In this clip from the OU/BBC programme Science Shack, Adam Hart-Davis and his team attempt to build a huge man-carrying balloon—made entirely out of just paper.

Even though they used paper, the team had to apply serious design and engineering principles. The construction of the balloon required the intricate assembly of many small pieces of paper. This caused considerable issues and problems during construction—was this a challenge too far for the team?

## Watch

Flies fly; birds fly; jumbo jets fly; even this thing flies, after a fashion anyway.  The question is; what’s the biggest thing that could possibly fly?  The choice seemed to be heavier than air, a plane, or lighter than air.  Well, the biggest things to have flown so far are airships and balloons, so I’ve asked Glenn and the team to try and make a man carrying hot air balloon entirely from paper.  So, Glenn, this is actually it is it?

Glenn

It is.

This is my beautiful balloon.

Glenn

Not quite that lovely colour unfortunately.  I’d love a pink one!

Glenn

Would you?

Our balloon is going to be huge.  We know that a conventional hot air balloon has to hold about 600 cubic metres of air to lift 200 kilograms, a bit more than me, which means a balloon 32 metres in circumference.  Why do you want it this shape and not just a sphere?

Glenn

It’s optimised for making, putting as little stress on this fabric as we possibly can so it’s optimised...

Having got a shape that looks like a balloon Glenn uses another piece of software to unwrap it, rather like opening a birthday present.  We have to make a giant version of this shape and then wrap it up again to make the full size balloon.

The basic problem about making a hot air balloon out of paper is that paper is flat and the balloon is spherical, i.e. three-dimensional.  Now, the way they’re doing it is to make a whole lot of shapes like this, long, thin, lozenge shapes.  Now nine of these have already been stuck together and here they are, this is the bottom all glued together and there’s the top and you’ll see that the final thing, there’s the inside with all those markings, the final thing will actually be roughly that shape because we haven’t made a third of it yet even and then it’ll be very much balloon shaped.  Isn’t that a lovely thing?  And the gluing, the taping down the edges is absolutely critical because not only do they have to fit together but there must not be any holes for the hot air to escape.

Right, so at last we’re inflating it.  Just filling it with cold air to get the shape up so we can then start pushing in the warm air, and basically it’s just a simple extractor fan pushing air into it and gradually you can see it taking shape.

I must admit the balloon looks stunning.  Now fully inflated with cold air it looks exactly like the computer picture we started from two days ago.  Glenn and the team have done an outstanding job.  It clearly is a balloon and I can’t wait to get on board.  We want to get the envelope as upright as possible before putting the flame in so that there’s no paper immediately above the burner.

Glenn

I think that’s fine for the time being, thanks.