OK, with NARAM fast approaching, who had figured out the ultimate duration airframe? Forget high altitude and sleek designs...
Would a Dude rocket, filled with a mix of He and air be allowed? Say in streamer duration? Say a mix of He that would almost counteract the weight of the Mylar, expended engine and rigging. Kick the motor out the rear, with a streamer tied around the casing or just between the airframe and casing.
Check-in weight? 6 grams? Or less.
If you built it so the sink rate is only slightly negative, it shouldn't be that hard to get durations measured in minutes, from a couple hundred feet.
Or, check-in weight? -1 gram? With a slight pin hole. Hey, maybe even an altitude version. Use a MicroMax to burn the tie down string, launching the balloon, err, I mean rocket and let the He leak out very slowly. At some point, it would come back down.
Is there a rule that would prohibit that? Interesting idea? Not quite really practical, given the variables to deal with, but interesting...
Heyen