The goal is to use blocks of foam as a structure for the payload. We'll carve out relatively closely fitted voids to hold the various components.
- balloon sheds turbulence during ascent; torpedo shape might be best for that
- APRS antenna with a 19" radius ground plane parallel to the ground would reduce signal energy sent upwards
Michael's original email:
Notes on foam:
- ) Probably want XPS (eXtruded PolyStyrene). This is a water proof, dimensionally stable, grain free foam. It tolerates very low temperatures well, and doesn't burn easily.
It cuts easily and cleanly with a sharp knife. It doesn't crumble or shed.
Brand names are 'Dow Hi-Load 60' or 'Corning Foamular 600'. Foamular 250 should work just fine (the difference in the number is the compression strength).
It appears that places like Lowes carry it, and it costs ~ $15 for a 2 foot by 8 foot by 2 inch block. (which is probably enough for about 70 million flights).