Stratos jump gear (was: Incident at Sebastian)

[JohnMitchell 14]

Kirkk0herra

Hello,

A noob question. If you pull your reserve first and for some reason you get a serious malfunction can you cutaway from your reserve and attempt a main deployment? Not a very likely scenario but from a pure technical aspect I think one should. Just crossed my mind that's all.

Nope. The main risers, of course, attach to your harness with the 3 ring release system, so the main can be released. The reserve risers are sewn into the harness and can't be.

One thing to remember is that your main parachute, while very reliable, has a few design compromises that make it softer landing, more responsive in turns, glide farther, etc. It's can be packed in minutes by semi-skilled people.

The reserve is designed with one thing in mind: to make it as reliable as a parachute can be. It takes a highly trained rigger up to an hour or so to inspect and carefully pack it.
The rig that Velocity Sports Equipment built for the Red Bull Stratos high altitude jump actually had a releasable main and releasable reserve. Once you pulled the cutaway handle for either one, it deactivated the cutaway handle for the other. That way you could never release BOTH canopies.

[lyosha 46]

JohnMitchell

***Hello,

A noob question. If you pull your reserve first and for some reason you get a serious malfunction can you cutaway from your reserve and attempt a main deployment? Not a very likely scenario but from a pure technical aspect I think one should. Just crossed my mind that's all.

Nope. The main risers, of course, attach to your harness with the 3 ring release system, so the main can be released. The reserve risers are sewn into the harness and can't be.

How about a hook knife?

[JohnMitchell 14]

lyosha

How about a hook knife?

Yes, but it better be a good one and it's harder than you think. One of those little ones on the rig probably won't cut it.

[rouey 0]

Quote

How about a hook knife?

I remember something like this being mentioned in FJC:

- If you find yourself hanging from the plane's tail and it's your main, cut away immediately;

- If it is your reserve you're screwed. You could use a hook knife, but we won't let you carry one since you might end up cutting the wrong stuff;

[ianyapxw 0]

JohnMitchell

main parachute, while very reliable, has a few design compromises that make it softer landing

I'm curious about this. This will complicate things if a jumper passes out under a reserve when flying an above average wing loading? I personally would have assumed reserves are designed to land softer, what's the design philosophy behind this?

Quote

The rig that Velocity Sports Equipment built for the Red Bull Stratos high altitude jump actually had a releasable main and releasable reserve.

I'm curious why they did this, are there certain situations where he would go for reserve instead of main and then be able to cut away the main. I would assume he would always go for main first, and I'm unsure of the rationale behind a reserve cutaway.

[JeffCa 0]

ianyapxw

Quote

The rig that Velocity Sports Equipment built for the Red Bull Stratos high altitude jump actually had a releasable main and releasable reserve.

I'm curious why they did this, are there certain situations where he would go for reserve instead of main and then be able to cut away the main. I would assume he would always go for main first, and I'm unsure of the rationale behind a reserve cutaway.

My wild-ass guess is that a premature deployment of the reserve at over 100,000 feet would have been very bad and need to be cutaway.

"So many fatalities and injuries are caused by decisions jumpers make before even getting into the aircraft. Skydiving can be safe AND fun at the same time...Honest." - Bill Booth

[rmarshall234 13]

>a premature deployment of the reserve at over 100,000 feet would have been very bad and need to be cutaway.

After the explosion, I'm not sure there would be anything left to cut-away :-(

[JohnMitchell 14]

JeffCa

***

Quote

The rig that Velocity Sports Equipment built for the Red Bull Stratos high altitude jump actually had a releasable main and releasable reserve.

I'm curious why they did this, are there certain situations where he would go for reserve instead of main and then be able to cut away the main. I would assume he would always go for main first, and I'm unsure of the rationale behind a reserve cutaway.

My wild-ass guess is that a premature deployment of the reserve at over 100,000 feet would have been very bad and need to be cutaway.

That is absolutely the correct scenario. The life support is good for the 5 minute freefall, but not a 60 minute canopy ride.

[JohnMitchell 14]

rmarshall234

>a premature deployment of the reserve at over 100,000 feet would have been very bad and need to be cutaway.

After the explosion, I'm not sure there would be anything left to cut-away :-(

No kidding. Going that fast it'd certainly roll your socks down, wouldn't it.

[Divalent 89]

JohnMitchell

***>a premature deployment of the reserve at over 100,000 feet would have been very bad and need to be cutaway.

After the explosion, I'm not sure there would be anything left to cut-away :-(

No kidding. Going that fast it'd certainly roll your socks down, wouldn't it.

But wouldn't the air density be so low that it would be pretty much a wash?

I'd have guessed that a deployment way up there would feel pretty much like one you'd get from a typical skydiving jump. IOW, maybe you'd be falling at 5 times the velocity you'd fall at 10K, but because the air was only 1/5th the density, the force of the relative wind on the deploying canopy would be 1/5th as great. Am I missing something?

[billvon 2,395]

>I'd have guessed that a deployment way up there would feel pretty much like one
>you'd get from a typical skydiving jump.

I don't think it would feel like much of anything, and if you had a mind to you could probably take off the rig, reclose the container and put it back on if you wanted to. (Probably hard to do in zero-G and you'd have to be fast about it.)

[craddock 0]

billvon

>I'd have guessed that a deployment way up there would feel pretty much like one
>you'd get from a typical skydiving jump.

I don't think it would feel like much of anything, and if you had a mind to you could probably take off the rig, reclose the container and put it back on if you wanted to. (Probably hard to do in zero-G and you'd have to be fast about it.)

Zero G? Are we missing a sarcastic icon?

That spot isn't bad at all, the winds were strong and that was the issue! It was just on the downwind side.

[RiggerLee 61]

Depends on what your jumping from. We can do you a couple of minutes of zero G before you reenter the atmosphere.

Lee

Lee
[email protected]
www.velocitysportswear.com

[craddock 0]

Ya never-mind. I screwed up. I really only said it because I hold BV to a higher standard because he likes to be technical himself and correct others. I guess I am being hypocritical because I use the term zero g and negative g in regards to the forces we feel in planes and roller coasters and such but would use the word "feeling" behind it in regard to a leo or the jump in question strictly because of the misconception among some that zero g means a lack of gravity up there.

I wasn't trying to be a smart ass I just didn't realize the term was that well accepted in that situation and I was totally wrong for my comment. He did seem pretty sarcastic with his post however. I still prefer the word "feeling" or "environment" when using it with my 8 year old in that usage

That spot isn't bad at all, the winds were strong and that was the issue! It was just on the downwind side.

[skydiverek 54]

This is how the Stratos (Infinity) rig worked:

http://parachutistonline.com/safety_training/ask_a_rigger/the-stratos-rig

[JohnMitchell 14]

It's the ultimate balloon jump. There is a long period of near weightlessness as you accelerate towards the Earth. But even in that super thin air you'll start getting wind resistance and feel a G-load again. Think of astronauts returning from orbit way higher than that. They pull many G's in much thinner atmosphere.

Now . . . why does the chute open so hard?

Round figures. Let's say your terminal is 100 mph and your canopy descent rate is 10 mph at 2K feet. You open and in 3 seconds slow 90mph. You experience about an additional 1.4 G's.

Much higher freefall, higher terminal velocity, say 500 mph true airspeed, but indicated is only 100 mph, so it feels normal, the same amount of wind pressure on you. But should you open your canopy, it will go from 500 mph to 50 mph in about the same 3 seconds, a change in velocity of 450 mph! You'll experience over 7 additional G's. A snappy two second opening would approach 11 G's.

That's one of many reasons why premature openings on high altitude jumps are a bad thing.

[JohnMitchell 14]

skydiverek

This is how the Stratos (Infinity) rig worked:

http://parachutistonline.com/safety_training/ask_a_rigger/the-stratos-rig

Thanks for that article. Kelly and his wife Gen are good friends of ours and I got to see that rig under construction on one of our visits. Plus watch Luke do a lot of the test work at Kapowsin Air Sports in WA.

[katzas 0]

rmarshall234

>a premature deployment of the reserve at over 100,000 feet would have been very bad and need to be cutaway.

After the explosion, I'm not sure there would be anything left to cut-away :-(

At 100k ft I doubt that there is enough air density to even inflate a parachute much less blow one up.

[skydiverek 54]

katzas

***>a premature deployment of the reserve at over 100,000 feet would have been very bad and need to be cutaway.

After the explosion, I'm not sure there would be anything left to cut-away :-(

At 100k ft I doubt that there is enough air density to even inflate a parachute much less blow one up.

You would still want to cut it away, even if it is not inflated and falling in a big wad next to you. Imagine that (Felix's) flat spin with the parachute deployed right next to him...

[excaza 1]

katzas

At 100k ft I doubt that there is enough air density to even inflate a parachute much less blow one up.

Not true. NASA has deployed at lower air densities for its Mars missions. It's also important to remember that the majority of the opening forces on a gliding parachute come from bottom skin inflation, not full canopy inflation, because it's the largest change in drag area.

Even a partial inflation is enough to cause serious issues, on Kittinger's ~75k jump his drogue deployed too early, caught around his neck, and spun him fast enough to G-LOC him.

[billvon 2,395]

>NASA has deployed at lower air densities for its Mars missions.

At thousands of miles an hour. Remember that airspeed is density times actual speed. After even 20 seconds he's only going 400mph, which at those altitudes would be well below stall speed for parachutes.

Deploying after, say, ten seconds you would have the parachute just sitting next to you. It would slowly start to drift away from you; it would take a while to get up enough speed to unstow the lines.

What happened next would be very important. If the canopy rapidly inflated at very high altitude the parachute might well survive, since overall forces would be low. However the reefing system is not set up to rapidly deploy a parachute at low speeds. So the parachute would sit there, not unstowing lines or sending the slider down until much higher speeds and/or higher densities were reached. At that point you'd get an explosive opening.

[skypuppy 1]

JohnMitchell

******

Quote

The rig that Velocity Sports Equipment built for the Red Bull Stratos high altitude jump actually had a releasable main and releasable reserve.

I'm curious why they did this, are there certain situations where he would go for reserve instead of main and then be able to cut away the main. I would assume he would always go for main first, and I'm unsure of the rationale behind a reserve cutaway.

My wild-ass guess is that a premature deployment of the reserve at over 100,000 feet would have been very bad and need to be cutaway.

That is absolutely the correct scenario. The life support is good for the 5 minute freefall, but not a 60 minute canopy ride.
there was a russian jumper who found this out.

If some old guy can do it then obviously it can't be very extreme. Otherwise he'd already be dead.
Bruce McConkey 'I thought we were gonna die, and I couldn't think of anyone