’s most crucial limitation was in high-speed dives. The problem was not a lack of speed, but rather an excess of it. In a steep, high-speed dive, airflow over parts of its frame reached near supersonic velocity, causing a form of turbulence known as “compressibility” that could lock the flight controls and induce extreme vibration. In air combat this meant that P-38 pilots had to avoid extreme dives. One of the German fighters’ favorite tactics was to make head-on attacks against the bombers, followed by tight rolls and high-speed dive-aways. The Lightnings could not follow. The diving problem also deprived Lightning pilots of their own otherwise useful escape maneuver.
In May 1943 the Army Air Forces Proving Ground Command issued a report on the “Tactical Suitability of the P-38G Type Airplane as Compared to the P-38F.” In that report, the authors noted that the “general maneuverability of this aircraft is probably the lowest of any type of current fighter aircraft.” Due to its size and design, the P-38’s ability to roll—rotation of the aircraft around the front-to-back axis—was inferior to that of single-engine planes, and it was not as nimble in dogfights.
It was also expensive to produce. Lockheed had never expected to mass-produce the P-38 design and did not engineer it for fast or easy assembly, low-cost operation, or easy maintenance. Coming later in the war, the P-51 fighter had just one engine to maintain and was easier to manufacture and maintain. In 1943 the P-38 had a price tag of $106,000 compared to $59,000 for the P-51.5
Unrelated to the aircraft, pilot training was inadequate in some aspects of operation, due very much to the haste with which new pilots had to be trained and dispatched to combat squadrons. Many new replacement pilots had as little as twenty hours of flying time on the P-38, with little or no air-to-air gunner training, and were especially lacking in deflection shooting skills.
The P-38 was a particularly cold aircraft, because the pilot sat in a pod separated from the engines. With no conductive warming effect, and only an inadequate heating system to channel warmth from the nacelles, pilots suffered in their aptly dubbed “airborne ice wagons.” And with ground temperatures in North Africa extreme, pilots operating from Tunisia or Sicily could not add additional clothing to combat lower temperatures at altitude. Pilot Robert “Smoky” Vrilakas of the 1st Fighter Group reports trying to stay warm by wrapping his legs in pages taken from the Stars and Stripes newspaper.
The German View of the P-38
The German Air Force was of two views regarding the performance and capabilities of the P-38. The head of the Luftwaffe’s Fighter Section, General der Jagdflieger Adolf Galland, was unimpressed with the P-38, declaring “it had similar shortcomings in combat to our Bf 110; our fighters were clearly superior to it.”6
The head of the GAF in Sicily prior to and during Operation Husky felt much differently. Oberstleutnant Johannes Steinhoff recorded:
Our old Messerschmitts were still, perhaps, a little faster. But pilots who had fought them said that the Lightnings were capable of appreciably tighter turns and that they would be on your tail before you knew what was happening. The six machine guns mounted in the nose supposedly produced a concentration of fire from which there was no escape. Certainly the effect was reminiscent of a watering can when one of these dangerous apparitions started firing tracer, and it was essential to prevent them maneuvering into a position from which they could bring their guns to bear.7
Queried after the war about which of the Allied fighters he encountered was the most difficult to handle with a good pilot at the controls, Steinhoff responded: “The Lightning. It was fast, low-profiled, and a fantastic fighter, and a real danger when it was above you. It was only vulnerable if you were behind it, a little below and closing fast, or turning into it, but on the attack it was a tremendous aircraft.”8
Missions
It soon became apparent that the P-38 was capable of undertaking many different kinds of missions.
In aerial combat, early in the war the P-38 was the only U.S. fighter capable of engaging the Bf 109G and Fw 190A on equal terms.
On bomber-escort missions—the majority of missions flown in the MTO by P-38s—P-38s could escort bombers to targets far beyond the range of P-40s or Spitfires based in North Africa.
P-38s flew dive-bombing and strafing ground-attack missions in the MTO, inflicting heavy damage on the German and Italian air, sea, and land convoys attempting to reinforce the theater.
The P-38 design had the flexibility to carry a wide variety of weapons, including torpedoes, bombs, and later, rockets.
Conclusion
Gen. Jimmy Doolittle, who led the Raid on Tokyo in the spring of 1942 and later commanded the North African Strategic Air Force, was a great fan of the P-38. He flew a P-38 himself during the Normandy Invasion and declared it to be “the sweetest-flying plane in sky.”9
As a World War II fighter, the Lightning’s legacy is unmatched. In all theaters of operation, P-38s equipped a total of twenty-seven fighter groups and ten reconnaissance groups. At any one time in the war more than two thousand P-38s were stationed around the world, combat-ready.
In the European Theater, the P-38 was found to be less suitable for high-altitude escort duty than the P-51 Mustang. It was gradually withdrawn from combat service with the 8th Air Force, but was still widely used for high-altitude reconnaissance.
The P-38 became the model for combat aircraft of the future, which utilized speed, altitude capability, and firepower to defeat more maneuverable opponents.10