What happened to sea plane fighter jets?

Why does every fighter jet on earth need a runway? And yes, I know that sounds like something you'd come up with in the shower, but stay with me. Because in 1947, the British built a fighter that didn't even need one. Twin jet engines buried inside a boathull. It landed on the open sea and it could be moored by the pilot without ever leaving the cockpit. This worked. But two of the three ever built are now at the bottom of the English Channel. And the survivor is sitting in a museum with one of its engines missing because that engine went on to do something even stranger. So if the jet seaplane fighter actually worked, why have you never heard of one? Whatever happened to flying boat jet fighters? The Pacific, 1942. Air power decides everything out here. And air power has one enormous weakness. It lives on runways. Runways take months to carve out of coral and jungle, and they're the first thing that the enemy bombs. And across 4,000 miles of open water, there simply aren't enough of them. The Japanese found a workaround. They bolted floats onto a zero and got the Nakajima roofie. Then they went further and built a dedicated float plane fighter called the Kawanishi Koifu. Any Calm Lagoon became an airbase. There was no construction battalions, no concrete, and no waiting. The Allies looked at this and mostly shrugged. Britain trialed spitfires on floats and quickly dropped the idea because the physics seemed brutal. You see, the problem is floats are draggy, heavy, and awkward things, and a float plane fighter always showed up to the fight slower than the aircraft trying to kill it. The consensus was that the concept came with built-in death sentences. Then in 1943, the jet engine arrived and quietly deleted the problem. Think about why a seaplane needs all that ugly scaffolding in the first place. A propeller has to be kept well clear of the water. But if you remove the propeller and everything changes, you can bury the engines inside a proper boathull, sit the whole aircraft low and sleek on the water like a speedboat, and throw away the floats entirely. On paper, you get a fighter that performs like a land-based jet and operates from any sheltered stretch of coast on the planet. And one company saw this first. Sanders Roe were the flying boat specialists of the era. They pitched the idea to the Air Ministry in mid-1943, and by May 1944, they had a specification written around their design and a contract for three prototypes. The team behind it was about as good as British seaplane engineering got. The British plan was to send it to the Pacific, stage from seaplane tenders and quiet lagoons, defending island bases no land-based fighter could reach. But then in August of 1945, Japan surrendered. The war this aircraft was designed for ended before a single prototype was finished. But this is the interesting part. Nobody cancelled this project. Britain kept building all three prototypes. Partly because nobody in 1945 knew exactly what the next war would look like, and partly, honestly, because everyone involved wanted to know if it would actually fly. The workforce at Sanders Roe had already given it a nickname. They called it the Squirt. Making it fly meant solving a problem that nobody had faced before because jet engines and seawater despise each other. A jet at full takeoff thrust is inhaling a hurricane, and if that hurricane of wind contains spray off the hull as it goes across the water surface, the engine chokes at exactly the moment that you need it. The Sanders Roe answer was an intake in the nose that raised itself clear off the water. So on the surface, the aircraft sat nose up with its intake poking above the spray, essentially breathing through a snorkel. The two engines sat side by side inside the hull, exhausting through the sides of the fuselage behind the wing, keeping the hot jet blast off the water. It didn't have any floats and no nacelles and no props. It was just a clean hull with wings. It took a lot of testing to get it right, launching progressively bigger scale models in a pool to nail the hydro-aerodynamic effects, if that is a word. But let's talk about the weapons. It would have four 30mm cannons, or with some finessing of the engine, twin 40mm cannons. Definitely a powerful punch. In fact, it was double the size of the Spitfire's cannons, so it would rip apart any aircraft that it came across. And under the wings, they planned two 1,000lb bombs or eight rockets, but about half of that if carried fuel in drop tanks to extend its range. They even fitted it with the first two production ejection seats that Martin Baker ever built, which tells you exactly what the company knew might happen when you have a jet engine on the water. And hold that thought. On the 16th of July 1947, the test pilot Geoffrey Tyson opened up the throttles of the first prototype and took it off into the sky for about 12 seconds. But the numbers that came back from this testing regime frankly were absurd for a flying boat. It had a top speed of 512 miles per hour. The Vampire, the RAF's brand new land-based jet fighter, managed around 548 miles per hour. So that gap is tiny. And then their flying boat, when it went into a dive, recorded 624 miles per hour. So what do we have here essentially? It's a jet-powered speed boat that could go toe-to-toe with RAF's frontline fighters of the era. And its runway was two-thirds of the surface of the earth. Two months later, after the first flight, it was at the Farnborough Air Show. And a year later, Tyson flew the third prototype past a crowd at low level inverted. The program wasn't just alive. It was now showing off. Then came the summer of 1949. And in six weeks, the whole thing nearly ended. In August of 1949, at the controls of the third prototype, the Royal Navy's chief test pilot, the man who would eventually fly more aircraft types than any other pilot in history, was coming into land when a late wind shift forced him to adjust his approach. And with too little fuel to go around and inspect the new landing run, he committed. The hull hit something submerged and it split open. The aircraft cartwheeled and it started going down with the pilot unconscious inside of it. Geoffrey Tyson, the test pilot from the first prototype, was watching from a support boat. And he dove into the river, fully clothed, and dragged out the Navy pilot from the sinking wreck. The Navy pilot would survive, but the aircraft went to the bottom and has actually been never recovered. Five weeks later, squadron leader Peter Major was rehearsing an aerodynamic display with the second prototype. During a slow roll, the nose dropped whilst he was inverted. And instinct did what instinct does. He pulled back on the stick. The one input you must never make, upside down. The aircraft dove into the sea and broke up. And no trace of him was ever found. And a quick note here, because sources genuinely disagree on which airframe was in which crash, and we've gone with the documented record. And there's more on that in the pinned comment. Two prototypes destroyed in six weeks, with one pilot dead and another saved only because his colleague jumped into the sea after him. And while Sanders Rowe was absorbing that, a third blow landed quieter than the crashes, but far more fatal. Metropolitan Vickers, the company that was building the engines, was being pushed by the government to exit the gas turbine business entirely. Their engine expertise went to Armstrong Siddeley, and the engine that was going to go in this seaplane jet fighter was discontinued. The squirt now had no production engine, and you can't sell an aircraft whose engine doesn't exist no matter how well it flies. In the early 1950s, the last surviving prototype then went into storage. And that should have been the end of the story. But then in June 1950, North Korea invaded the South, and suddenly the map looked very familiar. A war on a peninsula surrounded by water, islands everywhere, sheltered inlets up and down both coasts, and no aircraft that was best suited for it. Except this one. So just a few months after it went into storage, by November 1950, the Survivor came back out, and the project data was shared with the Americans. And there was serious talk of re-engineering production aircraft with a new Armstrong Siddeley Sapphire engine. This version was even proposed to be a single engine, thanks to the size of the Sapphire. And it's quite interesting when you look at the blueprints, how they had to mount it there in the centre, compared to the original design that had twin engines. This lasted about a few months. The Sapphire was so different that fitting it meant rebuilding the hull from scratch. And meanwhile, off the Korean coast, US Navy carriers were projecting air power just fine without anyone having to actually land on the sea. The RAF's verdict was blunt. It offered nothing that aircraft already in service didn't do with less complication. So in June 1951, the last prototype made its final flight up the Thames over London for the Festival of Britain, a victory lap for an aircraft that never made it to the war that it was built for. Then it was grounded for good. So thanks so much for watch- Well, hold on. Hold on. Now, here's where the competitor histories usually stop. The museum shot, sad music, and roll credits. But that's not actually the answer to our question, because the jet seaplane fighter didn't actually die on the Isle of Wight. It moved to America, and it got faster. Much faster. In 1951, the US Navy, worried that supersonic jets might soon be too hot and too heavy for carrier decks, gave Convair a contract for something that makes the squirt look conservative. The Sea Dart. A delta wing interceptor with an afterburner that took off from the water on retractable skis, hydroplaning across the surface at over 100 miles an hour before lifting off. The prototype would fly in 1953, and in August of 1954, a Sea Dart passed Mark 1 in a shallow dive, the only seaplane in history to break the sound barrier. For a moment, the water-based fighter wasn't a curiosity anymore, it was at the leading edge of aviation. Three months later, on the 4th of November 1954, Convair put on a demonstration over San Diego Bay for Navy officials and the press. Mid-display, the Sea Dart actually disintegrated in the air, killing the test pilot in front of the cameras. The program staggered on for a while as a test project, but as a fighter, it was now finished. The Navy's other great water jet gamble, the Martin Seamaster nuclear flying boat bomber, and I've got a whole video on the channel about that, was cancelled in 1959 with production aircraft literally sitting on the ramp. The Soviets got their Bereiv B-10 flying boat into actual service, where it set speed records for seaplanes that still stand to this day, and then quietly retired it after a few years. By the 1960s, everyone everywhere was now out. So what actually happened to flying boat jet fighters? Here's the strange truth, Not one of them actually failed at the thing that was supposed to be impossible. The Squirt handled open water and nearly matched the Vampire. The Sea Dart actually went supersonic. And the B-10's records still stand. The engineering of these concepts worked, but what killed them was the question that they answered simply evaporated. Aerial refueling meant fighters could cross oceans. Supercarriers meant the runway came to you. NATO's paved runways across half of the planet and guided missiles took over the interception job that these aircraft were designed for. And the daily grind of operating jets in saltwater, with corrosion eating everything and every takeoff hostage to a safe state, the maths finally collapsed. By the mid-1950s, no amount of clever engineering could save an aircraft whose reason to exist simply disappeared. Which brings us back to that museum shot in Southampton. The sole surviving SR-A1 sits across the water from where it was built, and it really is missing an engine. That engine was pulled out and handed to a man named Donald Campbell, who bolted it to a hydroplane called the Bluebird K7 and used it to set water speed records on his way to seven world titles. The fighter that lived up on the water ended up making a boat the fastest thing on it. And honestly, that might be the perfect ending. The aircraft the world didn't need powering a record the world would never forget. If you enjoyed this video today, I have another video all about what Saunders Road did next, where they pivoted to flying jetliner boats. And that is ridiculously incredible because it makes so much more sense. Yes, we didn't need jet fighters that could go on the water, but what about passenger planes? There must be so many island nations in the world that need a jet to come and visit them, but they can't build a runway. What happened with that story? I think you'll find truly fascinating.