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  • You're watching a test run of one of the fastest cars ever made.

  • Zipping across the South African desert at 628 miles per hour, this car is the result

  • of over a decade of extreme engineering and aerodynamic modeling.

  • All with the end goal of breaking the world land speed record.

  • But the team behind this project wants to go even further.

  • They want to reach speeds nearing 1,000 mph, aiming to be the fastest car in the world.

  • The land speed record is all about taking a manned vehicle across the surface of the

  • earth as fast as possible.

  • Of course, it's not as simple as it sounds.

  • Regulated by the International Automobile Federation, this competition has some ground

  • rules.

  • Basically, you have to have a car that's controlled by a human onboard.

  • The vehicle must have at least four wheels which are in contact with the ground.

  • And it's your average speed over a measured mile that you do in two opposite directions

  • within the space of an hour that gets you your land speed record.

  • The current record holder is the Thrust Supersonic Car, or Thrust SSC.

  • Back in 1997, it plowed across the Black Rock Desert in Nevada at 763 miles per hour, breaking

  • both the sound barrier and the world record.

  • Now, Ben and this team have engineered a next generation supersonic carBloodhound.

  • It's designed to go speeds north of 800 miles per hour, with a stretch goal of a whopping

  • 1,000 mph.

  • A lot of the team's benchmarks are written in miles, so we'll be using this conversion

  • box so the metric system is never too far away.

  • One of the things that makes Bloodhound an incredibly complex, arguably one of the most

  • complex vehicles ever to be designed aerodynamically is the fact that we're traveling at supersonic

  • speeds, but over the surface of the earth.

  • From an engineering point of view, that's an incredibly complex problem.

  • As a travelling object approaches the speed of sound, it starts to catch up to its own

  • soundwaves-- compressing the air in front of it.

  • Once it goes faster than those waves can be created, it generates areas of extremely high

  • pressure called shock waves -- along with a deafening sonic boom.

  • Today, we have military aircraft that can handle these shockwaves and travel at supersonic

  • speeds with ease, but for a carit's a little bit more challenging.

  • Whereas supersonic aircraft have the luxury of generating these shock waves and then the

  • shock waves propagate out into this effectively infinite space around them, a car by definition

  • is rolling along the ground.

  • And that presents two major challenges.

  • One: How do you keep the car on the ground?

  • The shock waves that get underneath the car will interact with the ground plane and actually

  • can start generating lift.

  • We want a car that's not going to generate so much lift that it could take off the ground.

  • The second part of the challenge is all about drag minimization.

  • When those shock waves form, they generate a lot of drag.

  • How do we keep the resistive forces as low as possible so that we've got sufficient thrust

  • to accelerate it to the target speeds?

  • And as if those two challenges weren't difficult enough,

  • The strength of the shockwaves that we're going to be generating are higher than any

  • vehicle travelled over the surface of the earth before.

  • So managing those extremely strong shock waves, at those kind of speeds, is really the key

  • aerodynamic challenge that we're trying to overcome.

  • To optimize the car's shape for these conditions, the team looked to Computational Fluid Dynamics.

  • Essentially what CFD is, is virtual wind tunnel testing.

  • Now, behind me here, we've got a real physical wind tunnel.

  • This circulates air round at high speed and passes that airflow over a body that you can

  • then measure forces, pressure distributions and so on.

  • In CFD, we do all of that, but in the virtual world, inside a large supercomputer.

  • The way it works essentially is we go back to the fundamental governing equations of

  • high speed aerodynamic flows and those are the Navier Stokes equations.

  • It turns out that they are very, very difficult equations to solve directly.

  • And so we need large high performance computers.

  • Once the team nailed down the optimal shape for Bloodhound, the next hurdle was figuring

  • out how to build it.

  • The design of the wheels was a massive challenge.

  • They rotate at 10,000 rpm and the forces at the rims of those wheels is extraordinary.

  • To prevent the wheels from literally tearing themselves apart under those forces, the team

  • had them forged out of an aircraft-grade aluminium alloy.

  • Then, there's the engine.

  • As you'd imagine, it's nothing like what you'd see under the hood of an ordinary

  • car.

  • We've actually taken a modern military jet engine that's operating in the Eurofighter

  • typhoon aircraft.

  • And that's kind of the main thrust source that we've been using.

  • That delivers nine tons of thrust.

  • To take the newly built Bloodhound out for a spin, the team packed up shop and took a

  • trip to the desert of South Africa.

  • The Hakskeenpan is an incredible place to run a straight line racing car like Bloodhound.

  • We've prepared 19 kilometers of track by about three kilometers wide.

  • We actually clear the stones off the track

  • to make what is now the world's best straight line racing track.

  • From October to November of 2019, the car went through various speed tests, hitting

  • 450, 550 and eventually 600 miles per hour, the final goal for this round.

  • I was about 300 meters to the side of the track and it is an incredible thing to witness.

  • The first thing you experience is the noise of the cars.

  • You hear the jet engine at this point, it's over the horizon.

  • And what is incredible is seeing this white speck, and then within seconds, it's 300 meters

  • away from you. It is an incredible thing to witness.

  • I've been working on Bloodhound for over a decade and over that decade it's been very

  • much a theoretical thing for me.

  • It's been pictures and plots on a computer screen.

  • So to be there in South Africa and see this vehicle in real life, it felt like you were

  • witnessing history.

  • With this year's testing now complete, there's mountains of data to sift through and engineering

  • improvements to be made before their attempt at a world record.

  • During the high speed test program, the car was heavily instrumented with sensors measuring

  • pretty much everything you could think of measuring on a car like this.

  • What we're now doing is mapping those measurements back to the CFD model that was used to design

  • the car in the first place to see how well that CFD model corresponds with how the car

  • actually behaved.

  • That will help us define the size of some winglets, which we might need to add onto

  • the car for a record attempt.

  • The team also needs more thrust.

  • The military jet engine they used during testing was enough to get the car to 628 miles an

  • hour, butto break the record and head towards 800 miles

  • per hour and north of that, we're gonna need to supplement that thrust with a mono-propellant

  • rocket engine.

  • We just need to get the rocket system developed and installed in the car and then we'll be

  • ready for a record attempt.

  • If all goes to plan, Bloodhound will attempt its record breaking drive in 2021.

  • But regardless of the outcome, the team's pursuit is really about pushing the limits

  • of our world.

  • Bloodhound is important because it's really difficult.

  • And whenever engineers and scientists do things that are difficult, we learn lots.

  • For me, as an aerodynamicist, Bloodhound is the fastest transonic aerodynamic test bed

  • that has ever existed.

  • The data will get back off of this will be incredible in helping us understand how well

  • CFD methods, computer modeling methods can predict aerodynamics on a complex body like

  • this.

  • But almost on a bigger level than that Bloodhound is all about showcasing new technology, which

  • is going to be really important for inspiring a whole new generation of engineers who are

  • going to solve the problems that the world needs to solve.

You're watching a test run of one of the fastest cars ever made.

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B1 中級

這款火箭動力汽車的設計打破了音障。 (This Rocket-Powered Car Is Engineered to Break the Sound Barrier)

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    林宜悉 發佈於 2021 年 01 月 14 日
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