The Insane Engineering of the P-38 Lightning

This is where it all began. Hidden away from prying eyes, a revolutionary fighter aircraft awaited its maiden flight. Like something out of a science fiction, it looked like nothing that came before it. The P-38 Lightning. Twin booms, twin engines, turbochargers bolted on like artificial lungs, five machine gun barrels aligned together and staring forward in a deadly gaze. Its engineers didn't just build a plane, they assembled a monster. The P-38 pushed everything to the limit. Two liquid cooled Allison V-17 engines, each force fed by a two stage turbo supercharger, carefully packaged inside its twin booms. Turbines, impellers and intercoolers all working in unison, to keep the plane breathing in the rarefied air above 25,000 feet. With drop tanks attached, this plane had a range other fighters could only dream of. Designed by one of the most revered aeronautical engineers in history, Kelly Johnson, it was a bold reimagining of what a fighter plane could look like. It was the first of its kind, the genesis of skunkworks. This is the unique engineering of the P-38 Lightning. Kelly Johnson was just 27 years old when the design he spearheaded won Lockheed's first ever military production contract. Johnson was respected and revered from an extraordinarily young age. Joining Lockheed as a humble tool designer, he managed to convince senior management at the age of 23 that their upcoming aircraft, the Model 10, was unstable and needed a major redesign of its tail, from a T-tail to a H-tail. He was right, he had a habit of being right. By the age of 28, he was Lockheed's chief research engineer. By 29, he was leading the most advanced aeronautical lab to ever exist, Skunkworks. People listened when he spoke, because he didn't waste words. Be quick, be quiet, be on time he'd say. Three rules that weren't just good advice, they were doctrine. At Skunkworks, those words cut through government red tape. Kelly's knack for innovation, under tight budgets and even tighter deadlines earned legendary status in aviation history. The design genius behind the P-38, the U-2 spy plane, and the SR-71. It all started with the P-38. Answering the call for a high altitude interceptor, capable of reaching a top speed of 580 km per hour and racing to bomber cruise altitude in just 6 minutes from the ground. A specification that essentially no other plane manufacturer in the deemed worthy of even attempting. Lockheed's design for the P-38 was one of just two applications for this contract, and the designs young Kelly Johnson came up with were so radical that it set Lockheed up to skyrocket from a floundering civilian aircraft company in depression era America to the world's largest defence company. The P-38 Lightning began simply on a sketchpad, where Kelly Johnson doodled potential configurations to fulfil circular proposal X-608 issued by the United States Army Air Corps. It asked specifically for a high altitude interceptor, a word tactically used to avoid labelling this new aircraft as a pursuit aircraft. The P-51 Mustang, the P-47 Thunderbolt, and the P-40 Warhawk, all pursuit aircraft, and restricted by the military's requirement that single seat pursuit aircraft should have just one engine. No American engine existed in the 1930s that could enable a heavily armed high speed, high altitude aircraft. Two engines were the only way to go, but there are so many ways to integrate two engines into an aircraft. These are Kelly Johnson's own drawings of potential configurations. Leaving no stone unturned, he explored every possibility. From recognisable twin wing mounted engines, to strange looking asymmetrical configurations, some with the cockpit offset to the left or right side alongside the second engine. These two, twin pusher and puller engine configurations, looked like they had wing mounted engines, but Johnson envisioned filling a large internal fuselage with two engines, driving the wing mounted propellers through drive shafts passing through the wings. This would give the plane the profile of a single engine aircraft and remove weight from the outer wings, making the plane more agile in turns. Just like an ice skater, weight far from the spinning axis slows a turn. So bringing the engines to the centre axis makes for a rapid rolling plane. However, stuffing two engines in would require an incredibly long fuselage, and the drive shafts and gearing needed to send power to the wings would just be a nightmare to protect and maintain. Instead, Kelly Johnson went with what is honestly a pretty unintuitive option. A single fuselage, mounted in the centre of the wings with no engine. Leaving an absolutely outrageous amount of space directly in front of the pilot, with no propeller in the way, for guns. Lots of guns. The central fuselage was like a ball turret with wings and engines attached to it. It had four .50 calibre machine guns and a 20mm cannon. All pointing forward, with zero convergence issues. Convergence issues plagued fighter planes of this era. With guns mounted directly in front of the pilot, they can easily spot their target, lead their shots according to distance and speed, and pull the trigger. However, most World War 2 fighters had machine guns or cannons mounted in the wings, where they had more space to fit them. This raises the question, where should the guns actually point? You could point them forward and have two hit zones coming from each wing, but this spread of bullets would make aiming a nightmare and almost guarantee multiple misses in a single burst even with perfect aim. Or you can angle them in slightly, so that they converged at an optimum distance in front of the pilot. But now the question was, what was the optimum distance? This distance would determine how close the pilot had to be in a dogfight. For fast turning, close quarter, fighter on fighter action, you wanted a shortened convergence point. But as soon as the bullets passed that convergence point, they spread out at a rapid rate, with shorter convergence distances spreading out even quicker. For this reason, for longer distance strafing attacks on bombers or ground targets, a longer convergence distance was better. Pilots often had their own preferred convergence distance too, requiring ground crews to realign all their guns manually. This was a massive disadvantage that shooting forward would eliminate completely. Weapon placement was one of the more nuanced decisions engineers of World War 2 fighters had to make, and some radical designs were created to avoid these problems. The fearsome German Bf 109 installed a massive cannon that shot directly through the engine, with a little bullet tunnel that exited through the propeller hub, with two smaller machine guns that shot through the propeller blades with the help of an interrupter gear. The P-38 in comparison was armed to the gills. This level of armament was only rivalled by the likes of the P-47 and the Fw 190, both of which had to deal with convergence issues. It wasn't until the introduction of the Me 262 in late 1944, the first ever operational jet aircraft, that the P-38 was truly outgunned, but with these troublesome early turbojet engines, certainly not outflown. Engine development was one of the core scientific battles of World War 2. The first flight of the Wright Brothers took place less than 40 years before the P-38 took to the Building lightweight, efficient engines that could extract as much power from their fuels as possible while upside down, breathing low density air, or with holes shot in the fuel tank, was a unique challenge that became a rapidly evolving battlefield of engineering prowess. Compression is the name of the game when it comes to power extraction. The more fuel and air we can squeeze into those piston cylinders, the more power we can extract. And to do that we need forced induction, where we push air into the engine with much higher compression. But compression comes with heat, and that heat can cause a lot of problems. Pre-ignition of the fuel, caused by hotspots in the engine, can cause catastrophic vibrations. To deal with this, engines need radiators and ways to cool themselves down. Many of the most famous planes of World War 2, like the Spitfire and Bf 109, opted for liquid cooling because it allowed for a sleek, streamlined V-12 inline engine. Despite the inherent danger of having a critical point of failure running in tubes around the engine, one unlucky bullet could drastically reduce engine power. Where other planes like the P-47 opted for the larger, bulkier, air cooled radial engines. It was primarily designed to be a damage resistant ground attack vehicle. Ridding themselves of those delicate fluid lines was deemed worth the trade off in the enormous bulk of the radial engine. This entire issue is a battle with thermodynamics. We actually need to transfer as much heat out of the plane as quickly as possible. Increasing surface area for heat transfer to occur over is a great way to improve cooling, but that increases drag. And Kelly Johnson came up with a unique solution that would allow the P-38 to dump heat overboard with a fraction of the drag penalties, but more on that later. The genius of the P-38 starts here. The twin tail boom gave Lockheed a huge amount of internal volume to play around with. With the first clue to the unique machinery inside peeking out of the top of each boom, the P-38's turbocharger poked out of the cowling like the muscle cars of Detroit. A hint to the power hidden inside. Two inline V-12 turbo supercharged liquid cooled engines. The pinnacle of American engine development in 1939. The Allison V-17-10 itself was a compact engine with decent performance, similar to the British liquid cooled inline V-12 Merlin engine in many respects. However, the Merlin engines integrated two speed, two stage superchargers. The preferred setup of the best single engine fighters of the war. The Allison V-17-10 came with a single stage, single speed supercharger as standard, installed on the back of the engine here. The P-40 Warhawk was installed with just this engine and it was lousy at high altitude fighting, but with the extra space afforded to it by its iconic twin booms, the P-38 could fit an additional turbocharger system behind the engine. Both superchargers and turbochargers serve the same purpose, to force air into the combustion chamber to increase compression and increase power output. To do this we need a way to power the impeller that drives the air into the engine. The key difference between a turbocharger and a supercharger is how they are powered. Superchargers use mechanical power from the engine's driveshaft. This saps some power from the driveshaft. Many of the superchargers of World War 2 required the equivalent horsepower of a modern day luxury sports car to run at full boost. However, turbochargers are powered by a turbine that's driven by the engine's exhaust. This reduces the direct power being taken from the engines and recovers some of the heat energy being expelled to the atmosphere, but it does come with downsides. With a mechanically powered supercharger the throttle response is immediate. When the throttle is opened the engine speed increases, and with a direct mechanical connection to the impeller it spins up in unison, giving an immediate boost. However, turbochargers have lag, as exhaust pressure does not increase immediately when the pilot opens the throttle. The Merlin's compression boost system was simply superior to the P-38's. Here's why. Two speed is vitally important, as it allows for more efficient use. At low altitudes we don't need as much boost, there is plenty of air there. In fact, if we produce too much boost we could destroy the engine. So a single speed supercharger needs to be designed for an optimum altitude where the plane is expected to operate, and it will work less effectively at every other altitude. This is evident from the performance of the P-40 Warhawk. This plots achievable top speed of the aircraft at different altitudes, and here we can clearly see that the V-17-10 supercharger was optimised for 15,000 feet. However, with a geared two-speed supercharger it could have looked like this. Allowing the supercharger to increase speed and compression at higher altitude. Giving two points of optimised performance. This is the performance chart of a Spitfire. To compete the P-38 came with these B-33 General Electric turbochargers. This increased the engine boost, but nowhere near as effectively as a two-stage two-speed supercharger. This is what the performance chart of the P-38 looked like against the Spitfire. In this scenario, if a P-38 wanted to compete with a Spitfire it would be in it's best interest to do it here, at 20,000 feet, where it had a slight advantage over the Spitfire. The P-38 never managed to compete against advanced single engine fighters like this, and one of the reasons for that was that innovative cooling method, which was incredible when first introduced, but could not keep up with the rapid development of forced induction throughout the war. Inside the two pods and the wings were a complicated network of tubes designed to manage and cool air before it was forced into the engine. This is the primary inlet. You may think these are the engine air inlets, but these were in fact the oil radiator air intakes. Air enters the engine here, with an additional filtered intake in the undercarriage for dirt runway takeoffs. Air first enters the turbocharger unpressurised, but as the plane gains speed on takeoff ram air pressure builds, increasing compression. While this is happening, the supercharger, mechanically linked to the engine, is working to increase the compression too. All the while, the exhaust outlet pressure is also rising, gradually spinning the turbocharger's turbine up to speed. Pilots could control the speed of the turbo by opening or closing this wastegate that controls the flow of exhaust gases into the turbine. However, at full boost, the engine is going to start experiencing knocking without something to dump that heat overboard quickly enough. This is where the intercooler comes into play. It exchanges heat between this hot compressed air and the cold atmospheric air outside. Most intercoolers rely on prominent air scoops to force air over a large front facing heat exchanger, but those scoops come at a cost, they create extra drag. Johnson took a different approach. Instead of bolting on a traditional intercooler system, he built it directly into the wings leading edge. This was pretty radical design that was taken out of necessity. The P-38 was a big plane and those two engines added a lot of frontal surface area to create drag. The engine power could counteract that, but Kelly Johnson knew he was going to need to decrease drag wherever possible to keep the P-38 competitive in the air. So, in the leading edge there is a network of small tubes running the length of the wing, where the turbocharged air passes through before entering the supercharger. They are cooled by air entering this small opening, which exits through this hole in the wingtip. It's a strange design, but it had very little drag penalties. However, as engine power increased during the war, it could no longer dump enough heat to keep the engine cool at full power settings. This wasn't just a problem for the P-38, every plane of the war was actually in battle with thermodynamics, but this was a problem that was never solved for the P-38. Pilots simply needed to keep an eye on their engine temperatures. Yet, despite it's shortcomings, the P-38 remained competitive throughout the war. It's capabilities always found a niche in the war zone. The P-38 was one of the first fighters to use a tricycle landing gear, and that made a real difference in the Pacific. Most planes at the time were tail draggers. A tail dragger, like the Spitfire or P-51 Mustang, has two main wheels under the wings and a small wheel or skid at the tail. This setup tips the nose up, which can block the pilots forward view while on the ground. It also makes takeoff and landing a little bit more tricky, especially on rough surfaces, since it's easier to tip forward and strike the propeller off the ground. The P-38's tricycle landing gear gave the pilots a much clearer forward view of the ground and a much more stable landing experience. This was incredibly useful in the island hopping war of the Pacific, where pilots were frequently operating from makeshift airstrips scattered across the Pacific, usually just flattened coral or dirt, with minimal support infrastructure. Out here a broken prop could mean being out of action for quite some time. The P-38 was a rugged plane with a superb range, making it perfect for the island hopping war of the Pacific theatre. No mission exemplifies this more than Operation Vengeance. Operation Vengeance was one of the boldest and most precise missions of World War 2, and it only worked because of the unique capabilities of the P-38 Lightning. In April 1943, American codebreakers had intercepted a golden piece of intelligence. Admiral Yamamoto, Japan's top naval strategist and the man behind the attack on Pearl Harbour, was scheduled to fly from Rabaul to an airfield near Bougainville in the Solomon Islands. He was famously punctual, down to the minute, and the Americans saw an opportunity to take him out right as he was landing. The problem was, Yamamoto's flight path took him deep behind enemy lines. This was a 1600 kilometre trip, far beyond the reach of most fighters of World War 2. The only aircraft in the US arsenal with the speed, range and firepower to even attempt the mission was the P-38 Lightning. With its twin engines and massive fuel capacity, boosted by gigantic drop tanks, the P-38 could make the 1000 kilometre trip out, spot and destroy the bomber transport with the Admiral aboard, engage in an energy intensive battle with the A6M Zero escort fighters, and still have enough fuel to return to base 600 kilometres away in Guadalcanal. No other allied fighter could do that. 16 P-38s took part in the raid, with 4 planes acting in the assassins low flying group, 2 in front, with 2 in reserve behind, with the remainder flying on a time delayed route in support at high altitude for the expected retaliation from nearby airfields. The pilots flew low over the ocean, to avoid detection by Japanese radar, and arrived one minute early, giving them time to jettison their drop tanks as their target broke cloud cover. One of the group's drop tanks failed to disengage right as the Japanese Admiral's A6M Zero fighter support group spotted the danger and began to engage, giving the two reserve pilots their opportunity to take part. There were 2 transport bombers ahead and the pilots did not know which one Yamamoto was aboard. With the danger spotted, time was ticking as the pilots of the transports began their panicked descent over the island. The attack group increased power and gained altitude in preparation. Energy is vital in a dogfight, speed and altitude, kinetic and potential energy. The P-38s were going to be coming against the A6M Zero. At this altitude the Zeros had a manoeuvrability advantage. A light, single-engined, extremely nippy aircraft, it was not something you wanted on your tail at slow speeds. One of the P-38s reportedly received 104 hits from these Zeros, and tanked every single one of them. The P-38 was entirely metal skinned with self-sealing fuel tanks. It was a sturdy aircraft. The A6M Zero in comparison was covered in fabric with no self-sealing fuel tanks. One hit could ruin their day, if you could get them in your gun sights. American pilot reports of the day claimed downed Zeros, but Japanese records have zero mention of any Zeros being lost. However, one thing was for sure, both bomber transports were shot down. Amid the chaos, attribution was unclear and code-breaking rules were broken as one pilot claimed success over the radio, giving away that the pilots knew the Admiral was aboard, and thus giving away that codes were broken to anyone listening. But the mission was a success. The man responsible for Pearl Harbour was dead, thanks to this plane. The P-38 was far from perfect. Cooling issues were one problem. Another was that it had the lowest critical mach number of any plane in the war. I must have explained what critical mach number is at least 50 times on this channel over the last 10 years. It's the speed at which airflow turned supersonic somewhere around the plane, but this was the first time anyone had to battle with it in a dogfight. When diving, the P-38 could break the speed of sound, while the plane itself was only going 70% the speed of sound, all because of the plane's strange design. It's thick wing root and pods created local airflows that exceeded the speed of sound. When this happened the planes lift began to shift backwards and pitch the plane down even more, and to make a bad situation worse, the control surfaces also stopped working when this happened. To counteract this, dive flaps were added to the underside of the wings, that gave the pilots enough control authority to pull the plane out of the dive. But the low critical mach number was never fixed. Both of the P-38's biggest issues were a product of their time. The P-38 was just so far ahead of it's time that it encountered problems it's designers couldn't have possibly predicted. That's what happens when you push the envelope. But despite that, it was an extremely capable plane that stayed competitive throughout the war, despite being designed before the war even started. That's because Kelly Johnson was a visionary, arguably the best plane designer in history, responsible for some of the most iconic planes we've ever laid eyes on. The leader of Skunk Works, the man who won Lockheed their first military contract, before it grew to be the biggest military company in the world. This plane was the beginning of it all. The Model T of fighter aircraft. But not every legacy in science and engineering is so widely respected. Most scientific papers pass quietly through the world, read only by a handful of specialists, nudging human innovation forward one reference at a time. But every so often a single paper can spiral into something far bigger. A controversy. A scandal. A wedge of doubt that leaves a permanent mark on public trust in science. That's the story behind 17 Pages. A new feature length documentary on Nebula, it unpacks one of the most dramatic scientific ethics cases in the 20th century. An event so explosive it was dubbed the Scientific Watergate. What began as a routine co-authored biology paper, escalated into a national scandal. With whispers of fraud, political agendas, and a high stakes investigation that reached the halls of congress, and even caught the attention of federal agencies. Through never before seen interviews, gripping footage, and congressional testimony, 17 Pages explores and reconstructs how bias, media spectacle, and public perception reshaped the fate of the scientists involved. Not just about science, but how truth gets decided when politics and personal reputation are on the line. And it's only available on Nebula. That's where I and a growing group of creators are releasing original, thoughtful, ad-free content that goes deeper than what the algorithm wants. And I love YouTube as much as the next person. It's where I forge my career, and I plan to post here long into the future, but I think we've all seen where the platform's priorities are going. When I search for a video, sometimes only shorts show up. 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