Placeholder Image

字幕表 動画を再生する

  • Thanks to SkillShare for making this video possible. SkillShare is an online

  • community where you can learn almost anything, including many of the skills

  • used to make this video. The first 300 people to click the link in the

  • description, get a 2 month free trial.

  • Some consider the period just before the jet age to be a golden era for air

  • travel. But flying aboard a piston powered propeller aircraft, well it

  • wasn't always glamorous. Flights took a lot longer than they do today and the

  • relentless noise and vibration from the piston engines; well it was exhausting.

  • And most aircraft couldn't fly high enough to avoid bad weather, so you'd be

  • in for a bumpy ride. And you'd better have your air sickness bag ready.

  • But then, seemingly out of nowhere in 1949, along came a new kind of

  • aircraft. It was sleek, quiet, and nearly twice as fast as some conventional

  • airliners. Cruising at 40,000 feet, it could avoid messy weather. This was the

  • de Havilland comet. It shattered conventional thinking and proved that

  • jet travel was the future. But the excitement would be short-lived because

  • within months things started to go seriously wrong. And the leap into the

  • jet age it wouldn't go as smoothly as hoped.

  • In the 1940's, the British set out to change civil aviation. In fact they

  • really had no choice. Because after the Second World War, American manufacturers

  • had the Civil Aviation market cornered. At one point, ninety percent of the world's

  • airline passengers were flying aboard these: American built Douglas DC-3's. The

  • Americans left the Second World War with a lot of experience designing and

  • building military transport aircraft. After the War, with their industry fully

  • intact, manufacturers could switch to producing civil aircraft based on their

  • military transport designs. But Britain on the other hand, had to rebuild. Much of

  • its focus during the war had been on building heavy bombers. So it now needed

  • to develop the infrastructure and the expertise to compete in the civil

  • aviation market. If the British were going to become leaders in aerospace,

  • they had better come up with something extraordinary. But a jet powered airliner,

  • that was dismissed by a lot of people. The conventional thinking of the day

  • amongst manufacturers and airlines was that jet engines produce too little

  • power relative to their fuel consumption, and they were just too unreliable for

  • civil aviation. But at the same time piston engines were approaching their

  • limits. To squeeze out ever more power, they had grown large and complex with

  • superchargers and dozens of cylinders. This made piston powered propeller

  • engines increasingly expensive to maintain. And you can only spin a

  • propeller so fast before its efficiency starts to diminish. As part of a larger

  • effort to develop Britain's post-war aviation industry, the de Havilland

  • Aircraft Company was awarded the task of building the world's first jet-powered

  • airliner. The aircraft, which would later be

  • named the Comet, was developed in secrecy. In fact, untenable designs were

  • deliberately used to confuse competitors. So when the comet was revealed just

  • three years later in the summer of 1949, it stunned the world.

  • Its sleek lines, swept wings, and for integrated turbojet engines, well they

  • were straight out of the future. Even today, a lot of this aircraft looks

  • pretty modern. So you can only imagine the impression it would have left on the

  • flying public in 1952. The comet sent a powerful signal to the

  • world about Britain's newfound superiority in aerospace. Orders poured

  • in, and even in America where airlines were still skeptical of jets, Pan Am

  • placed orders for a larger lengthened version. The Comet was revolutionary

  • because it had solved a key barrier to efficient jet travel. While turbojets

  • consumed enormous amounts of fuel at lower altitudes, where most planes of the

  • year a flew, the Comet would instead cruise at an unprecedented 40,000 feet. Where the air is thin and there's less drag.

  • Allowing the Comet to consume much less fuel. But to allow its passengers to breathe at such high altitude, the cabin

  • needed to be pressurized. And while the Comet wasn't the first airliner to

  • have a pressurized cabin, no other flew so high. The Comet went into service in

  • 1952 and immediately began breaking travel time records. And in doing so, it

  • became a point of national pride for the British public. But here's the thing, in

  • some ways, the comet was a little too ahead of its time. With such a clean

  • sheet design, there were suddenly so many new variables to work with. There were

  • numerous problems with its electrical and hydraulic systems. But when two

  • Comets skidded off the runway in 1952 and 53,

  • the pilots were blamed. It was suspected that they were still flying the Comet as

  • if it were a piston powered airliner. Over rotating the aircraft on takeoff. It

  • was later determined that a design change of the leading edge of the

  • comet's wing was needed. But public confidence in the comet had not been

  • shaken. and the British remained enthusiastic about jet-powered air

  • travel. But then, just two months later, another incident. This time far more

  • catastrophic. A Comet leaving Calcutta ominously disintegrated while flying

  • through a severe thunderstorm. And only eight months later, another Comet

  • exploded shortly after taking off from Rome. After these rapid succession of

  • incidents, BOAC, the airline with the most Comets in service had no

  • choice but to ground their fleet. The focus shifted to a suspected turbine

  • explosion in one of the engines. So the engine housing on the other Comets was

  • reinforced. But public confidence still remained high and when the Comet

  • re-entered service. Airlines had no trouble selling seats. Yet just three

  • months later, another comet disintegrated over the Mediterranean. Now the entire

  • worldwide fleet of comets had to be grounded as their Certificate of

  • Airworthiness was revoked, An unprecedentedly large investigation

  • began. And it would reveal that sudden catastrophic depressurization of the

  • Comet's cabin was to blame, essentially causing comets to suddenly explode apart

  • in midair. See, the Comets cycles of pressurization and depressurization were

  • faster than those of any other aircraft. After many cycles, the fuselage began to

  • fatigue and cracks started to form. Especially around the Comets square

  • windows, where hard edged corners concentrated stress forces. The entire

  • comet fleet was grounded for years while the investigation lumbered forward.

  • But in the end, none of the grounded planes would ever fly again.

  • And while de Havilland worked to modify its design, switching to round windows

  • and increasing fuselage thickness, the rest of the world was catching up.

  • Aircraft manufacturers from around the world introduced their own jet-powered

  • offerings. And in 1958, the Boeing 707 entered service and Douglas began

  • producing the DC-8. That same year the, de Havilland Comet 4 entered service. But it

  • couldn't compete with the American offerings, which were now larger, faster

  • and more efficient. Only 76 Comet 4's were ever delivered to Airlines. That

  • compares to over 500 DC-8's and over a thousand 707's America's stranglehold on

  • the civil aviation market would only grow tighter in the coming decades.

  • According to de Havilland's chief test pilot, Boeing and Douglas both privately

  • admitted that they had learned from the Comets pressurization problems. And if it

  • were not for the Comet, they could have made the same mistakes. The later, larger

  • and improved Comets would reliably serve airlines

  • into the 60's and 70's. The Comet last flew commercial passengers in 1980. But

  • there's no question that the Comet paved the way. The British had taken a massive

  • risk and brought the world into the Jet Age.

  • A lot of people ask how I put together these videos. So I'd like to share with

  • you some insights and to plug our sponsor SkillShare. SkillShare is an

  • amazing online learning community with over 17,000 courses covering just about

  • anything you can think of, from video production to how to start and grow a

  • YouTube channel. It's easy to assume that to create impressive visuals you need to

  • first become an expert in one single piece of software, like Adobe After

  • Effects. Of course that helps, but personally I think for someone just

  • starting out, a better approach is to instead learn the basics of a few

  • different tools, so you can get right down to creating. I used several pieces

  • of software to make this video, and I'm not an expert in any of them. But I know

  • the strengths of each tool, and when I want to learn something new,

  • I often rely on video tutorials. And SkillShare is an excellent resource. You

  • can get started with introductory courses like learning the in's and out's

  • of Illustrator, or you can learn advanced techniques like how to use a 3D camera

  • in After Effects. With such a huge selection of courses on offer, you don't

  • need to waste your time and energy searching for instructions hidden

  • somewhere on some message, board blog post, or YouTube video. The first 300

  • viewers who sign up for SkillShare using the link in the description will

  • get two months of learning for free. After that, it's just ten dollars a month

  • Whatever your passion SkillShare have got you covered.

Thanks to SkillShare for making this video possible. SkillShare is an online

字幕と単語

ワンタップで英和辞典検索 単語をクリックすると、意味が表示されます

B2 中上級

Why You Wouldn't Want to Fly The First Jet Airliner: De Havilland Comet Story

  • 23 1
    joey joey に公開 2021 年 06 月 01 日
動画の中の単語