BLiNC
Magazine
Everything you ever wanted to know about
BASE-JUMPING
Jumping Hand-held
Old June 7th, 2009   #1 (permalink)
Mac
BASE813
 
Mac's Avatar
 
Join Date: Aug 2000
Location: Oxford - UK
Posts: 1,888
Rating: 0% (0)
Default Concern - Flicking

Quote:
#131 Aleksei Irzhembickij - Feb 28, 2009 Aleksei Irzhembickij
Object: Antenna
Location: BELARUS, , Minsk
COD: Impact
Description:
Report from the Russians-

gusting winds changing from crosswind to tailwind measuring 18-22mph (8-10m/s)
the throw was clearly visible as a forward throw immediately after exit. The PC was inflated prior to the exit, and the jumper was not really able to throw. It seemed like right after the throw, the PC was blown behind the jumper. The PC was already inflated at the time of exit as he was holding it by the mesh. It was most likely unintentional as the jumper was experienced and new to throw instead of letting go. The container opened really low, he impacted right before complete linestretch, with lines partially out.

Witness Speculation : exit - inflated PC - sudden gust of crosswind blows the PC behind the jumper - jumper tries to change body position as he realizes something is amiss - the PC clears the burble, but it's too low.
I would like more detail on this fatality.
Quote:
as the jumper was experienced and new to throw instead of letting go.
Actually I never throw....

I always exit with my PC able to inflate, and I just "flick" my wrist.

This write up suggests several things, so I would like more detail.

Thanks

Michael
Mac is offline  
Digg this Post!Add Post to del.icio.usFurl this Post!
Reply With Quote
Old June 7th, 2009   #2 (permalink)
I Support BLiNC Magazine (Silver)
 
nicknitro71's Avatar
 
Join Date: Oct 2003
Location: DeLand, FL (Where blue skies don't mean shit!)
Posts: 336
Rating: 0% (0)
Default Re: Concern - Flicking

When holding the PC by the attachment point, partially inflated, without throwing, you are minimizing the effect of snatch force. Snatch force is related to the PC sudden deceleration. If there is little deceleration like in the case of the PC being already open, then there is little snatch force and you are relying upon the aerodynamic drag of the PC which can be easily canculated (see table). Snatch force can be calculated via simple differential equation models (see paper) as it is a simple system.

Now, with some PC, the drag w/out the snatch force is enough to open the container and extract the tarp, with others the opposite is true. My biggest PC is a 46 unvented z-po that never gage me an hesitation. I used to have a vented 46 that gave me several hesitation in go and throw situations.

I think in the end you have less chances of a hesitation if you throw the PC after about one second instead of flicking it as you leave the object. On the other hand, in ideal conditions, the latter technique should give you a higher deployment.

This jump happened in windy conditions. Windy slider down jumps are some of the most fucked up. Going stowed on such jumps is not wise. Go and throw on such jumps is not wise. Freefalling a 220' in no wind conditions with proper techniques might work every time...the same might not aply in windy conditions.

Carrying a static line with you could make a difference between walking with a smile on your own or not walking at all...they will call you chicken and gay but at the end of the day you will get to fuck all the bitches!
Attached Files
File Type: pdf PC Drag Data Chart.pdf (14.9 KB, 19 views)
File Type: pdf ijee1097.pdf (134.0 KB, 16 views)
__________________
Dr. Nick

Nitro Rigging
nicknitro71 is offline  
Digg this Post!Add Post to del.icio.usFurl this Post!
Reply With Quote
Old June 8th, 2009   #3 (permalink)
Mac
BASE813
 
Mac's Avatar
 
Join Date: Aug 2000
Location: Oxford - UK
Posts: 1,888
Rating: 0% (0)
Default Re: Concern - Flicking

Nice one Nick, cheers

Michael
Mac is offline  
Digg this Post!Add Post to del.icio.usFurl this Post!
Reply With Quote
Reply

Bookmarks

Tags
deployment, fatality, static line

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Flicking off Brento! blinc News Feeds 0 March 27th, 2009 02:12 PM
Another BD Concern... imported_mknutson The 'Original' BASE Board 7 April 29th, 2002 03:09 AM
SSN's: Interesting (tho soporific) base311 The 'Original' BASE Board 3 March 13th, 2002 09:40 AM
Media crap guest The 'Original' BASE Board 10 August 28th, 2001 12:53 AM
Big cliff height measurment???? simon The 'Original' BASE Board 23 November 27th, 1999 08:42 AM


All times are GMT -7. The time now is 02:17 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2010, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.3.0
BLiNC MagazineŠ 1994-2009 all rights reserved