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morris

How big (how many persons) do you build stacks?

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Can you/do you build stacks with as many persons as you have jumpers available? Or do you usually "switch" to planes once the formation starts getting bigger?

Additional question:
Lets say you are flying a 5way-stack. What inputs should be given? Half brakes at the very top? A little bit of brakes by number 2? A bit of frontrisering by the lowest person to create some tension? What to take care about while flying it?

Thanks for any kind of information and/or input!

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I once saw a 12 -way stack being build (i was the cameraman) by a group of english crw-nuts ;) it was partly build as using a planed formation, partly stack. The biggist problem was that it was swinging at the low-end, making it VERY hard to dock. Eventually the succeeded the full formation (uk record as i remenber)
I should have the video somewhere..... If i find them i will post them

edit: picture found and attached

Caren

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There's a pic on the wall at West Tennessee Skydiving (Mullin's home DZ) of a stack that I think is the state record. I don't remember exactly how many were in it, but it was around 15. It was set a long while ago.

My largest is a 10 stack, which is the Alabama state record. I was next to last on the bottom. I found it harder to dock there than higher up in the stack due to the increased sink rate.
"Mediocre people don't like high achievers, and high achievers don't like mediocre people." - SIX TIME National Champion coach Nick Saban

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Hi Morris
You plane the stack for stability. Unplaned stacks tend to sway as they are longer and pivot around the ankle/line grips on the centre cell.
Planed stacks are shorter and far more stable.
We built an 18-way planed stack in South Africa in 1988, and even that had quite a sway at the bottom.
Cheers
Andre

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Now we are finally "closing in" on what I want to know...
I understand that planed stacks are far more stable than unplaned ones. This was exactly what I´ve been asking for.
My question was:
a) Do you plane the stacks - from a certain number of persons on - for stabilitiy reasons (I know the answer is yes)?
and b)
What I don´t know is:
What is that number???
With how many persons can you build UNPLANED stacks??
Or do you always plane ´em as soon as possible?
let´s add c)
What is the largest UNPLANED stack on record?
let´s add d)
What to take care about flying ´em?
I´ve seen pictures of 5ways that flew very nice.
I have not been looking/searching for pics of larger ones yet, I thought it´d be better to ask you guys as words will tell me more than any pic.
We´ve tried to build an unplaned 5way stack with regular Storms (not CF-Storms but with the CF-option and dacronlines) of various sizes and loadings ranging from ~1.5 to 1.6.
After the final jumper docked (myself) the formation became very "nervous" very fast. This was not caused by the dock! After the final dock it flew very nice - but just for some moments...

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What to take care about flying unplaned stacks?
Quite a lot of brakes at the very top?
A little bit of brakes right below the very top/towards the middle?
Or would you recommend building planes if we´re exceeding four persons because unplanned stacks of 5 or more persons are too difficult to fly especially at higher loadings?

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Quote

I once saw a 12 -way stack being build (i was the cameraman) by a group of english crw-nuts ;) it was partly build as using a planed formation, partly stack. The biggist problem was that it was swinging at the low-end, making it VERY hard to dock. Eventually the succeeded the full formation (uk record as i remenber)
I should have the video somewhere..... If i find them i will post them



found some footage, look between 8:56 and 9:21 and you see some clips that show the setup of the 12 way. And yes, no stack but almost all in plane....
http://www.youtube.com/watch?v=yo1xXtZrsuc

(by the way, I grew some muscles keeping track of the stack going down... :-)
Caren

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To be technical, a "planed stack" is an oxymoron. A plane is where feet are at risers, a stack is where feet are at bottom skin. Planes are more stable because the canopy is supported by the lines of the canopy above, whereas on a stack the canopy can pivot around the feet.
Stay Safe - Have Fun - Good Luck

The above could be crap, thought provoking, useful, or . . But not personal. You decide.

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