Seeing how it all worked out with the first balloon, we instantly started working on the second one. Going a tiny step back, I was wondering how much lift we produced with our Tiny. I did some rough calculations and I think that my optimism caused me problems again – it was max 0.200m3 of Hydrogen. Very likely less.

Works on the “Big boy” started on the “Little guy” night.

With this in mind, I made sure that this time we have min 1m3. The circumference is calculated from C=2πr, so our radius here is r=C/2r -> 240/(2*3.14) = 38cm. If we are aiming to have at least 1m3 we need to use a formula for the volume of a cylinder V=πr2h. 3.14*0.38*2 = 2.38m -> Our new balloon needs to be at least 2.38m long! The picture below shows a mark at around 280, when we take some wobbles on both sides – I think we are sort of there.

An important part of gluing your own balloon – a pressure test!

And 10 minutes later …

Sebi came with a bottle of detergent – and well, it was pretty leaky. We needed to do ~5 iterations to make it rock-solid and we’ve got a couple of new assistants to do the hard work (Zoya & Stella)!

Lesson learnt here .. wash off the detergent first, before putting a patch on! This particular one was pretty painful to learn. :/

Finally, we deflated the balloon and took the last, but perhaps the most important, measurement… the balloon’s weight! The empty box came as 120g.

While the whole set weighted 358g.

This makes our big 1m3 guy’s weight 238g. Let’s say we’ll get 1.2kg lift out of our 1m3 of Hydrogen … that means that we should end up with almost of 1kg of lift this time! Let’s see 😉