Basejumper.com - archive

Hi,

I write MA thesis about BASE jumping, and one of the charpters is about freefaling.

Does someone have some data or information about the distance from the object, which jumper covers directly proportional to the fallen distance, while using a normal clothes, track suit and wingsuit?

I would like to make a graph of curve to illustrate jumpers path in this three cases, compare it and analyse e.g. how high vertical wall does the wingsuitflyer/tracker needs to jump off and safely fly away, or how would looks the terrain profile, of the possible most gentle slope to make a safe jump from in the normal clothes, track suit and wingsuit.

Regards,
Piteras

That very much depends on your skills so drawing one line for each is pretty much impossible. Rough estimation would be (in my opinion, based on absolutely nothing):

WS - 1:1 - 4:1
Tracking suit 0.1:1 - 1.75:1
Normal clothes 0 - 1:1

But that of course is average glide ratio in quite long freefall. In subterminal jumps you'll have much smaller numbers and of course peak performance would be bigger

So could we focus on the case of the imaginary the best tracker, that man could be?

Terminal speed glide ratio would be relatively easy to estimate. Lets assume possibly maximum glide ratio values, but how would the jumpers falling path looks like, in the sub terminal part of the jump?

In that case I guess the result for WS would be like 4-5:1 and tracking suit something like 2:1. But you have to take into consideration that track kicks in after about 4-5 seconds and something like 2-3 sec for WS (I could be wrong about that though).

I think for the accurate falling path it would be bets to ask Robbie or some other guys from Phoenix-Fly, Tony Suits, Pressurized and Intrudair..
In a nutshell it starts with straight fall down and slowly graduates into the maximum glide (probably with some logarithmic growth at some point), if we assume normal standing exit. But this is altered (quite much) when you do running exit or how much you push.

But as I said there are to much variables to make a simple estimation. Apart from skills of the jumper you have also factors like altitude, temperature, air pressure etc.

Excluding sub terminal part of jump, and thermals...

Street clothes upto about .8:1
Tracking suit around 1.2:1
Wingsuit 2.5:1 - 2.8:1

We can assume the following factors:
jumper has the perfect body build and skills for tracking, altitude is 1000 m ASL, temperature 25 celsius degrees, air pressure 1000 hPa.

Can we now define the subterminal jumpers path?

If wingsuiter reaches the maximum glide ratio after 3 seconds, than how much vertical and horizontal distance does he cover in each of this 3 first seconds of the jump?

And the same for a man in a track suit and in normal clothes.

Can you estimate it?

None of them will reach anywhere near max glide ratio in 3 seconds, it'll be more like 10-15 seconds but will be different for each type of jump.

OK, so lets assume the correct time, which is needed to get max glide ratio for each type of the jump.

I just need to know, what is the vertical and horizontal distance covered by the jumper in each second, before he reach the max glide ratio.

WS will never reach maximum glide ratio at 3 second mark. At this point the glide will only start. The maximum glide will be at terminal (WS terminal) speed.

The vertical drop for each time instant you can find from the freefall distance tables.

To make a graph I need to combine covered vertical and horizontal distance from each second.

You'd have to dig up in the you tube. There were few videos of gyus jumping wingsuits with all the real time data displayed at the bottom. Data included vertical and horizontal distance, speed, glide ratio.
I think you'd find it very useful. I'll post it if I find it

Not the one that I had in mind, but still I think it'll be helpful:

http://www.youtube.com/watch?v=lkOkY4PmpI8

I did a similar study for my BS. After a few years of collecting data, this is what I came up with. I hope you can understand it, it's pretty techy...

Feel free to use any data for your research.

Your data is faulty, You misspelled Squirrel.

Yea, I know. I fixed it though

I'm stealing this picture!

Here are some glide ratio numbers based on a competition results:

wingsuit : 3,01:1 -> 1,32:1
tracking suit : 1,73:1 -> 0,52:1
naked tracking : 1,06:1 -> 0,4:1

If you only looking for the maximum performance of each method then your better basing your results on one part of the jump.

Eg: from the 20-25sec mark.

If so then this site may help as it shows actual results in competition.

Each race is conducted over 1000 vertical meters on a skydive. Should be easy to see the max glide ratio. This will be your top end as obviously in the competition you dive for speed then flatten out at the entry altitude, also negating any winds present. Work back from there to find the average max glide ration with any other data you will be collecting.

http://www.paralog.net/ppc/

The skydiving competition results have significant wind influence.

"Wingsuit terminal" is tricky to define. Just reaching your maximum fall rate doesn't mean you are automatically at best glide, you must reach your optimum forward speed and this takes more time. While you may reach maximum fallrate in 7-10 seconds it could take twice a long to reach best glide rate.

OP: Accurate data for tracking in street clothes and tracking suit will be harder to come by, but if you are serious about it, you can try asking VKB boys.

Otherwise Gauleyguide's graph is probably as accurate as anthing you'll find!

+1 nice post, even checking the world base race event and tracking race wont hold ground...

Thanks, that's something I was looking for!

The video, that you had in mind, is probably this one: http://www.youtube.com/watch?v=HnMf26MNQ5I

Not really, the one I saw had big white text at the bottom. But more importantly it had the real time glide ratio which I guess is what you're looking for. And the guy had bigger suit and I remember him reaching over 4:1 glide ratio (hence my guess of the max glide ratio on WS)

And I also remember Jokke Sommer (I think) posting on facebook a glide graph for his test flight on V4, which would be the exact solution for you. If you have FB you can probably ask him

This one?
https://vimeo.com/22353340

Max rate after dive/flare or in rising air/wind is very different to sustainable rate in still air. For comparison purposes it's better to use the sustainable rates.

Exactly!

Yes I know it's the peak glide, but I though we were talking about perfect conditions and a perfect flier :)

Covered distance from the wall compared with vertical fall is enough for me to make a graph :)


That's perfect!

By that rational should we take data with GR of 9:1 or even level flight for a microsecond after a huge dive and say that the perfect flyer in perfect conditions can fly at 9:1 or level? What's the point in that?

There are not many people that can fly regularly with sustained 2.5:1 for 30 seconds+ without diving/flaring, or rising air / tail wind to help them.

There are a few, and some can probably do better, but that's where we are at today and it's going to be a while before we can say the figure is 3:1.

I totally agree. If you want to talk about GR honestly, you have to talk about it from exit to landing. I will guarantee there are very few jumpers who are getting >2.0 GR from exit to opening unless we are talking about some very high jumps. I cant remember what this one averaged out to be, but I dont think it was quite 2.0, and I have only seen one other jumpers pull over the beach, and several of the really good guys not.

http://vimeo.com/24207597

Nice video and flight!
I make it almost 2.5:1 between 20sec and 40sec.
Looks like lots of lift close to the wall just before 20 seconds (I'm assuming 20mph vertical isn't sustainable)?

Looking at exit to opening average means you can't compare jumps of different usable altitude because the exit will be a larger percentage of overall jump on short flights like this one. The exit phase should be looked at sepratly to the cruise phase.

If the forward speed usually 70-75mph?

but i think, if you want to draw a graph you should cut the jump into sections and focus on each separately. Otherwise you just get a straight line

WTF ..! . Is yuri base go-in ?
Can not believe he has not already Posted in this Thread. A six page mathematical composition analysis complete with graph on glide angle ratio . ????
.

I think thats true, you just have to take the whole picture in to account too. If I went straight head down off exit and built up a bunch of speed, then came out and had a a 3.4 GR, you could say man look how good his glide is once he gets started, but I might have a lower total average GR for the jump. Hard in base too because exits can range from 2000-12000+ ft ASL.

True that.

Anyway, it all depends what are we talking about. I had the impression that (among other things) we talk about maximum performance one can get from the suit. So if we consider a perfect scenario - perfect flier, perfect exit, perfect glide, perfect weather. If today some people slightly exceed 3:1, and I bet they and all the other factors are quite far from perfect, then if everything else adds up we can achieve 4:1 or be quite close to it. And I'm not talking about flaring or stalling the suit.

And of course it's not realistic, but if we want to have some average values, we have to take into consideration two extreme cases.

BUut of course I might be wrong.