HDTenEightyP/NetNews huggingface dataset:
From: SKYDIVE@f15.n233.z1.fidonet.org (SKYDIVE)
Newsgroups: rec.skydiving
Subject: Airspeed vs Groundspeed
Date: 13 Sep 92 00:45:06 GMT

Reply-to: Bill.Caefer@p0.f853.n102.z1.fidonet.org (Bill Caefer)
Fido-To: romulus!uoft02.utoledo.edu!dsouth

 r> All this talk of ground speed and airspeed brings up a point I was
 r> discussing with an intermediate jumper this weekend.

 r> Canopy AIRSPEED is the same wether you are facing in an upwind, downwind
 r> or crosswind direction.  The only thing that changes is the GROUNDSPEED.

 r> I realize how obvious that statement is (generally, it is covered in most
 r> first jump courses), but I cannot count the number of times that I have
 r> overheard a jumpmaster/instructor telling others to turn into the wind
 r> to help inflate closed endcells...it doesn't help 

Absolutely, and how about this one?  (also wrong)  That a canopy will turn downwind if you don't steer it.  Clearly impossible since a canopy feels no wind.

And I just had my flying instructor tell me yesterday (I argued with him) that an airplane will weathervane.  Jeez, how do these things survive?

Bill Caefer
D-7510

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From: bchurch@oucsace.cs.ohiou.edu (Robert Church)
Newsgroups: rec.skydiving
Subject: Re: The HERD boogie
Keywords: herd boogie
Date: 9 Sep 92 22:47:09 GMT
Organization: Ohio University School of Art. Athens

In article <BuBqsJ.3Iq@virtech.uucp> mark@vti.com writes:
>*sigh*
>
>There was one almost-fight in the crowd (who knows what the hell happened,
>but beer was spilling so it must have been important).  Personally, I
>saw the first round and left.

Carbone didn't happen to be in this 'two way' did he? :-)



-- 
*********************************************
*    bob church                             *
*    bchurch@oucsace.cs.ohiou.edu           *
*    D-8195 NFS #27                         *
Newsgroups: rec.skydiving
From: eap@leland.Stanford.EDU (Eric Perozziello)
Subject: Re: Looking for pictures of formations
Organization: DSG, Stanford University, CA 94305, USA
Date: Thu, 10 Sep 92 19:31:58 GMT

In article <SHIBUYA.92Sep9144637@chute.mailhost.bl.cad.slb.com> shibuya@mailhost.bl.cad.slb.com writes:
>In article fbm@ptcburp.ptcbu.oz.au (Farrell McKay) writes:
>
>>   Hmmmm .... thinking a bit more about this .... simple black and
>>   white images would be a good way of sharing ideas about good
>>   formations/jumps to do.  Or even to see what the shape of the
>>   latest 225-way blob was like.  Or even .... sorry, just thinking
>>   out loud here.
>
>I want to go even further.  I want to have electric representation of
>sequetial RW which contains all the essential abstraction which define
>a whole skydive, including all the grips, angles, transition between
>points, targetings, keys.  I want to have a dive editor where I can
>electronically engineer a dive and animate it.  Further, calculate all
>the translational and rotational motions/accelerations of the
>transitions and generate optimum dive plan.  Oh also I like to have 3D
>human figures and all the possible jump plane door model for exit
>engineering....  (Could anybody tell me exact dimension of King Air
>door?)
>
>

Hey, I don't see a smiley here !!!  Somebody, PLEASE say this is a joke!

Just go have fun, damnit!
From: tjreynol@zephyr.cair.du.edu (The Jumpin Dude)
Subject: Re: St. Louis Arch Base Jump
Organization: University of Denver
Date: Wed, 16 Sep 92 04:31:29 GMT

In article <BunKBG.GEJ@news.cso.uiuc.edu> mandel@jumprun (Hector Mandel) writes:
>tjreynol@zephyr.cair.du.edu (The Jumpin Dude) writes:
[arch story]
>: anyone know what happpened to him?
>: tim

>I heard something on the radio this a.m. too.  I didn't hear any details though
>Can somebody post the story?  It sounded like it was a very successful jump.
>I'm not sure about the suction cups though; is The Arch smooth enough that
>suction cups would help?  :)

i'm guessing the Arch is concrete. i can't imagine suction cups working
well on concrete. i do know of a guy dressed as Spider Man that climbed
a Denver Skyscraper with cups, tho. that's some scary stuff.

i'm suddenly reminded of some story about a guy who did a similar cup
climb up a freshly-cleaned/otherwise-slippery surface; his cups were 
sliding down at about half the rate he was climbing. don't know where 
that came from, tho.

i know the Spider Man thing happened, tho, i saw it.
tim
From: SKYDIVE@f15.n233.z1.fidonet.org (SKYDIVE)
Newsgroups: rec.skydiving
Subject: Re: how often does this happen?
Date: 4 Sep 92 22:16:44 GMT

Reply-to: Bill.Caefer@p0.f853.n102.z1.fidonet.org (Bill Caefer)
Fido-To: romulus!cd.amdahl.com!drp40

 r> Cutting away separately allows you to make sure that 
 r> your main clears before
 r> you deploy your reserve, avoiding entanglement.

Should you have to cut away some day at 8 or 10 thousand feet.  There is a lot to be said for being able to skydive on down to 2 grand instead of floating around up in the air traffic and cold for 15 minutes.

Also, it also allows you the option of going straight for the reserve should the need arise without the main risers being loose.  And is a simpler (hardware wise) system.

Changing/removing the main from the rig is also simplified if you don't have to worry about accidentally dumping your reserve.

I (opinion here) think it's the better system overall.

Bill Caefer
SCSA-91

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From: boucher@hpcc01.corp.hp.com (Richard A Boucher Jr)
Date: Tue, 8 Sep 1992 17:49:02 GMT
Subject: Re: dreams
Organization: the HP Corporate notes server
Newsgroups: rec.skydiving


Tim,  let's hear about your dreams...

My first skydiving dream was fantastic.  It started out as one of those 
nightmare falling, no-way-out, Oh-my-God-I'm-going-to-die, massive-ground-rush
type dreams when I found myself thinking "Hey, no problem".  I did a clean
relaxed arch, rode for awhile, then did a calm arch, look, reach, and pull. It
was a clean deploy but *hard*, and I awoke upon opening shock!

I had a huge smile on my face when I woke though! After all those years of
waking up terrified after a falling dream it felt unbelievable to have 
conquered one!

-RB      

PS-I held on to my ripcord too! (This was during AFF).
From: SKYDIVE@f15.n233.z1.fidonet.org (SKYDIVE)
Newsgroups: rec.skydiving
Subject: How to calculate freefall time ?
Date: 10 Sep 92 15:11:58 GMT

Reply-to: Bill.Caefer@p0.f853.n102.z1.fidonet.org (Bill Caefer)
Fido-To: romulus!stout.atd.ucar.edu!nws

 r> Can someone post the correct formula to use in calculating
 r> freefall time. In a recent post the following 'C' code
 r> was used:

You mean you actually took that thing seriously?


 r> freefall time right? (10000 - 4000)/200 = 30 + 5 = 35.
 r> Yet on my log book completed by a AFF JM I have 45 seconds of freefall
 r> time for this type of jump. Our class was told that if we multiply 
 r> (jump_altitude - opening_altitude) by seven and add 3 we would get
 r> our correct freefall time.

Then plug that into the program and see what you get...

 r> I am keeping my own log now and want to make sure I keeping
 r> track of freefall time correctly.  What is the correct way to
 r> calculate freefall time?

The best way (other than stopwatch) is to use a chart.  Logbooks used to come with one but that seems to have gone out of practice.  Ask around.

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Newsgroups: rec.skydiving
From: bdaniels@ssf-sys.DHL.COM (Ben Daniels)
Subject: Re: 1 in 80000 dies.  Oh dear!
Organization: DHL Systems, Inc.
Date: Tue, 08 Sep 1992 19:20:41 GMT

In article <1992Sep4.004202.19715@selway.umt.edu> sh666@selway.umt.edu (Wolverine) writes:
>Oh no!  I just happen to be on my 79,999 jump!  Now what!?!?
>

To quote a friend of mine:

"Don't worry about death
 It's perfectly safe

 It's like taking off a tight shoe"

Which is why I think I liked to skydive in the first place.
It reminded me of that freedom.

Anyway, since it is statistical, we're mostly good for a couple more
sigmas anyway :-)

Skratch

--------------------------------------------------------------------------------
email:  bdaniels@ssf-sys.DHL.COM 
Newsgroups: rec.skydiving
From: bdaniels@ssf-sys.DHL.COM (Ben Daniels)
Subject: Re: You may pick up your pencils...
Organization: DHL Systems, Inc.
Date: Tue, 08 Sep 1992 22:20:18 GMT

>
>From: boucher@hpcc01.corp.hp.com (Richard A Boucher Jr)
>
>All this talk about reserve rides and a couple of recent dreams about 
>malfunctions have got me to wondering...
>
>Statement: One cannot fully define one's commitment to or relationship with 
>the sport of skydiving until one's first reserve ride.
>
> 1. True or False?
>
> 2. Explain your answer.
> 
>You have 30 minutes. Begin.

Now *that's* an interesting question. I'm glad you put a time limit on
it or I'd never get any work done :-)

When I started (sometime around the first jump) skydiving took on a life
of its own and I unquestioningly gave whatever it took - which turned
out to be all I had. I immediately forgot that it was a voluntary activity.
Whatever happened, whatever it took, that's how it was and who I was.

I had around 1400 jumps before I realized that I too could die. I mean
really realized it, even though I had seen one, been present for several
and knew many. That was when Jim Heydorn went in. Jim was one of my
teachers. He was in some fundamental sense more together than I was.
When he wnet in I knew that I could too.

Jump 1701 was my first reserve - not counting stupid things I had done
which left me under a reserve.

It wasn't until around 15 years and 2300 jumps one day in 1977 or 78 -
one day when I was deep in the mull of the universe, life, meaning etc
the thought crossed my mind:

   "How much of your life do you want to spend skydiving?"

Up until then it had never even occured to me that I might ever do
anything else.

I don't think I can define my relationship with skydiving.

Skratch

--------------------------------------------------------------------------------
email:  bdaniels@ssf-sys.DHL.COM 
Newsgroups: rec.skydiving
From: tjreynol@zephyr.cair.du.edu (The Jumpin Dude)
Subject: Re: First jump? Me too!
Organization: University of Denver
Date: Tue, 15 Sep 92 20:11:47 GMT

In article <5250001@hpnmdla.sr.hp.com> glenb@hpnmdla.sr.hp.com (Glen Baker) writes:
>
> Me too! Sorta. Well, actually it was on Labor Day and it was at Skydance,
> Yolo County. My girlfriend gave me a card on my birthday that said I
> had a choice of a leather jacket or an AFF jump...<grin>, took about
> 1 uS to make my choice.

this just reminds me of  the leather jump suit i'd like to get built
someday :-) i think it was Charolyn's idea to add chain grips and a spike
on the helmet ;-)

> Unfortunately I didn't even know this group existed so I hadn't read the
> FAQ. Now it seems that I'm in serious violation of a time-honored 
> tradition. Hmm, guess the only thing to do is to go back and jump again!

it's honorable to bring your beer the 2nd time ;-)

> ..glen "seen the video a million times now"
yea, i've seen all mine about a million times each too; pisses my 
roommate off
From: SKYDIVE@f15.n233.z1.fidonet.org (SKYDIVE)
Newsgroups: rec.skydiving
Subject: Re: 1 in 80000 dies.  Oh dear!
Date: 4 Sep 92 22:29:54 GMT

Reply-to: Bill.Caefer@p0.f853.n102.z1.fidonet.org (Bill Caefer)
Fido-To: romulus!leland.stanford.edu!eap

 r> ... Think I'm going back to knitting.

 r> Well, here's something another netter posted a while ago- 
 r> might make you reconsider your change to knitting, and
 r> put things in perspective:

 r> Activity       Participants    Fatalities  Rate per 100,000
 r>                                 per year    participants
 r>  All accidents   230,000,000     96,000         42
 r>  Traffic
 r>  Fatalities      162,850,000     46,000         28
 r>  Hang Gliding         25,000         10         40
 r>  SKYDIVING           110,000         28         25

Let's add this:

     Knitting        110,000,000     65,000         59

 r> It says the skydiving stats are for 1988, and it implies
 r> that the other figures are for 1989.

 r> Hope this helps!
Me too.


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From: shibuya@mailhost.bl.cad.slb.com (Hiroto Shibuya)
Newsgroups: rec.skydiving
Subject: Re: Looking for pictures of formations
Date: 14 Sep 92 05:15:22 GMT
	<SHIBUYA.92Sep9144637@chute.mailhost.bl.cad.slb.com>
	<1992Sep10.193158.15328@leland.Stanford.EDU>
Reply-To: shibuya@mailhost.bl.cad.slb.com
Organization: Schlumberger Technologies CAD/CAM Division

> Eric Perozziello writes:
> 
> shibuya@mailhost.bl.cad.slb.com writes:
> Farrell McKay writes:
>
>>   Hmmmm .... thinking a bit more about this .... simple black and

	[ deleted ]

>>   out loud here.
>
>I want to go even further.  I want to have electric representation of

	[ deleted ] 
>
> Hey, I don't see a smiley here !!!  Somebody, PLEASE say this is a joke!
> 
> Just go have fun, damnit!

Well Eric, skydiving is fun.  That's why I do it, too.  But I believe
most of the skydiver also enjoy challenges in skydive, to improve your
skill, which will lead to different kind of fun.  I had a good fun
jump a couple weeks ago, 20 way smiley face dive :) (well, you asked
for it so...) It takes relatively skilled skydivers and good planning
and dirt dives.  We couldn't just go for it with 1 minute dirt dive,
but it was fun.

This year, I joined a intermediate 4 way team and planning to compete
in U.S. National this fall.  Since the know-how of competition 4 way
skydiving is not that available in New England area, we pretty much
started in the dark, putting our heads togather over the part 55 dive
pool.  We bought 1991 National tape and studied it frame by frame.  We
made creepers and trying to learn how to creep.  Yes, occasionally we
go up and skydive, but we hire camerajumper for almost all our dives,
and study the result frame by frame.  It's a whole different skydive
for me.

There are so many thing we have to think and plan between one point
and next point.  And we can't simply copy what Knights do, but we have
to make our own skydive according to our flying skill (which is not
that great).  My latest finding is the challenge of designing exits.
Watching the National video, no team does a same exit. (it was nice
relief to know that even Knights funneled an 4 way exit at the
National) It is very individual and there are no definitive answer to
it.  It is a fine balancing of risk (funnel) and time.

I know that all these sounds way too serious for many of the
skydivers, and gets a comment such as Eric's.  But I like these
challenges and I enjoy it.  I'm having fun, seriously.  Please don't
alienate a jumper like me because I'm serious.  The most painful thing
about being on a team, for me, is that I have much less opportunity to
jump with my friends who's not in the team.  I want to jump with them
as much as I used to, but time and resources are limited.

Oh BTW, I should have put smiley after the following part.

>transitions and generate optimum dive plan. 
		 ^^^^^^^^^^^^^^^^^^^^^^^^^^ 

I knew it is not computationally feasible including all the factors
described in Jerry's description in his followup, thus, it is joke.
(ok, that my sence of humor)  Anyway, blue skies and have fun.

				Hiroto Shibuya
				D-14028
Newsgroups: rec.skydiving
From: joe@avs.com (Joe Peterson)
Subject: Re: Spotting and Ground Speed
Organization: Advanced Visual Systems Inc.
X-Newsreader: Tin 1.1 PL5
Date: Thu, 10 Sep 1992 17:37:40 GMT
X-Posted-From: hal.avs.com
X-Posted-Through: sol.ctr.columbia.edu

B}rd Kjos (baardkjo@idt.unit.no) wrote:
: Jumper #1 exits and is carried away horizontally by the wind. At 2000'
: he pulls  and  the  canopy  opens  over farmer McNasty's barn  2 miles
: downwind.  Jumper #2 exits 10 sec. after #1, he is also carried  away.
: The aircraft stood still, they exited at the same place (actually, you
: could  consider this a  base  jump  in heavy weather  conditions),they
: experienced the same wind forces and pulled at the same altitude after
: equally long free-falls.   Thus,  canopy  #2 also opens  above  farmer
: McNasy's barn.   The only separation they experience is the 10 seconds
: of canopy ride #1 has had before #2 is down at opening altitude.
: 
: One could possibly argue that #1 would be carried  away  with the wind
: under canopy,  thus avoiding collision with #2.  This  would, however,
: not be the case if the  wind decreased  to (almost) zero  at  2000', a
: situation which is not unusual. The jumpers would still experience the
: same wind forces.
: 

Ok, here I go out on a limb...

I agree with the above, but the statement that "ground speed is the
relevent factor" seems misleading.  The key factor is not air speed
or ground speed, but the difference in air speed between jump altitude
and opening altitude.  Let's take two equivalent cases (although not
realistic):  no wind at any altitude and equal wind at every altitude.
The second case is equivalent to there being no wind at all and having
the ground rush by us below.  This cannot happen due to friction with the
ground, but let's say it could.  The exit times should not matter, since
drift under canopy would "move the first group out of the way" (remember,
we are assuming the the wind at opening altitude is just as strong as
at exit).  Since we can think of this as being in still air with a fast
moving ground, that ground should have no effect until we touch down (ouch!).

Now let's take the realistic view.  On a very windy day the wind at exit
altitude is much stronger than at opening.  Because of this, even though
two groups might exit with good separation air-wise, they would converge
to a close opening position because of the lower winds down at opening
altitude.

The reason ground speed seems relevent is because the lower the ground
speed, the higher the winds aloft, and the higher (most likely) the
difference in wind speed at different altitudes.  Approaching the ground
(and hitting lower wind speeds) is transitioning from one frame of
reference (the "still air") to another (the moving ground).  This
gradual transition throws off that "good" separation up high.

Make sense?  Or did my limb break?

					Joe Peterson
					D-13839
Newsgroups: rec.skydiving
From: mark@virtech.uucp (Mark Smith)
Subject: Night jumping!
Summary: good night jumping this weekend!
Keywords: night
Reply-To: mark@vti.com
Organization: Virtual Technologies, Inc.
X-Newsreader: Tin 1.1 PL5
Date: Mon, 14 Sep 1992 10:52:35 GMT

Full moon this last weekend.  This was the best night jumping
weekend I've seen in a long time.  Clear skies, very bright moon.
Good fun!

My lighted altimeter worked great.  I docked onto a 4-way quite
nicely.  It's a totally different feeling beeing in FF in the
dark.  The wind had died down completely, and with night perception
being the way it is, it was hot landings for everybody.

Yahoo!
-- 
      /_\   Virtual                  Mark Smith          USPA D-13761
    /-~_  \    Technologies          mark@vti.com
  /      ~-_\     Incorporated       703-430-9247,   FAX 703-450-4560
/_____________\      46030 Manekin Plaza, Suite 160, Dulles, VA 20166
From: ryoder@zds-ux.UUCP (Robert Yoder)
Newsgroups: rec.skydiving
Subject: Re: 7th floor drop--Acceleration of G, minus wind resistance
Date: 14 Sep 92 11:43:00 GMT
Followup-To: poster
Organization: Zenith Data Systems



The formulas for freefall are given below:

Y  = Vt^2 * ln( cosh( g * t / Vt ))
Y' = Vt * tanh( g * t / Vt )
Y" = g / (cosh( g * t / Vt ))^2

where Y  = distance fallen
      Y' = instantaneous velocity
      Y" = instantaneous acceleration
      Vt = terminal velocity
      g  = gravitational acceleration, ( ~9.8 m/s^2 or ~32 ft/s^2)
      t  = time

The following is the first equation solved for time.  Just plug in
the freefall distance, (Y), and solve for t. 

t = Vt * acosh( exp( Y * g / Vt^2)) / g

NOTE: These formulas ASSUME constant air density.  When the equations
from which these formulas are derived, are modified to take varying
air density into account, they become transcendental and cannot be
solved.  The only recourse is then to use numerical iterative methods
such as Roger Clifton uses.

These formulas are generally adequate for our purposes, since jumpers 
normally talk about terminal velocity as being a single number, when
in fact it varies with altitude, being higher at high altitudes.  In
other words, Vt is your "average" terminal velocity.

Using a stopwatch and an altimeter, you can find your own Vt;
If you have access to a calculator with a "SOLVER" function, you can
plug your freefall time, (t), and freefall distance,
(exit altitude - opening altitude = Y), into the first equation and
solve for Vt.

For those who don't have a calculator with hyperbolic functions, check
a calculus book for the formula to convert hyperbolic functions to ones
using exponentials.

Robert Yoder  r.yoder@zds.com
(use this address, my newsfeed is uucp)
From: SKYDIVE@f15.n233.z1.fidonet.org (SKYDIVE)
Newsgroups: rec.skydiving
Subject: You may pick up your penc
Date: 6 Sep 92 07:00:00 GMT

Reply-to: RANDY.SCOTT@p0.f1205.n202.z1.fidonet.org (RANDY SCOTT)
Fido-To: romulus!hpcc01.corp.hp.co

R> Statement: One cannot fully define one's commitment to or relationship wi 
R> the sport of skydiving until one's first reserve ride.

R>  1. True or False?

R>  2. Explain your answer.

Well, I won't take 30 minutes.  Before I had my first mal at about 
200 jumps, I had concidered that we practice emergency proceedures 
more than anything else in our lives but hope to never use them.
And you'll never know for sure until it happens how you'll react. 
But those of us who do not _KNOW_ deep in their heart that they'll 
do the right thing in an emergency self select out long before that 
need arrises (hopefully).  That is why all skydivers have such big 
egos.  If we didn't have complete confidence in ourselves, this
would be a silly sport to pursue.

So, I think your statement is false - unless your first reserve
ride shows you that you _DON'T_ have what it takes for long term
survival in this sport.

 -- SPEED 1.20 #1056: Today is the last day of your life, so far.
 * SLQWiK 1.02.d #UNREGISTERED

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Newsgroups: rec.skydiving
From: nws@stout.atd.ucar.edu (Eddie Roberts (The National Weather Service))
Subject: HELP: Things to consider when buying a hand altimeter?
Organization: Atmospheric Technology Division/NCAR Boulder, CO
Date: Wed, 9 Sep 1992 16:09:38 GMT


 I am about to purchase my first piece of skydiving gear.... an
 altimeter that straps onto the back of your hand ( for some
 reason I have a hard time with the chest mounts provided at
 our DZ). Anyway are there different things to look for 
 in altimeters or are all altimeters about the same? Is there a better
 manufacturer etc. etc.?

	Thanks in Advance
		Eddie.

		e-mail  nws@stout.atd.ucar.edu

Newsgroups: rec.skydiving