All the subsystems below that last piece of string need to be packed somewhere...but where?
The obvious candidate for packaging, in terms of both insulation, impact protection and light weight is expanded polystyrene (EPS) foam (Styrofoam, or equivalent). So where in Cambridge (UK!) does one find the stuff in large enough chunks to fabricate into an enclosure?
As it turns out, more or less anywhere that sells DIY products. The magic word to use is Jablite. This is what the construction industry calls the large-size EPS sheets that are used for wall and lofy insulation. So that's easy enough: next time we're in a DIY barn, we can pick up plenty of it, and maybe a hot-wire cutter too.
That's just the matierial, though. We have to consider:
- The shape of the package:(aerodynamics, impact resistance, anti-spin vanes/fins, radar profile);
- Where instruments are sited;
- What external ports will be needed (camera vewports (open or covered with plexiglass/acetate/...?), antennae, defeat switches, lights, sounders, ...)
- Radar reflectors ( what to use, and where to site them);
- Siting of identity information (STARS logo, finders' notices; ...)
Much to think about.
We've been doing some scouting around for EPS materials. Jablite is,,,well, it's OK, but it's also a bit more dense than we'd like, particularly given the compromise we've had to accept for payload weight (see Balloons and Parachutes for more on this). However - Springvale do EPS sheet that's rather lighter, and that's looking good. We're probably going to source it from Ridgeon's of Cambridge, and they've agreed to supply at trade price, now they know what we're planning to do with it!
Still looking for a hot-wire cutter, though...
Last Updated (Monday, 15 August 2011 13:19)