YouTuber flies secret U2 spy plane 70,000ft high to reach ‘coffin corner’ on edge of space

A YouTuber and former United States Air Force veteran flew a secret US spy plane to a staggering 70,000 feet and ended up on the edge of space in the dangerous 'coffin corner' zone.

Straight out of the nostalgia of Cold War conflict, the Lockheed U2 - nicknamed Dragon Lady - was built by the US Air Force (USAF) and CIA back in the 1950s and has been in operation ever since.

A mainstay of the Cold War, it flew numerous reconnaissance missions over China, Soviet Russia, Vietnam, and Cuba.

Well, for content creator Sam Eckholm - who knows a thing or two about the US military having served in USAF - it was right up his street as he set his sights on journeying 70,000 feet into the skies above Earth at the edge of the world.

The Lockheed U2 spy plane (Getty Stock Images)

The only problem with this is that it takes you to a region dubbed 'coffin corner' where even the slightest change can end in a very sticky ending for those flying at such an altitude.

See, the thing with the U2 spy plane is that they need to get really high to evade being noticed. First put together in 1956, it was ruled necessary by the US government to stop another attack like the one of Pearl Harbour.

The surprise attack in 1941 by Japan saw the USA enter the Second World War on the side of the Allies - a move that many historians say was decisive in Nazi Germany losing the war.

Mid reconnaissance journey (Greg Mathieson/Mai/Getty Images)

In order to get in to the spy plane, Eckholm revealed he had to wear a specialised space suit purpose made for those flying the U2 plane.

He also had to undergo a claustrophobia test lasting for hours on end, with the time spent in the Lockheed U2 hardly being a short commute.

In getting to the insane altitude of 70,000 feet, Eckholm revealed he was at a region between space and the Earth known as 'coffin corner'.

"It refers to the region of flight where even the slightest changes in airspeed or altitude can result in, well, I think you get the point," he grimly states in his YouTube video documenting the journey.

The U2 is still used to this day (USAF/Getty Images)

Instructor pilot Mongo, who co-piloted Eckholm to the edge of space, explained: "The higher we climb, the closer we are to both over speed and stall up at altitude, putting us at a razor's edge flying margin at any given time."

"Go too slow and you'll stall the jet. Go too fast and you'll exceed your critical Mach number," Eckholm said, with your 'critical Mach number' being the speed at which air flow over the wings becomes unstable.

Effectively, if you move too quickly, you risk your wings breaking at altitude and quite literally snapping off.

On the other end of the scale, move too slow and you'll stall the jet. Not a good ending, either.

Doing either of these bits would be catastrophic for those on board, with it labelled a 'coffin' for obvious reasons we don't really need to expand upon.