The plan for flights started when fellow HABber Mark Jessop suggested we fly two balloons, mine with Hydrogen and his with Helium, to see which gets higher and by how much. The maths gives a certain figure but recent flights in the UK seem to show that hydrogen does rather better than that. Now, this was hardly going to be a scientific test as balloons vary a lot and you’d need to do a lot of flights to get the answer, but this did seem like a challenge so in true Top Gear stylee we decided to have a race.
Mark set about making his payload, including a “cut down” device so that if the balloon floated (his last UK flight did) then he could command the device to release itself from the balloon before it floated out to sea. He reported back that he was expecting a total weight of around 150g, rather more than my tiny (and cutdown-less) payload weight of around 40 grams. So I decided to even the playing field somewhat by adding a camera to mine. By this time the weather forecasts for the next available flight day showed “sun, sun and more sun” so for once I could get back photos from a relatively cloud-free sky.
To keep the total weight low, I chose a canon A495 camera which weighs just 125 grams. 2 AA cells inside add 30 grams. Normally my tracker runs on its own cells, but to save weight I connected a tracker board directly to the AA cells inside the camera, saving around 30 grams. Instead of one of my trackers, I used one designed by fellow HABber Anthony Stirk who’d added a DC-DC step-up converter, meaning that the approx 2.5 – 3V from those 2 cells would be converted to 3.3V for the tracker electronics.
I then cut holes in a solid polystyrene foam ball for put the camera and tracker, and protected the lot in a hollow polystyrene ball. Here are the parts and the completed payload, weighing in at a mere 185 grams (less that a fifth of the weight of my first payload).
Now, as Mark is an Australian, and he and I had a little battle for the UK altitude record last year (both flights have been comfortably beaten since by others), we decided to make our flights a UK vs Oz thing. So we decorated our payloads accordingly; here’s mine:
I had time before the launch day to sort out my new HAB-mobile, an old Mitsubishi Shogun that’s been labelled a “heap” by a neighbour. Well, for chasing balloons size is an advantage, and this beast has size in abundance. Plenty of space in the back for gas cylinders and all the launch and recovery kit, and space up front for radios and computer screens. My previous launch was the first time I used the Shogun on a chase, and that time we had wires eeverywhere. So I spent a couple of hours tidying everything up. here’s the result, with computer screen over on the left, scanner and radio on and in the centre console, and a standard car sat nav on the right.
On launch day I collected Mark from the local train station, then we drove over to the launch site in Cambs where Steve Randall was also launching. All 3 of us were using 1600g balloons, and Mark and I chose the same “neck lift” so the balloons would ascend at about the same speed. Here’s Mark’s balloon on the left, waiting for launch, whilst I check the lift on mine:
The launch was straightforward. Click for the YT video – Launch Video
I expected the balloons to then drift apart, but watching them it seemed that they just wanted to keep each other company:
and this was born out in the telemetry, with the two traces (red for Cloud and orange for Horus) following each other closely:
I was hoping for Cloud 7 to get up to 42km or so, but it burst at 40.57km, giving Mark’s balloon a distinct chance of beating it. But I needn’t have worried – it burst at 40.449km, losing out by a mere 121m!
By then we were collecting Steve’s XABEN payload from a field:
and after that we set off after Cloud 7 which had landed by the time we got there. Fortunately the camera was still running so I knew I should have a good set of photos.
HORUS 28 was also in a field, but this time a field occupied by green stuff. This seemed to be something of a novelty for Mark but he did eventually figure out how to negotiate this new type of obstacle:
By now the sun was going down, producing a lovely backdrop to our activities:
After that we drove home, with Mark sifting through the photos that CLOUD 7 had captured, mainly looking for any that captured HORUS. It seemed that every minute he’d find such a photo at an even great altitude, eventually finding one at 34.8km. We both believe that this is (comfortably) the highest that one weather balloon has been photographed from another. Here are some payload-payload photos:
and some of the very pretty cloud formations
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