Forums: Skydiving: Safety and Training:
Tail Strike Safety Day Presentation?

 


Skwrl  (C 36419)

Feb 1, 2012, 9:45 AM
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Tail Strike Safety Day Presentation? Can't Post

Hi all,

A couple of my fellow wingsuiters and I are preparing a talk on avoiding tail strikes for our upcoming Safety Day. I am wondering if anyone has prepared such a presentation before, and if they'd care to share it.

We plan on creating our own content for this presentation, but insights as to how others have talked about it in the past would be useful. We'll make our presentation available on dz.com when we have completed it (which should be in advance of Safety Day, obviously).

We're not just interested in tail strikes by wingsuiters - we're aware that lots of other, non-wingstuited, jumpers have hit the tail from time to time, so it doesn't need to be wingsuit-specific.

Thanks for any help you can share.

-Jeff


(This post was edited by Skwrl on Feb 1, 2012, 9:46 AM)


Southern_Man  (C License)

Feb 1, 2012, 10:22 AM
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Re: [Skwrl] Tail Strike Safety Day Presentation? [In reply to] Can't Post

There is a resource on tail strikes that Jan Meyer has written. Pretty sure you can find it with a search. Nothing specific to wing suiters if I remember right.

http://www.makeithappen.com/spsj/collisio.htm

edit: There's the link.


Para5-0  (D 19054)

Feb 1, 2012, 5:26 PM
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Re: [Skwrl] Tail Strike Safety Day Presentation? [In reply to] Can't Post

I would contact DSE and get his input.


fencebuster  (D 29918)

Feb 1, 2012, 8:10 PM
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Re: [Para5-0] Tail Strike Safety Day Presentation? [In reply to] Can't Post

+1


Premier DSE  (D 29060)

Feb 1, 2012, 10:44 PM
Post #5 of 6 (566 views)
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Re: [Para5-0] Tail Strike Safety Day Presentation? [In reply to] Can't Post

In reply to:
I would contact DSE and get his input.

Jeff is looking for non-wingsuit tailstrike info. I've shared the same doc with him that was shared with you.

There was the one at Lodi, and a camera flyer down east (Deland?) that I'm aware of, I'm sure there are more that I'm unaware of.


MakeItHappen

Feb 2, 2012, 6:37 PM
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Re: [Skwrl] Tail Strike Safety Day Presentation? [In reply to] Can't Post

The stuff I have is related to specific incidents and is generally work product done for others (some related to lawsuits).
Thus, it cannot be released, except for the article already cited.

General trends can be stated.
A larger projected surface area perpendicular to the relative air stream will slow your velocity component in the direction of the relative air stream much faster than a smaller projected area perpendicular to the relative air stream.

Collisions between an aircraft and jumper occur when the trajectories cross.
The trajectories cross when the individual vertical velocity components of each body do not provide sufficient separation during the time that the jumper is supposed to pass under the tail or equivalently when the differential between the horizontal velocity components of each body is such that there is insufficient time for the bodies to separate vertically.

In jumper speak, if you present a huge surface area to the relative wind on exit you are more likely to hit the tail.
Also with WSs, the lift coefficient of the jumper needs to be assessed, even if the projected area perpendicular to the relative air stream is 'small'.


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