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What is the current thinking/experience on this (which I made up as I couldn't find the original thread)


0s to 3s delay Slider down/off = high chance that the canopy will open on heading

4s to 6s delay Slider up = significantly reduced chance that the canopy will open on heading. Best to take a longer delay or if not possible then go 3s Slider down/off

7s+ Slider up = high chance that the canopy will open on heading


I might be having a chance of some B's in the range of 700ft to 900ft (rock drop)

If you're asking these questions I assume you're fairly new. 700-900ft YOU should do slider off. And there is no high chance of anything but the unexpected.

And scratch that rock drop crap and get a range finder so you know for sure. Just my one cent right there, good luck dude.

 

When you went thru that window was that with or without a slider?

Get the Nikon Forestry Pro rangefinder, some of the best money I have spent on gear. It does the math for you, worth every penny and I am a cheapskate.

As for heading performance, just assume it's gonna be off-heading. every time. your profile shows enough experience to appreciate that!

 
Thanks Colm

I have a Bushnell Yardage Pro. Had it for 10 years. I added the rock drop comment purely as an indicator of the object vertical AGL height so as to negate comments about the amount of height available for free fall.

Yes, I do have years in the sport and some limited experience to go with it.

My question is based on numerous threads going back to 2009 discussing the higher probability or perhaps better put, the lesser certainty of an on heading opening at a specific bandwidth of velocity due to the introduction of a slider into the equation. This uncertainty seems to incrementally diminish as velocity increases over time. I believe the band of most significant uncertainty is around the 4s to 6s slider up region. It is a function I guess of Vector and pivotal forces around the slider whose resultant at lower speeds is less predictable than at higher speeds.

I was hoping that over the past 10 years or so more data and experience had been gathered and there might be some consensus.

Your chart looks spot on. The problems I’ve seen are from jumpers packing SU and then not even taking 4 seconds.

Ya, that seems mostly right, but don't forget to take canopy model and size into consideration. I've seen some canopies that open beautifully at 4s delay and others look like shit. You also want to take the exit into consideration. A 4s delay poised is very different from a 4s delay with a sprinting, strong exit. Also, what about the LZ? You may want more altitude so that you could have a 180, turn it around, and still have plenty of altitude to navigate the LZ. A really tight and technical LZ would warrant more altitude after opening to set up for and sink into.

Breaking it down into the 3 categories you did is a decent start, but other factors are just as important if not more so.

I'd also add here the slider type to the factors.

800 ft with OSP and big mesh slider I would still consider OK, if you take at least 4 seconds of delay.

Non-vented canopy with small-mesh or slow slider goes into "Tried that, cannot recommend to anybody" category.

Ive exited a 500' PT, with my slider up, no reefing / direct control whatsoever, and all my nose cells packed like slider down.

Was almost as fast as a slider down opening after 4 seconds but with a tiny bit of cushion

What size, model and fabric of canopy
and type of slider and PC ? Thanks

700-900 ft is not going to be considered full terminal and in my opinion you should always error on the side of taking a nice deep delay slider off/down instead of sub terminal slider up deployment. Its safest to always go slider down vs sub terminal especially when you're on an object that isn't forgiving. If it was a bridge, let's say at bridge day, go ahead and go slider up because heading performance isn't required or necessary. Since its a B, you are way safer and better off to go slider down, take a nice deep delay so you have a fast deployment, and take the canopy for a ride. Until you get more proficient and comfortable with your own decision making, always resort to slider down unless its full terminal. Just my 2c.

This totally resonates with my thinking and limited experience.

In fact it sort of answers my original question; there probably isn't any best time for sub-terminal slider up deployments from a solid object. Adding a slider into the sub-terminal deployment equation introduces an unecessary and higher level of risk. If possible don't do it!

Woooahhh you're such an original dickhead. Never heard that one before. It was slider off, if you knew what you were doing here you'd know. Don't go in..

Yea.....but Hank stood up the landing.....

Ody

Once you are more comfortable there will definitely be sub terminal slider up jumping in base jumping. You can sometimes use it to your advantage in some scenarios. However, the more you stack your odds in your favor, the longer you'll jump for.
best of luck

I'm with you on this. A few years back I opened up a mountain in bandit country in Northern Kenya. I got 6 seconds using an old style tracking suit and got far enough away that the object wasn't an issue.

+1 to all of this.

I still do slider-up sub terminal from time to time for various reasons but never forget it's a more technical type of jump.

Awesome!!

I have a shit ton of 2-3 sec slider up delays, and a good number of 3-6. I’ve found that my vented canopies tend to open with better heading performance, and off headings tend to occur more often for sure on the shorter end delays. That being said, probably 90%+ I’d say are on heading (within 15 degrees). Significant off headings (90 degrees plus) are still probably 1% or less for either group of delays, and you can definitely steer you canopy through opening if you’re quick on the short delays during the snivel. I’ve done a handful of short slider up cliffs, but don’t make it much of a habit.

What are your 3 sec delays off?

My local S.

To the original question, depending on the lz, the exit, and the weather conditions 700-900 ft I’d consider doing a B slider up. Slider down is definitely the safer option. If it’s on the 900 end, I’d probably try to take a 4-5 and be pretty confident with that.

My lowest slider up jump was 150 ft, and wasn’t intentional. It did open on heading though.