Nova (1974–…): Season 43, Episode 13 - Bombing Hitler's Supergun - full transcript
Historians and engineers investigate how Allied forces conspired to destroy Hitler's "supergun".
It is the height of World War II
Allied intelligence officers
spot something terrifying:
the muzzle of an enormous cannon
protruding from an underground
Nazi bunker
It's a supergun,
a monstrous new weapon,
part of Hitler's plan
to reduce London to rubble
and win the war through terror
It's a very cruel and it's
a very nasty way of making war,
but they believed it might work
The Allies hatch two bold plans
to defeat it
One involves Joe Kennedy Junior,
eldest son of what would become
an American political dynasty
He would be piloting
an explosive drone
What happened to Joe Kennedy
and his co-pilot on that plane
is actually one of the greatest
mysteries of World War II
The other scheme
would use the biggest bomb
the world had ever seen
But would either plan work?
Three, two, one!
Now, in a series
of explosive experiments,
engineer Hugh Hunt
will investigate
the Allies' bunker-busting
technologies
It's vanished
There's ground zero,
and there's nothing there
And he will build
his own supergun
Firing!
To see if the weapon
really could have brought London
to its knees
"Bombing Hitler's Supergun,"
right now on NOVA.
By spring of 1943,
the tide of World War II
was beginning to turn
against Hitler
In an effort
to regain the offensive,
he drew up plans
for the world's biggest gun,
with 25 barrels
This enormous cannon
would be buried deep underground
in Nazi-controlled France
It was designed to fire shells
100 miles,
cripple London, and pave the way
for a Nazi victory
In a desperate race
to knock out Hitler's supergun,
the Allies devised
their own miracle weapons
The Americans
pioneered the drone,
a radio-controlled heavy bomber
packed with 12 tons
of high explosives
Leading the drone mission was
29-year-old Joe Kennedy Junior,
a man groomed from birth
to be the first Catholic
president of the United States
The British drafted in
the brilliant engineer
Barnes Wallis
He came up with the original
bunker buster,
a bomb that would
explode underground
and trigger
a man-made earthquake
The Allied efforts were focused
on the tiny hamlet
of Mimoyecques,
five miles inland
from the French coast
On the surface,
it's now just a ruin,
but hidden inside
this hollowed-out hill
is the secret installation built
to house the V-3 Nazi supergun
Good grief!
I can't quite make sense of this
This isn't natural rock,
this is concrete
No, this is a roof, look at it!
It's four or five meters thick!
Engineer Hugh Hunt
and battlefield archaeologist
Tony Pollard
have been drawn here
to find answers
to the many questions
that remain
about this mysterious
superweapon
This was the entrance
of a tunnel?
Yeah, it looks as though
there is some sort of hatchway
How did it work?
Was it powerful enough
to hit London 100 miles away?
And could it have ended the war?
These are the mysteries
that Tony and Hugh
are trying to solve
This is a glorified pillbox
with a 130-meter-long gun
I'd love to see
what's underground
Right, let's go
The fortified bunker
has not been fully explored
since the war
Whoa!
That's slippy, that's slippy
You okay?
Yeah
They rappel down
one of the steep shafts
that would have each contained
five barrels of the supergun
Wow, look how steep it looks
from the bottom!
This is certainly big
This, we reckon,
is about 50 meters
And it was 130 meters
And this is one third
of the way down
The shaft extends a further
300 feet beneath them,
but now it's blocked by rubble
Today, there is no sign
of the barrels,
but the design of the shaft
reveals a telling detail
This tunnel is centered very
accurately on a particular line
Here we are,
here at Mimoyecques,
and this particular tunnel
that we see here
points directly over here
at Westminster Bridge,
which is astonishing
Hitler's gun was trained
right on central London
By the spring of 1943,
the Nazis had tasted defeat
in the deserts of North Africa,
and they had been driven
from the Soviet Union
after a bloody battle
at Stalingrad
Hitler was determined
to strike back
Taking center stage
in his war room
was the supergun,
or the London Cannon,
as he called it
Its five shafts
would each contain five barrels
That's a total of 25 barrels
firing 300 shells an hour,
24 hours a day
Maintaining this onslaught
would require
an enormous infrastructure:
a network of galleries
to store ammunition,
1,200 troops to man the guns,
and an underground railway
to supply them
This was artillery warfare
on an industrial scale
Whoa!
Hugh and Tony explore
the farthest reaches
of the complex,
looking for clues
to how the tunnels were built
It's almost like a city
underground, isn't it?
Yeah
Look at this, Hugh, look
What they've done is they've
actually used drills or spikes
What they find shows them
the tunnels were carved by hand
using pick axes and jackhammers
with steel spikes
Look at that!
Look at that!
That fits
They're just using them
to prize away
fragments of the stone
And imagine the effort,
all day, every day,
hammering these spikes in
and then moving away
all the rubble
It's just a horrible thought
The supergun's first victims
were not the people of London,
but the slave laborers
who built the installation
This complex was built
by a large number of people
that had been conscripted
against their will
And there can be no doubt
that many, many people
lost their lives
This wasn't
a normal building site
Work here never stopped
They had gangs of workers
on site
24 hours a day, 7 days a week
The priority here was
to get those guns into action,
and the human cost didn't matter
Hitler wanted to rush
his wonder weapon into action
because he was hungry
for revenge
He had bombed London
during the blitz
in the early days of the war
But since then, his Luftwaffe
had lost air superiority
in the skies over Europe
The Allies were exploiting
this lack of air cover
by relentlessly bombing
German cities
In return, Hitler began building
fortified installations
all over northern France:
massive concrete bunkers
hidden in remote woods
that would house a new
generation of secret armaments
called V-weapons
They're called the V-weapons
because they're about vengeance
They're about retribution
This is Hitler
getting his own back
What the RAF and the American
air force have been doing
is bombing German cities,
killing German civilians
And Hitler is absolutely
outraged by this
and decides he's going
to take it out on London
So all of these weapons
are designed
to hit London from France
These were technologies
straight out of science fiction
There was the V-1,
a jet-powered flying bomb
There was the V-2,
a rocket that would shoot
beyond the stratosphere
before falling back to earth
These weapons had the potential
to reduce London to rubble,
but they were untested in battle
and unreliable
Initially at least,
Hitler was fairly skeptical
about these new
experimental weapons
Rockets and missiles,
not really his bag
His was a more traditional
military background
molded in the trenches
of the First World War
But what that experience
did give him
was knowledge of how effective
artillery could be
He'd seen how artillery
could cut men apart
Upwards of 80% of the casualties
on the Western front
were caused by artillery
And the V-3 was a supergun
It was old school,
but with a new twist
The twist was that
unlike traditional artillery,
the shells of the V-3 supergun
would not be falling
on frontline soldiers,
but raining down on London's
terrified civilians
In September 1943, in a country
house in Buckinghamshire,
the first evidence
began to emerge
of Hitler's secret plot
against the British capital
An elite team of specially
trained intelligence officers
had been posted here to comb
through aerial photographs
taken on reconnaissance missions
over occupied northern France
They were searching for signs
of Nazi weapons sites
Officers examining pictures
of the Mimoyecques area
spotted something mysterious:
railway tracks disappearing
into a hill
They couldn't see
what was going on underground,
but they wondered if the complex
concealed a new kind of weapon
For two years,
a corner of Britain
had already been
on the receiving end
of big Nazi guns
And the K5 railway gun
just outside Calais, in France,
was one of the biggest
It was used for pounding
the English coast, and in fact,
they would quite regularly hit
the town of Dover
Right
And that corner
of southeast England
got pounded so heavily
through the years of the war,
it became known as
Hellfire Corner
What the population would do
would be to run into the caves
in the cliff behind the town,
and the Germans were a bit cruel
in that they would wait
until the all-clear
had been sounded,
until people started
to come out again,
and they'd fire another one
to try and catch them
in the open
They hit the coast very hard
Something like
10,000 houses in Kent
had been destroyed
by this artillery fire
The K5 could fire a shell
40 miles,
but Hitler wanted
to reach London,
more than double the distance
To get there, his engineers
had to find a way
of increasing the speed
of the shell
One method was simply
to increase the length
of the barrel
This kept a bubble
of rapidly expanding gas
from a gunpowder blast
pushing on the shell for longer
But lengthening the barrel
causes a problem
One thing that people
don't necessarily think about
is that this bends
under its own weight
Really?
Even a gun barrel?
Even a gun barrel
And the longer you make it,
the more flexible
it's going to be
But supporting a longer barrel
isn't the only problem
If the barrel
is extended too far,
the expanding gas
propelling the shell
will eventually peter out
One possible solution
was to increase the amount
of gunpowder,
but that would risk
blowing the barrel apart
A German military engineer
named August Coenders
came up with a radical proposal
He would not set off
the whole charge in one go
Instead, he would split it
into smaller amounts
and place them in chambers
along the length of the gun
After the shell was fired
conventionally,
the cascade of explosions would
boost the speed of the shell
as it traveled down the barrel
Hitler ordered his engineers
to build a prototype supergun
in German-occupied Poland,
and stepped up work
on the stronghold
that would house it in France
Then in the fall of 1943,
the Allies took the first steps
to knock out the site
219 bombers took off
from airfields around Britain
The American and British
bombing campaign to destroy
the mysterious building site
at Mimoyecques had begun
In total,
they would fly 18 missions
1,375 aircraft
would drop 6,517 bombs
But conventional bombs
made little impact
on the fortifications
buried deep underground
The Allies were forced back
to the drawing board
Engineers working
on both sides of the Atlantic
tried to find
a powerful enough weapon
to destroy sites like this
in a single blow
The British called on
their go-to engineering genius:
Barnes Wallis
Wallis was an original thinker
with ideas
years ahead of their time
He had designed one
of the most successful aircraft
of World War II:
the Wellington Bomber
But it was the weapon
he invented to destroy
the hydro-electric dams that
powered the Nazi war machine
that made his name:
the legendary bouncing bomb
The success
of the dam busters raid
carried out in May 1943
by the Royal Air Force 617
Squadron
secured Wallis's position as
Britain's top military engineer
Now his challenge would be
to create the biggest bomb
the world had ever seen
and use it
to trigger an earthquake
that would shake
a powerful structure apart
The American military
began experimenting
with an extraordinary innovation
of its own: the drone
The idea was to pack an aircraft
with explosives
and turn it into a flying bomb
A pilot would take the plane
into the air before bailing out,
and then a remote pilot
would guide the aircraft
to the target by radio control
Volunteering
for this hazardous mission
was a 29-year-old naval aviator
He was the eldest son
in a family that would become
a great political dynasty
His name was Joe Kennedy, Jr,
son of Joseph Kennedy,
one of America's richest men
and former ambassador to the UK
Joe's path through life
had already been mapped out
by his family
His grandfather, upon his birth,
had announced to the press
that his grandson would be
the first Catholic president
of the United States
So from day one,
literally and figuratively,
Joe Jr had this focus on him...
That that was his destiny
I mean, it was very much like
an heir to the throne,
the way he was raised
Joe was a naval pilot
patrolling the Atlantic Ocean
on the lookout
for German U-boats
With more than 50 missions
to his name,
he never caught so much as
a glimpse of an enemy submarine
Still, he could have
returned home with honor,
but the chance to lead
the attack on Hitler's supergun
was irresistible
I think he really believed that
this would be his contribution
He didn't think that what
he had done so far was enough,
yet to everyone else,
it was more than enough
But he felt compelled
to keep performing
Neither Kennedy nor his team
fully appreciated the threat
that London was now under
By May 1944,
the Germans were on the verge
of reaching the British capital
with their prototype supergun
They had managed
to fire shells 80 miles
at their secret test site
in Poland,
farther than any other gun
in history
But just how
gun designer Coenders
managed to time
the booster charges
to go off one after the other
with microsecond precision
remains a mystery to this day
One theory is that he used
the hot gases behind the shell
to ignite the boosters
as the shell passed down
the barrel
Engineer Hugh Hunt
wants to test that theory,
so he's asked explosives
engineer Charlie Adcock
to build him a supergun
of his own
They'll use the barrels
of six rifles,
fit each section
with a booster chamber,
and join them end-to-end
If Hugh can get his
experimental model to function,
it will help him
solve the mystery
of how Hitler's supergun
might have worked
There's a couple of things
we want to look at here
One is we want to see
if it was indeed the hot gases
that initiated
the booster charges
And the other thing is,
do the booster charges
make the bullet go any faster?
They'll shoot the bullet
through two beams
of infrared light
The time it takes for it
to pass between them
will give an accurate speed
Here's the live round
First, they'll fire the gun
without the boosters
to set a benchmark speed
We're all good
We can retire to the chamber
Blast on the hooter
Okay, firing!
There we go
That's got a velocity
of 742 meters per second
Now they will try
to speed up the bullet
with the booster charges
Let's load up
these side chambers
So these booster charges,
what have you put in them?
These are rifle cartridges
full of high explosives
Charlie's got
a fantastic instinct
for what's going to work
And handling these high
explosives is a bit scary,
but what I'm most interested in
is whether it's going to make
this projectile go faster
Stand by
Firing!
Whoa!
That's nearly
1,000 meters per second
Hugh has made a key observation
He can clearly see that
the boosters were set off,
as expected, by the hot gas
behind the shell
What have we got?
Everything's fired
Yeah, they've all gone
And as Hugh discovers,
there's an added bonus
There's been a 30% increase
in speed,
and that's going to translate to
maybe a 60% increase in range
In terms of what Hitler
might have been wanting
to achieve with his gun,
booster charges massively
increased the range
And now that Hitler's supergun
was nearing completion,
there was a new urgency
for him to use it
On June 6, 1944, D-day,
150,000 Allied troops
stormed the beaches of Normandy
in the biggest invasion
in history
In just 24 hours, they smashed
through the German defenses
and gained a toehold
in Nazi-occupied Europe
Hitler demanded a rapid response
London was the target
Within a week of D-day,
he had pressed the first of his
vengeance weapons into action
The jet engines
of the V-1 flying bombs
were timed to cut out
over the city
Up to 100 bombs fell
from the sky every day
Over an 80-day period,
about 6,000 people were killed
and a million buildings damaged
or destroyed
The philosophy was that
if you could destroy
the morale of a people,
you would basically
break their will to fight
And so rather than going
for the hard military targets,
you go for the soft
civilian targets
It's a very cruel and it's
a very nasty way of making war,
but they believed it might work
In July 1944,
at a secluded American airbase
in the east of England,
a specially modified bomber
loaded with top-secret equipment
flew in from Philadelphia
This was the centerpiece
of the daring American plan
to wipe out Hitler's supergun
Instead of merely
dropping its payload
on the target from above,
the aircraft itself
would be used
as a remote-controlled bomb
As leader of the mission,
Joe Kennedy chose to downplay
the jeopardy he faced
He writes his father, saying,
"I'm going to stay
just for one more mission
"There's hardly any danger
I'm sure it'll be fine"
And Joe Sr,
while incredibly disappointed,
wrote back and said,
"Please, I understand,
just don't push your luck"
I think he had a sense
of a little bit
of a golden aura about him,
and I think he really believed
he could pull it off
Kennedy's aircraft
would be loaded
with 12 tons of Torpex
high explosives
Then he and his co-pilot would
take the plane up to 2,000 feet,
accompanied by another aircraft
known as the mothership
Using a state-of-the-art
guidance system,
the mothership would
take control of the aircraft
while the crew parachuted out,
itself a risky maneuver
Bailing out
of one of these drones
was very dangerous
because the plane was flying
at very high speed
You might be jumping out
into a 200-mile-an-hour
slipstream
And there were several deaths
that occurred,
and at least one amputation
where somebody's arm
got caught up
in the parachute shrouds
Once the crew had bailed out,
an operator in the mothership
sent a radio signal to prime
the explosives for detonation
They would then explode
on impact
This was the world's first
precision-guided attack drone,
made possible by a piece
of remarkable new technology
What's really amazing,
and I think it's something that
most people don't appreciate,
is before television arrived
in your house,
it had actually already been
used on the battlefield
What we have here
is an actual World War II-era
Iconoscope television camera,
and it's absolutely authentic
It hasn't even been restored
And we've got it hooked up
to a TV monitor,
and I've pointed it
at a somewhat distant object,
an American flag
up on the pole there
Now, I can make out the stripes,
no problem,
but I really can't see the stars
very well at all
But this was good enough to use
for a military application
Adding television
into the system
meant that they could see
exactly what the weapon saw
as it tracked into the target,
and that was
a revolutionary development
The plane was fitted with two
prototype television cameras
One pointed straight ahead,
showing the way to the target
The other was focused
on the gauges on the dashboard
The live pictures
were relayed back
to the operator
in the mothership,
who used a joystick
to manipulate the controls
of the unmanned aircraft
The TV camera made the drone
a truly precise weapon,
something you could fly
by remote control
and see where it was headed,
and you could literally
put yourself
in the cockpit of that aircraft
It was going
to be able to deliver
that 12 tons of Torpex
directly on this target
It was not going to miss
Neither Kennedy's men
nor their British counterparts
had much idea of the scale
of the task they faced
taking on the supergun
Once installed, the barrels
would be encased in rock
over 300 feet thick,
and shielded
by 16 feet of concrete
And so far, the complex had been
impregnable to Allied bombs
But fortunately for the British,
they could call
on the mastermind
behind the bouncing bomb
Barnes Wallis
had already proven his worth
by busting the formidable
German dams
But could he crack a Nazi
stronghold like Mimoyecques?
The thing which runs through
all of his work is efficiency
He was always after
the most efficient solution
to the problem
What he realized was that
it was more efficient
to destroy a factory
than it is to destroy
all of the tanks or airplanes
that come out of the factory,
and it's even more efficient
if you can destroy
the power sources
that the factories were using
Wallis started thinking
about the most efficient use
of explosives
and came up with a brilliantly
original idea:
a bomb that would explode
underground
and create an earthquake
Now Hugh Hunt wants to see
if a bomb going off below ground
would be more destructive than
one exploding on the surface
Well, suppose that this is
a bunker in Northern France
and you want to blow it up
Barnes Wallis's method
was to bury a bomb
deep in the ground
to create a mini earthquake
You only have to push
the foundations a short distance
and you've destroyed
the structure
We're going to do two tests
One test is with some explosive
on the ground nearby,
and then we'll bury
that same amount of explosive
deep in the sand,
and we'll see what happens then
Firing!
Three, two, one!
The pressure has created
a crack in the building
I think it will be
interesting to see,
with the same amount
of explosive, what happens
when we put it in the ground
underneath the building
They bury a second
identical charge
12 inches beneath the surface
Firing!
Three, two, one!
Look at that
Look at how far
the sand has gone
There's ground zero,
and there's nothing there!
It's vanished
That's amazing!
I don't think anybody
had looked at the effect
of bombs exploding underground
at that point
People instinctively thought
it was the bit
of the bomb exploding
that you could see visibly
which did all the damage,
but in fact,
that's only part of the damage
Most of the damage is caused
by the pressure wave,
which is actually invisible
With the help
of slow-motion photography,
it's possible to see
the pressure wave
moving at supersonic speed
ahead of the blast,
rippling the ground
as it travels along
Wallis had found that
above ground,
this wave of energy
would quickly dissipate
and do comparatively
little damage
But below the ground,
through solid earth,
it would travel
with more destructive force
So pound for pound,
an underground bomb
would be more efficient than
one exploding on the surface
But getting it to penetrate
deep into the earth
was the challenge
Each bomb was laboriously
sculpted on a lathe
into the perfect shape
that would allow it
to pierce the ground
and move the earth aside
as it burrowed in
The steel casing had to be thick
where strength was most needed,
but taper away elsewhere
to save weight
So this section down here
is virtually solid,
for hitting the ground very fast
without squashing up
That's really solid
And then it's nice and hollow
down that part
It's only about an inch thick
at this point
And then this would have
penetrated into the ground
to 50 feet or more, and this
would all have exploded,
and the massive shockwave
would have permeated out
through the ground,
and anything nearby would have
been shaken to pieces
The RAF started ordering up
earthquake bombs
It was not a moment too soon
In a dramatic breakthrough,
intelligence officers studying
photographs of Mimoyecques
spotted suspicious openings
in a concrete slab
that protected the supergun's
underground bunker
Just visible
in one of the openings
was an object they identified
as the end of a barrel
It looked like the Nazis had
started installing the supergun
The response from the British
was immediate
The elite 617 Squadron
was called in
Famous for its dam busting raid
with Wallis's bouncing bombs,
the squadron was chosen
to deliver his latest weapon
You were with a group
of really experienced crew,
people who'd been
on the dams raids, you know,
and you looked up to them
And here was a squadron equipped
with yet another
Barnes Wallis weapon
It had to be good
It was that sort of feeling
in the squadron,
that you really got something
with which you could hit
the enemy with
And here was a beautifully
streamlined bomb,
and it really looked as though
it was going to do the business,
like throwing a dart
at the board
and getting a bull's-eye
every time
And this would be
a precision strike
17 bombers, each equipped with
a single Barnes Wallis bomb,
would attack in broad daylight
This rare footage shows
the earthquake bombs exploding
Interpreters examining
photographs of the hill
immediately after the raid
identified eight
enormous craters
made by Wallis's
earthquake bombs
Although the concrete slab
had been hit,
it was impossible to tell
just how much damage the bombs
had done below ground,
so the hill remained
a prime target
One month later,
it was the Americans' turn
to attack the supergun site
Joe Kennedy was ready
to lead the experimental mission
to turn a heavy bomber into
a remote-controlled missile
But as the plane sat
on the apron,
a young officer named Earl Olsen
spotted what he thought was
a flaw in the system
On the control panel
designed to arm the explosives,
a special "safety pin"
had been inserted
This was supposed to prevent
a rogue radio signal,
one that hadn't been transmitted
by the mothership,
from accidentally
arming the bomb
Earl was worried that jamming
the arming panel with the pin
might damage another part
of the system
He took his concerns
right up the chain of command,
but no one would listen
Out of everybody in the field
with the drone program,
Earl Olsen was
the most qualified person
to make an assessment
of this panel,
but he was dismissed
by a number of people because
he was a junior grade officer,
he was not a college graduate,
a lot of what he knew about
electronics was self-taught,
and the people
at the Naval Aircraft Factory
who had built this panel
were viewed as experts,
as world-class experts,
and who was Earl Olsen
to argue with them?
Exactly what the flaw was
that Earl Olsen spotted
has been lost
Finding the one document
that might identify it,
the circuit diagram
of the panel,
has long obsessed Nick Spark
I just kept looking,
and I looked in every
nook and cranny there is:
the National Archives;
contacted the Navy;
and filed Freedom of Information
Act requests
And finally,
after about two years,
in a pile of documents
that I had received,
I turned over a page,
and there it was: a diagram
of this arming panel
So when I saw that, I knew
I had found the smoking gun
Using Nick's diagram,
Hugh Hunt reconstructs the panel
to try to uncover the fault
Olsen had identified
When a radio signal comes in
from the mothership
to arm the explosives,
it essentially powers up
this board, like this
They'd perhaps rather sensibly
put in a safety pin
so that the mechanical
arming system
would never accidentally operate
And if there was a rogue
radio signal like this,
then the lever doesn't move,
which means that the mechanical
arming system is safe
But look,
this light is still on,
and that means
the electrical power
continues to run
to these little solenoids
that are not designed
to have current
flowing into them continuously
The jammed lever
has inadvertently
held down a switch
that allows electricity to flow,
illuminating the bulb
and overheating the solenoid
This could start a fire
and set off the explosives
These tiny components,
called solenoids,
were part of the aircraft's
backup arming system
They would only be activated
if the unmanned drone
ever went out of control
over Britain
and it was necessary
to blow it up in midair
In such an emergency,
the mothership
would signal the arming panel
to send a pulse of electricity
to the solenoids
These would then pull out pins
from the detonators,
priming the explosives to go off
The plane could then be safely
blown up in midair
But if the arming panel
received a rogue radio signal,
as Olsen feared, the jamming
action of the safety pin
would allow electricity to flow
continuously to the solenoids,
and this would cause them
to dangerously overheat
This explains why Olsen
was so desperate
to delay the mission
Before his death in 2011,
he described his final
conversation with Joe Kennedy
Zero hour had arrived
for the drone strike
on Mimoyecques
Joe Kennedy decided
he would take his chances
At 6:00 p m,
he and his co-pilot
squeezed past the 12 tons
of high explosives
and the suspect arming panel
All Earl Olsen could do
was watch and pray
An armada of support aircraft
followed Kennedy's plane
into the air
Olsen was able
to watch the events unfold
as television pictures
from the drone
were transmitted
back to the airfield
Kennedy's plane,
Zoot Suit Black,
had a perfect take-off
It climbed to about 2,000 feet,
which was the mission altitude,
and at that point,
Kennedy went on the radio
and said the code word
"Spade Flush" twice
That was the signal for the
control pilot in the mothership
to take over command
of the airplane,
and he began to test it
methodically:
turning the television
on and off,
putting the plane
into various turns
No one will ever know for sure,
but it seems likely that
sometime after take-off,
a stray radio signal was
picked up by the arming panel,
triggering the chain of events
that Earl Olsen had feared
The aircraft exploded
over England,
almost 100 miles from the target
No human remains were ever found
Joe Kennedy, Sr received
the news the following day
He was devastated beyond words
All his plans, everything
that had happened to him,
he could understand
and he could cope with
But having this happen
to his son
was beyond devastating
To Olsen's deep regret,
his prediction had come true
He had tried so desperately
to prevent them from flying,
and even at the risk
of court-martial
And he was not a drinker at all,
but he got dead drunk
the night that that happened,
and it stayed with him
throughout his life
Joe Kennedy and his co-pilot
Bud Willy gave their lives
to save the people of London
But just 23 days
after their fateful flight,
Allied soldiers made a discovery
that cast the two Americans'
sacrifice in a tragic light
On the 5th of September, 1944,
Canadian troops fought their way
through to Mimoyecques
and found the bunker in ruins
The British attack
the previous month
had destroyed Hitler's supergun
after all
The earthquake bomb
created by Barnes Wallis
had lived up to its name
All of these
carefully constructed arches
of concrete
and all the foundations
for the gun itself
and for the infrastructure
for the gun
was damaged way,
way beyond repair
Many eyewitnesses at the time
described it as being like
an earthquake
In the nick of time,
Hitler's plot to destroy London
had been foiled,
and with it, his hopes
of turning the tide of war
in his favor lay in ruins
The shockwaves
from the American supergun raid
reverberated way beyond
the borders of Europe,
especially for Joe's younger
brother, Jack Kennedy
Jack gets the word
of his brother's death,
this incredible golden brother
who he's adored and revered
since birth,
and yet it also means
something else to him,
and he's very well aware of it
And as he says to his friend,
"Now the burden falls to me"
Jack Kennedy picked up where
his golden brother had left off,
and in 1961 was inaugurated
as the first Catholic president
of the United States
Two years later, at a naval
test site in California,
the president came close
to meeting the man
who tried to save
his brother's life
When John F Kennedy
visited Point Mugu,
Earl Olsen worked there
And people there knew
that he had worked
with Joe Kennedy in the war,
and they said,
"Hey, don't you want to meet
John F Kennedy?"
And he said, "I can't do that
"I wouldn't want to have
to tell him the truth
about what happened
to his brother"
70 years after the war,
bunker-busting bombs are still
part of military arsenals
and drones are in common use
But no nation
has ever successfully deployed
a supergun
Allied intelligence officers
spot something terrifying:
the muzzle of an enormous cannon
protruding from an underground
Nazi bunker
It's a supergun,
a monstrous new weapon,
part of Hitler's plan
to reduce London to rubble
and win the war through terror
It's a very cruel and it's
a very nasty way of making war,
but they believed it might work
The Allies hatch two bold plans
to defeat it
One involves Joe Kennedy Junior,
eldest son of what would become
an American political dynasty
He would be piloting
an explosive drone
What happened to Joe Kennedy
and his co-pilot on that plane
is actually one of the greatest
mysteries of World War II
The other scheme
would use the biggest bomb
the world had ever seen
But would either plan work?
Three, two, one!
Now, in a series
of explosive experiments,
engineer Hugh Hunt
will investigate
the Allies' bunker-busting
technologies
It's vanished
There's ground zero,
and there's nothing there
And he will build
his own supergun
Firing!
To see if the weapon
really could have brought London
to its knees
"Bombing Hitler's Supergun,"
right now on NOVA.
By spring of 1943,
the tide of World War II
was beginning to turn
against Hitler
In an effort
to regain the offensive,
he drew up plans
for the world's biggest gun,
with 25 barrels
This enormous cannon
would be buried deep underground
in Nazi-controlled France
It was designed to fire shells
100 miles,
cripple London, and pave the way
for a Nazi victory
In a desperate race
to knock out Hitler's supergun,
the Allies devised
their own miracle weapons
The Americans
pioneered the drone,
a radio-controlled heavy bomber
packed with 12 tons
of high explosives
Leading the drone mission was
29-year-old Joe Kennedy Junior,
a man groomed from birth
to be the first Catholic
president of the United States
The British drafted in
the brilliant engineer
Barnes Wallis
He came up with the original
bunker buster,
a bomb that would
explode underground
and trigger
a man-made earthquake
The Allied efforts were focused
on the tiny hamlet
of Mimoyecques,
five miles inland
from the French coast
On the surface,
it's now just a ruin,
but hidden inside
this hollowed-out hill
is the secret installation built
to house the V-3 Nazi supergun
Good grief!
I can't quite make sense of this
This isn't natural rock,
this is concrete
No, this is a roof, look at it!
It's four or five meters thick!
Engineer Hugh Hunt
and battlefield archaeologist
Tony Pollard
have been drawn here
to find answers
to the many questions
that remain
about this mysterious
superweapon
This was the entrance
of a tunnel?
Yeah, it looks as though
there is some sort of hatchway
How did it work?
Was it powerful enough
to hit London 100 miles away?
And could it have ended the war?
These are the mysteries
that Tony and Hugh
are trying to solve
This is a glorified pillbox
with a 130-meter-long gun
I'd love to see
what's underground
Right, let's go
The fortified bunker
has not been fully explored
since the war
Whoa!
That's slippy, that's slippy
You okay?
Yeah
They rappel down
one of the steep shafts
that would have each contained
five barrels of the supergun
Wow, look how steep it looks
from the bottom!
This is certainly big
This, we reckon,
is about 50 meters
And it was 130 meters
And this is one third
of the way down
The shaft extends a further
300 feet beneath them,
but now it's blocked by rubble
Today, there is no sign
of the barrels,
but the design of the shaft
reveals a telling detail
This tunnel is centered very
accurately on a particular line
Here we are,
here at Mimoyecques,
and this particular tunnel
that we see here
points directly over here
at Westminster Bridge,
which is astonishing
Hitler's gun was trained
right on central London
By the spring of 1943,
the Nazis had tasted defeat
in the deserts of North Africa,
and they had been driven
from the Soviet Union
after a bloody battle
at Stalingrad
Hitler was determined
to strike back
Taking center stage
in his war room
was the supergun,
or the London Cannon,
as he called it
Its five shafts
would each contain five barrels
That's a total of 25 barrels
firing 300 shells an hour,
24 hours a day
Maintaining this onslaught
would require
an enormous infrastructure:
a network of galleries
to store ammunition,
1,200 troops to man the guns,
and an underground railway
to supply them
This was artillery warfare
on an industrial scale
Whoa!
Hugh and Tony explore
the farthest reaches
of the complex,
looking for clues
to how the tunnels were built
It's almost like a city
underground, isn't it?
Yeah
Look at this, Hugh, look
What they've done is they've
actually used drills or spikes
What they find shows them
the tunnels were carved by hand
using pick axes and jackhammers
with steel spikes
Look at that!
Look at that!
That fits
They're just using them
to prize away
fragments of the stone
And imagine the effort,
all day, every day,
hammering these spikes in
and then moving away
all the rubble
It's just a horrible thought
The supergun's first victims
were not the people of London,
but the slave laborers
who built the installation
This complex was built
by a large number of people
that had been conscripted
against their will
And there can be no doubt
that many, many people
lost their lives
This wasn't
a normal building site
Work here never stopped
They had gangs of workers
on site
24 hours a day, 7 days a week
The priority here was
to get those guns into action,
and the human cost didn't matter
Hitler wanted to rush
his wonder weapon into action
because he was hungry
for revenge
He had bombed London
during the blitz
in the early days of the war
But since then, his Luftwaffe
had lost air superiority
in the skies over Europe
The Allies were exploiting
this lack of air cover
by relentlessly bombing
German cities
In return, Hitler began building
fortified installations
all over northern France:
massive concrete bunkers
hidden in remote woods
that would house a new
generation of secret armaments
called V-weapons
They're called the V-weapons
because they're about vengeance
They're about retribution
This is Hitler
getting his own back
What the RAF and the American
air force have been doing
is bombing German cities,
killing German civilians
And Hitler is absolutely
outraged by this
and decides he's going
to take it out on London
So all of these weapons
are designed
to hit London from France
These were technologies
straight out of science fiction
There was the V-1,
a jet-powered flying bomb
There was the V-2,
a rocket that would shoot
beyond the stratosphere
before falling back to earth
These weapons had the potential
to reduce London to rubble,
but they were untested in battle
and unreliable
Initially at least,
Hitler was fairly skeptical
about these new
experimental weapons
Rockets and missiles,
not really his bag
His was a more traditional
military background
molded in the trenches
of the First World War
But what that experience
did give him
was knowledge of how effective
artillery could be
He'd seen how artillery
could cut men apart
Upwards of 80% of the casualties
on the Western front
were caused by artillery
And the V-3 was a supergun
It was old school,
but with a new twist
The twist was that
unlike traditional artillery,
the shells of the V-3 supergun
would not be falling
on frontline soldiers,
but raining down on London's
terrified civilians
In September 1943, in a country
house in Buckinghamshire,
the first evidence
began to emerge
of Hitler's secret plot
against the British capital
An elite team of specially
trained intelligence officers
had been posted here to comb
through aerial photographs
taken on reconnaissance missions
over occupied northern France
They were searching for signs
of Nazi weapons sites
Officers examining pictures
of the Mimoyecques area
spotted something mysterious:
railway tracks disappearing
into a hill
They couldn't see
what was going on underground,
but they wondered if the complex
concealed a new kind of weapon
For two years,
a corner of Britain
had already been
on the receiving end
of big Nazi guns
And the K5 railway gun
just outside Calais, in France,
was one of the biggest
It was used for pounding
the English coast, and in fact,
they would quite regularly hit
the town of Dover
Right
And that corner
of southeast England
got pounded so heavily
through the years of the war,
it became known as
Hellfire Corner
What the population would do
would be to run into the caves
in the cliff behind the town,
and the Germans were a bit cruel
in that they would wait
until the all-clear
had been sounded,
until people started
to come out again,
and they'd fire another one
to try and catch them
in the open
They hit the coast very hard
Something like
10,000 houses in Kent
had been destroyed
by this artillery fire
The K5 could fire a shell
40 miles,
but Hitler wanted
to reach London,
more than double the distance
To get there, his engineers
had to find a way
of increasing the speed
of the shell
One method was simply
to increase the length
of the barrel
This kept a bubble
of rapidly expanding gas
from a gunpowder blast
pushing on the shell for longer
But lengthening the barrel
causes a problem
One thing that people
don't necessarily think about
is that this bends
under its own weight
Really?
Even a gun barrel?
Even a gun barrel
And the longer you make it,
the more flexible
it's going to be
But supporting a longer barrel
isn't the only problem
If the barrel
is extended too far,
the expanding gas
propelling the shell
will eventually peter out
One possible solution
was to increase the amount
of gunpowder,
but that would risk
blowing the barrel apart
A German military engineer
named August Coenders
came up with a radical proposal
He would not set off
the whole charge in one go
Instead, he would split it
into smaller amounts
and place them in chambers
along the length of the gun
After the shell was fired
conventionally,
the cascade of explosions would
boost the speed of the shell
as it traveled down the barrel
Hitler ordered his engineers
to build a prototype supergun
in German-occupied Poland,
and stepped up work
on the stronghold
that would house it in France
Then in the fall of 1943,
the Allies took the first steps
to knock out the site
219 bombers took off
from airfields around Britain
The American and British
bombing campaign to destroy
the mysterious building site
at Mimoyecques had begun
In total,
they would fly 18 missions
1,375 aircraft
would drop 6,517 bombs
But conventional bombs
made little impact
on the fortifications
buried deep underground
The Allies were forced back
to the drawing board
Engineers working
on both sides of the Atlantic
tried to find
a powerful enough weapon
to destroy sites like this
in a single blow
The British called on
their go-to engineering genius:
Barnes Wallis
Wallis was an original thinker
with ideas
years ahead of their time
He had designed one
of the most successful aircraft
of World War II:
the Wellington Bomber
But it was the weapon
he invented to destroy
the hydro-electric dams that
powered the Nazi war machine
that made his name:
the legendary bouncing bomb
The success
of the dam busters raid
carried out in May 1943
by the Royal Air Force 617
Squadron
secured Wallis's position as
Britain's top military engineer
Now his challenge would be
to create the biggest bomb
the world had ever seen
and use it
to trigger an earthquake
that would shake
a powerful structure apart
The American military
began experimenting
with an extraordinary innovation
of its own: the drone
The idea was to pack an aircraft
with explosives
and turn it into a flying bomb
A pilot would take the plane
into the air before bailing out,
and then a remote pilot
would guide the aircraft
to the target by radio control
Volunteering
for this hazardous mission
was a 29-year-old naval aviator
He was the eldest son
in a family that would become
a great political dynasty
His name was Joe Kennedy, Jr,
son of Joseph Kennedy,
one of America's richest men
and former ambassador to the UK
Joe's path through life
had already been mapped out
by his family
His grandfather, upon his birth,
had announced to the press
that his grandson would be
the first Catholic president
of the United States
So from day one,
literally and figuratively,
Joe Jr had this focus on him...
That that was his destiny
I mean, it was very much like
an heir to the throne,
the way he was raised
Joe was a naval pilot
patrolling the Atlantic Ocean
on the lookout
for German U-boats
With more than 50 missions
to his name,
he never caught so much as
a glimpse of an enemy submarine
Still, he could have
returned home with honor,
but the chance to lead
the attack on Hitler's supergun
was irresistible
I think he really believed that
this would be his contribution
He didn't think that what
he had done so far was enough,
yet to everyone else,
it was more than enough
But he felt compelled
to keep performing
Neither Kennedy nor his team
fully appreciated the threat
that London was now under
By May 1944,
the Germans were on the verge
of reaching the British capital
with their prototype supergun
They had managed
to fire shells 80 miles
at their secret test site
in Poland,
farther than any other gun
in history
But just how
gun designer Coenders
managed to time
the booster charges
to go off one after the other
with microsecond precision
remains a mystery to this day
One theory is that he used
the hot gases behind the shell
to ignite the boosters
as the shell passed down
the barrel
Engineer Hugh Hunt
wants to test that theory,
so he's asked explosives
engineer Charlie Adcock
to build him a supergun
of his own
They'll use the barrels
of six rifles,
fit each section
with a booster chamber,
and join them end-to-end
If Hugh can get his
experimental model to function,
it will help him
solve the mystery
of how Hitler's supergun
might have worked
There's a couple of things
we want to look at here
One is we want to see
if it was indeed the hot gases
that initiated
the booster charges
And the other thing is,
do the booster charges
make the bullet go any faster?
They'll shoot the bullet
through two beams
of infrared light
The time it takes for it
to pass between them
will give an accurate speed
Here's the live round
First, they'll fire the gun
without the boosters
to set a benchmark speed
We're all good
We can retire to the chamber
Blast on the hooter
Okay, firing!
There we go
That's got a velocity
of 742 meters per second
Now they will try
to speed up the bullet
with the booster charges
Let's load up
these side chambers
So these booster charges,
what have you put in them?
These are rifle cartridges
full of high explosives
Charlie's got
a fantastic instinct
for what's going to work
And handling these high
explosives is a bit scary,
but what I'm most interested in
is whether it's going to make
this projectile go faster
Stand by
Firing!
Whoa!
That's nearly
1,000 meters per second
Hugh has made a key observation
He can clearly see that
the boosters were set off,
as expected, by the hot gas
behind the shell
What have we got?
Everything's fired
Yeah, they've all gone
And as Hugh discovers,
there's an added bonus
There's been a 30% increase
in speed,
and that's going to translate to
maybe a 60% increase in range
In terms of what Hitler
might have been wanting
to achieve with his gun,
booster charges massively
increased the range
And now that Hitler's supergun
was nearing completion,
there was a new urgency
for him to use it
On June 6, 1944, D-day,
150,000 Allied troops
stormed the beaches of Normandy
in the biggest invasion
in history
In just 24 hours, they smashed
through the German defenses
and gained a toehold
in Nazi-occupied Europe
Hitler demanded a rapid response
London was the target
Within a week of D-day,
he had pressed the first of his
vengeance weapons into action
The jet engines
of the V-1 flying bombs
were timed to cut out
over the city
Up to 100 bombs fell
from the sky every day
Over an 80-day period,
about 6,000 people were killed
and a million buildings damaged
or destroyed
The philosophy was that
if you could destroy
the morale of a people,
you would basically
break their will to fight
And so rather than going
for the hard military targets,
you go for the soft
civilian targets
It's a very cruel and it's
a very nasty way of making war,
but they believed it might work
In July 1944,
at a secluded American airbase
in the east of England,
a specially modified bomber
loaded with top-secret equipment
flew in from Philadelphia
This was the centerpiece
of the daring American plan
to wipe out Hitler's supergun
Instead of merely
dropping its payload
on the target from above,
the aircraft itself
would be used
as a remote-controlled bomb
As leader of the mission,
Joe Kennedy chose to downplay
the jeopardy he faced
He writes his father, saying,
"I'm going to stay
just for one more mission
"There's hardly any danger
I'm sure it'll be fine"
And Joe Sr,
while incredibly disappointed,
wrote back and said,
"Please, I understand,
just don't push your luck"
I think he had a sense
of a little bit
of a golden aura about him,
and I think he really believed
he could pull it off
Kennedy's aircraft
would be loaded
with 12 tons of Torpex
high explosives
Then he and his co-pilot would
take the plane up to 2,000 feet,
accompanied by another aircraft
known as the mothership
Using a state-of-the-art
guidance system,
the mothership would
take control of the aircraft
while the crew parachuted out,
itself a risky maneuver
Bailing out
of one of these drones
was very dangerous
because the plane was flying
at very high speed
You might be jumping out
into a 200-mile-an-hour
slipstream
And there were several deaths
that occurred,
and at least one amputation
where somebody's arm
got caught up
in the parachute shrouds
Once the crew had bailed out,
an operator in the mothership
sent a radio signal to prime
the explosives for detonation
They would then explode
on impact
This was the world's first
precision-guided attack drone,
made possible by a piece
of remarkable new technology
What's really amazing,
and I think it's something that
most people don't appreciate,
is before television arrived
in your house,
it had actually already been
used on the battlefield
What we have here
is an actual World War II-era
Iconoscope television camera,
and it's absolutely authentic
It hasn't even been restored
And we've got it hooked up
to a TV monitor,
and I've pointed it
at a somewhat distant object,
an American flag
up on the pole there
Now, I can make out the stripes,
no problem,
but I really can't see the stars
very well at all
But this was good enough to use
for a military application
Adding television
into the system
meant that they could see
exactly what the weapon saw
as it tracked into the target,
and that was
a revolutionary development
The plane was fitted with two
prototype television cameras
One pointed straight ahead,
showing the way to the target
The other was focused
on the gauges on the dashboard
The live pictures
were relayed back
to the operator
in the mothership,
who used a joystick
to manipulate the controls
of the unmanned aircraft
The TV camera made the drone
a truly precise weapon,
something you could fly
by remote control
and see where it was headed,
and you could literally
put yourself
in the cockpit of that aircraft
It was going
to be able to deliver
that 12 tons of Torpex
directly on this target
It was not going to miss
Neither Kennedy's men
nor their British counterparts
had much idea of the scale
of the task they faced
taking on the supergun
Once installed, the barrels
would be encased in rock
over 300 feet thick,
and shielded
by 16 feet of concrete
And so far, the complex had been
impregnable to Allied bombs
But fortunately for the British,
they could call
on the mastermind
behind the bouncing bomb
Barnes Wallis
had already proven his worth
by busting the formidable
German dams
But could he crack a Nazi
stronghold like Mimoyecques?
The thing which runs through
all of his work is efficiency
He was always after
the most efficient solution
to the problem
What he realized was that
it was more efficient
to destroy a factory
than it is to destroy
all of the tanks or airplanes
that come out of the factory,
and it's even more efficient
if you can destroy
the power sources
that the factories were using
Wallis started thinking
about the most efficient use
of explosives
and came up with a brilliantly
original idea:
a bomb that would explode
underground
and create an earthquake
Now Hugh Hunt wants to see
if a bomb going off below ground
would be more destructive than
one exploding on the surface
Well, suppose that this is
a bunker in Northern France
and you want to blow it up
Barnes Wallis's method
was to bury a bomb
deep in the ground
to create a mini earthquake
You only have to push
the foundations a short distance
and you've destroyed
the structure
We're going to do two tests
One test is with some explosive
on the ground nearby,
and then we'll bury
that same amount of explosive
deep in the sand,
and we'll see what happens then
Firing!
Three, two, one!
The pressure has created
a crack in the building
I think it will be
interesting to see,
with the same amount
of explosive, what happens
when we put it in the ground
underneath the building
They bury a second
identical charge
12 inches beneath the surface
Firing!
Three, two, one!
Look at that
Look at how far
the sand has gone
There's ground zero,
and there's nothing there!
It's vanished
That's amazing!
I don't think anybody
had looked at the effect
of bombs exploding underground
at that point
People instinctively thought
it was the bit
of the bomb exploding
that you could see visibly
which did all the damage,
but in fact,
that's only part of the damage
Most of the damage is caused
by the pressure wave,
which is actually invisible
With the help
of slow-motion photography,
it's possible to see
the pressure wave
moving at supersonic speed
ahead of the blast,
rippling the ground
as it travels along
Wallis had found that
above ground,
this wave of energy
would quickly dissipate
and do comparatively
little damage
But below the ground,
through solid earth,
it would travel
with more destructive force
So pound for pound,
an underground bomb
would be more efficient than
one exploding on the surface
But getting it to penetrate
deep into the earth
was the challenge
Each bomb was laboriously
sculpted on a lathe
into the perfect shape
that would allow it
to pierce the ground
and move the earth aside
as it burrowed in
The steel casing had to be thick
where strength was most needed,
but taper away elsewhere
to save weight
So this section down here
is virtually solid,
for hitting the ground very fast
without squashing up
That's really solid
And then it's nice and hollow
down that part
It's only about an inch thick
at this point
And then this would have
penetrated into the ground
to 50 feet or more, and this
would all have exploded,
and the massive shockwave
would have permeated out
through the ground,
and anything nearby would have
been shaken to pieces
The RAF started ordering up
earthquake bombs
It was not a moment too soon
In a dramatic breakthrough,
intelligence officers studying
photographs of Mimoyecques
spotted suspicious openings
in a concrete slab
that protected the supergun's
underground bunker
Just visible
in one of the openings
was an object they identified
as the end of a barrel
It looked like the Nazis had
started installing the supergun
The response from the British
was immediate
The elite 617 Squadron
was called in
Famous for its dam busting raid
with Wallis's bouncing bombs,
the squadron was chosen
to deliver his latest weapon
You were with a group
of really experienced crew,
people who'd been
on the dams raids, you know,
and you looked up to them
And here was a squadron equipped
with yet another
Barnes Wallis weapon
It had to be good
It was that sort of feeling
in the squadron,
that you really got something
with which you could hit
the enemy with
And here was a beautifully
streamlined bomb,
and it really looked as though
it was going to do the business,
like throwing a dart
at the board
and getting a bull's-eye
every time
And this would be
a precision strike
17 bombers, each equipped with
a single Barnes Wallis bomb,
would attack in broad daylight
This rare footage shows
the earthquake bombs exploding
Interpreters examining
photographs of the hill
immediately after the raid
identified eight
enormous craters
made by Wallis's
earthquake bombs
Although the concrete slab
had been hit,
it was impossible to tell
just how much damage the bombs
had done below ground,
so the hill remained
a prime target
One month later,
it was the Americans' turn
to attack the supergun site
Joe Kennedy was ready
to lead the experimental mission
to turn a heavy bomber into
a remote-controlled missile
But as the plane sat
on the apron,
a young officer named Earl Olsen
spotted what he thought was
a flaw in the system
On the control panel
designed to arm the explosives,
a special "safety pin"
had been inserted
This was supposed to prevent
a rogue radio signal,
one that hadn't been transmitted
by the mothership,
from accidentally
arming the bomb
Earl was worried that jamming
the arming panel with the pin
might damage another part
of the system
He took his concerns
right up the chain of command,
but no one would listen
Out of everybody in the field
with the drone program,
Earl Olsen was
the most qualified person
to make an assessment
of this panel,
but he was dismissed
by a number of people because
he was a junior grade officer,
he was not a college graduate,
a lot of what he knew about
electronics was self-taught,
and the people
at the Naval Aircraft Factory
who had built this panel
were viewed as experts,
as world-class experts,
and who was Earl Olsen
to argue with them?
Exactly what the flaw was
that Earl Olsen spotted
has been lost
Finding the one document
that might identify it,
the circuit diagram
of the panel,
has long obsessed Nick Spark
I just kept looking,
and I looked in every
nook and cranny there is:
the National Archives;
contacted the Navy;
and filed Freedom of Information
Act requests
And finally,
after about two years,
in a pile of documents
that I had received,
I turned over a page,
and there it was: a diagram
of this arming panel
So when I saw that, I knew
I had found the smoking gun
Using Nick's diagram,
Hugh Hunt reconstructs the panel
to try to uncover the fault
Olsen had identified
When a radio signal comes in
from the mothership
to arm the explosives,
it essentially powers up
this board, like this
They'd perhaps rather sensibly
put in a safety pin
so that the mechanical
arming system
would never accidentally operate
And if there was a rogue
radio signal like this,
then the lever doesn't move,
which means that the mechanical
arming system is safe
But look,
this light is still on,
and that means
the electrical power
continues to run
to these little solenoids
that are not designed
to have current
flowing into them continuously
The jammed lever
has inadvertently
held down a switch
that allows electricity to flow,
illuminating the bulb
and overheating the solenoid
This could start a fire
and set off the explosives
These tiny components,
called solenoids,
were part of the aircraft's
backup arming system
They would only be activated
if the unmanned drone
ever went out of control
over Britain
and it was necessary
to blow it up in midair
In such an emergency,
the mothership
would signal the arming panel
to send a pulse of electricity
to the solenoids
These would then pull out pins
from the detonators,
priming the explosives to go off
The plane could then be safely
blown up in midair
But if the arming panel
received a rogue radio signal,
as Olsen feared, the jamming
action of the safety pin
would allow electricity to flow
continuously to the solenoids,
and this would cause them
to dangerously overheat
This explains why Olsen
was so desperate
to delay the mission
Before his death in 2011,
he described his final
conversation with Joe Kennedy
Zero hour had arrived
for the drone strike
on Mimoyecques
Joe Kennedy decided
he would take his chances
At 6:00 p m,
he and his co-pilot
squeezed past the 12 tons
of high explosives
and the suspect arming panel
All Earl Olsen could do
was watch and pray
An armada of support aircraft
followed Kennedy's plane
into the air
Olsen was able
to watch the events unfold
as television pictures
from the drone
were transmitted
back to the airfield
Kennedy's plane,
Zoot Suit Black,
had a perfect take-off
It climbed to about 2,000 feet,
which was the mission altitude,
and at that point,
Kennedy went on the radio
and said the code word
"Spade Flush" twice
That was the signal for the
control pilot in the mothership
to take over command
of the airplane,
and he began to test it
methodically:
turning the television
on and off,
putting the plane
into various turns
No one will ever know for sure,
but it seems likely that
sometime after take-off,
a stray radio signal was
picked up by the arming panel,
triggering the chain of events
that Earl Olsen had feared
The aircraft exploded
over England,
almost 100 miles from the target
No human remains were ever found
Joe Kennedy, Sr received
the news the following day
He was devastated beyond words
All his plans, everything
that had happened to him,
he could understand
and he could cope with
But having this happen
to his son
was beyond devastating
To Olsen's deep regret,
his prediction had come true
He had tried so desperately
to prevent them from flying,
and even at the risk
of court-martial
And he was not a drinker at all,
but he got dead drunk
the night that that happened,
and it stayed with him
throughout his life
Joe Kennedy and his co-pilot
Bud Willy gave their lives
to save the people of London
But just 23 days
after their fateful flight,
Allied soldiers made a discovery
that cast the two Americans'
sacrifice in a tragic light
On the 5th of September, 1944,
Canadian troops fought their way
through to Mimoyecques
and found the bunker in ruins
The British attack
the previous month
had destroyed Hitler's supergun
after all
The earthquake bomb
created by Barnes Wallis
had lived up to its name
All of these
carefully constructed arches
of concrete
and all the foundations
for the gun itself
and for the infrastructure
for the gun
was damaged way,
way beyond repair
Many eyewitnesses at the time
described it as being like
an earthquake
In the nick of time,
Hitler's plot to destroy London
had been foiled,
and with it, his hopes
of turning the tide of war
in his favor lay in ruins
The shockwaves
from the American supergun raid
reverberated way beyond
the borders of Europe,
especially for Joe's younger
brother, Jack Kennedy
Jack gets the word
of his brother's death,
this incredible golden brother
who he's adored and revered
since birth,
and yet it also means
something else to him,
and he's very well aware of it
And as he says to his friend,
"Now the burden falls to me"
Jack Kennedy picked up where
his golden brother had left off,
and in 1961 was inaugurated
as the first Catholic president
of the United States
Two years later, at a naval
test site in California,
the president came close
to meeting the man
who tried to save
his brother's life
When John F Kennedy
visited Point Mugu,
Earl Olsen worked there
And people there knew
that he had worked
with Joe Kennedy in the war,
and they said,
"Hey, don't you want to meet
John F Kennedy?"
And he said, "I can't do that
"I wouldn't want to have
to tell him the truth
about what happened
to his brother"
70 years after the war,
bunker-busting bombs are still
part of military arsenals
and drones are in common use
But no nation
has ever successfully deployed
a supergun