Friday, July 2, 2010

Using two balloons for controlled descent instead of a parachute?

It has always come to mind that using 2 balloons would provide a slow and controlled descent of the payload. Parachutes won't open at high altitudes because the atmosphere is too thin. So usually, after the balloon pops, the payload starts plummeting and spinning like crazy until it reaches an altitude where the pressure allows the parachute to open. During its crazy nose-dive, the payload, the load line and the parachute itself are very likely become an entangled mess with the whole thing hitting the ground at free-fall speed. Plus I fear the antenna will break as well.

How to prevent this?

Well, Kyle has reported his experience using 3 balloons. The theory is that when 2 of them pop, the 3rd one doesn't have enough lift and starts going down smoothly. I'm really looking forward to him elaborating more on his blog.

Also check out Todd's write up. He used a parachute and a ring to prevent the parachute lines from tangling during descent.


  1. Note, I did not intend to use 3 balloons. For more info, see my comment here:

  2. Also, what sort of antenna are you using on your transmitter? Is it the 1/4-wave with radials? We've had some good luck with a j-pole made out of 300-ohm twin lead similar to: When it lands on it, it doesn't do much since it's just wire.

  3. Thanks for your exhaustive explanation! And for the jpole hint. My 1/4 wave antenna has a very weak point at the soldering point between the radiator and the SO239 connector. I'm not even sure it'll withstand the jet stream, let alone free fall landing...

  4. Actually, video we shot on our balloon a week ago suggests that our parachute opened immediately at 83,000 feet. After tangle issues on our first balloon, my kids chose a chute with only 4 leads and developed a clever mechanism to contain the chute on the way up and then have it deploy itself and retract the balloon remains after burst. It worked perfectly, though it may not be obvious without frame-by-frame review: (2:00)