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This is the largest American helicopter.

But back in 1971, this is what the Soviet Union brought to the Paris Airshow.

A helicopter so large, it baffled observers.

Because it could carry nearly two hundred passengers, and set world records for lifting

power that still stand to this day.

But after returning to the Soviet Union, the world's largest helicopter seemingly disappeared.

In the Soviet Union, the helicopter emerged as an indispensable tool.

A machine that could go where no other machine could, lifting people and supplies into remote

regions that were once virtually inaccessible.

And in a country as vast as the Soviet Union, the helicopter would help build a nation.

By 1960, the Soviets were building some of the largest and most technically advanced

helicopters in the world.

But at the height of the Cold War, the need to build a truly enormous helicopter would

become a matter of national security.

By 1960, American spy planes were beginning to uncover the location of Soviet Intercontinental

Ballistic Missiles.

For years, the Soviets had been hiding their nuclear missiles by building launch sites

deep in the remote wilderness.

But the only way to move heavy first-generation nuclear missiles was by train.

And it meant building a rail line out to each launch site.

The Americans soon learned that to find the missile sites, they simply needed to follow

the rail lines.

Keeping nuclear missiles hidden was a matter of national security.

So the Soviets devised a bold plan.

Instead of using trains or roads, they'd airlift their missiles to remote locations.

If helicopters could deploy missiles deep into the remote wilderness, it would be virtually

impossible for American spy planes to spot them.

But in 1960, even the largest helicopter in the world was nowhere near powerful enough

to lift a 25 ton ballistic missile.

The Soviets would need to design a new helicopter with at least twice the lifting power of anything

before it.

One option was to take what was already the largest helicopter in the world

and scale it up.

Enlarging the Mi-6's fuselage so that it could safely carry a nuclear missile.

But a larger helicopter would also require developing a new more powerful engine and

larger rotor.

To save development time, another option was to reuse the engines, rotor and gearbox from

the Mi-6, but use two sets of them.

It was a configuration that had already been popularized by the Americans.

But the approach wouldn't work for soviet designers.

In a tandem configuration, exhaust from the forward set of engines would interfere with

airflow to the aft engines.

The solution would be to arrange the rotors transversely, mounting the assemblies on a

set of wings.

This would allow engineers to reuse the Mi6's rotors, engines and gearboxes entirely to

build a truly enormous helicopter.

They would designate the prototype as the V-12

The enormous machine would end up looking like a half-helicopter, half-airplane with

inversely tapered wings supporting the two rotors.

To keep the helicopter stable, the rotor blades would spin in opposite directions, cancelling

out reaction torque.

During hover, directional control was achieved by variably tilting each rotor.

And at higher speeds, the V-12's large tailplane further enhanced maneuverability.

Operating the giant machine required a crew of six.

With a pilot, co-pilot and flight engineer seated in a lower level cockpit and a navigator,

radio operator and electrical engineer on a second level.

The V-12's enormous cargo hold could carry combat matériel and machinery, or be converted

into a civilian transport with seating for up to 196 passengers.

But the V-12's primary role would be to deploy intercontinental ballistic missiles.

And the first step would be to load ICBMs onto cargo planes that would then fly thousands

of kilometers to remote landing strips.

From there, the missiles would be transferred onto waiting V-12's and airlifted with support

crew and equipment to locations hundreds of kilometers into the remote wilderness.

With more than 12 million square kilometers of forest across the Soviet Union, American

spy planes would be searching for a needle in a haystack.

When the V-12 appeared at the 1971 Paris Airshow, it had already broken world records.

Including lifting an incredible 44 tones of payload up to over six thousand feet in 1969.

The equivalent weight of 25 mid size cars.

Western observers could only speculate as to the V-12's true purpose, But many were

expecting hundreds to be pressed into service.

In reality, by 1971, impressing the west was about the only use the Soviets had left for

the giant machine.

Developing the V-12 had taken the better part of a decade, with design studies beginning

in 1959 and the official go ahead given in 1962.

But construction of the first prototype didn't start until 1965, with the first successful

flight occurring three years later.

A machine this large comes with compromises.

And engineers had to work through numerous challenges around control and stability.

But the biggest problem was that by 1971, the V-12 no longer had a purpose.

The Amercians launched the first spy satellite into orbit in 1959.

And in a single day it could photograph more Soviet territory than all earlier spy plane

missions combined, making it far more difficult for the Soviets to hide their ICBMs.

And by the 1970s, the Soviets were developing a new generation of ICMBs small enough to

fit on trucks, which could evade reconnaissance by simply moving around.

The V-12 was just too large and cumbersome to be useful beyond its original mission.

There were just too few scenarios that called for lifting 44 tons of cargo or 200 passengers

in a single helicopter.

In 1974, development of the V-12 was ended after only

two prototypes had been built.

With many technical problems still unresolved, the program was cancelled in favor of developing

a new heavy-lift helicopter with a more conventional single rotor design.

Soviet Engineers weren't afraid to think outside the box, and while the V-12 was still

under development, engineers over at the MiG design Bureau had another crazy idea.

To turn a MiG-25 into the world's fastest VIP transport, swapping out the MiG's radar

and missiles for a passenger cabin.

You can learn more about this crazy Soviet proposal in my latest video available right

now, on Nebula.

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