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go n throw altitude loss
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pedrooliv

Jan 3, 2018, 3:17 PM
Post #1 of 26 (4985 views)
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go n throw altitude loss Can't Post

hello everyoneSmile so i was thinking about this, and i know that it varies greatly with the gear used, its configuration, among other factors.. but lets imagine someone with 170lbs, a 260 unvented canopy, standard 9 foot bridle and 46pc.. how much altitude would it be from jumping the object and throwing the pilot chute to bottom skin expansion of the canopy? something like 25m?(82ft) let me know your experienceSmile thanks

Skez

Jan 3, 2018, 7:53 PM
Post #2 of 26 (4927 views)
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Re: [pedrooliv] go n throw altitude loss [In reply to] Can't Post

to many variables... but im sure somone who jumps low shit will have more of an idea,,, but the actual throw of the pc itself would make big difference on how u do it..plus the way its packed in your hand like all bunched up tight zp and mesh folded and others leave the zp out etc....dwain weston wrote alot about it i think its on this site somewhere he did alot of stupidly low freefall...lower then most are ever willing to go

maretus

Jan 3, 2018, 10:36 PM
Post #3 of 26 (4895 views)
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Re: [Skez] go n throw altitude loss [In reply to] Can't Post

Skez wrote:
to many variables... but im sure somone who jumps low shit will have more of an idea,,, but the actual throw of the pc itself would make big difference on how u do it..plus the way its packed in your hand like all bunched up tight zp and mesh folded and others leave the zp out etc....dwain weston wrote alot about it i think its on this site somewhere he did alot of stupidly low freefall...lower then most are ever willing to go

I agree that there are so many variables that its impossible to give one figure and say its always going to work so. Add air density, wind etc to the equation as well. Dwains shit was quite advanced and Greeny did some pretty out there shit as well in the low FF area and wrote quite a lot about it to these forums but I think the OP was not asking about how low CAN you go but more like general feeling on standard technique and standard gear (not any advanced techniques with customized gear). Freefalling from 60m I guess can be said is pretty much standard issue and I know lot of people have gone go and throw from 50m with still quite good amount of canopy time. So taking from those I guess you could say that with standard technique and gear you should in AVERAGE have a bottom skin expansion in say 30m. This however does not mean that you should start FFing 35m as, like stated above, there are too many variables around which will impact the height loss significantly. Personally, Ive freefalled 59m to a concrete landing but wouldnt do it now as Im not that current on that shit. Currently I have my absolute lowest hard deck on FF at 60m and my comfort zone starts probably somewhere around 70-80m.

pedrooliv

Jan 4, 2018, 2:59 AM
Post #4 of 26 (4835 views)
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Re: [Skez] go n throw altitude loss [In reply to] Can't Post

so true.. the one that did the worst for me was having the pc in my hand folded the same way like it was in a boc. in the video it was pretty clear that the pc had much more dificulty to do its work. i cant tell yet the diference between holding the whole pc s folded and holding only the mesh.. it seems that holding the whole thing s folded helps the pc reach bridle strech much faster after you throw it, but then it has to inflate still. maybe at this point there are chances for small hesitations? when using the mesh only, the pc is already kinda pre inflated.. but its hard to make it go to bridle strech right away, it seems the jumper has to fall for a bit and let the air take the pcSmile
i heard he jumped something like 100ft over hard ground..Crazy 52 pc, 6 ft bridle, oiled and primed pins and the pc was preinflated and thrown upwards on exit.. but this is just a storyLaughLaugh

GreenMachine

Jan 4, 2018, 5:11 AM
Post #5 of 26 (4795 views)
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Air Density [In reply to] Can't Post

In my experience, most jumpers do not understand

How important field elevation and temperature Are.

pedrooliv

Jan 4, 2018, 5:46 AM
Post #6 of 26 (4779 views)
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Re: [GreenMachine] Air Density [In reply to] Can't Post

you mean because of the air density diference? i never thought much of it either.. do you think there would be a noticeable change from lets say florida (thats where your from rightSmile) and twin falls?

GreenMachine

Jan 4, 2018, 5:59 AM
Post #7 of 26 (4773 views)
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Re: [pedrooliv] Air Density [In reply to] Can't Post

Neuwanda Tower 16 feet MSL
Quincy 2J9 Airport 222 feet MSL
Twin Falls TWF Airport 4,153 feet MSL
Moab Canyonlands Field CNY Airport 4,555 feet MSL

YES, the difference is noticeable between locations.
YES, the same place Winter vs. Summer is noticeable.

Skez

Jan 4, 2018, 8:12 AM
Post #8 of 26 (4729 views)
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Re: [GreenMachine] Air Density [In reply to] Can't Post

Negligible if that ...the pc size, technique of the throw and all that other shit will make most difference . if I need to worry about if its spring fall winter or what the barometer is doing then fuck that shit Im out...unless u rolling Mount Everest etc then well


(This post was edited by Skez on Jan 4, 2018, 8:14 AM)

pedrooliv

Jan 5, 2018, 2:03 AM
Post #9 of 26 (4554 views)
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Re: [Skez] Air Density [In reply to] Can't Post

Deployment timings aside.. now that you mention mount Everest, that reminds me of a video of some Russian friends who went to great trango tower (after the Australians) and it really took them forever to finally have some air to work with.. they were using tracksuits and had to "swim" for an unusual long time until at last they started moving forwardTongue

Skez

Jan 5, 2018, 2:37 AM
Post #10 of 26 (4549 views)
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Re: [pedrooliv] Air Density [In reply to] Can't Post

Yeh I think helicopters etc have a hard time there

Heat

Jan 5, 2018, 6:45 AM
Post #11 of 26 (4503 views)
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Re: [pedrooliv] Air Density [In reply to] Can't Post

But is it air density or poor exit performance and lack og skill during recovery and freefall? Vince and Fred cerrainly had no problem freeflying from 33.000 ft.

https://m.youtube.com/watch?v=me6BgmeTH3k

epibase

Jan 5, 2018, 8:10 AM
Post #12 of 26 (4476 views)
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Re: [Heat] Air Density [In reply to] Can't Post

Airspeed...
The airspeed after exiting a moving aircraft is highly beneficial to stabilizing oneself in freefall.

Exiting an object requires the time to build up that airspeed.

I for one have certainly noticed that it takes much longer to get my wingsuit flying after exiting at 4000M than it does when exiting at 2000M.

I can only imagine that exits above 6000M would take more...


They did tumble a lot in that original Trango jump though...

jakee

Jan 5, 2018, 12:09 PM
Post #13 of 26 (4406 views)
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Re: [Heat] Air Density [In reply to] Can't Post

Heat wrote:
But is it air density or poor exit performance and lack og skill during recovery and freefall? Vince and Fred cerrainly had no problem freeflying from 33.000 ft.
That's a skydiving video.

Exit speed (TAS) is muchly higher from the same 'plane at 33,000ft vs 12,000ft or 5,000ft. That's where the control comes from in thin air.

Exit speed is identical (duh) from a 20,000ft cliff vs a 5,000ft cliff or a 500ft bridge. That's where the lack of control comes from in thin air, and why exit performance sucks.

(Not to say that Fred and Vince wouldn't make a super high altitude BASE exit look like butter. Those guys are basically wizards at this point, right?)

Heat

Jan 5, 2018, 1:11 PM
Post #14 of 26 (4375 views)
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Re: [jakee] Air Density [In reply to] Can't Post

Still, Valery managed to do many smooth and controlled exits with fast starts at high altitudes. So Im not entirely sold on the thin air explanation altogether. Its a factor for sure, but I really do believe that excellent skills can make up for the thinner air and what not.
Not to take away from any such jump by anyone though, its an incredible feat to pull of something like that :)

try2live

Jan 5, 2018, 11:34 PM
Post #15 of 26 (4295 views)
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Re: [pedrooliv] go n throw altitude loss [In reply to] Can't Post

There was an object I used to jump all the time with a platform 130' below exit. We would frequently stand there and watch people jump. It was a 252' power tower that we would free fall constantly. plus or minus ~10 ft we would see openings at around 130' with go and throws. This is not scientific, but just what I personally saw with my own eyes ~40 times. Go and throw is about 130' before opening

jakee

Jan 5, 2018, 11:56 PM
Post #16 of 26 (4286 views)
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Re: [Heat] Air Density [In reply to] Can't Post

Heat wrote:
Still, Valery managed to do many smooth and controlled exits with fast starts at high altitudes.
Until (to be blunt) one of them killed him.

The added time and difficulty of recovering from a less than perfect launch at those higher altitudes could easily have been a factor.

Heat

Jan 6, 2018, 12:09 AM
Post #17 of 26 (4278 views)
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Re: [jakee] Air Density [In reply to] Can't Post

That was a botched exit at an unforgiving short start with a ledge. That will kill you at any air density. My point being: people have bad swimming and tumbling exits at Kjerag too, freefalling half the wall before regaining stabilityTongue The Meru Peak jump is a perfect example imo: an unstable exit, not caused by low air density but by sloppy exit technique. You see plenty of poor exits like that all the time at lesser altitudes...

pedrooliv

Jan 6, 2018, 2:27 AM
Post #18 of 26 (4263 views)
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Re: [Heat] Air Density [In reply to] Can't Post

Heat wrote:
That was a botched exit at an unforgiving short start with a ledge. That will kill you at any air density. My point being: people have bad swimming and tumbling exits at Kjerag too, freefalling half the wall before regaining stabilityTongue The Meru Peak jump is a perfect example imo: an unstable exit, not caused by low air density but by sloppy exit technique. You see plenty of poor exits like that all the time at lesser altitudes...
exactlySmile

pedrooliv

Jan 6, 2018, 2:35 AM
Post #19 of 26 (4256 views)
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Re: [try2live] go n throw altitude loss [In reply to] Can't Post

try2live wrote:
There was an object I used to jump all the time with a platform 130' below exit. We would frequently stand there and watch people jump. It was a 252' power tower that we would free fall constantly. plus or minus ~10 ft we would see openings at around 130' with go and throws. This is not scientific, but just what I personally saw with my own eyes ~40 times. Go and throw is about 130' before opening
thats a great way to see it... really interesting. adam savage said that the diference between screwing arround and science is writting it downLaugh so your not too far..Winklol.. but yea with some cameras, slomo and all you would be able to see it pretty clearly. your observation matches that of previews posters and what other people have been telling me.. so 100/130 ft thats where the magic happensSmile

jakee

Jan 6, 2018, 1:54 PM
Post #20 of 26 (4162 views)
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Re: [Heat] Air Density [In reply to] Can't Post

Heat wrote:
That was a botched exit at an unforgiving short start with a ledge. That will kill you at any air density.
Depends how botched it is. With less air to work with not only will the good start be longer, the recovery from a botched exit will be not just proportionally longer but actually significantly worse again - having to wait longer for usable airflow means that the same unwanted rotational velocity off the exit will put you further off axis before you can even start the recovery.

An exit that might be nearly OK at close to sea level could look pretty sketchy at higher altitude, and as an extreme example an exit that's pretty crap at near sea level might be completely unrecoverable without a tumble at high altitude.

sjtravjr

Jan 7, 2018, 3:17 PM
Post #21 of 26 (3981 views)
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Re: [pedrooliv] go n throw altitude loss [In reply to] Can't Post

I've been jumping with a Flysight lately to figure out the same thing. I'm jumping an OSP 265 LW loaded at .69 with a 48'' Toxic. I'm folding my PC like I would stow it but I'm going handheld and I'm taking 1 second delays. The exit point is 300' and I'm usually underneath a fully inflated canopy at 170'-180'. I'm going to start jumping with my PC almost fully exposed just holding on to some mesh and bridle to see if it makes a noticeable difference. I've jumped that way before on lower objects and I think it does.

So there's one guys experience with a little bit of tech help.

hjumper33
Moderator
Jan 7, 2018, 10:27 PM
Post #22 of 26 (3918 views)
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Re: [sjtravjr] go n throw altitude loss [In reply to] Can't Post

I used to regularly freefall a 200ft power tower. Id say I was open around 130 every time. Usual canopy time around 8 seconds. Felt pretty much the same on a variety of vented canopies. 46 in pilot chute, AV.

sjtravjr

Jan 8, 2018, 3:47 AM
Post #23 of 26 (3792 views)
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Re: [hjumper33] go n throw altitude loss [In reply to] Can't Post

Damn that's quick. Im curious to see what the flysight picks up when I start changing the deployment time/methods. If I can get below 100ft or 70-80 feet like you're saying that would be sweet.

I can't imagine there are to many things to make it happen quicker but do you mind sharing what you do when free falling that low?

hjumper33
Moderator
Jan 10, 2018, 6:43 AM
Post #24 of 26 (3448 views)
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Re: [sjtravjr] go n throw altitude loss [In reply to] Can't Post

Nothing much special. Handheld, throwing the pilot chute slightly up and forward. Open flap, pins primed to about half. Its not uncommon to freefall 200ft and even a bit below, which makes me think your 170
Ft estimate might be a bit high. Theres a cliff in SoCal thats around 180 that gets freefallen not infrequently.

pedrooliv

Jan 13, 2018, 1:40 PM
Post #25 of 26 (2908 views)
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Re: [sjtravjr] go n throw altitude loss [In reply to] Can't Post

sjtravjr wrote:
I've been jumping with a Flysight lately to figure out the same thing. I'm jumping an OSP 265 LW loaded at .69 with a 48'' Toxic. I'm folding my PC like I would stow it but I'm going handheld and I'm taking 1 second delays. The exit point is 300' and I'm usually underneath a fully inflated canopy at 170'-180'. I'm going to start jumping with my PC almost fully exposed just holding on to some mesh and bridle to see if it makes a noticeable difference. I've jumped that way before on lower objects and I think it does.

So there's one guys experience with a little bit of tech help.

nice... now we're getting all like proper scientificSmile i would like to take a look at all the data from your flysightWink let us know how the experimentation goes! which technique does what in terms of altitude and all... thanks!Smile

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