The Secret Life of Machines (1988) s02e01 Episode Script
The Car
[Door opens, footsteps.]
[Jazzy music: 'The Russians Are Coming' - Val Bennett.]
Tim: The car does almost have a religious status in the modern world.
It's certainly more than just a practical means of transport.
People get more passionate about their car than any other machine.
At the same time, there's something very cheap and nasty about the things.
The way they so quickly rot and fall to bits, and end up looking like these ones.
It's all such a vast subject, that today I'm going to concentrate on the part of the car that people lavish most love and care on.
Which is also the part that leads to the car's rapid demise.
This is the steel skin which gives the car its shape and its rigidity, the body shell.
I'm going to look at how it developed and also at its structure.
[Squelchy footsteps.]
The invention that really created the market for the car, by giving people a taste of the fun that could be had from a personal means of transport, was the bicycle.
[rattly bike on wet ground.]
It was the popularity of cycling that led to several intrepid engineers trying to go faster by adding one of the new internal combustion engines.
Gottlieb Daimler added one to a wooden wheeled bicycle a bit like this.
And Karl Benz based his design on a tricycle.
[quiet gear noise.]
Benz was a mechanical engineer, born in Germany in 1844.
[squeaking.]
He bought a bicycle in the 1860s and became obsessed by the idea of motorised personal transport ever since Cyclist: Pants and Sighs.
[Wedding bells.]
Man: Ah here Benz, see here marry my daughter, and I give you lots of money Benz: Ah! My engine! My engine! At last I can build it.
AHHH! Tim: He spent his wife's dowry on a small engineering works, and eventually managed to make a simple engine and tricycle.
[engine noise.]
Benz: Liebschen? Liebschen? Would you like to come for a drive? Mrs Benz: I hope it vas vorth vaiting for Karl! [Engine noise.]
You and your engine! Aah! Ooh! Aah! Tim: He never saw the point of faster speeds, and refused to change his basic design.
Man: You won't change with the times, so we have no confidence! By 1906 he was hopelessly outdated, and his fellow directors threw him out.
Benz: Could zis be a boardroom coup? All: Ja! Benz: Aaaaaaah! Tim: At exactly the same time, Daimler was also experimenting, only 30 miles away, Though neither knew of the other's work.
Daimler was really only interested in engines.
He perfected one which ran at 900 rpm, [fast engine noise.]
Over three times faster than anything else at the time.
He then tried to find all sorts of uses for it.
[clank.]
[engine noise.]
Daimler: Arrrgh [clink clink clink.]
[Horse whinnies.]
[engine noise.]
[CRASH!.]
[water lapping.]
Tim: He was never very successful at making complete vehicles, Daimler: Oooaaaaarrrrggghh! [engine noise.]
Tim: but his engines were adopted by other firms and formed the basis of the first successful cars.
This is a 1902 Wolsey.
Cars had quickly lost their resemblance to bicycles, and started to look literally like horseless carriages.
The body, the interior, the wooden frame, the wheels, even the patent leather mudguards and the lamps look exactly like a horse drawn carriage.
In fact the whole, this part of it would have been made by a traditional carriage builder.
Mechanically though, it's already surprisingly like a modern car, with the steering wheel and the pedals in exactly the same place.
[rattly exhaust noise outside.]
Donald: It is ready.
He has bought one! Man: Why, the fellow hasn't a horse of his own yet, has he? Man2: Well I think we ought to go and see what he has got anyway.
Man: Certainly.
I'm not prejudiced.
Come along vicar.
Tim: With a 20 mph speed limit, which stayed in force until 1930, cars still weren't particularly useful.
Donald: old man, how are you? Driver: Hello Donald, boy.
[woman exclaims.]
Tim: But motoring quickly became a fashionable hobby for the rich.
This is part of a film made by Morris in the 1920s about the history of motoring.
[dismissive sniff.]
Driver: Come on, jump in sir.
[All chat at once.]
[rattly engine noise.]
[chatting.]
[music.]
Tim: The idea of mass producing cars, started by Henry Ford in 1906, slowly spread to Europe after the first world war.
This is Morris's factory in 1925.
[music continues.]
The bodies were still being made with the traditional wooden frames, like horseless carriages.
Although they were mass produced, it was all still very labour intensive.
[music.]
Girl: Oh Mother! Here's Dad with my new car! Tim: It wasn't long though, before there was a revolutionary change in the way that cars were made.
[girl giggles.]
Dad: Well, do you like it? Mother: Well it certainly looks very nice.
Girl: I think it's lovely! Girl: Is it really all made out of steel Dad? Dad: Yes, practically all of it.
Tim: Today all cars are built round a steel body shell.
It's a good name for it, because it is a bit like an egg shell.
the material it's made of is very weak, it's the shape that gives it its strength.
The steel the car's made of is incredibly thin.
It's only just over half a millimetre thick.
And I can actually just about cut it with a pair of kitchen scissors.
(mutters) with a little bit of a struggle! [metallic scraping noises.]
However, when it's pressed into curved, rounded shapes Curved, rounded shapes like this.
This is actually the bit from the bottom of one of the doors.
Its strength increases enormously.
It's now quite strong enough to stand on! The idea of making cars like this came from an American engineer called Edward Budd, who's one of my heroes.
Budd set up his factory, determined to make complete pressed steel cars.
In 1912.
His first successful car body, for the 1916 Willis Knight, looked indistinguishable from a conventional wooden one.
Budd started making bodies for almost all the American car manufacturers, and in 1925 he set up a pressing plant at Cowley for Morris.
[Music.]
Voiceover: The Morris standard ensures that the 'okay' stamp is placed only on the best, and that's how they get beautiful stamped sheets of steel.
Girl: Dad, the car hasn't got fat sides and beautiful curves.
Dad: Yes I know, Miss Inquisitive, I thought you'd want to know how that's done.
Well, those beautiful curves you like so much, are made on huge machines called presses.
Some are as tall as a house, and weigh as much as 30 tonnes or more.
[music continues (distorted).]
Voiceover: A machine of especial beauty of a great machine pressing steel.
[music.]
[industrial noises.]
500 tons presses(distorted).
.
weight on a sheet of steel, producing the rear quarter panels of an Austin 7.
[music.]
Tim: The rounder the panel the stronger it is.
This modern bonnet is almost completely flat and it's extremely weak.
[rumble of sheet steel.]
It needs this elaborate piece behind to make it stiff enough.
This old Morris Minor bonnet needs hardly any stiffening at all.
It is made of slightly thicker metal, but the main reason for its strength is its shape.
Deeply rounded curves like this are the obvious way to give pressed steel strength.
and I'm sure this is why such rounded bulbous cars came into fashion in the '30s and '40s.
[Music.]
Voiceover: In the truly modern home, or the truly modern car, its functional design that counts.
Smart styling is styling with a purpose.
As seen in this new 1948 futuramic Oldsmobile.
Futuramic is a brand new word created to describe this brand new post-war General Motors car.
Luxuriously appointed inside and out.
The futuramic Oldsmobile brings truly modern post-war design to the automotive field.
[crunching gravel.]
Tim: The rigidity of the steel pressings can be greatly increased by welding them together to make hollow box sections A bit like that! This welding is done by machines like this, called spot welders.
Although it looks rather complicated, all it's doing is, er, squash the two bits of metal between it's jaws, and pass a large electric current through it.
This heats the metal up enough to weld it together.
(mutters) So, erm [jaws ratchet closed.]
[electric buzz.]
[clicliclick.]
[Bzzzzt.]
This now feels completely rigid.
If you look at any modern can, you can actually see the little spots.
They're all welded together like this.
[Music.]
Although at first the welding was done by portable machines like this.
Today it's usually done by robots.
[music.]
[engine.]
Cars were traditionally build around a strong chassis like this.
[engine.]
All the components were fixed on, and then a fairly flimsy body could be dropped on over the top.
[music.]
However, Edward Budd's techniques changed all this.
[engine.]
[engine gets even louder.]
Budd realised that, er, all steel bodies [radiator bursts.]
Whoops! giggle Budd realised that his all steel bodies could be made so strong, that you really didn't need a chassis at all.
All the mechanical components could be bolted straight on.
Girl: Dad! I thought the engine, axles and wheels were always fixed onto the chassis.
Dad: On ordinary cars yes, but this Morris is the latest product of engineering science, and the wheels are fixed directly onto the body.
[music.]
Tim: The enormous advantage of making a whole pressed steel shell, without a separate chassis, is that it's highly suited to mass production.
Once you have the dies and presses, the whole process is very quick and cheap.
Lead by America, the car industry lost its dependence on earlier industrial techniques and became a dominant industry in its own right.
[Music.]
Presses like these have been used to mass produce cars ever since.
Although today cars look very different and have improved in countless small ways, they're basically very similar.
Almost the only radical change, on a par with pressed steel construction, has been the introduction of front wheel drive.
In many ways the 1934 Citroen Traction Avant was really the first modern car.
It was front wheel drive, it was the very first mass produced car without a chassis, and it even had independent suspension.
Andre Citroen was friends with Budd, was much more adventurous than any of the American car manufacturers, who'd rejected Budd's ideas.
Front wheel drive was slow to catch on, the first popular car to use it in Britain was the mini, not introduced until 25 years later.
Voiceover: Some baby! Loaded! [music.]
Remember that family at the bus stop? You know, the ones who just couldn't get away? The new Austin 7's transformed their lives.
[music.]
But what about all that luggage? Can they get it in? [music.]
Tim: With all the mechanical parts at the front, there was much more room inside.
which was a big selling point.
[music.]
The Mini has its driving wheels at the front, this makes it all very compact, particularly with the engine mounted sideways.
The big advantage to the manufacturer was that all the mechanics would be assembled together, and fitted under the body shell in one lump.
[engine starts and drives off.]
In the last few years front wheel drive has suddenly become very popular.
It's now actually more common than rear wheel drive.
Today, body shells are designed very scientifically with computers.
Which has made them lighter and more aerodynamic.
It's also made them look more and more alike.
This shell could have come from almost any car.
Even professional mechanics who've seen it couldn't tell what make or model it was at first sight.
[buzzing noise.]
Despite all this design, the steel body shell still has considerable limitations.
Superficially, the panels bend ridiculously easily, and sorting out even a small dent is quite an elaborate process.
[buzzing continues.]
Some outer panels are now made of plastic, which doesn't dent so easily.
But this isn't suitable for the car's structure.
Another problem with the steel body shell, is that even a small dent can distort a large part of it.
And put vital parts like the suspension mountings out of alignment.
Straightening it out is quite an elaborate process.
First the body shell has to be firmly fixed to the jig for the model of car.
Precisely locating all the important points.
The damage can then be pulled out [clanking of metal noises.]
[compressor.]
The badly damaged bits still have to be replaced, but it pulls most of the shell back into alignment.
For more serious impacts, Budd was originally very proud of the safety of his steel bodies.
and arranged all sorts of stunts to prove it.
Citroen did the same.
[crash clang bang.]
[footsteps on gravel.]
[clanking.]
[engine starts, moves off.]
Mother: Well I must say, I admire your choice John.
Girl: It really is perfect, and it's so nice to know you're surrounded by steel.
Dad: Yes, you'll be just like a knight of old.
Girl: Yes, just as safe.
Much more comfortable, and a car I'll be proud to own.
[loud rattling noise.]
[pumps up jack.]
Tim: however, as car speeds have increased over the years, the forces the body shell has to cope with have increased enormously.
The force needed to stop a car with the breaks quickly makes them glow red hot.
[engine drives hub against brakes.]
In a crash, the car stops in a fraction of a second so the force is many times greater.
And it all has to be absorbed by crumpling the body shell.
Manufacturers try to design areas that collapse, called crumple zones, that in any serious impact leaving the interior as rigid as possible.
But safety's only one of many factors that goes into designing a body shell.
Cost, appearance, ease of manufacture, etc.
are all equally important.
Certainly cars aren't as safe as they have to be, when for instance, you're designing a stunt for a film, and safety's the priority.
Rex: The difference between a real road car accident, and a stunt like I'm now going to do, is the fact that I know exactly what's going to happen in the stunt.
I prepare myself and the car for that eventuality.
the body shell is no where near strong enough, so we have to reinforce that with a roll cage, and that's made out of strong tubular steel.
And I know exactly where the car will be hitting the ground.
Most of the impact will happen on that corner, so we reinforce that really strongly above my head.
The doors are welded shut, this last door when I get in will be wired shut, to make sure it can't possibly open when it rolls, cos the door could rip off and go inside the car, and do quite a lot of damage.
I also put two bars up at the window to make sure that the bonnet, if it did come off, wouldn't come through the window and hit me.
I'm not really worried about the glass, the glass is minor, it can't possibly cut me - I'm wearing a visor and gloves.
Although it looks dangerous, I don't consider it to be even slightly dangerous.
Because I know what I'm doing.
[engine revs hard.]
[BANG-CLASH.]
[bang reverberates.]
[eerie music.]
[engine revs.]
[crash crash.]
[engine revs up and stops.]
Rex: As I predicted, most of the impact was taken by the corner of the roof over my head.
And as you can see, it is possible to build a structure strong enough to take even this drastic punishment.
[metal clanking.]
Tim: The other big problem with a steel body shell is rust.
Despite manufacturer's claims about corrosion protection, about half of all cars are scrapped by the time they are ten years old.
Most cars are still runners when they reach the yard, it's almost always the body shell, not the mechanics, which seals their fate.
this car still looks immaculate, but underneath it's so rusty it's impossible to repair.
[hydraulic whine and engine noise.]
[clank clank crunch.]
[hydraulics.]
Tim: Budd realised this limitation of his material, and spent much of the '30s experimenting with stainless steel.
He developed the beautiful stainless steel trains that are still in use in parts of America and Europe.
Although the rusting steel used on today's cars leaves a lot to be desired.
It does have one final compensation.
Cars get more thoroughly recycled than any other machine.
There's a whole industry of scrap yards which salvage and resell the mechanical parts and squash up the body shells to be remelted.
Scrap yards really deserve a greener image.
[traffic noise.]
Perhaps its almost a relief that cars don't last very long.
With almost 20 million cars on the road in Britain.
"Come on!" Manufacturers in Europe producing over 30 million more every year.
[car horns hooting.]
3 times more cars are being produced than babies are being born.
[car horns hooting.]
[baby begins to cry.]
[slurps milk.]
[loud barfing noises.]
Man: Oh No, I'm losing millions.
I'm stuck in traffic jam! Tim: They're hardly the symbols of freedom and progress they once were.
There's so many of them, they're now often slower than the bicycle they originated from.
[car horns.]
[bicycle bell.]
Man: Bloody Cy-clists! [BEEEEP! BEEEEP!.]
Tim: It's a sad sight seeing what was once someone's possession coming to such an ignomious end.
But watching this body shell being squashed does make you realise just how ingenious its design is.
[tailgate clatters.]
The way the whole thing can be made from such a small amount of metal.
[clatter.]
[hydraulics.]
[Crunch!.]
[Jazzy music: 'Take 5' - Dave Brubeck.]
[car continues to be crushed.]
[Jazzy music: 'The Russians Are Coming' - Val Bennett.]
Tim: The car does almost have a religious status in the modern world.
It's certainly more than just a practical means of transport.
People get more passionate about their car than any other machine.
At the same time, there's something very cheap and nasty about the things.
The way they so quickly rot and fall to bits, and end up looking like these ones.
It's all such a vast subject, that today I'm going to concentrate on the part of the car that people lavish most love and care on.
Which is also the part that leads to the car's rapid demise.
This is the steel skin which gives the car its shape and its rigidity, the body shell.
I'm going to look at how it developed and also at its structure.
[Squelchy footsteps.]
The invention that really created the market for the car, by giving people a taste of the fun that could be had from a personal means of transport, was the bicycle.
[rattly bike on wet ground.]
It was the popularity of cycling that led to several intrepid engineers trying to go faster by adding one of the new internal combustion engines.
Gottlieb Daimler added one to a wooden wheeled bicycle a bit like this.
And Karl Benz based his design on a tricycle.
[quiet gear noise.]
Benz was a mechanical engineer, born in Germany in 1844.
[squeaking.]
He bought a bicycle in the 1860s and became obsessed by the idea of motorised personal transport ever since Cyclist: Pants and Sighs.
[Wedding bells.]
Man: Ah here Benz, see here marry my daughter, and I give you lots of money Benz: Ah! My engine! My engine! At last I can build it.
AHHH! Tim: He spent his wife's dowry on a small engineering works, and eventually managed to make a simple engine and tricycle.
[engine noise.]
Benz: Liebschen? Liebschen? Would you like to come for a drive? Mrs Benz: I hope it vas vorth vaiting for Karl! [Engine noise.]
You and your engine! Aah! Ooh! Aah! Tim: He never saw the point of faster speeds, and refused to change his basic design.
Man: You won't change with the times, so we have no confidence! By 1906 he was hopelessly outdated, and his fellow directors threw him out.
Benz: Could zis be a boardroom coup? All: Ja! Benz: Aaaaaaah! Tim: At exactly the same time, Daimler was also experimenting, only 30 miles away, Though neither knew of the other's work.
Daimler was really only interested in engines.
He perfected one which ran at 900 rpm, [fast engine noise.]
Over three times faster than anything else at the time.
He then tried to find all sorts of uses for it.
[clank.]
[engine noise.]
Daimler: Arrrgh [clink clink clink.]
[Horse whinnies.]
[engine noise.]
[CRASH!.]
[water lapping.]
Tim: He was never very successful at making complete vehicles, Daimler: Oooaaaaarrrrggghh! [engine noise.]
Tim: but his engines were adopted by other firms and formed the basis of the first successful cars.
This is a 1902 Wolsey.
Cars had quickly lost their resemblance to bicycles, and started to look literally like horseless carriages.
The body, the interior, the wooden frame, the wheels, even the patent leather mudguards and the lamps look exactly like a horse drawn carriage.
In fact the whole, this part of it would have been made by a traditional carriage builder.
Mechanically though, it's already surprisingly like a modern car, with the steering wheel and the pedals in exactly the same place.
[rattly exhaust noise outside.]
Donald: It is ready.
He has bought one! Man: Why, the fellow hasn't a horse of his own yet, has he? Man2: Well I think we ought to go and see what he has got anyway.
Man: Certainly.
I'm not prejudiced.
Come along vicar.
Tim: With a 20 mph speed limit, which stayed in force until 1930, cars still weren't particularly useful.
Donald: old man, how are you? Driver: Hello Donald, boy.
[woman exclaims.]
Tim: But motoring quickly became a fashionable hobby for the rich.
This is part of a film made by Morris in the 1920s about the history of motoring.
[dismissive sniff.]
Driver: Come on, jump in sir.
[All chat at once.]
[rattly engine noise.]
[chatting.]
[music.]
Tim: The idea of mass producing cars, started by Henry Ford in 1906, slowly spread to Europe after the first world war.
This is Morris's factory in 1925.
[music continues.]
The bodies were still being made with the traditional wooden frames, like horseless carriages.
Although they were mass produced, it was all still very labour intensive.
[music.]
Girl: Oh Mother! Here's Dad with my new car! Tim: It wasn't long though, before there was a revolutionary change in the way that cars were made.
[girl giggles.]
Dad: Well, do you like it? Mother: Well it certainly looks very nice.
Girl: I think it's lovely! Girl: Is it really all made out of steel Dad? Dad: Yes, practically all of it.
Tim: Today all cars are built round a steel body shell.
It's a good name for it, because it is a bit like an egg shell.
the material it's made of is very weak, it's the shape that gives it its strength.
The steel the car's made of is incredibly thin.
It's only just over half a millimetre thick.
And I can actually just about cut it with a pair of kitchen scissors.
(mutters) with a little bit of a struggle! [metallic scraping noises.]
However, when it's pressed into curved, rounded shapes Curved, rounded shapes like this.
This is actually the bit from the bottom of one of the doors.
Its strength increases enormously.
It's now quite strong enough to stand on! The idea of making cars like this came from an American engineer called Edward Budd, who's one of my heroes.
Budd set up his factory, determined to make complete pressed steel cars.
In 1912.
His first successful car body, for the 1916 Willis Knight, looked indistinguishable from a conventional wooden one.
Budd started making bodies for almost all the American car manufacturers, and in 1925 he set up a pressing plant at Cowley for Morris.
[Music.]
Voiceover: The Morris standard ensures that the 'okay' stamp is placed only on the best, and that's how they get beautiful stamped sheets of steel.
Girl: Dad, the car hasn't got fat sides and beautiful curves.
Dad: Yes I know, Miss Inquisitive, I thought you'd want to know how that's done.
Well, those beautiful curves you like so much, are made on huge machines called presses.
Some are as tall as a house, and weigh as much as 30 tonnes or more.
[music continues (distorted).]
Voiceover: A machine of especial beauty of a great machine pressing steel.
[music.]
[industrial noises.]
500 tons presses(distorted).
.
weight on a sheet of steel, producing the rear quarter panels of an Austin 7.
[music.]
Tim: The rounder the panel the stronger it is.
This modern bonnet is almost completely flat and it's extremely weak.
[rumble of sheet steel.]
It needs this elaborate piece behind to make it stiff enough.
This old Morris Minor bonnet needs hardly any stiffening at all.
It is made of slightly thicker metal, but the main reason for its strength is its shape.
Deeply rounded curves like this are the obvious way to give pressed steel strength.
and I'm sure this is why such rounded bulbous cars came into fashion in the '30s and '40s.
[Music.]
Voiceover: In the truly modern home, or the truly modern car, its functional design that counts.
Smart styling is styling with a purpose.
As seen in this new 1948 futuramic Oldsmobile.
Futuramic is a brand new word created to describe this brand new post-war General Motors car.
Luxuriously appointed inside and out.
The futuramic Oldsmobile brings truly modern post-war design to the automotive field.
[crunching gravel.]
Tim: The rigidity of the steel pressings can be greatly increased by welding them together to make hollow box sections A bit like that! This welding is done by machines like this, called spot welders.
Although it looks rather complicated, all it's doing is, er, squash the two bits of metal between it's jaws, and pass a large electric current through it.
This heats the metal up enough to weld it together.
(mutters) So, erm [jaws ratchet closed.]
[electric buzz.]
[clicliclick.]
[Bzzzzt.]
This now feels completely rigid.
If you look at any modern can, you can actually see the little spots.
They're all welded together like this.
[Music.]
Although at first the welding was done by portable machines like this.
Today it's usually done by robots.
[music.]
[engine.]
Cars were traditionally build around a strong chassis like this.
[engine.]
All the components were fixed on, and then a fairly flimsy body could be dropped on over the top.
[music.]
However, Edward Budd's techniques changed all this.
[engine.]
[engine gets even louder.]
Budd realised that, er, all steel bodies [radiator bursts.]
Whoops! giggle Budd realised that his all steel bodies could be made so strong, that you really didn't need a chassis at all.
All the mechanical components could be bolted straight on.
Girl: Dad! I thought the engine, axles and wheels were always fixed onto the chassis.
Dad: On ordinary cars yes, but this Morris is the latest product of engineering science, and the wheels are fixed directly onto the body.
[music.]
Tim: The enormous advantage of making a whole pressed steel shell, without a separate chassis, is that it's highly suited to mass production.
Once you have the dies and presses, the whole process is very quick and cheap.
Lead by America, the car industry lost its dependence on earlier industrial techniques and became a dominant industry in its own right.
[Music.]
Presses like these have been used to mass produce cars ever since.
Although today cars look very different and have improved in countless small ways, they're basically very similar.
Almost the only radical change, on a par with pressed steel construction, has been the introduction of front wheel drive.
In many ways the 1934 Citroen Traction Avant was really the first modern car.
It was front wheel drive, it was the very first mass produced car without a chassis, and it even had independent suspension.
Andre Citroen was friends with Budd, was much more adventurous than any of the American car manufacturers, who'd rejected Budd's ideas.
Front wheel drive was slow to catch on, the first popular car to use it in Britain was the mini, not introduced until 25 years later.
Voiceover: Some baby! Loaded! [music.]
Remember that family at the bus stop? You know, the ones who just couldn't get away? The new Austin 7's transformed their lives.
[music.]
But what about all that luggage? Can they get it in? [music.]
Tim: With all the mechanical parts at the front, there was much more room inside.
which was a big selling point.
[music.]
The Mini has its driving wheels at the front, this makes it all very compact, particularly with the engine mounted sideways.
The big advantage to the manufacturer was that all the mechanics would be assembled together, and fitted under the body shell in one lump.
[engine starts and drives off.]
In the last few years front wheel drive has suddenly become very popular.
It's now actually more common than rear wheel drive.
Today, body shells are designed very scientifically with computers.
Which has made them lighter and more aerodynamic.
It's also made them look more and more alike.
This shell could have come from almost any car.
Even professional mechanics who've seen it couldn't tell what make or model it was at first sight.
[buzzing noise.]
Despite all this design, the steel body shell still has considerable limitations.
Superficially, the panels bend ridiculously easily, and sorting out even a small dent is quite an elaborate process.
[buzzing continues.]
Some outer panels are now made of plastic, which doesn't dent so easily.
But this isn't suitable for the car's structure.
Another problem with the steel body shell, is that even a small dent can distort a large part of it.
And put vital parts like the suspension mountings out of alignment.
Straightening it out is quite an elaborate process.
First the body shell has to be firmly fixed to the jig for the model of car.
Precisely locating all the important points.
The damage can then be pulled out [clanking of metal noises.]
[compressor.]
The badly damaged bits still have to be replaced, but it pulls most of the shell back into alignment.
For more serious impacts, Budd was originally very proud of the safety of his steel bodies.
and arranged all sorts of stunts to prove it.
Citroen did the same.
[crash clang bang.]
[footsteps on gravel.]
[clanking.]
[engine starts, moves off.]
Mother: Well I must say, I admire your choice John.
Girl: It really is perfect, and it's so nice to know you're surrounded by steel.
Dad: Yes, you'll be just like a knight of old.
Girl: Yes, just as safe.
Much more comfortable, and a car I'll be proud to own.
[loud rattling noise.]
[pumps up jack.]
Tim: however, as car speeds have increased over the years, the forces the body shell has to cope with have increased enormously.
The force needed to stop a car with the breaks quickly makes them glow red hot.
[engine drives hub against brakes.]
In a crash, the car stops in a fraction of a second so the force is many times greater.
And it all has to be absorbed by crumpling the body shell.
Manufacturers try to design areas that collapse, called crumple zones, that in any serious impact leaving the interior as rigid as possible.
But safety's only one of many factors that goes into designing a body shell.
Cost, appearance, ease of manufacture, etc.
are all equally important.
Certainly cars aren't as safe as they have to be, when for instance, you're designing a stunt for a film, and safety's the priority.
Rex: The difference between a real road car accident, and a stunt like I'm now going to do, is the fact that I know exactly what's going to happen in the stunt.
I prepare myself and the car for that eventuality.
the body shell is no where near strong enough, so we have to reinforce that with a roll cage, and that's made out of strong tubular steel.
And I know exactly where the car will be hitting the ground.
Most of the impact will happen on that corner, so we reinforce that really strongly above my head.
The doors are welded shut, this last door when I get in will be wired shut, to make sure it can't possibly open when it rolls, cos the door could rip off and go inside the car, and do quite a lot of damage.
I also put two bars up at the window to make sure that the bonnet, if it did come off, wouldn't come through the window and hit me.
I'm not really worried about the glass, the glass is minor, it can't possibly cut me - I'm wearing a visor and gloves.
Although it looks dangerous, I don't consider it to be even slightly dangerous.
Because I know what I'm doing.
[engine revs hard.]
[BANG-CLASH.]
[bang reverberates.]
[eerie music.]
[engine revs.]
[crash crash.]
[engine revs up and stops.]
Rex: As I predicted, most of the impact was taken by the corner of the roof over my head.
And as you can see, it is possible to build a structure strong enough to take even this drastic punishment.
[metal clanking.]
Tim: The other big problem with a steel body shell is rust.
Despite manufacturer's claims about corrosion protection, about half of all cars are scrapped by the time they are ten years old.
Most cars are still runners when they reach the yard, it's almost always the body shell, not the mechanics, which seals their fate.
this car still looks immaculate, but underneath it's so rusty it's impossible to repair.
[hydraulic whine and engine noise.]
[clank clank crunch.]
[hydraulics.]
Tim: Budd realised this limitation of his material, and spent much of the '30s experimenting with stainless steel.
He developed the beautiful stainless steel trains that are still in use in parts of America and Europe.
Although the rusting steel used on today's cars leaves a lot to be desired.
It does have one final compensation.
Cars get more thoroughly recycled than any other machine.
There's a whole industry of scrap yards which salvage and resell the mechanical parts and squash up the body shells to be remelted.
Scrap yards really deserve a greener image.
[traffic noise.]
Perhaps its almost a relief that cars don't last very long.
With almost 20 million cars on the road in Britain.
"Come on!" Manufacturers in Europe producing over 30 million more every year.
[car horns hooting.]
3 times more cars are being produced than babies are being born.
[car horns hooting.]
[baby begins to cry.]
[slurps milk.]
[loud barfing noises.]
Man: Oh No, I'm losing millions.
I'm stuck in traffic jam! Tim: They're hardly the symbols of freedom and progress they once were.
There's so many of them, they're now often slower than the bicycle they originated from.
[car horns.]
[bicycle bell.]
Man: Bloody Cy-clists! [BEEEEP! BEEEEP!.]
Tim: It's a sad sight seeing what was once someone's possession coming to such an ignomious end.
But watching this body shell being squashed does make you realise just how ingenious its design is.
[tailgate clatters.]
The way the whole thing can be made from such a small amount of metal.
[clatter.]
[hydraulics.]
[Crunch!.]
[Jazzy music: 'Take 5' - Dave Brubeck.]
[car continues to be crushed.]