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Hey guys,

Starting to try and calculate my own jumps and get my head around all the factors.

One thing I'm having difficulty finding information on is delay, PC and height used for opening.

Ie. If I use a 48 with a 1 second delay, how much height will it take from throw to canopy inflation?

I'd imagine canopy size/vents etc would play a part in this as well...?

Is there any charts out there that give an indication on pc, delay opening height comparison?

I've seen the APEX one that looks at height, delay, pc, slider etc but it doesn't give an indication on what heights it takes to open.

I hope this question makes sense.

Any info would be rad!

FYI: I'm jumping an unvented Troll 225, soon to have 5 vents retrofitted.


Edited to add: The reason i want to know this is to calculate whether I have enough height to make it to the landing area safely. It's 300ft jump but there's obstacles and the landing area is a short distance away. Knowing what height I'll be open at will help me work out whether I can make it there and if I would still make it there after a 180, pc hesi etc.

You would be hard pressed to find any usable statistics. Variables are infinite.

If you're worried to make the LZ, PCA it first and work up from there. If it is a one-off kind of jump, simulate and record data on a known object . Use that experience to translate a workable formula and even then add Murphy's, Amera's, Hofstadter's and most importantly Cunningham's law. Numbers are difficult in BASE. Everyone does everything a little different.

I like this idea!

How would you suggest actually calculating opening height on the test jump? Video from the ground and estimate? Any other techniques that I don't know about?

He may be talking about doing a bunch of jumps from a known object with different configurations and delays and record how far you can fly with each. You then have an idea of how far you may get.
If you really are looking to get the opening height on given delay/config you could try having a friend shoot the canopy with a laser rangefinder from directly above or below as soon as you open. Never tried it but it may work.

Experience and mental notes.

You could always try a static line first and if you have plenty of height/time FF it next time.

Or send someone else off first. If they make it FF it, if not, tie off.

Laters

What did you learn in your FJC?

Collapsible 29".

That will be $20

There are a lot of variables. There isn't a good table or chart for these things. Opening height with the same canopy, PC size, and delay will change quite a bit depending on wind (and lots of other really small factors).

Putting this all to the side and assuming the EXACT same wind conditions, PC, canopy, exit weight, etc...there are still two huge factors:

Opening heading and the way you take your canopy into flight from brakes. The question shouldn't be just whether or not you can make the LZ imo. If you had a 90 or a 120 off-heading, how sure are you that you could turn it (with toggles) in a way that minimizes your sink rate and gets you, most efficiently, into full flight toward the LZ? After correcting for the off-heading, can you still make the LZ? If you can't make the LZ, what are your outs and how sure are you in your canopy skills, experience, and currency to calmly decide to take the out and put it down safe?

Just based off some previous posts, I think you're a new jumper right? I was in a similar boat and scouted/jumped a lot of new objects soon after my FJC. Later when I came back I was wondering what the hell I was thinking on a couple of them. They were most definitely jumpable and 9 times outta 10 they'd be a cake walk...but 9 outta 10 are shitty odds in BASE so make sure that if you find yourself in that 1 outta 10 you have a plan and have covered all the angles of what can go wrong. Take your time when analyzing new objects and start VERY conservatively. There were some times where I went to a similar sized freestander in an open field and measured out LZ size and distance to practice. Sometimes maybe it's better to keep an object in the back of your mind while you jump a lot of other objects for fun, currency, experience, and training for a jump that you think might just be a little outside your comfort or skill/experience area.

Good luck!

Absolutely. I'm not planning on jumping this object for a long time!

I really love talking it through though... I'm a huge believer in practicing and learning for myself and not just believing what other people say... I know I could get an experienced friend look at the jump and say "yea it's totally doable, you can go hand held and do a one sec delay and you'll have heaps of height"... But I want to be able to work it out for myself as well before checking it against others opinions... I won't learn anything if I'm just following others off the exit point...


Definitely! As i mentioned in my first post, I will be taking into account off headings, pc hesitations, longer delays etc and working out a plan B C & D if I can't make it to the LZ.
Like I said before, this isn't an object I'm planning on jumping any time soon, I'm just enjoy practicing what I've learnt so far and seeing if my calculations and processes are starting to line up with others who are more experienced. :)

Thanks for all the input guys.

I'll take it off another local object with different configs and start to get some data.

Stop being a pussy. Jump it now.

If you are talking about a famous local object which I think you are talking about then just go and jump it. You don't need vents for it and any PC 42 up would do, I jumped it with a 42, a 46 and a 48 with plenty of time to build a landing pattern and sightseeing. If you are too sketched, then I am sure someone can PCA you the first time. I agree that the object looks very menacing and I remember walking around it for about 5 months before I got the confidence to do it (and I had no mentor-ship) but all things considered it is actually a super safe student object with plenty of outs, two LA options and a third out which would soil your ego and clothes but would keep you safe :) After you lob it you'd be like: pfff, what was I on about? Trust me.

We need a like feature on Basejumper.com

If you're a Melbourne local, I would have though you would be focusing more on the skyline around the CBD........ So ripe.

I don't think we're talking about the same object

I was referring to the multiple objects well in excess of 300ft sprouting up everywhere

I was replying to msk but yes you're right… I know exactly the one you're talking about … Very tight landing area and a closing window of opportunity I think. Haha

There are a few around if you are feeling adventurous!

Why not record data with high-speed, accurate GPS? Plenty of choices available, starting with a cheap WBT-201/202 that can be used at 5Hz ($60?), more expensive Bluetooth units from BadElf (10Hz, $170?) and Dual (5Hz, $100 and 10Hz $160), ending with expensive (~$400), but amazing 20Hz of VBox Sport. You can then overlay data from your previous jumps in different configurations and scenarios on your new jump you're researching and get a feel of what you can expect.

I didn't even know you could use a gps for that sort of data.

Thanks, I'll check it out

Once you have data, it's very easy to do a simple analysis using a spreadsheet. (You can use Google Earth, but it won't give you visualization of your obstacle's heights.) Just put some X (distance from exit) and Y (height) numbers of your prospective jump's profile, including obstacles and LZ, in Excel. Make a graph. Then copy your GPS data and draw the trajectories on the same graph (many GPS log the distance from origin; if not, you'll need to put some formulas to calculate X's from latitude/longitude). Now you have a visualization of your various previous jumps and the obstacle profile. As always, account for the worse scenario - use data from the jumps with 180 and see what your options are. I don't jump slider down but use similar analysis for new wingsuit jumps.

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Well....what most experienced BASE jumpers do For quick pre-jump notes . Is better just to drag along another BASE jumper with you of lower experience, or even better if just out of an Idaho FJC . Then PCA Him/Her off the object 1st for you gain the knowledge your lacking in knowing the proper delay and help you guide your assessment of flight approach plan of your equipment that you should take .
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I have no idea what you just said.

I think he is telling you to throw a buddy of the object first, take notes and then jump yourself.

Hahaha!! This is becoming comical

DO A PCA!!!!!

You only notice that kind of stuff after you post, or mail, or text... you get the point, but indeed - it gave me a laugh aswell :P

Better yet have a wuffo pca you !

When I was really young(er) and dumb(er) I tried this from a 190 E. She was at least 11 years old I really thought she could handle it.

She of course dropped me and I opened low and whistled into boulders.... but hey I got that BASE number!

Honestly, the best tool you can get is experience. It looks like you're in an unfriendly area for stuff like repeated jumps where you hang around to measure things.

The second best tool that should be taken with a grain is other jumper's experience off the same object. Chances are they will have the info most useful to you.

Good luck! Have a good jump.

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you said this...

Edited to add:
" The reason i want to know this is to calculate whether I have enough height to make it to the landing area safely. It's 300ft jump but there's obstacles and the landing area is a short distance away. Knowing what height I'll be open at will help me work out whether I can make it there and if I would still make it there after a 180, pc hesi etc ".
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What I am talking about is what You were, or 'are' talking about in your Post . Not novel Idea but.. you ever try progression up where you want to draw the Line ?
Rather than trying to search random on internet to compile a bunch of theoretical data on where the line is . You know height of Exit . But what if you did not even consider the Idea of Free-Fall on the 1st jump of a Object you never jumped before ?
Not a novel Idea but just something I was taught . My friends & I used to do this when going to new jump objects and not knowing the limits . We did not do GPS or Spreed sheets etc. . We would actually do real Progression jumps and work to find the survivable working perimeters, so as to Not go over the Line on your 1st time on a new object . We would work and do progression of PCA, Static line to Hand-Held delay. To actually freefalling it . Then we would do Freefalling progression with longer delays until we figured out where the line was and where to stop progression .
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I get what you mean... On an antenna or bridge or something I would totally do this.. This is an urban object so there's a good chance I might only be able to jump it once... Obviously I wouldn't push the freefall on the first jump but it would be a shame to static line it if I could easily do a go n throw with a 1 second delay with plenty of height :) That's why I want to try an calculate it before.. Also I'm just a bit of problem solving nerd and kind of enjoy trying to work out the variables.

Asking a bunch of horny internet trolls is hardly working out the variables.

2014=lazyBASE

You can't really win in here can you.

Thanks to the people who private messaged me with serious responses.

most of these people are brining up valid points. theyre just doing it in a completely sarcastic, bullshit way.

if youre asking on an internet forum about an urban object that can possibly only be jumped once, and havent put in the work to get enough experience on something much more forgiving to be able to asses said object properly, you shouldnt be jumping it, regarldess of all the PMs you get.

you have 2 options: get your fucking shit together somewhere else first, or just go blindly jump the fuckin thing and hope for the best.

wtf ever happened to mentorship and paying dues? jesus

Come on man, she just completed her FJC! She paid her dues already!

No seriously, you nailed it in your post.
Why the rush Alexa? Take your time on forgiving, less complex jumps and build up experience? Your object is probably not going anywhere soon? Remember the good old line "when in doubt, there is no doubt".
Stay safe and beware horny supportive basejumpers

She clearly stated earlier that she's not planning on jumping this object for a long time, so i'd say she's not in a hurry.

It's funny...if "she" was a "he" people would be flaming her for asking questions about delay and PC use on an urban object, especially in a place where there are active jumpers, and especially right out of a FJC. It cracks me up the difference the female presence makes among canopy people.

Lex, take everything you read online, posted or PM, with a grain of salt. Your locals are your best tool until you figure out your gear.

Thank you! I don't know how many times I need to say it! I'm just trying to learn from more than one or two people! Everytime I ask a question I have to defend myself.

FFS... I do have mentors and experienced jumpers I jump with, but who am I to assume that they are the best in the world or know everything.... Speaking of a grain of salt.

I've obviously incorrectly assumed that a forum for asking base jumpers around the world for their opinions is here for that purpose.

New jumpers cop shit for not asking questions, then cop shit for asking questions.

Kill Line 29", 3 second delay. Because your original question has too many obvious variables to give a real answer.

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Hey honey you CAN WIN > and That still goes for what I am talking about .

Also . Quote:
" Asking a bunch of horny internet trolls is hardly working out the variables . "
And to that I say, " a Big Fuck You ".
& As for ..."Working out the variables " . . you got to be fucking joking right ??
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Also If I really was a fucking dick & Horny fucking internet Troll . I would say that your predicament & question is not even worthy of being labeled as ( technical ) . But Truly belongs in the Beginners Forum of this website .
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But I am not a big fucking Dick . And here is very small non-technical answer .
So . You got an object that is Urban with known height but not jumped . You probably heat-up after you jump so one try is all you get .

You got a tight landing area that you need to 'stick' . You are Not 100% positive on flight distance in relationship the LZ .. ( but who is Not ? ) even if very experienced jumper ?
You NEED to have appropriate open height in-case of 180 or any other problem that might eat-up altitude and cut you short of the LZ . It's and easy solution to a problem done a thousand times by jumpers . Experience says . Go hand held on the PC on a go & throw at the Exit . Open and set-up High and then sink a line to the LZ and Land .
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That's all you had to say

So back to my original point about FJCs ruining BASE(some do a pretty good job, most are the puppy mills of BASE).

When people have mentors, which hopefully are people who have an interest in the person they are teaching and are qualified to mentor, then these questions get answered, and previously jumped objects are properly shown to the new jumper, as well as various techniques. And as the new jumper progresses in understanding and skill, the mentor increases the level of technicality as well as encouraging the new jumper to make increased decisions about jumps. Pretty soon the new jumper has the confidence and skill to jump more and more independently. FJCs often give just enough info to be able to jump one or two objects, then release the jumper into their community to go learn from some local they find or some internet forum.

It seems like anybody with 200 jumps (not you, I've seen you carve head down like a boss) can take an FJC and be released into the community to go do as they please with whatever delicate objects they live near. Its frustrating. Many are fine with it, so its just the way things are going. I accept that, but I will still express my opinions on other peoples posts as I see relevant.

I'll just say once more. I'm not intending to jump this object.

I have a mentor/mentors that I have heard their opinion. I thought it would be smart to hear from other people about how they calculate their opening heights...instead of just blindly following.

I know of the people that you're referring to, just don't assume we're all like that.

This post was just intended to be a learning exercise.

All of the things you just said about progression is exactly what I'm doing. I do get where you're coming from though.

 Not implying that you should "blindly follow" anyone. And if something said in a chat room could debunk the info you get from a mentor than it's time to search for a new mentor. So I guess the internet is good for some stuff (other than cat memes and sarcasm, both rad!).

Fuck I love cat memes

I take it all back, I love her.

Just when I thought basejumper couldn't get any worse then I see a thread like this and totally redeem itself.

forums are only good for certain questions. not to mention, there are less and less useful opinions on this website every day. remember, http://www.basedouche.com is 99% entertainment. the other 1% is shared with the classifieds and service bulletins.

but i do enjoy a good cat meme.

There sure is a lot. But there's also so many fucking overhead tram lines. They're ruining all the fun!