HDTenEightyP/NetNews huggingface dataset:
From: mark@virtech.uucp (Mark Smith)
Subject: Re: HELP: Things to consider when buying a hand altimeter?
Reply-To: mark@vti.com
Organization: Virtual Technologies, Inc.
X-Newsreader: Tin 1.1 PL5
Date: Fri, 11 Sep 1992 19:31:58 GMT

traurig@ncavax.decnet.lockheed.com wrote:
: In article <BuDv80.2wE@virtech.uucp> mark@virtech.uucp (Mark Smith) writes:
: >for it (not unlike a chest mount) and then mount it on your "mud-flap."
: 
: Unique, I don't think so...seen it lot's of places.

Oh well.  Everywhere I go, I find someone staring at me and then
eventually walking over and examine it (that is the mount, not me).

: These are all of the altimeter mounting positions I've seen in regular use:
: 
: 			Chest
: 			Mud Flap
: 			Wrist/Hand
: 			Hip
: 			None!
: 
: Does anyone have any others they've seen?

I've heard of leg strap mountings.  I suppose it was with thread
through straps instead of B-12 releases.

The legends of lore tell of a race of sky beings who used a metal
bar mount connected to the chest strap facing down towards the
bellybutton and mounted their altimeter there (thus avoiding the
"ouch! my altimeter just bounced up during opening shock and split
my lip" syndrome).

: -in-the-goggle readout, but I love electronic toys, although I haven't
: purchased a digital altimeter yet.

That new digital altimeter with the lcd display seems like it might
be hard to read in the sunlight.  Does anyone out there have one?
and is it difficult to read under certain conditions?
-- 
      /_\   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
Newsgroups: rec.skydiving
From: geer@world.std.com (Dan Geer)
Subject: Re: Computerized LogBook
Organization: The World Public Access UNIX, Brookline, MA
Date: Wed, 16 Sep 1992 01:02:13 GMT

In article <1992Sep9.203938.27562@zia.aoc.nrao.edu>
	dbriggs@zia.aoc.nrao.edu (Daniel Briggs) writes:
> ...
>Of course, for a real electronic log book, there are all sorts of stuff
>that you'd like to record.  &c, &c, &c

actually, the real electronic log book
is the one that goes with you on the
jump...  something like that Sharp Wizard
gizmo that seems to have replaced everything
except the desk chair for lots of folks.

--dan


Newsgroups: rec.skydiving
From: jcwasik@srv.PacBell.COM (Joe Wasik)
Subject: Re: sinus pressure
Organization: Pacific * Bell
Date: Mon, 14 Sep 1992 19:43:46 GMT

In article <1992Sep14.163316.15822@mercury.cair.du.edu> tjreynol@zephyr.cair.du.edu (The Jumpin Dude) writes:
>last thursday i got something of a cold, and was pretty congested 
>on saturday when i went jumpin; my first freefall was pure agony
>by 6,000', i thought my head was going to explode. something
>seems to have. i took some decongestant stuff (suphedrine?)
>and things were fine after that. then sunday, i took more pills
>before making a jump; after each jump, i had a mild pressure
>that i had thought due to my taking the foam thing off of my 
>over-the-glasses Kroops, but i started spitting a bit of blood
>and on my third jump, i had blood running up my goggles :-(
>this ever happened to anyone else? 

Actually, I think your head would have *imploded* :-)  But seriously, don't
do this.  You may have already damaged your eardrums beyond their ability to
heal.  If you must jump when congested, use the 12-hour spray variety. 

-- 
Joe Wasik, Pacific Bell, San Ramon, CA (510)823-2422, jcwasik@pacbell.com
Newsgroups: rec.skydiving
From: tjreynol@zephyr.cair.du.edu (The Jumpin Dude)
Subject: more thumb twiddling
Organization: University of Denver
Date: Tue, 15 Sep 92 19:40:37 GMT

I called JJ today... the Lost Prairie Video isn't expected for 
another couple of weeks yet :-/

it's still $25.


I forgot to ask about the Convention Video, but you can guess.


tim
From: glenb@hpnmdla.sr.hp.com (Glen Baker)
Newsgroups: rec.skydiving
Subject: First jump? Me too!
Date: 15 Sep 92 15:46:19 GMT
Organization: What, me? Organized?


 
 6500fly@ucsbuxa.ucsb.edu (Carmen Mullenhoff) writes:

> I went for my first skydive out at Lodi, CA on Sunday.

 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.

 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!

 ..glen "seen the video a million times now"
From: bchurch@oucsace.cs.ohiou.edu (Robert Church)
Newsgroups: rec.skydiving
Subject: Re: dreams
Date: 8 Sep 92 20:27:47 GMT
Organization: Ohio University School of Art. Athens

The Jumpin Dude (tjreynol@zephyr.cair.du.edu) wrote:
> then the dream faded away, like it was on video tape. i woke up screaming
> IS IT DEATH, OR IS IT MEMOREX?? (not really;-) this was the first time
> i never pulled out of the problem at the last minute; but i've still not
> gone in in a dream.
> i have dreamed of about 8 people from my DZ going in :-(

These dreams are brought on by the unconscious mind which is often aware of
things that the 'conscious' mind blocks out. In this case, your brain is trying
to tell you that you're not buying your share of beer.


-- 
*********************************************
*    bob church                             *
*    bchurch@oucsace.cs.ohiou.edu           *
*    D-8195 NFS #27                         *
Newsgroups: rec.skydiving
From: tjreynol@zephyr.cair.du.edu (The Jumpin Dude)
Subject: relative play stuff
Organization: University of Denver
Date: Mon, 14 Sep 92 17:03:47 GMT

Jan and I have been trying to front loop a cat, and we just cannot
get it all the way over. on our best attempt, yesterday, I took his
legstraps on exit and got my chin right on his main pin flap, then 
we tracked off and Jan does the worst front - oh, wait, he was barrel
rolling it, yea he _Barrel Rolled_ the cat, then we tracked some more
Jan dove, I went over and under, but just when it seems like we going 
to get it, we funnel all over. this is a lot of fun, but we sure would
appreciate any tips on how to complete the loop. 

another fun thing we've done we call a Dose E. Doe (sp?) where we track 
at each other head on and knock the shi, nonono we take elbow grips and then
both track to generate a spin; we discovered we can go *WAY FASTER* and hold
on much longer if we take harness grips bye the hips. Jan tried to barrel
roll this too :-) when we couldn't hold on any longer, I flung off into 
4 360s, and was incredibly dizzy. i knew i had a heading on the runway
but it sure felt like i was still spinnning violently. I wouldn't try 
this at the bottom of a dive. this would make an interesting rodeo dive.

anyway, i had a great weekend, except for the headaches and blood
From: dbriggs@zia.aoc.nrao.edu (Daniel Briggs)
Newsgroups: rec.skydiving
Subject: Re: how often does this happen?
Date: 8 Sep 92 15:22:57 GMT
Organization: National Radio Astronomy Observatory, Socorro NM

In article <810.2AACA79B@ehsnet.fidonet.org>
  SKYDIVE@f15.n233.z1.fidonet.org (SKYDIVE) writes:
>Reply-to: Bill.Caefer@p0.f853.n102.z1.fidonet.org (Bill Caefer)
>Fido-To: romulus!cd.amdahl.com!drp40
>
>[good reasons for 2 handled cutaway systems]

Don't forget about jumping on windy days, too.  An SOS system can be a real
*drag*, if cutting away your main immediately dumps your reserve.  I
usually leave my RSL engaged while jumping, even on windy days, then
disable it while under canopy.  I'm balancing the odds of forgetting this
against maybe needing it in freefall, but I think it's a net win.  (And
yes, I've remembered to do this while setting up for final!)

-- 
| Daniel Briggs  (dbriggs@nrao.edu)                      |        USPA B-14993
| New Mexico Tech / National Radio Astronomy Observatory |            DoD #387
| P.O. Box O / Socorro, NM 87801   (505) 835-7391        |
Support the League for Programming Freedom  (info from league@prep.ai.mit.edu)
Newsgroups: rec.skydiving
From: porman@fenix.encore.com (Paul Orman)
Subject: Re: You may pick up your pencils...
Organization: Encore Computer Corporation
Date: Thu, 10 Sep 1992 19:21:26 GMT

In article <4190012@hpcc01.corp.hp.com>, boucher@hpcc01.corp.hp.com (Richard A 
Boucher Jr) writes:
|> 
|> 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.
|> 
|> -RB

Absolutely false.  When I started skydiving 6 years ago, I did two tandem jumps
(the DZ called them ACC - Accelerated Canopy Control) and then my AFF level I.
On AFF-I (ie 3rd jump) I had a reserve ride.  I've never had one since.  If I
had never had the reserve ride - I would have definately continued skydiving.
Even though I did have the reserve ride I already knew I would continue.  As a
matter of fact I *knew* I would continue, after my first jump.  No matter what
happened.

This isn't quite relevant, but its the same type of logic that we see when
someone says they can not *really* define their commitment to a marriage until
after they've lived with the other individual for awhile.  If we extend this
to enough areas of life, one day we'll be able to walk into stores and take a
product home and pay for it after a few years worth of use.  After we've had
a chance to determine if we're really committed to it or not.
-- 
................................................................................
Paul Orman - porman@encore.com         |  I don't know enough to speak for
ENCORE Computer Corporation            |  myself, let alone my employer.
Ft Lauderdale, FL (305) 587-2900       |
From: jerrys@umiacs.umd.edu (Jerry Sobieski)
Newsgroups: rec.skydiving
Subject: Re: dreams
Date: 11 Sep 92 18:39:27 GMT
Organization: UMIACS, University of Maryland, College Park, MD 20742

In article <6730166@hplsla.hp.com> artb@hplsla.hp.com (Art Bori) writes:
>As long as we're talking about dreams, here's one of mine.       
...
>I hit the ground and bounce up and down 
>like a basketball.  I stop bouncing after 4 or 5 times and I'm uninjured.
>I'm just really embarrassed and afraid that the DZ owner will ground
>me for not pulling.  I quickly get to my feet, dump my main, wad it up 
>like I just landed, and try to act as if nothing happened.
>
>Blue skies,
>Art Bori
>D-11402

A twisted mind is a terrible thing to waste:-)

Jerry

-- 
Domain: jerrys@umiacs.umd.edu		    Jerry Sobieski
  UUCP:	uunet!mimsy!jerrys		University of Maryland
 Phone:	(301)405-6735		Institute for Advanced Computer Studies
 					College Park, Md 20742
Newsgroups: rec.skydiving
From: tjreynol@zephyr.cair.du.edu (The Jumpin Dude)
Subject: Re: dreams
Summary: dream descriptions follow
Keywords: hit 'n' if you don't wanna read 'em...
Organization: University of Denver
Date: Sat, 5 Sep 92 16:02:58 GMT

In article <4015@keele.keele.ac.uk> csa18@seq1.keele.ac.uk (R.J. Husmo) writes:
>In article <1992Sep4.012837.11267@mercury.cair.du.edu>, tjreynol@zephyr.cair.du.edu (The Jumpin Dude) writes:
>> Richard's article finally got me; I've had about 10 skydiving nightmares.
>> anyone else?

make that 12 :-/

>No. I haven't had any skydiving nightmares. On the contrary. Know those
>Freudian nightmares where you fall without control? And keep falling and 
>falling? (They've probably got some sexual connotation or other, but
>never mind that for now!) Those nightmares have changed slightly for me
>since I started skydiving - I now fall _with_ control. Complete control.
>I've even started to look forward to those 'nightmares!' :-)

mine changed too; now i have dreams where i launch my body straight up
into the air, up and up and up, using some vague partof my psyche to defy
gravity; but i inevitably realize that i shouldn't be able to do this, and
then i fall - and wake immediately.

>Unfortunately I usually cannot remember my dreams. :-(

i got a badgrade in Psych class because i was completely unable to remember 
any of my dreams; i remember all the skyiving ones vividly. the other
night i dreamed that one of the local riggers was an undertaker. he won't
be packing MY reserve. just this morning i dreamed (once again) that i had
a pilot chute in tow. this one is recurring, and i may be motivated to check
out the pullout system. anywy, on this one, i was flying as if i had an 
inflated canopy, but i was trying desperately to get my main out, which i did
but it wouldn't inflate. now you know those dreams where your legs are weak
and you cannot run from the horror whatever it is? in this dream i couldn't 
pull my cutaway; i finally got it out, and pulled and pulled on my reserve
handle and went into a perfect arch waiting for my reserve to deploy, and
then the dream faded away, like it was on video tape. i woke up screaming
IS IT DEATH, OR IS IT MEMOREX?? (not really;-) this was the first time
i never pulled out of the problem at the last minute; but i've still not
gone in in a dream.
i have dreamed of about 8 people from my DZ going in :-(

>Radar
>--
>Semper in fecalum, solus altam variat

what does that mean, something about only altitude varying?
tim
Newsgroups: rec.skydiving
From: bisc@zellweger.ch (Thomas K. Bischoff)
Subject: Re: Computerized LogBook
Reply-To: bisc@zellweger.CH (Thomas K. Bischoff)
Organization: Zellweger Uster AG, Switzerland
Date: Fri, 11 Sep 92 17:51:13 GMT

In article <BuC6vn.BqM@virtech.uucp> mark@vti.com writes:
>Daniel Briggs (dbriggs@zia.aoc.nrao.edu) wrote:
>: In article <BuBpHK.28I@virtech.uucp>
>:   mark@vti.com writes:
 
 [ logbook stuff deleted]
 
>As long as we're talking about computers and skydiving... I know of
>one dz which has a computerized interface to the manifester.  There
>is no paper involved.  A jumper at Gardner NY exchanged jumps for
>a complex program to handle everything.  And that's what they use
>right now.  Are there any other computerized systems out there?

Pink Boogie in europe uses a computerized manifest. The use machine
readable id-cards ( like credit cards) for every skydiver.

-- 
Thomas K. Bischoff    Net: bit@ten.ch,bisc@zellweger.ch 
***** Minds, like parachutes, only function when open.

Newsgroups: rec.skydiving
From: tjreynol@zephyr.cair.du.edu (The Jumpin Dude)
Subject: Re: You may pick up your pencils...
Organization: University of Denver
Date: Wed, 9 Sep 92 16:20:58 GMT

In article <1992Sep08.222018.17214@gateway.ssf-sys.DHL.COM> bdaniels@ssf-sys.DHL.COM (Ben Daniels) writes:
>
>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.

the story of Jim's death is printed in United We Fall; I've read it 
about a hundred times, and I about cried everey time )-;
the author of the story, who watched it from under his PC 
pretty much sums up the way I feel about living (jumping)
and dying (not jumping) and death (whatever). more recommended
reading.

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

now 1701 would indicate a hard disk or controller failure; funny
how - ah, never mind...

>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 started asking myself that question shortly after i started jumping;
the answer is becoming clearer with every day that i cannot make a jump -
pick a guess, any guess :-)

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

i don't even try; i'd rather drink, fuck, and skydive. don't have to 
think so much :-)


>Skratch
>
>--------------------------------------------------------------------------------
>email:  bdaniels@ssf-sys.DHL.COM 

tim
From: bob@pta.pyramid.com.au (Robert Vernon)
Newsgroups: rec.skydiving
Subject: Re: How to calculate freefall time ?
Date: 8 Sep 92 23:18:40 GMT
Organization: Pyramid Technology Corporation, Sydney

In article <1992Sep8.175625.24581@ncar.ucar.edu> nws@stout.atd.ucar.edu (Eddie Roberts (The National Weather Service)) writes:
>
>Can someone post the correct formula to use in calculating
>freefall time. In a recent post the following 'C' code
>was used:

I always use 12 seconds for the first 1500' and 6 secs per 1000' after
that.  This matches the tables that were worked out many many years
ago.  With a normal opening height of 2500' the table looks like :

     Exit Height    FF-time (secs)
         4000           12
         5000           18
         6000           24
         7000           30
         8000           36
         9000           42
        10000           48
        11000           54
        12000           60

>>      if (jump_altitude > standard_opening_altitude)
>>      	ff_time += (jump_altitude - standard_opening_altitude)/200 + 5;
>
>If I exit at 10,000 ft. and pulled at 4000 ft. I should get 35 seconds of
>freefall time right? (10000 - 4000)/200 = 30 + 5 = 35.

By my reckoning you get 39 seconds.  Call it 40.

>Yet on my log book completed by a AFF JM I have 45 seconds of freefall
>time for this type of jump.

Maybe you are a slow faller :-)

>                            Our class was told that if we multiply 
>(jump_altitude - opening_altitude) by seven and add 3 we would get
>our correct freefall time.

Not exactly correct.  But an easy estimate.  As all these methods are.
The tables I use were worked out back in the real early days of jumping
when people had nothing better to do than jump out with stopwatches.
People fall faster these days or do they fall slower.  They certainly
fall faster than when I started mostly because of the switch from big
jumpsuits to slick suits.

You would think in this age of accurate timers on video cameras,
someone would work out an accurate algorithm.  But everytime someone
does, someone else disagrees with it.  Oh well.

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

If Roger Clifton is still around (haven't seen him post for a while),
he could give a very accurate graph of your freefall time, based on
your weight, height, surface area, the temperature and pressure of
the air, the angle of your body and probably numerous other factors.
Just how accurate do you want it.

So make it up like everyone else does.  Use any of the methods above
and use it consistently but remember they are only estimates.  You
probably don't exit at exactly 10000' and you probably don't open at
exactly 4000'.  Somedays you fall faster than others depending on the
type of maneuver you are doing.  And if you spend half the jump in a
funnel, then you've probably blown 20 seconds worth.


>		Eddie 	

Bob V!
From: ryoder@zds-ux.UUCP (Robert Yoder)
Newsgroups: rec.skydiving
Subject: Re: 7th floor drop--Acceleration of G, minus wind resistance
Date: 15 Sep 92 01:20:47 GMT
Organization: Zenith Data Systems

In article <190l08INNdsa@bigboote.WPI.EDU>, megazone@penny.WPI.EDU (MegaZone23) writes:
[text deleted]

> Velocity(t)=velocity(initial)+acceleration(9.8m/sec^2)*time(in seconds)-
>   (Cd(coeff. of drag)*surface area*density air*vel.^2)/(2*grav. const. 9.8))

This equation is incorrect.  Converting each term to units yields:

m/s = m/s + m/s - kg


By definition:  drag force = Cd * p * A * v^2 / 2
Where: Cd = coefficient of drag
       p  = air density
       A  = area
       v  = velocity

Since:
force = mass * acceleration

Therefore:
acceleration due to drag = Cd * p * A * v^2 / (2 * m)
Where: m = mass of object

net acceleration of object = acceleration due to gravity
                             - acceleration due to drag
Or:
dv/dt = g - Cd * p * A * v^2 / (2 * m)
Where g = acceleration of gravity

Solving this differential equation gives the equation for
velocity in my previous posting.  Taking the integral and
derivative gives the other two.

Now at terminal velocity, net acceleration is 0, so:
0 = g - Cd * p * A * Vt^2 / (2 * m)
Where: Vt = terminal velocity

Therefore:
Vt = sqrt(2 * g * m / (Cd * p * A))

---------------------------------------------------------
Robert Yoder  r.yoder@zds.com

Newsgroups: rec.skydiving
From: baardkjo@idt.unit.no (B}rd Kjos)
Subject: Re: Spotting and Ground Speed
Reply-To: baardkjo@idt.unit.no
Organization: Div. of CS & Telematics, Norwegian Institute of Technology
Date: Wed, 9 Sep 92 09:41:48 GMT

In article <1992Sep9.020400.12349@mercury.cair.du.edu>, jvilhube@diana.cair.du.edu  (Jan  Vilhuber)  writes:  
|>  In   article <6730163@hplsla.hp.com> artb@hplsla.hp.com (Art Bori)
writes:
|> >same relative  horizontal separation.  Other  jumpers I talked to
argue
|> >that *ground* speed is irrelevant.  
|> >What I  wanted to ask was: 1) Do  you  agree  or  disagree  and why?  
|> >			    2) What (other)  factors  do  you consider when  
|> >                           multiple groups exit?  
|> > 
|> Ground speed would indeed seem to  be irrelevant. The  wind, after all. is 
|> what  carries the jumpers away from the  aircraft. The  plane could be  standing  

Consider  a little  further  the "extreme"  situation where  the  plane
stands still due to very high winds:

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.

Conclusion: Ground speed is relevant, air speed is not. Ensure proper
exit spacing in heavy winds! (And get the hell out of the plane in
zero wind conditions! :-) 

--
Baard, D-555

=============================================================================
| Baard Kjos                                 | Phone: +47 7 593470          |
| Division of Computer Science and Telematics| Fax:   +47 7 594466          |
| The Norwegian Institute of Technology      | Email: baardkjo@idt.unit.no  |
| N-7034  Trondheim                          |                              |
| NORWAY                                     |                              |
=============================================================================