Basejumper.com - archive

http://www.youtube.com/watch?v=iiTCQIo3YL0

ok so, right at 2:47 ish, you notice that the jumper starts tracking within 2-3 seconds, whereas the first jumper barely started to track after 9.........

my question is, is the second jumpers immediate track the product of exiting in a track position? if so, do you want to exit SLIGHTLY head low in a track position, or would you exit at the same belly to earth angle that you do for boxman (but just with arms and legs extended?)

http://www.basejumper.com/...ng/Tracking_799.html

If someone exits and holds perfectly level , even in a wingsuit it is possible to fall straight down the tube.

fuckin thank you, that was literally all the information i needed to know. now its just about execution............

It has to do with one´s forward speed. Presentation of one's body to the relative wind. Box man is only useful into a cave or off a bridge. It is the norm to teach students to do the box man braking position for stability but it is wayyyy overkill for an experienced track hunter. The vid shows nothing in relationship to your post. No one was going anwhere with a track.
Take care,
space

 

well i guess what i got out of this random question is that forward speed into a full track position will push you away from the exit point. we can talk all fuckin day on the internet until kingdom come, but im about to try this shit out. im about to jump an 850 foot A, and i know thats not a huge amount of altitude to track from, but im gonna exit from a solid platform up top with a good running exit..........thanks for the replies

Are you worried about cables? I just PM'ed you, hit me back.

I just wonder if this is really true?


Im not thinking about the canopy opening hard but that your airspeed.
Because when you track you get in to a (to the relative wind) head down position.
Your body will probably never be at the exact angle of the relative wind, but is it really true that your airspeed wont get higher than box?

When i skydive with a GPS the total groundspeed is much higher than stable box.

Airspeed is only one of the components that give us a "hard" opening.

The feeling that we perceive as a "hard" opening is the result of a change in motion (properly called acceleration, but generally thought of as deceleration).

If you are decelerating cleanly in a straight line (no changes of direction) then you will generally perceive an opening as "softer" than a corresponding opening that includes a change in direction (i.e. a surge backward or to the side). Because the tracking motion includes a forward component (as well as the normal downward component of the box position), an opening from a track may feel "harder" even if it happens in the same number of vertical feet and the same amount of time.

Body position is another component of the feeling we call "hard openings." If you are deploying in a head down position, you will perceive the opening as "harder" because of the change in your body's position, as compared to a flat box (or head up) position.




Groundspeed is only going to show you horizontal speed. the major component of stable box airspeed is vertical, so on your GPS it will not show as groundspeed.

Ok sorry for the confusion, what i meant as groundspeed was the my speed towards the ground.
Since the GPS logs both horizontal and vertical speed i can calculate the total speed im having towards the ground.

I know that wind is a big factor when you are tracking from an airplane, usually i get a much higher speed than box.
I just looked trough some of my GPS logs and found one jump where i had a total speed of ~200 km/h (stable box) but i know this jump was in a strong headwind.
I have one jump where my total speed was 304 km/h but that was with my old GPS and even if i trust that the number is correct, that GPS didnt work properly in high horizontal speeds.

Your fall rate is greater in a track than in a flat box position?

First you should understand the basics!

Forget about head winds and tail winds
when skydiving (A. most jump runs are
into the wind and B. a good track will be
stronger than wind dirft).

Oh and if you want to talk falling with
friends learn the terms to accurately
describe your direction of travel.

If I am 20 feet below you how do you
get to me? Arch harder, reduce your
surface area to reduce drag, this will
increase your fall rate down to earth.

When tracking you should have your
arms and legs extended, this extra
surface area slows your fall rate and
makes you move forward, this would
be horizontal movement and referred
to as your ground speed.

Sigh
No, still talking about the speed at the angle you are falling/gliding/flying

Ah. Ok. So you're recorded speed overall is faster in a track than falling straight down?

I'd believe that.

quick comment...
his profile indicates he is from Sweden.
I'm thinking that is correct.

why not assume Swedish is his native tongue and give him some slack regarding jargon?
it might not be correct, but it strikes me as the polite thing to do.

I Hate to admit it but we were
both thinking the same thing...
I sent him a PM this afternoon
and finished it with this:

I know there is a language barrier
plus a learning curve, so please do
NOT waste any effort getting upset.

And miss out on the chance to be a condescending dick. No way man!

Yes.
And thats why i asked the question in the first place.
As the statement in the article is that you wont have a higher (total) airspeed than falling straight down in stable box.

The problem i see is that there is really no good way of knowing your real speed when you are tracking as the GPS records a 'correct' vertical speed, but the horizontal speed is recorded as groundspeed.
The groundspeed is most used in groundbased travel but when you become airborn the groundspeed is more or less irrelevant.
So the GPS kind of mixes airspeed (vertical movement) and groundspeed (horizontal) with no care for wind.

The winds aloft charts that we have around here only shows ground wind and 100 altitude, but i just now looked at it and i now see there is 050 aswell, what altitude is that?
Anyway, its not detailed enough to compare with GPS data in my opinion.
So the end result of the GPS data is only half assed, unless you know what the wind was at the jump time at all altitudes.
So basicly i agree with you Tom, Fuck the gadgets
But still i wonder if the statment is correct.

About the terms, what word should be used to describe the angled velocity ( SQRT(Horizontal_Velocity^2 + Vertical_Velocity^2) )?
The most common i have seen is 3D speed, but that is not correct as you only move in two dimensions.
GlideSpeed? AngledSpeed? Total airspeed (not correct either as you have groundspeed in the horizontal level)?

Shut up and jump?

Your problems with accurately calculating
exactly your vector and velocity is nothing
new, in fact there are numerous thought
experiments used by genius guys (like
Einstein) when exploring/teaching physics.

Here are 2 quick ones:

Image you are riding in a train and playing
catching with a guy riding in another train.
You are both going 100 MPH west but the
ball is easily being caught and passed
with little effort because you, the ball,
and your buddy are ALL going 100 so
the ball going 115 is really perceived a
gentle 15 MPH - relatively.

Image you are in an elevator of a building
10 times as tall as that fucker in Dubai and
the cable releases, everything inside goes
down at the same rate, so speed relative
to the building would be different than inside.



Basically the problem is that everything in
our world is always moving, sometimes at
different speeds and sometimes the same.

In SKY jumping you leave a moving plane,
fly through moving air, deploy your chute at
different x, y, z location every jump and land
slightly different spot every time relative to
a planet that is constantly rotating. yikes.

SO you can lean towards using calculus,
gadgets, and assumptions to fly better
or you can focus on mechanics of a good
track, stretching, body conditioning, and
visualization.

Please note: my longest delay ever in BASE
was only 7 seconds so I am not an expert,
or a dick, but I am a great SKY tracker

It is not really a case of fuck the Gadgets, it is just a case of figuring out how to correctly use the data that is obtained from them.

The generalization that you made about presenting more area and thus slowing down may not always hold true. The angle at which the relative wind is striking the body when tracking is not the same as it is during box man. My tracks(skydiving) tend to be faster along the flight path than boxman.


If you hold perfectly level with the horizon with arms to the side, there will be no forward movement at all and then the fall rate will definitely be slower than box man.

Hellis,

I would guess that the author is comparing 'skydiving boxman speeds' to 'BASE tracking speeds' because unfortunately there isn't a BASE jump that affords us to simply jump and open at boxman terminal.
When wearing a modern tracking suit(or good smoking pants) and jumping from cliffs(thick air), the statement as it was made in the article may hold true almost always.

yes, there are plenty.

http://www.youtube.com/watch?v=e8kyj5zg1dY

Yeah, but they all track at the end right?. How many people simply exit not track at all and open?

I spend ~20 days in 2006 and 2007 over there and everyone tracks .

Any antenna over 1500 feet qualifies as a boxman terminal basejump, regardless of whatevers in that video link, or where you stayed for 20 days..

chinese sinkhole.........

Sure, it does.

My point was just to illustrate the not many jumps are actually done in boxman to terminal in BASE, so that may be why the author stated it that way in that article.

hey man!!
just push hard look vertically down have leg straight an shoulder push in the direction you want to go, try to ake speed and track "in the angle" no flat;
then as soon as you track try to not think about people talking shit in the forum this will not help you.
have fun and don forget to low pull it grow the racking distance!!!!!