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Balloon crash thread of armchair analysis and condolences


CoTex

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When 8 people jump out of a balloon it will tend to rise.   To prevent this you can pull a chord that opens an air chute at the top and lets hot air out.   Malfunction or failure of that chute could be bad.  Worst case you have a hole at the top and the whole balloon deflates.  

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Here's a long description of what happens when a bunch of skydivers jump out of a hot air balloon.   You can see that this has the potential to go very wrong.  Here the "parachute" is the valve at the top that lets hot air out.

https://www.balloonadventures.it/record-breaking-parachute-jump-balloon/

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People were chatting all the way up to 8000 feet, where the 24 jumpers got ready, hanging from the edge of the basket like bunches of grapes(see photo).  As planned with Mike, we got into a 1000 feet a minute descent and dropped all the parachutists at 07:16:09 local time from 6955 feet.  To no one’s surprise, the balloon started climbing rather violently, reaching a maximum rate of climb of 1870 feet per minute.  Also as expected, the parachute “fell in” looking very similar to a windy inflation when half of the parachute falls in.  I grabbed the “candy stripe line” initially to slow down the rate of climb and it became clear within seconds that I have to keep pulling it to keep it under tension so that the whole thing does not collapse.  The drama only lasted a minute or so, when it became obvious that the balloon will get through it and will be stable soon again.

 

Edited by ClubWhatever
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Aha!  Informative.

Is there an upper limit in ballon ascent velocity?  As I understand it - dropping all the skydiver weight causes so much positive ascent that may exceed balloon’s limits.  So they start off in rapid descent to ameliorate that, and then start dumping lift as soon as it gets light?

More dangerous than I initially thought.

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It is bewildering to me that ballooners will just go up in the air with zero lateral control, and where they go and land is wholly dependent on the fucking winds?

Atleast with gliders, even if you don't catch air lift, you can steer and glide towards the target.  Balloons are like....uppsies...downsies...

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“We’re going to put this thing in a steep dive and as soon as the skydivers jump, we’ll go up like a ballistic missile.  Then we’ll dump a bunch of air until we level off.  It’s gonna be great - hold onto your champagne flutes everybody.”

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13 hours ago, ClubWhatever said:

Here's a long description of what happens when a bunch of skydivers jump out of a hot air balloon.   You can see that this has the potential to go very wrong.  Here the "parachute" is the valve at the top that lets hot air out.

https://www.balloonadventures.it/record-breaking-parachute-jump-balloon/

 

Does a balloon have a terminal velocity?  I would think horizontal wind speed would always be zero. Wind blows you blow with it - feels like no wind.

But vertical - thermal rising… if you go up too quickly the think inverts or collapses or something sporty like that?

what is terminal V?

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12 hours ago, jimmyjazz said:

My thought is "no freakin' way am I going up in a balloon where most of the passengers are gonna jump off".  Maybe it's just me.

Shit, I will ride in a hot air balloon, at all, right after I enroll in grad school at ou.

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22 minutes ago, CoTex said:

Does a balloon have a terminal velocity?  I would think horizontal wind speed would always be zero. Wind blows you blow with it - feels like no wind.

But vertical - thermal rising… if you go up too quickly the think inverts or collapses or something sporty like that?

what is terminal V?

I don't know.   It could be calculated based on the lost ballast (skydivers) and the drag on an object of the same approximate shape at altitude.   The one in the article I quoted was going 21 mph upward according to the quoted figure.  That top surface is relatively flat and at that speed it is going to generate a large drag force that tends to flatten it out further.  That's a  potential problem, because there will be a fight between the internal pressure on the chute and the drag trying to push it in.  The way to mitigate this would be to jump one at a time so the adjustments needed aren't so drastic.

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Word I've read is group of 8 were together. 6 were ok to jump at once, possibly other 2 too quickly (possibly from overly dramatic rise) or didn't adhere to plan.  Either way, too much weight dropped too quickly causing the rise of balloon to "over" flatten/collapse balloon causing dramatic descent that couldn't be recovered from as balloon needs to replace the hot air forced out with new air that would then need to be heated to keep it afloat.

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On 1/14/2024 at 8:13 PM, CoTex said:

 

Lol, the article puts quotes around "tragic". 

 

Four people died when a hot air balloon crashed in Eloy, Arizona, on Sunday morning, police said.

A fifth person was in critical condition after the “tragic” crash, Eloy police said.

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