Amazing photos. This is the kind of thing that we read the Reg for.
The Replay XD camera looks really good too. I'm looking for a motorbike helmet mounted camera, and this might be ideal to capture those near-misses caused by brain-dead drivers.
Watch Video It's a traditional tip of the hat today to Tim Middleton of Replay XD for providing a couple of the company's vid cameras for a recent Low Orbit Helium Assisted Navigator (LOHAN) imaging test flight, during which they captured the moment of mighty orb burst in all its glory. The Replay XD The above video speaks …
"Probably talc for the abovestated reason."
Probably, but it sure remained in close to the same volume for a *very* long time. I believe that model records at 60 FPS, which is quite a long time when gas (and debris within that gas) becomes rapidly decompressed by confinement loss.
It's a good question.
How about finding some boffins who can answer it for sure? I'm assuming that the cloud probably is the helium but an expert might at least find the pictures interesting enough to explain what we are looking at in detail.
IIRC the fragmentation of the balloon seen in the video does not happen where we mere mortals and El-Reg stalkers live. Regardless, an amazing clip from the LOHAN team. Well done!
Perhaps someone with more experience than me (nil at this point in time) can tell me if those balloons disintegrate like that here on mother earth. My limited experience with party balloons suggests no, but I'll be be very happy to be proven wrong.
Lift is generated through the displacement of the ambient air; more specifically, the weight of the displaced volume. As the balloon rises, the outside pressure drops, and with it, the weight per unit volume of the outside air. So the balloon needs to displace a bigger volume to keep positive buoyancy. And as long as the balloon is capable of expanding (pressure difference between inside and outside, versus 'stretchiness' of the balloon skin) it will keep rising.
If you start venting pressure to keep the balloon from bursting, you will simply not reach maximum volume, so no maximum displaced ambient air, so no maximum height.
Yes... true. But what is happening instead is that the balloon bursts BEFORE reaching the maximum height - due to the pressure overload on the skin. Releasing that overload should allow a higher altitude. Venting some gas would also reduce the weight (less gas needed to maintain the same volume). Of course there is the offset of the weight of the valve..
In the old days, this was handled by having a balloon only 1/3 filled. As the balloon rises, the envelope does expand... and due to the larger envelope, does not burst. (reference to the "rockoon" launches --- still going on).
Now one advantage to having the balloon burst is that you don't have to worry about cleanup :)
I hear sound on the video. Although there's not much to hear at 30 km, the structural vibrations are recorded. Does this camera have the option to turn sound recording off? That might no save much space on the SD card, but for longer flights it could be worth it. Or perhaps the sound track could be used to record encoded flight data.
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