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On super low freefalls, what is more important? (I am only referring to pilot chutes and nothing else involved with low freefalls. I'm not trying to debate which method of PC toss os better.)

Method #1 You exit and throw the pilot chute up to bridle stretch. As soon as you start to fall away from the exit point, the PC inflates and you drag the PC down. As you fall, the pins pop and the canopy travels to line stretch. There is no major "snatch force" but more of a steady drag as you fall.

Method #2 You exit and toss the PC up but not to bridle stretch. As you fall, there is some slack in the bridle and the PC is already inflating. When you hit bridle stretch, there is a definite "snatch" as the pins are popped and the bridle loads the canopy attachment.

Now, assuming the same PC was used, which is better? Which method would get the canopy to linestretch faster, Ceteris Paribus ?

Is a pilot chute more effective as a generator of snatch force? Or Drag? Does it matter?

I'd go with snatch force, following on from this I also reckon on a low freefall a 0.5 second delay is better than a 0.001 second delay.

I'm not sure. Think of this though. With snatch force after the pins pop and the canopy starts to extract now you have a bit of slack in the bridle/canopy/lines system. Then as you keep falling the system becomes loaded again. So you have a load then no load then a load again. Whereas with drag (no snatch) there is no shockload on the system and therefore no induced slack afterward. Now I don't know if this small amount of slack would really do much but just a thought.

I prefer women's snatches since I don't want to have a drag!

Can you elaborate on the experiences that have led you to this conclusion?

How low are the objects you are freefalling?

Would the best method be dependent on pin tension?

Tight pins might show that deployment is quicker when the snatch force is greater.

However, when the pins are hardly loaded with any tension, would the continuous drag force mean a quicker deployment?

...thoughts anyone?

I tend to think the same way.

In a more extreme example, think of loose pins vs. new velcro. The velcro needs some snatch to get open in the first place, but the pins will come out straight away with just the drag.

'195 (once)
'210 (twice)
'220 (once)
'240 (five)

About 100 slider down jumps in total.

My conclusions were based from jumping a '370 (exit point) freestander (about 20 jumps). Have experimented from it with delays from go and throw to 2 second delays, also with various PCs. Those jumps above were the freefalls only. Apart from the '220 I SL'd all the others first to get an idea of the 'picture' under canopy and the landing. I've also made 15 jumps from the same '330 cliff. I can feel the difference in hang time, this is backed up by ground video.

Based on my experiences above and from observation of others I believe on low freefalls a 0.5 second delay is better than a 'throw and go'. I also make some small rigging changes, PM me if you want details. Being able to jump the same object back to back is useful, I'll be able to give more accurate feedback when I have identical canopies.

Will

It seems to me that the initial snatch is only going to be helpful for the first pin (assuming a 2-pin rig). Once the first pin pops, whether by drag or snatch, you'll still have the 10 inches or so of bridle giving a couple inches of slack for the next pin. After the first pin, the rest of the deployment should be the same.

If you pack big or with short loops, causing tight pins, the second pin may not benefit much from a snatch or drag induced popping of the first pin.

Either way, I'm a big fan of throwing all the way to bridle stretch and far away from my body. I've got 40-ish jumps from a 250 foot E, all FF/handheld with a 48" pilot chute. Anywhere from go and throw to slightly more than 1.5 seconds. I haven't noticed a significant difference between go and throw and .5 second delay on opening height, but then again, I'm not opening so low that 10 feet of difference would matter much. Testing from 180' might yield a better sight picture.

Lou

Will,

I'm interested in your "small rigging changes" that you make before a low freefall.... do you do anything other than prime your pins/velcro and release your riser covers?

I am currently going with DRAG.

I throw my PC (48zp) up to bridle extention as I am leaving the object

7 FF's from 175ft

My pin tention is low (2 pin)

If I am above 200ft then I 'Go & Throw' as normal

Greeny

For pin extraction, thinking of Dynamic Force, I would vote for snatch. My bottom pin tends to be tighter than the top.

For canopy extraction, thinking of Center Cell Stripping, I would vote for drag.

Overall, I just want those damn pins to extract in a timely manner... So my overall vote is snatch...

im Whith Greeny on this one...

Chad were were all your low objects?i mean i think the lowest i did were 240 or so

Need to speak to you about your low object,when do you want me back

Are you guys switching out the closing loops for the low stuff?


Sorry Chad, I realize I'm side tracking your thread, I'd better watch out for the moderator.

I would think that this was more important with velcro.
pins should pop either way right? so wouldn't getting the bridal to line stretch be the factor that would get a canopy over head faster?
~J

On my velcro rig (perigee 2) I prime the velcro on lower stuff (sub 250ft). I lift the edge of the velcro with my fingers before I kit up.

On my 2 pin rig (Vertex) I try to get my pin tention as low as possible and my pin tips only just in when low (sub 200ft). My aim is to have my pins only just holding the rig closed, so minimum force is used to pull them.


I have a pair of 'Cyprus' closing loops I will fit to my new rig for low stuff (sub 180ft) as they are made from a different material and should slide off the pins easier. If I need to I will get some one on the exit point to hold my pins in and then adjust them just before I jump. Dwain talk's about some of this in his "low freefall" posts. I think that is where I got the idea from.

Greeny

----
Based on my experiences above and from observation of others I believe on low freefalls a 0.5 second delay is better than a 'throw and go'. I also make some small rigging changes, PM me if you want details. Being able to jump the same object back to back is useful, I'll be able to give more accurate feedback when I have identical canopies.

Will------

I agree with Will, but for a different reason.

I feel the bridle snatch/stretch time is largely negligable when compared to the difference in time/altitude a canopy takes to open with low airspeed (eg. go and throw; but excluding statics/PCA) and with higher airspeed. My experience is that with higher airspeed, my canopy opens quicker, and pressurises quicker.

The effect: more groundrush and better canopy control right after opening.
But then, this is only me....

Ronald Overdijk

Method 2 has reliability issues.

You are assuming that the p/c orientation will allow the appropriate relative air flow to create the maxuimum drag force you desire to get you to line stretch.

You are also assuming the the deployment sequence will always occur as it is supposed to. i.e. from top the bottom you will have p/c, then mesh, then bridle, then the rest of it. Think about the reason that large p/c don't have external handles?

It is kind of like the toggle v riser debate. You need to look at the complete picture to see which method is better. Isolating individual characteristics is fine for simplifying the analysis but it all mist be put together prior to acting. i.e. you have to consider everything prior to doing a LOW jump.

I personally believe that if you did 100 test jumps. You would find that the average for method one would be better than for method two. The spread of distance/times would be less. I think you would have the fastest times in method two but not consistantly.

When pushing the limits of BASE jumping, you are not looking for the extreme edge of the bell curve, you are looking for reliability, repeatability, consistancy. You want to know that when I do this, that WILL happen. Otherwise you are simply playing Russian Roullette.

Stay Safe
Have Fun
Good Luck

p.s. I have assumed that it was a go and throw, no real delay. I have also assumed that the resistance forces throughout the deployment sequence are negligible. i.e. insignificant pin/velcro tension, canopy has clean access out of the container, etc.

p.s.s there are issues with how the canopy pressurises with the two "methods" of snatch and drag. Couple this with brake settings and wing loadings - this means that what is right for one situation, may not necessarily be correct for another.

Just my humble opinion.

Ronald / Will,

[ Based on my experiences above and from observation of others I believe on low freefalls a 0.5 second delay is better than a 'throw and go'. ]

Depends on the altitude

I 'm trying not to put too many numbers on this:

I agree with this above a certain height (maybe 200 0r 220ft). As 1 sec of free fall only equals a 16 foot drop and gives the PC and canopy a bit more airspeed to work with, that has to be good. I am also thinking a faster opening is more likely to be on heading.

That said once I get down to 175ft and work my way lower I no longer think I can afford to loose that 16ft. At this sort of height I think I need a big PC (currently 48zp)and to get it inflate ASAP, acting as an anchor. My aim is to almost have My PC staying still (as little drop as possible) and me dropping away from it (think PCA with no one holding it).

I was told the idea of not throwing my PC up but keeping it in my hand and inflating it prior to jumping.

I'll try to explain better.

Reaching up hold the PC in your hand (by bridle attachment)and while bringing your hand down, place the PC into the air, inflating it as you do so. The aim is to have the PC inflated and set in the air before you step off the object. I was told this works better with a shorter bridle (no burble due to no airspeed) and less distance to fall before your bridle is at extention. Your pins should be coming out by the time the PC passes the point where your feet were. You can inflate the PC as many times as you like and only step off when you are sure it is properly inflated.

I have not tried this yet but will be playing with it when I get back to the US in 8 weeks.

My point on all this:

I'm not worried about 'Snatch V Drag' my pins are coming out quickly with both. What I am worried about is when I have Minimum altitude, I need to keep it all. But when I have altitude, I can trade for some airspeed and will take as much airspeed as I can get to improve my opening performance.

Greeny

popping your pins dosnt mean your canopy get out faster,in that case you could use a 38´off sub 200ft right...

Nope you want a PC act as a ancor(see Greenys post),were you freefall away from the PC while the pc is pulling out the canopy while your freefalling away from it,that way you´ll get a flying canopy faster...


atleast thats my oppinion,and as long it keeps me alive,ill keep doing that

Faber brings up an important point that bears repeating. The force required to lift a packed canopy out of the container is surprisingly large, often larger than the force required to pop the pins. This is especially true when you jump larger canopies in the 300 range.

We use 80 pound breakcord on static-line jumps not to pop our pins, but to deal with the sudden shockload when it starts lifting your canopy out of the packtray.

actualy i only jump spectra loop theese days..
why?
to start whith i were too borred to shift the loops,then i realiced that you can have some high tention on your spectra loops and still get the canopy out,which means my loops right now(havnt dont anything low lately)is slightly tighter than i would have my dacon loops,but they still preform about the same...

That said i´ll still loosen the loops as soon as i will jump the low stuff again...

Others who had experience about this?

NOTE:i as i havnt been at terminal BASE ever so please take my experience whith a grain of salt...