字幕表 動画を再生する 英語字幕をプリント This video was made possible by CuriosityStream. Watch thousands of high-quality documentaries and get access to Nebula by using the link in the description. This is a Rotodyne. And it might look like a helicopter and an airplane mashed together, but it's neither. It's a lot more revolutionary. Because when it debuted over 60 years ago, the Rotodyne was going to be a new form of mass transport. The quickest way to move from one city center to the next. Landing on downtown rooftops and heliports, but flying much faster, further and more economically than any helicopter. And airlines were interested. But then, as the Rotodyne looked set to revolutionize intercity transport, it just disappeared. To understand why this machine was so revolutionary, consider that it doesn't work like a helicopter. A helicopter uses engine power to spin a rotor blade, which forces air down to create lift.Tilting the rotor is what allows the helicopter to move in a given direction. That's the basic idea. But that's not how Rotodyne works. On a Rotodyne, the large rotor isn't powered. It isn't even connected to a motor. Instead, as air passes naturally through the rotor blades, it causes the rotor to spin around like a pinwheel. And this creates lift. The Rotodyne still has wings and a pair of turboprops, much like an airplane. But in forward flight, the un-powered spinning rotor lifts more than half the aircraft's weight. With this unique design, the Rotodyne flew faster than any helicopter of the era. And it was far more efficient. And even though the rotor wasn't driven by a motor, the Rotodyne could still hover and take off and land vertically just like any helicopter. That's because at the end of each rotor blade were small tip jets. During takeoff and landing, fuel and compressed air supplied by the turboprops would ignite to spin up the rotor. Once in forward flight, the tip jets were shut off and the rotor would once again spin freely. By 1959 the Rotodyne was attracting worldwide interest. Because for one thing, it promised to revolutionize the way we traveled between cities. In the 1950's and 60's, intercity air travel was on the rise. But while a trip from New York to Boston by airplane might only take about an hour, you'd also need to get to and from the airport. And in many congested cities, that was beginning to take longer than the flight itself. One solution was to use helicopters. In April, the new helicopter service is due to open from the top of the Pan-Am building. If the service does come about, you'll be taking off from the fourth highest building in New York. 59 storeys up. it's hoped that eventually the service will carry 5,000 passengers a day. 5,000 passengers who would otherwise be condemned to this. By the 1960's helicopter airlines had cropped up in major American cities. Letting passengers and skip the traffic by flying right over it. The problem was, none of them were actually making money. Because helicopters were simply too inefficient, operating anywhere from 20 to 30 cents per seat mile. And the only way helicopter Airlines like New York Airways could even exist was through government subsidies to offset operational costs. But the Rotodyne was going to change all that, bringing costs down to as little as 4 cents per seat mile, which would make helicopter airlines profitable. And the Rotodyne wasn't just a better helicopter. With vastly improved speed and range, it would be a new way to travel between cities, linking one city center to the next. The concept behind the Rotodyne dates all the way back to the early 1920's, when a pioneering Spanish inventor set out to build a safer plane. By adding an un-powered freely spinning rotor, his planes could fly slowly without stalling, making them inherently safer than airplanes. In fact, without any forward motion, the planes would simply glide back to earth, slower than a parachute. They were called autogyros. Over the years, they were used in military reconnaissance and even to deliver mail. But by the 1940's, helicopter technology improved and autogyros largely fell out of favor. But decades later, British aircraft manufacturer Fairey aviation still saw enormous potential in the autogyro concept. If the vertical takeoff and landing capability of a helicopter could be combined with the speed and efficiency of an airplane, Fairey would have something truly special on their hands. With the help of funding from the British government, the first Rotodyne prototype took to the skies in 1957. It could carry 40 passengers 700 kilometers and reach speeds of over 300 kilometers per hour. All while being able to land and take off on a space not much larger than the aircraft itself. And after 350 successful test flights, the Rotodyne proved to be safe and capable. But of course, it all went to [expletive]. For one, the Rotodyne's tip jets made a lot of noise. And that was going to be a problem right in the middle of a city. From the start, there were doubts about whether the public would tolerate it. And noise is often believed to be the reason why the Rotodyne failed. But that's not the whole story. After proving their prototype, fairy moved on to develop a production version. A larger more capable Rotodyne that could carry up to 75 passengers. And it promised to be quieter. Ferry spent years developing noise suppressor technology for the Rotodyne's tip jets. And while progress was slow, by 1960 the engineering team had reduced noise by over 15%. And airlines were interested, with small orders coming in from around the world. Not bad for an entirely new kind of transport. But to get the production version built, Fairey still needed about £10 million more in funding from the British government. And it was money they'd never get. Because at the start of the 1960's, Britain's aviation industry was a mess. Too many aircraft builders were building too few planes and relying heavily on government sponsored projects. The solution was to force these companies, including Fairey Aviation to merge. And the Rotodyne got caught in the shuffle, competing with a number of other helicopter projects. progress was also slowed by difficulties sourcing more powerful engines. And the need to reduce tip jet noise even further. When it became clear that the Rotodyne wouldn't be delivered to Airlines on time, and the eventual cost of each Rotodyne would have been too high, one by one orders were cancelled. In 1962, the British government, facing economic pressures, suddenly pulled funding for Rotodyne. And the half helicopter, half plane, once promising to revolutionize intercity travel... just disappeared. The working prototype and technical research were quickly destroyed. Leaving only a few small pieces for museum display The Rotodyne failed to change air travel and only a single prototype was ever built. But not all ambitious leaps forward in engineering lead to such failure. Take the DC-3. A machine that in its time, revolutionized air travel and earned a legendary status in wartime. Over 16,000 DC-3 variants were built. This remarkable plane took the skies just three decades after the Wright brothers first flight. And yet, hundreds of DC-3's are still flying today. Learn about this plane's incredible story on CuriosityStream. A streaming service with thousands of full-length documentaries by some of the best film makers in the world. From history and nature, to engineering and design. You can get an entire year of CuriosityStream for just $19.99. But if you sign up using the link in the description, you'll also get a subscription to Nebula, an exciting new platform built by some of YouTube's top educational creators. 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