Buzz – To 40km and beyond!

Well, that’s the plan! The aim with my first balloon launch was to take photographs from around 29km (100,000 feet); this one will be to get as high as possible. The UK record was till a few weeks ago set at around 36km, but is now 40.5km. My target is to get above 40km with Buzz1, and maybe even break that record.

To get to high altitudes, the theory says that you use a large balloon, attach a small payload, and fill with a minimum of gas. However when people tried that combination, they found that the balloon reached a lower height than planned, and then floated. Nevertheless, that was my plan when I started to design and build Buzz1.

Since then, two balloons have exceeded the old record. One was a 1600g balloon (same as mine) and a 150g payload (a bit heavier than mine), filled with a lowish amount of helium. It reached about 39km and then started to bounce in height, slowly increasing the average height of each “bounce” till it finally reached 40.5km and then burst.

The next balloon was a lot smaller at 800g, and was filled with a more normal amount of helium. This one didn’t bounce but did reach over 39km. The launch was made simultaneously with another balloon of the same size, same payload weight and same amount of helium, but with a balloon made by Totex instead of Hwoyee. That balloon burst about 5km lower – an enormous difference.

So from these flights it seems that Hwoyee balloons have a distinct advantage, so it’s just as well that Buzz will be using one of them!

My first balloon payload was a “full fat” version, weighing a total of just over 1kg. That’s much to high for an altitude record attempt, so Buzz’s payload has a target of 100g. To achieve that means cutting out everything that’s not necessary, meaning the video (150g), camera (170g) and backup tracker (60g). It also required replacing the flight computer with a much smaller and lighter version, and doing the same with the GPS receiver and antenna. The new parts were specially chosen to be able to run at low voltages (meaning using 3 batteries instead of 4) and running at low currents (meaning using AAA’s instead of AA’s). Of course, with smaller and few parts, the packaging can be a lot smaller so that saves more weight. When you’re aiming for 100g, every gram counts and everything needs weighing to a gram or better!

Despite aiming for a low weight, I wanted to have some fun with the design. So instead of being a tiny foam box, it’s shaped like a UFO. UFOs have flashing lights, so this has them too. They have shiny surfaces, so this has a foil underbelly that doubles as the “ground plane” for the transmitting antenna. UFOs make whistling noises and so does this (when it lands, to help us find it).

Getting a payload to 40km would be an achievement, but bringing back photos from that height would be much better. So Buzz1 will actually have a camera, albeit a tiny Chinese crap-o-cam with unimpressive photo quality but with the useful quality of only weighing 15g including battery. Also, since so few balloons have reached these altitudes, it would be good to send back environmental conditions such as temperature and air pressure. So Buzz1 will have sensors for those too. adding these things does compromise the achieved height somewhat, but to me an actual record (which would soon be exceeded anyway by someone else) is much less important than learning things and having some fun doing it!

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