My friends and I did this twice when we were in college in Oklahoma back in the late 80s.
We ran the balloon line up through a hole in the center of the parachute, which itself was tied off with several strings terminating to a single string tied to the payload. Tests showed that even if a large amount of the balloon stuck around on the string after it popped, it would have a negligible effect on the performance of the chute, basically laying on top of the chute as it did its job.
The balloon itself was call the "Sky Buster" and cost about $35 from a local shop. I had a welding shop at the time, so had access to large quantities of helium. The Air & Gas driver would give helium to me for free.
We did a tethered launch of a video camera first (at those times quite large and heavy) and waited until dusk to launch the balloon without the camera. A modified camera flash was hung below the balloon and had a variable flash pattern programmed into it. If it was going up, it would flash every 15 seconds or so. Coming down, it was like once every 5 seconds. We used that for tracking.
The first time we launched it, we tracked it for over an hour before recovering it 20 miles from where we launched it. Both launches were on a windless night (in Oklahoma a rarity) and once the balloon was at altitude, it clearly started moving with purpose. We lost the second one after following it for about 50 miles.
Back when we did it, we didn't have no stinking GPS or cell phones like these whippersnappers nowadays. Shoot, there weren't even digital cameras! We'd have had to do it with film, if we did it at all.
Great memories, and ones I plan on repeating with my son.
We ran the balloon line up through a hole in the center of the parachute, which itself was tied off with several strings terminating to a single string tied to the payload. Tests showed that even if a large amount of the balloon stuck around on the string after it popped, it would have a negligible effect on the performance of the chute, basically laying on top of the chute as it did its job.
The balloon itself was call the "Sky Buster" and cost about $35 from a local shop. I had a welding shop at the time, so had access to large quantities of helium. The Air & Gas driver would give helium to me for free.
We did a tethered launch of a video camera first (at those times quite large and heavy) and waited until dusk to launch the balloon without the camera. A modified camera flash was hung below the balloon and had a variable flash pattern programmed into it. If it was going up, it would flash every 15 seconds or so. Coming down, it was like once every 5 seconds. We used that for tracking.
The first time we launched it, we tracked it for over an hour before recovering it 20 miles from where we launched it. Both launches were on a windless night (in Oklahoma a rarity) and once the balloon was at altitude, it clearly started moving with purpose. We lost the second one after following it for about 50 miles.
Back when we did it, we didn't have no stinking GPS or cell phones like these whippersnappers nowadays. Shoot, there weren't even digital cameras! We'd have had to do it with film, if we did it at all.
Great memories, and ones I plan on repeating with my son.