US engineer building a flyable airplane that's 95% cardboard

This US engineer is building a flyable airplane that will be 95 percent cardboard.

For YouTuber Peter Sripol, this is his fifth airplane project.

As you might expect, he knew he had a big challenge ahead of him.

After all, who would even consider building a cardboard airplane, let alone flying one?

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Why did this US engineer want to make a flyable airplane out of cardboard?

Sripol said constructing an airplane out of cardboard is something he’d ‘always’ wanted to do.

But it presented a huge challenge for him – how could cardboard be used structurally for such an endeavour?

We think of planes being made out of sturdier stuff, right?

And sure, cardboard isn’t necessarily flimsy or weak.

But if you’ve ever overpacked a cardboard box while moving house, you’ll have learnt about its limits the hard way.

Sripol knew he had to do some experimenting before this plane would be anywhere near a successful take-off.

He had to figure out how cardboard reacted under stress, so he made up some miniature beams and tested them with sand as a weight load.

Each beam had a different flute orientation – that’s the internal structure that gives cardboard its rigidity.

The cardboard with vertical flutes failed after four cups of sand, while the horizontal flutes held up at nine cups.

From this, Sripol opted to use cardboard with horizontal flutes.

He then constructed the 13.5-foot spar, which will bear the load of the airplane’s wings.

Sripol estimated that it could bear between 150-300lbs across the wingspan – and each wing would weigh between 11 and 15lbs.

Did we get to see this unorthodox airplane take flight?

Later in the process, it was time to cover the structure.

Sripol’s first idea was to use a full cardboard skin, but this proved to be too heavy.

He then decided to go with brown craft paper instead, partially because it gave the plane a taut aerodynamic finish when it tightened.

The total wing weight was 44lbs at this point, acceptable for his ultralight design.

All in all, the plane was estimated to weigh around 120lbs while empty, and 150lbs with the power system inside.

Unfortunately, we didn’t get to see the plane in action – that’s coming in a later video.

But let’s just say, we’ll be very curious to see how this pans out.

If his previous work is anything to go by, that cardboard airplane is in very capable hands.

He previously created a homemade electric plane, alongside an F-18 fighter jet made from foam and paper.

But it’s not just planes that he’s working on – he’s been putting a lot of energy into converting an old lobster boat using homemade parts and resin.

Whenever we see someone taking on a plane restoration project, we have to applaud their efforts.

For some people, it’s a creative endeavour.

But others have their own reasons – one man from Wisconsin decided to build an airplane to save himself some money.

To see the construction process of this flyable airplane made of cardboard for yourself, visit Peter Spirol’s YouTube channel.

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