- 2 days ago
Britain develops defenses against German zeppelins that drop bombs on London during World War I....
Category
📺
TVTranscript
00:0118 months into World War I, the Germans devastate British cities with enormous airship bombers called Zeppelins.
00:12It's an entirely new kind of terror campaign.
00:16There was a policeman running down the road shouting,
00:18They're here! They're here! The Germans are here!
00:22In a game-changing strategy,
00:26the Germans ruthlessly bomb ordinary civilians from the air.
00:31It's the beginning of modern warfare, red in tooth and claw.
00:34But exactly how these mighty machines worked has been lost to history.
00:40Now, engineer Hugh Hunt will investigate the incredible technology behind these gas-filled monsters.
00:51It's an explosive tale of bombs and bullets with a mystery at its core.
00:58A big bag full of hydrogen. Why couldn't we shoot them down? They were just there, surely.
01:03Hugh will discover an unexpected personal connection to the events.
01:08What we have here is the bullet your uncle designed.
01:12And he will unravel an amazing story of ingenuity and courage.
01:17Good on you, Uncle Jim.
01:18Zeppelin terror attack, right now on NOVA.
01:47As the city of London sleeps, German commanders 500 miles away are planning a deadly attack.
02:01It's 1915, and World War I battles are raging in the trenches of Northern Europe.
02:10But at 11 p.m., May 31st, the Germans open a new battlefront.
02:19They strike at the enemy in their own backyard.
02:23For the first time in history, London is under attack from the air.
02:29But these bombs aren't being dropped from planes.
02:33The Germans have deployed a terrifying new weapon of mass destruction, the Zeppelin.
02:41For the next two and a half years, these mighty airships rained down death on British streets,
02:48claiming the lives of hundreds of innocent civilians.
02:52They're the biggest flying vessels ever built,
02:55able to travel higher and further than any airplanes of the day.
03:01How did the Germans construct these colossal machines?
03:05What was the secret of their lethal success?
03:09And why were they so difficult to destroy?
03:28The Zeppelin NT airship is the last word in sleek aeronautical engineering.
03:37It is the latest in a long line of airships going back 100 years,
03:42that have carried passengers on scenic pleasure cruises.
03:49Taking his seat in the gondola is Cambridge University engineer Dr. Hugh Hunt.
03:56But today, he is taking a trip into the past to discover how the Germans built the Zeppelin bombers of
04:03World War I,
04:04and how the British strove to bring them down.
04:09Just like that.
04:14They've just taken off, and I'm just amazed at how quick that was.
04:19Hugh was expecting the airship to be slow and cumbersome,
04:23but this one is full of surprises.
04:27The Zeppelin's noted to talk about maneuverability, or is it generally airships are maneuverable?
04:33Definitely. The new Zeppelin is definitely very maneuverable,
04:36and far more maneuverable than a lot of the others because...
04:38Whoa!
04:40Yes, as you can see.
04:42Whoa!
04:44So yes, it turned very rapid.
04:46That is remarkable.
04:53This machine can reach a top speed of 78 miles per hour,
04:58and stay in the air for 24 hours.
05:01And its predecessors of a century ago were almost as fast,
05:06just as far-ranging, and over twice as big.
05:15On July 2nd, 1900, three years before the first airplane flew,
05:22a retired German soldier called Count Ferdinand von Zeppelin
05:27unveiled his own revolutionary flying machine.
05:35He produced a fleet of these airships,
05:38and fitted them out like luxury liners.
05:42They carried well-heeled passengers on grand excursions over the Alps.
05:50To an enthusiastic German public,
05:52Zeppelins were shining beacons of the superiority of their nation's engineering.
06:00But with Germany on the brink of war with Britain,
06:03the military had other plans for the airships.
06:11They would make perfect long-range bombers to strike at the enemy in their own backyard.
06:19Bombing London would cause panic in the civilian population,
06:23and force the British government to pull out of the war.
06:31The brains behind the Zeppelin bombing campaign was Navy Commander Peter Strasser.
06:38A confirmed bachelor married only to his job.
06:42He was an inspirational leader who didn't mince his words.
06:46Your holy duty is the destruction of London.
06:50You are ready to bring the highest punishment for your fatherland,
06:54the crowned sword for every humble son of Germany.
06:59In a corner of Commander Strasser's war room,
07:02Hugh has assembled a Zeppelin think tank.
07:06Among the experts is military historian Professor Eric Grove.
07:12Strasser was one of that group of officers of the armed forces
07:16who actually came into airships and caught the bug.
07:21He suddenly became a convert.
07:23He rode to Damascus conversion.
07:25And this new technology was going to win the war.
07:32War had broken out on August 4th, 1914.
07:38The forces of Austria and Germany lined up against those of Russia, France and Britain.
07:47Initially, World War I looked like it might be over by Christmas.
07:55But it degenerated into a long, bloody war of attrition
07:59that would claim the lives of over 16 million people.
08:08Strasser believed he could bring a swift end to the carnage on the battlefield
08:12by bombing civilian targets like London into submission.
08:18The weapon that would deliver victory was the new Zeppelin bomber.
08:23The Zeppelin raids demonstrate what 20th century war was going to be all about,
08:29where the war is carried into the heart of the enemy territory.
08:32And you rationalize it by saying the more frightful you are,
08:35the sooner the war will end, the sooner the enemy will give in.
08:41The technology Strasser pinned his faith on employed the latest lightweight materials.
08:47Unlike a blimp, which relies on the pressure of the gas inside to keep its shape,
08:51the Zeppelin had a rigid aluminum alloy skeleton.
08:58This strong lattice structure meant the engineers could make Strasser's new airship enormous.
09:05At 650 feet, it was more than twice as long as a jumbo jet.
09:14Beneath its canvas skin, it contained 19 bags filled with hydrogen gas.
09:27Hydrogen is lighter than air and provided lift to the airship.
09:35But molecules of hydrogen are so small that they pass easily through the weave of most fabrics.
09:43Stopping the gas from leaking was one of the major challenges facing the Zeppelin engineers.
09:54Leaking hydrogen gas was blamed for the notorious Hindenburg disaster of 1937,
10:00when the highly flammable gas caught fire and destroyed the giant airship at Lakehurst, New Jersey.
10:09Of the 97 people on board, 35 perished.
10:18So this is eight tons, which I can...
10:25God, I'm lifting an airship.
10:28Today, it's non-flammable helium, rather than hydrogen, that makes the modern Zeppelin lighter than air.
10:52The helium is held in an envelope made of laminated plastic.
10:58But stopping the gas from leaking is still a problem.
11:01Gas will escape.
11:04We average somewhere 10 to 15 cubic metres a day of natural loss.
11:13Is it through sort of pinprick holes in the thing, or is it just through the fabric?
11:19Most of the helium could be pinprick holes that occur over a period of time.
11:24Very, very difficult to completely seal it.
11:27You've got a good seal when there's not so much pressure.
11:29When there's pressure, and it's stretching, you've got a little bit of a leak.
11:32But here we are in 2012, and we've got pretty fancy materials, and the bloody thing still leaks.
11:40What about in the early days?
11:42To make the leak-proof bags that held the hydrogen, the airship pioneers needed a material that was light and
11:49strong and in plentiful supply.
11:53They found it in an unlikely place, inside a cow.
12:03One of the things that I found so fascinating is the story of what these bags are made of.
12:08And they were made of this stuff, which, well, you look at this and you kind of think, well, is
12:16it paper? What is it?
12:18It's the intestinal lining of a cow.
12:21That's extraordinary, isn't it? I've never actually seen this stuff before.
12:25No, I haven't. I haven't read about it.
12:26And it's, it's tough.
12:30At this processing plant in Middlesborough, England, animal intestines arrive by the barrel load from the slaughterhouse.
12:40Incredibly, this stuff was the raw material for zeppelins.
12:47Hugh investigates, reluctantly.
12:50I'm not sure I should have had a cooked breakfast this morning.
12:54These intestines are used to make sausage skins just as they were in Germany during the First World War.
13:01Today, the guts are processed on an industrial scale, as factory owner John Veschenfelder explains.
13:08First machine's taking grass out.
13:10The second machine?
13:11Grass.
13:12What grass?
13:13.
13:14Go to the second machine.
13:16Yeah.
13:16The second machine's taking mucus out.
13:19All right.
13:20The final machine is what we call the finishing machine.
13:24Hugh wants to find out how narrow tubes can be turned into enormous balloons.
13:34And then, you probably make balloons out of it.
13:42Sensibly, the zeppelin builders started with the biggest piece of cowgut they could find.
13:49This is the appendix.
13:51Right.
13:51I see.
13:52It's called the blind end of the stomach.
13:55So that's a cow's appendix.
13:58The thin membrane that lines the cow's appendix is made of collagen, the same stuff that forms skin and bones.
14:06It has some very special properties.
14:09See its texture.
14:10Look at that.
14:11It's like a balloon.
14:12It's strong.
14:14If we get some warm water and just dip it in the warm water now.
14:17Somehow, the German zeppelin builders stumbled across the technique for joining the membranes together using nothing more than water.
14:24Like this.
14:25Yeah.
14:26If we get it over the edges, it'll actually hold on the edges.
14:29All right.
14:31If I get another one, just overlap it.
14:34Using this magical process, the Germans were able to piece together their gigantic gas bags from small strips of cowgut.
14:42All we need to do now is leave that to dry.
14:44So we did one, and after two hours, this is what we found.
14:49You see the way it's joined there, it's just melted, blended together, and it's absolutely perfect.
14:56That won't come apart?
14:56Just the moisture has bonded it together.
14:59But I want to understand why.
15:06To find out, Hugh takes the sample back to Cambridge University and asks his colleague, collagen expert Michelle Oya.
15:16They take a close look at the overlapping joint under a scanning electron microscope.
15:23Oh, wow.
15:25Golly.
15:27We've got all of these tiny, tiny, tiny little fibrils going across the interface here.
15:34All the fibers.
15:36All the fibers.
15:37But if this is the interface, what's extraordinary is just how much intertangling and intertwining has happened.
15:44This doesn't look like just two sheets of anything.
15:46It looks like something really quite...
15:49Structurally complicated.
15:50Structurally complicated.
15:52The entwined fibers bind the two sheets of collagen together.
15:59When the collagen is wet, the fibers at the interface slide across one another without sticking.
16:05But as they dry out, they become tacky and adhere to one another.
16:13Our ancestors were very crafty and the fact that they figured out how to use this natural polymer for other
16:20uses doesn't surprise me at all.
16:25The cow gut was a zeppelin's secret weapon.
16:39The cow gut was a zeppelin's secret weapon.
16:43They discovered that for a time, sausage making in Germany was verboten.
16:51By January 1915, the Germans had assembled a fleet of 13 zeppelin bombers.
16:58At last, Commander Strasse had the firepower to launch his terror campaign.
17:07He chose targets within easy reach of Germany.
17:11One was the seaside resort of Great Yarmouth in Norfolk.
17:17Here is where German bombs first fell on Britain.
17:22And this street is where the first civilians died.
17:44The next morning, sleepy towns along the coast awoke to find the war on their doorstep and bodies among the
17:53rubble.
17:55For the Germans, this was just the start.
17:59Strasse couldn't resist tweaking the lion's tail as well as by bombarding coastal towns, also bombarding British cities.
18:07And he thought that they could inflict so much damage that British morale would crack.
18:14The city Strasse prized above all others was London.
18:22For the next four months, the Germans launched raid after raid, feeling their way towards the capital.
18:33Then, finally, on May 31, 1915, a lone zeppelin made it.
18:44Zeppelin LZ-38 bombed the suburbs of North London before heading south, leaving a trail of destruction.
18:56In 20 minutes, it had dropped 28 bombs and a further 91 incendiary bombs that were designed to set London
19:06ablaze.
19:09The shot was incredible. There are huge burning fires in the streets, explosions going off.
19:15People are throwing up their windows to look out and see what's going on.
19:18And one man reported that there was a policeman running down the road shouting,
19:21They're here! They're here! The Germans are here!
19:29Two firebombs fell on a house in Hackney.
19:37This couple, Mr. and Mrs. Good, were in their bedroom and they couldn't get out.
19:41And they found Mr. and Mrs. Good, you know, burnt, but kneeling by the side of the bed.
19:46And the husband had his arm around his wife and it was almost like they were praying.
19:51The effectiveness of these German incendiary bombs was brutally obvious.
19:57One bomb identical to those that devastated London that night has survived intact.
20:04We have here an original incendiary bomb.
20:09It's a direct descendant of the projectiles used in earlier wars, which consisted of burning rags, rope and things like
20:17that,
20:17that were loaded into a cage and fired at the enemy positions to set fire.
20:20Didn't the Romans do that sort of stuff?
20:21Yes, they did. And it hasn't changed. It went right the way through the Napoleonic Wars and the Crimean War.
20:27And I think this is a direct successor.
20:30John Starling wants to find out what makes this bomb tick.
20:35So he takes it to an army colleague.
20:39Explosives expert Major Peter Norton.
20:41John's got the bomb here for us.
20:45They x-rayed the bomb to see what's inside.
20:49Excellent.
20:50This allows them to figure out how it worked.
20:56When the bomb hit its target, the impact would have triggered the fuse and set fire to a substance called
21:03thermite,
21:04a mixture of iron oxide and aluminum that burns with a fierce heat.
21:10This, in turn, would cause a tank of benzene, a form of gasoline, to explode.
21:17Peter wants to show John how the fire bomb worked.
21:20We certainly never made a World War I Zeppelin incendiary before.
21:27So it'll be very interesting to see what sort of target effect we get.
21:36While John and Peter build the bomb, Hugh Hunt prepares the target, a typical 1915 bedroom.
21:46One mystery they hope to solve is why the bomb is bound in rope coated in tar.
21:53And another is how the Germans managed to get the tar on in the first place.
22:05With the tar coating applied, the bomb is ready to be loaded with explosives.
22:11Fill this with thermite, that would make a good bedside lab.
22:14Well, you'd certainly be able to read a book for a short period of time.
22:19We're going to fill this with thermite.
22:21It gives off massive amounts of heat.
22:23So, as I say, typically for fish, you'd expect to see two to two and a half thousand degrees centigrade.
22:27We're going to put some benzene in there as well, and then initiate that electrically.
22:32Perfect.
22:33We hope we're going to get a fairly violent conflagration.
22:37Intense localized heat, which will spread, creating secondary fires.
22:42Three, two, one.
22:48As Peter predicted, the raging thermite immediately causes the benzene to explode in a fireball.
23:03But what's surprising is that the bomb is still burning 15 minutes later, thanks to the tarred rope.
23:11We thought the rope would add a burning effect, but it's quite surprising how much time it'll just continue to
23:18burn away and use up the fuel that's provided by the tar.
23:22That rope is actually a critical component to the bomb.
23:25You want to actually sustain the temperature to set fire to wood, the buildings, etc.
23:31If you drop enough of them, you'll overload the emergency services and things like that.
23:36So, incendiary is actually far worse in some ways than high explosives.
23:40You see things burning. It's more of a terror weapon.
23:45The Zeppelin commanders were already planning how to take full advantage of their new terror weapon.
23:52Some questioned the morality of firebombing civilians.
23:57But Strasser was steadfast. He had God on his side.
24:02My men are humble and gracious. Their duty is holy.
24:07So how can they sinify if they only suffer their sins?
24:12If that's what we're doing is terrible, then may the fear be the solution of Germany.
24:20As the war ground to a stalemate on the Western Front, Strasser wanted to ramp up his attacks on the
24:27British capital.
24:29But just getting an airship there was an almighty challenge.
24:35At high altitudes, the crew had to contend with unpredictable weather.
24:40Heavy rain soaking into the Zeppelin's canvas outer skin would weigh the airship down.
24:46And high winds could blow it miles off course.
24:51But there was a new problem that hadn't been anticipated.
24:55No one had flown so high before.
24:58And the crews began to suffer from the debilitating effects of altitude sickness.
25:07Hugh wants the full Zeppelin experience, altitude sickness and all.
25:12So he visits aeronautics engineer Andy Elson, the first man to pilot a hot air balloon over Everest.
25:19The old Zeppelins used to fly at 21,000 feet.
25:22So what we wanted to do is to experience what they would have suffered.
25:27And I won't tell you what the symptoms were, we're just going to see afterwards.
25:30Andy will take Hugh up to 21,000 feet, as high as a Zeppelin could go, without them having to
25:37leave the ground.
25:40By pumping out the air of his sealed chamber, Andy can simulate the thin atmosphere and low pressure of high
25:47altitudes.
25:49Usually, he tests the performance of airplane engines inside his chamber.
25:54Today, he's testing Hugh.
25:57We're 12,300 feet.
26:04To avoid the risk of Hugh passing out during the ascent, he will breathe oxygen until they reach Zeppelin altitude.
26:1221,600 feet.
26:15Andy to Pete, stop pumping.
26:18Now, Hugh will have to quickly adjust to the same thin air as the Zeppelin crews and pass a test
26:26designed for toddlers.
26:29Are you ready?
26:37He starts confidently.
26:43Certainly cold.
26:44Yeah, definitely cold.
26:47So name, address, dates of birth, and style sign.
26:53After a few minutes, Hugh struggles to spell the word Capricorn.
27:04I feel as if my eyebrows are falling off. My eyebrows are falling off.
27:09Hugh's brain is being starved of oxygen, and it's beginning to show.
27:14I feel as if I'm very heavy.
27:15Be careful.
27:15Whoa!
27:18Whoa!
27:21That's heavy.
27:23So, do I feel heavy because I'm lightheaded, or...?
27:28You haven't got enough oxygen in your muscles to make them work properly.
27:33So it's not because I've lost buoyancy?
27:35No, no.
27:37Wow, that's...
27:39Ah!
27:42A few puffs of oxygen brings Hugh back to normal.
27:48The Zeppelin crews realized the restorative effects of oxygen, too,
27:52and began carrying cylinders of the gas on high-altitude flights.
28:01But they hit another problem.
28:03Seeing where they were going when clouds obscured the ground.
28:12One solution seems remarkable today.
28:16They would dangle a tiny capsule called a sub-cloud car,
28:22thousands of feet below the airship,
28:24from where a crewman on a telephone would guide them in.
28:30The Zeppelin would be above the cloud,
28:32and the sub-cloud car would be below the cloud,
28:35and he could say left a bit, right a bit, forward a bit,
28:39and release the bombs from there.
28:40It's horrific, absolutely horrific.
28:43Given the difficulties,
28:44it's incredible that any Zeppelins made it to London.
28:51But on September 8th, 1915,
28:55Strasser launched a raid targeting the business and political centre
28:58of the British capital.
29:00And one Zeppelin got through.
29:03The airship that made the most impact that night
29:07was that captured by Heinrich Matty.
29:09And actually, he had been to London before as a tourist,
29:12so he actually knew what the landmarks were.
29:16Matty followed the chain of tourist sites right up to his primary target,
29:21the heart of the old city.
29:29This square mile of real estate was the financial hub of the British Empire.
29:36Matty's uncanny skills as a navigator would single him out
29:41as the most successful airship commander of the war.
29:45For his rendezvous with London,
29:47he packed a surprise package,
29:49weighing some 660 pounds.
29:53He's carrying on board the largest single bomb dropped
29:57from the air at that time in the war,
29:59and he called it his love gift,
30:01his gift of love to London.
30:06Matty delivered his gift,
30:08and much else besides.
30:12His firebombs left the textile warehouses
30:15around St. Paul's Cathedral burning out of control.
30:24His explosive bombs destroyed homes and shops,
30:29pubs and buses.
30:40In just 10 minutes, 22 civilians, including six children, were killed.
30:52Newspaper headlines reflected the anger felt by the British public,
30:56that Germany could indiscriminately target women and children.
31:02Peter Strasser saw things differently.
31:06...
31:07...
31:08and where his heart is,
31:10have been slaughtered as children and women.
31:13What we do is absurd, but necessary. Very necessary.
31:17Nowadays there is something like a non-fighter.
31:20Modern war is a total war.
31:38And the ammunition at the front.
31:41And therefore, if it killed children,
31:44and that had some terror effect, a morale effect,
31:46well, well and good.
31:47It's the beginning of modern warfare.
31:48It's the beginning of modern warfare.
31:50Red in tooth and claw.
31:56By the end of 1915,
31:58Londoners had watched German airships
32:01rain death down on their city
32:02on five occasions with total impunity.
32:08Public outrage at the lack of civil defense
32:11forced the British government into action.
32:21To take out the Zeppelins,
32:23they brought in the latest anti-aircraft guns from France
32:26and positioned them around the capital.
32:32But the airships flew at night
32:35and were virtually impossible to see in the dark.
32:38Could they try to hear them coming?
32:44At Spurn Point on the Yorkshire coast,
32:47where the Zeppelins crossed the North Sea
32:50and entered England,
32:52a concrete structure called a sound mirror still stands.
33:00It was designed to detect the sound of the approaching airships.
33:06The sound mirror worked by amplifying the Zeppelin's engine noise.
33:12Sound waves hitting the concrete dish would be reflected
33:16and focused by the concave surface onto a single spot.
33:21This concentration of sound waves would increase the volume.
33:28Using a horn on the end of a pole to pick up the sound,
33:32an operator would wait patiently night after night with his ears peeled.
33:39Once he detected the distinctive drone of Zeppelin engines,
33:42he would move the horn around until the sound was at its loudest.
33:48By tracing back along the line of his pole,
33:51he could locate the invisible airship in the night sky.
33:56With the help of acoustics engineer Dr. David Sharp,
34:00Hugh hopes to find out how effective this early warning system was.
34:05With the stethoscopes on, the listener would listen out
34:08and if they found that the sound was loudest in about this region here,
34:13then that would indicate that the aircraft was coming in
34:16in the direction that this is pointing effectively.
34:19Well, why don't we try an experiment?
34:21Yeah, why not?
34:23Hugh arranges for an aircraft to fly towards the concrete mirror.
34:36They set up two microphones.
34:39One picks up the ambient sound at the scene.
34:43The other, operated by Hugh, monitors the sound reflected by the mirror,
34:48just as the horn did during World War I.
34:52David monitors the output of each mic.
34:55Hugh's is in red.
34:57If the mirror works, Hugh's mic should pick up the plane first.
35:02So by Hugh moving the microphone around,
35:05you can see when the pole's actually pointing towards the sound source,
35:09that's when the sound's coming up as its loudest on the microphone.
35:13Although the plane is too far away to see,
35:16it's coming within range of the sound mirror.
35:23I'm hearing it directly behind me.
35:26Very clear peaks on the red.
35:30I can't hear it without the headphones.
35:33Hugh finds the area on the dish where the engine noise is loudest.
35:38His microphone pole points straight to a spot in the sky.
35:42I reckon it's out there.
35:48That's incredible.
35:50That's fantastic.
35:55We found that we were able to get an amplification of 20 decibels,
35:58maybe four times as loud as you would hear normally.
36:01But they were hearing aircraft as far as 15, 20 miles away,
36:05getting that sort of advance warning,
36:06and you could start to prepare for an imminent air attack.
36:13The alert would go out to makeshift airfields that had been set up around London.
36:19Young pilots were trained in the treacherous art of night flying.
36:24As soon as a Zeppelin was detected, they would leap into action.
36:29To save weight, they flew alone.
36:34Taking the place of the co-pilot, a Lewis machine gun,
36:38pointing straight up so the plane could attack from below.
36:48This is a replica of the BE-2C aircraft that fought the Zeppelins.
36:53Pilot Matt Boddington will take Hugh up for a spin.
36:58Did they have seatbelts in those days?
36:59They wouldn't have done in those days, no.
37:01They had no parachutes either,
37:03and had to fly the plane from the back seat.
37:19Matt will give Hugh a taste of what it was like to take on a Zeppelin
37:23in a flimsy contraption made of wood and canvas.
37:27Those Zeppelins, huge great piece,
37:30the size of an ocean liner.
37:33And yet, this tiny little aircraft,
37:35it's like a little flea taking down an elephant.
37:39But once the pilot located a Zeppelin,
37:42and needed to man the machine gun,
37:45the BE-2C really came into its own.
37:49They were actually so stable that,
37:51as you can see,
37:53I could quite have to take my hat off,
37:55it's happening on the shoulders,
37:56and we're flying along quite happily.
37:58This, of course, made it a really good stable gun platform
38:02to shoot in the Zeppelin.
38:03The aeroplane would almost fly itself.
38:17But with the Zeppelin in his gun sights,
38:20the pilot would soon discover the plane's crippling limitation.
38:24It lacked firepower.
38:28Its puny machine gun bullets would make such tiny holes in the envelope,
38:33and the gas would leak out so slowly
38:36that the Zeppelin would be able to carry on flying.
38:39What the BE-2C needed now was an armament to enable it to tackle the Zeppelins.
38:45And that's where a lot of work was going on behind the scenes
38:48to try and develop a bullet that was going to be effective against Zeppelins.
38:56One scheme was to use a flaming bullet that was meant to set fire to the Zeppelin's hydrogen gas,
39:04which is highly flammable.
39:07The brains behind the idea was a car manufacturer named James Buckingham.
39:15In the course of investigating the Buckingham bullet,
39:18Hugh discovered he has an unexpected connection to the man.
39:23He's my great-uncle Jim.
39:27No, here was I thinking that I was just going to be exploring Zeppelins and finding it out.
39:32But it's turned into a family.
39:34Part of the story, yeah.
39:35Oh, just incredible.
39:37Hugh wants to find out how his great-uncle's incendiary bullets worked.
39:43Munitions collector Tony Edwards has some answers.
39:48What we have here is an original factory drawing of the bullet your uncle designed.
39:54Cartridge, small arm, incendiary, Buckingham, 303-inch Mark 7B.
40:00Because he had the Buckingham Motor Company?
40:02That's right, the Buckingham Motor Company of Coventry.
40:04Yeah.
40:04And he was one of a number of engineers who, when war broke out, turned their creative mind to the
40:10problem of shooting down Zeppelins and balloons.
40:13But it's a bit of a leap, going from designing and building cars to going to bullets.
40:18Absolutely, I agree.
40:18You might have thought he would go into making sort of tanks or engines, aircraft engines or something.
40:24And what you have is this here is filled with phosphorus.
40:28Phosphorus ignites when it meets the air.
40:31And if you look at this bullet here.
40:32That's one of them, is it?
40:33Yes.
40:33You can see there the hole that's filled with solder.
40:39When the Buckingham Round is fired, it spins down the barrel and the friction generates heat.
40:47This melts the solder that plugs the hole.
40:54As the bullet exits the gun, the phosphorus ignites in the air and the spinning motion throws the burning chemical
41:02out through the hole.
41:10These bullets, I mean, these presumably don't work anymore, do they?
41:14Well, we're hoping that they're going to.
41:15This is not a spent bullet.
41:16No, this is not a spent bullet.
41:18This is an unfired...
41:19This is an unfired bullet, still with the solder in, still with the phosphorus in.
41:25So if I pick away with my pen knife at those little holes, that might be...
41:27I wouldn't advise you.
41:28No, okay.
41:29Fair enough.
41:29What we're going to do, we're going to try these out.
41:31We're going to fire them and to see if they work.
41:35They'll fire the precious 100-year-old Buckingham Rounds remotely, just in case they explode in the rifle.
41:46Tony captures the flying bullet using a slow-motion camera.
41:50Look at that.
41:51And you can see it spinning.
41:53Good on you, Uncle Jim.
41:55As it's being thrown out, it's igniting in the air.
41:58When that hits, some of that phosphorus will start burning, which will, of course, ignite the hydrogen.
42:04Well, that's a theory.
42:06We shall see.
42:09But for all their promise, when the British pilots fired the Buckingham bullets into a Zeppelin, nothing.
42:19Somehow, they passed straight through the gas bags, without the burning phosphorus igniting the hydrogen.
42:30To try and understand why, Hugh revisits aeronautical engineer Andy Elson, who'd watched over Hugh in the low-pressure chamber.
42:40I see a cylinder which says hydrogen on it.
42:43Andy is bubbling hydrogen through a bucket of soapy water to demonstrate to Hugh the flammability of the gas.
42:51We can ignite the bubbles and they'll burn on your hand without your skin burning.
42:55Uh-huh.
42:56OK.
42:57Righty-o.
42:58Those hydrogen bubbles.
42:59OK.
42:59Check that out of the way.
43:01If I grab hold of that...
43:07Bwaaah!
43:13Hey, look at that!
43:15Well, I knew I needed a shave, but I didn't want...
43:19The thing that really gets me about this whole Zeppelin thing is that we all know that hydrogen's flammable.
43:25And that was really easy to set fire to those bubbles.
43:29And why is it so bloody difficult to set fire to a Zeppelin?
43:33Andy has come up with an experiment to try and solve the mystery.
43:37So we've got a polythene bag, which we're going to fill with hydrogen.
43:41And inside is an electric heating element, which is going to glow red-hot, just like the burning phosphorus from
43:48the incendiary bullet.
43:54In this experiment, the heating element, red-hot at over a thousand degrees Fahrenheit, stands in for the flaming bullet.
44:03But surrounded by only hydrogen inside the bag and no oxygen, it doesn't start a fire.
44:11So that's definitely full of hydrogen.
44:14And I can feel the heat radiating from here.
44:17That heating element is glowing red-hot.
44:20If there was oxygen in there, that would have exploded by now.
44:23Hydrogen, like most things, simply cannot burn in the absence of oxygen.
44:29So what will happen if some is allowed into the balloon?
44:33Andy will find out by blasting big holes in it to let the air in.
44:44Oh, here we go.
44:48This is a difficult process to try and light this hydrogen.
44:52That handful of bubbles, easy, that was easy.
44:55Because the oxygen is close to the hydrogen, everything's nice and easy.
44:59Here, lots of hydrogen, no oxygen in sight, except on the other side of this piece of plastic.
45:05Nothing was ever going to happen.
45:08You then put holes in.
45:10Whoa, here we go.
45:12You've got to get the hydrogen and oxygen mixture right, in the right place.
45:15And you've got to get your ignition source in the right place.
45:22Fortunately for the British, engineers were already working on another innovation.
45:28An explosive bullet that would rip holes in the gas bag wide enough to allow plenty of oxygen to rush
45:34in.
45:38This bullet would contain nitroglycerin, an explosive chemical sensitive to shock.
45:48When the bullet hit the canvas skin of the Zeppelin, it would slow down.
45:53But a steel ball inside would keep moving forward, compressing the nitroglycerin until it exploded, blowing a big hole in
46:03the gas bag.
46:05The air would rush in, and the oxygen would mix with the hydrogen to create an explosive cocktail of gases.
46:16If the flaming bullet entered the Zeppelin at this moment, it would have a good chance of sparking a fire.
46:26The British airmen were told to alternate the bullets when they loaded their machine gun magazines.
46:32It would take both rounds to bring down a Zeppelin.
46:36They've now got the incendiary and the explosive bullet.
46:40And the pilots were instructed to mix their rounds and fire them alternately.
46:46And they'd alternate between incendiary and explosive.
46:49And the theory was if he fired enough of them into the aircraft, eventually he'll start a fire.
46:56The first opportunity to try out the new ammunition was September 2nd, 1916, when the Germans launched the biggest raid
47:06of the war.
47:10A fleet of 16 airships set a course for London.
47:17British fighters were scrambled at 11 p.m.
47:20The first pilot into the air was 21-year-old William Leif Robinson.
47:28At 2.15 in the morning, one of the airships was caught in searchlights 12,000 feet above North London.
47:38Anti-aircraft guns opened fire.
47:41The noise had been so intense that people started coming out of their houses.
47:46And up in the sky, they see this glowing monster.
47:50Shells bursting all around it.
47:52They describe it as like stars twinkling in the sky.
47:55But it's shrapnel shells exploding.
47:59Leif Robinson saw the cornered Zeppelin II and headed towards it.
48:05He had the airship at his mercy.
48:10He flew along the underside and fired a drum of his special bullets into it.
48:17To his dismay, they had no effect.
48:25Undeterred, he reloaded and went back in, but again to no effect.
48:32In desperation and with just one drum of ammo left, he was forced to improvise.
48:39He concentrated his fire onto one spot, emptying the whole drum of bullets into the stern.
48:48By clustering the rounds into one area, the young pilot managed to open up a big enough hole for the
48:54oxygen to rush in.
48:59And the alternating bullets finally set the airship alight.
49:12When the airship goes up, parents run in and drag their children from their beds.
49:17The cheers of the crowd were hard, merciless cheers.
49:21This was relief.
49:23The people were enjoying this moment.
49:25We were fighting back.
49:29As it hit the ground, railway engines were blowing into their hooters.
49:33People started singing the national anthem.
49:35People were dancing and singing in the streets.
49:37The newspapers the next day described it as the greatest free show London has ever seen.
49:45On the day that came to be known as Zepp Sunday, tens of thousands of relieved Londoners picked over the
49:52wreckage for souvenirs.
49:56Overnight, pilot William Leif Robinson became the most famous man in Britain.
50:03Babies, flowers and hats were named after him, and he was mobbed wherever he went.
50:11Within a month, the technique he perfected for taking out airships had brought down two more.
50:18It was the beginning of the end for the Zeppelin.
50:27Peter Strasser stubbornly refused to accept defeat.
50:34On August 5th, 1918, with the war effectively lost for Germany,
50:40he sent his airships out on one last raid.
50:46This time, he would lead the attack himself.
50:50Believe me, I don't want to die more than other men.
50:53But being there is the highest for me.
51:02Peter Strasser didn't live to see England.
51:05A British fighter spotted his Zeppelin over the North Sea.
51:10And Peter Strasser himself fell victim to the deadly alternating bullets.
51:18His master plan, to break an enemy's morale by deliberately targeting civilians, had failed.
51:33But the terror it inflicted on the people of Britain would find its full expression in the next war.
51:44The great airships would be overtaken by other technology, as engineers would find more efficient ways to deliver death from
51:54the sky.
52:06On August 5th, Zac Collins
52:222
52:24This NOVA program is available on DVD.
52:27To order, visit shoppbs.org or call 1-800-PLAY-PBS.
52:32NOVA is also available for download on iTunes.