Why do Racer owners think their rig would offer the fastest reserve openings?

[pchapman 261]

The Jump Shack PC drag claim has been around a long time, so I'd like to confirm that the comparison is against other types of PC's that are in current use.

Also, Cd on its own is not enough. One could have a 6 inch diameter pilot chute with great Cd drag characteristics, but much less drag than a 42" PC. It's the combination of Cd and a reference size (some measure of diameter) that makes up the total drag.

[Unstable 8]

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I thought this was settled a long time ago. No modern sport container system deploys, to line stretch, faster than any other. This fact was determined years ago in side by side tests. You can cheat on the tests by "front risering" for greater airspeed just before breakaway, or by packing for an extremely fast canopy inflation...but the fact remains: Given the same conditions, all modern gear performs about the same. The fact that we are still discussing this worn out topic, simply proves that the old saying is true: "A lie, repeated often enough, becomes legend". You can't believe everything you read on the internet, guys...Honest!

The man spoke - Good enough for me.

=========Shaun ==========

[teason 0]

You're right Bill, in the video I just looked at, there wasn't even 1/2 second difference between the skyhook opening time and the Racer opening on their website. (And that was freezing the video and counting the frames).

I would rather be a superb meteor, every atom of me in magnificent glow, than a sleepy and permanent planet.

[billbooth 10]

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You're right Bill, in the video I just looked at, there wasn't even 1/2 second difference between the skyhook opening time and the Racer opening on their website. (And that was freezing the video and counting the frames).

Without the Skyhook, the Racer line stretch time, and the Vector (or any other rig) line stretch time are the SAME...1 1/2 seconds. With the Skyhook, all rigs will give the same 1/2 second breakaway-to-line stretch time. Skyhook equipped rigs are simply a lot faster then non-Skyhook equipped rigs...period, exclamation point, no question. But the Skyhook is not just about speed. It gives many other advantages that I have spoken about before.

[teason 0]

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the Racer line stretch time, and the Vector (or any other rig) line stretch time are the SAME...1 1/2 seconds.

Not true, activation to line stretch is .97 secs. The video is real, the deployment has been timed with a frame count (cutaway to line stretch)

I don't have any vid to say what the Vector line stretch time is so I'll go by your more than ample knowledge of your product. Vector line stretch is 1.5 sec, with skyhook .5 sec.

But believe the vid. The one I saw had .97 sec to line stretch. That is less than 1/2 a sec difference from the skyhook equiped rig.

Geez, less than 1/2 a sec ain't much and I was agreeing with you!

I would rather be a superb meteor, every atom of me in magnificent glow, than a sleepy and permanent planet.

[badlock 0]

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Not true, activation to line stretch is .97 secs. The video is real, the deployment has been timed with a frame count (cutaway to line stretch)

Is ONE video enough to judge????
I don't think so.
Please remind this video for example:

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

This seems to be far faster than the 1/2 second...

Don't be a Lutz!

[billbooth 10]

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the Racer line stretch time, and the Vector (or any other rig) line stretch time are the SAME...1 1/2 seconds.

Not true, activation to line stretch is .97 secs. The video is real, the deployment has been timed with a frame count (cutaway to line stretch)

I don't have any vid to say what the Vector line stretch time is so I'll go by your more than ample knowledge of your product. Vector line stretch is 1.5 sec, with skyhook .5 sec.

But believe the vid. The one I saw had .97 sec to line stretch. That is less than 1/2 a sec difference from the skyhook equiped rig.

Geez, less than 1/2 a sec ain't much and I was agreeing with you!

OK. I just watched the Racer breakaway video with the "embedded stopwatch", I paused it at line stretch (canopy OUT of the bag), and the watch read OVER 1.5 seconds, or about normal for all the rigs I've seen videos of. (Did I do something wrong viewing the video?)

The reserve was "open" in just over 2 seconds. This means it took their reserve canopy around 0.5 seconds to inflate. Any canopy which inflates that fast sub-terminal would "kill" you at terminal. It was obviously packed for a fast sub-terminal opening. Normal reserve packjobs, that won't hurt you at terminal, should take just under 1.5 seconds. Remember, once the canopy is out of the bag, the rig it came out of has no effect on its opening time.

[hookitt 0]

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The reserve was "open" in just over 2 seconds. This means it took their reserve canopy around 0.5 seconds to inflate. Any canopy which inflates that fast sub-terminal would "kill" you at terminal.

First: I agree with the assessment of reserve to line stretch. This reply has nothing to do with Racers because the theory of faster reserve deployments was debunked a long time ago.

I have not watched the video yet but with personal experience, on low speed cutaways (planned and unplanned) the canopy inflated quite rapidly. (1/2 second range) It stands to reason that during low airspeed, the slider will not be influenced much by the relative wind.

During a planned break away, and a 1 second delay, the reserve was open in 2 additional seconds. Given the 1 1/2 second to line stretch you mentioned, it would agree with the 1/2 second opening time, or possibly more precise, bottom skin expansion.

During a high speed reserve opening, the slider would be influenced a lot more by the wind, better staging the opening. It will probably still be rather abrupt but may take longer to open after the freebag is off.

Does that sound reasonable?

My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto

[teason 0]

My Bad, The vid isn't on the site so I can't give you a link.
My claim that there is a .97 to line stretch video cannot be proved right now, I'll concede that.

But anecdotally, there is one that we timed with the vid editing software. If you don't believe it, that's ok.

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The reserve was "open" in just over 2 seconds. This means it took their reserve canopy around 0.5 seconds to inflate. Any canopy which inflates that fast sub-terminal would "kill" you at terminal. It was obviously packed for a fast sub-terminal opening.

C'mon Bill, I expect far more from you on this! What keeps the slider up?

Descent Velocity.

The slider comes down when the spread of the canopy is strong enough to overcome the force of the air keeping the slider up. If the system is descending to slow to give enough spread to force the slider down, the system must accelerate. For example, the skyhook will get the canopy out of the bag while the body is moving relatively slow.
If the system is descending fast, there is more force keeping the slider up than the spread of the canopy can over come. The system must slow down for the spread of the canopy to overcome the slider.

There is an ideal range of descent velocity for deployment. Imagine a bell curve. If the canopy is deployed within that range (like the cutaway from an open canopy) you'll get a quick inflation. Anything outside that range will not complete deployment until the conditions are met.

Take a look, the slider is up in all those videos. If Jumpshack wanted to make line stretch faster, they would use the smallest reserve they could find to make line stretch quicker.

Making a claim that Jumpshack obviously fixed the results to misrepresent their product is liable.

I would rather be a superb meteor, every atom of me in magnificent glow, than a sleepy and permanent planet.

[billbooth 10]

I've filmed dozens, perhaps hundreds, of low speed reserve deployments. Packed properly, I've never seen a 1/2 second reserve opening from line stretch. The slider balances forces. At higher speed, the air entering the canopy is also faster. It is very hard to get a properly packed reserve to open under 3 seconds from an RSL breakaway...without a Skyhook, that is.

[teason 0]

Bill,

Just because the evidence doesn't support your belief, does not mean that the evidence is wrong.

You have not had a reserve RSL deployment in the 2 sec. range that Jumpshack has (outside of the skyhook).

As you have said, it is hard to get (I will assume a vector) opening under 3 sec when properly packed.

I have spoken to Jumpshack who have told me that the Racer in the 2 sec. deployments have been packed according to the manual.


So here is the crux.
Either the Racer is faster or Jumpshack is lying.

Are you going to tell me that Jumpshack is lying? Or that you don't know how they get such fast openings.

Those are the only two options.
You have to pick one.

I would rather be a superb meteor, every atom of me in magnificent glow, than a sleepy and permanent planet.

[billbooth 10]

Jumpshack's own video shows a container opening to line stretch time of just over 1.5 seconds. (As I said above this is about average for all container systems have seen videos of.) This is the only time that matters when comparing container systems. How long a canopy takes to open after it gets out of the bag depends entirely on the design and packjob of that canopy. It has nothing to do with the container it was packed in.

I am not going to call Jump Shack liars. They are good people. They are my neighbors and friends. John Sherman is one of the few "originals" left in this sport, and Nancy is one of the nicest people I know. Our children grew up together...hell, even our dogs are brothers. I am only telling you what the video you asked me to watch shows.

[teason 0]

Well, I've already acknowledged that the video I saw is not on the site and my claim that the video exists will remain a claim until it appears on the website. (or you could go next door and ask John or Nancy for copy)

Now, back to what you claimed earlier. You claimed that

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It was obviously packed for a fast sub-terminal opening.

and implied dangerous reserve deployment

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Normal reserve packjobs, that won't hurt you at terminal, should take just under 1.5 seconds.

Now, Jumpshack still gets the reserve open in 2 sec.
Why?
They say the reserve is packed as per manual and certainly the slider is up. So why?
Why do they get it out in 2 secs?

By the way, opening time does not, as you claim, "depend entirely on the design and packjob of that canopy" Pilotchute and freeBag design and descent velocity also play a role by affecting snatch and relative force on the slider.
Remember, the greater the drag on the PC, the greater the snatch force.

Snatch force has an effect on opening! as well as the canopy's velocity on inflation!

I'll boil it down some more:
The drag that the RPC has slows the velocity of the freebag(and the canopy inside).The canopy therefore has a slower velocity.
When the canopy leaves the bag (the higher the drag, the more dynamic the release), it must be accelerated by the load (snatch force!).

That means what happens after the canopy leaves the bag is influenced by container design!

There is a seminar at the PIA called "The Anatomy of a Parachute Opening" Also Nancy promised to get you some videos of Racer deployments. She's done about 40 herself and they're all consistently in the 2 sec range and they've been doing these cutaways for years and years as you know.

I would rather be a superb meteor, every atom of me in magnificent glow, than a sleepy and permanent planet.

[billbooth 10]

We're whipping a dead horse here. Nothing further can be accomplished by this. I should have known better.

[hookitt 0]

I've had in the range of 2 second reserve deployments using an Eclipse several times. It's not a Racer thing.

Edit to add. Low speed cutaway with an Infinity had the same results.

My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto

[teason 0]

It's not out of the range of deployment times and is not exclusive to the Racer.

The Racer, however, has documented consistancy on that 2 sec. range and that is the basis for their claim and the reason for the OPs question.

The deployment of a canopy is extremely complex and can be affected by so many variables that understanding them will take a great deal of study and research.
Understanding the relationship between all the variables is what will lead us to better equipment and better design.

I would rather be a superb meteor, every atom of me in magnificent glow, than a sleepy and permanent planet.