Parachute and balloon entanglement

[Jim O'Hern]

In my previous balloon launches, the balloon frequently would tangle with parts of the payload once it burst.  Once, it tangled around a 433MHz antenna and RIPPED it from the payload.  Another time, it wrapped around the parachute.  I decided to try a method to separate the balloon debris from the parachute.

At the top of the parachute where you typically would tie the balloon, I put a very small gauge key-ring.  Then, at the bottom of the balloon tether, I put an identical ring.  Then, once the balloon was inflated, and just prior to launch, I connect the balloon to the parachute with an 'S' hook.  You do, of course, need to handle the payload carefully so as not to jar lose the S hook. (Don't ask how I know.)  The tension of the balloon's lift and the weight of the payload keep everything nicely secured to one another.  Then, when the balloon bursts, the jolt causes the S hook to separate from the two rings.  I have two excellent videos of this happening.  In both examples, the balloon is left behind (it falls MUCH slower) and the parachute fully inflates. 

Jim O'Hern, AD4XX

[Christopher Gorski]

Pretty good idea!

Just a thought -- You might make a point of clamping the 'S' hook down over one of the rings...  the remnants of the balloon provide some drag and of course so does the parachute, but I wouldn't really want to get hit by a chunk of metal falling at its own terminal velocity from 100,00 feet if it separated from both.  As long as it's attached to one or the other piece, though, it seems fine!

Do you have the video of the separation posted online anywhere?  Sounds like fun to watch!

--me

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[Jim O'Hern]

https://www.youtube.com/watch?v=YhnsKZeNGLo should take you to the first successful disconnect...at 1:55:25 you will be a few seconds prior to burst.  The S-hook is so light, I doubted that it would cause damage, even from 100K feet....but it would be very easy to connect the S-Hook to both the parachute and the balloon with two separate, very light threads.  That way, it would break away from one of the pieces but not both.  I appreciate the thought!  You will notice that even in a very thin atmosphere, the balloon parts get left behind pretty quickly, unlike the feather and hammer experiment conducted on the moon about 5 decades ago.  ;-)

Jim

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