0
Freeflysmiley

Low cut-away

Recommended Posts

Quote

***What's the point of having an RSL if you're going to disconnect it?:S

Quote

I was trying to find out if a spinning main and consequent unstable body position would likely induce a spinning reserve, and if you had altitude to spare if it would be worthwhile to get stable before deploying reserve. Anyway some good resolute answers to that. Thanks for clearing it up.

I've got simliar questions about line twists on reserves. I've never had line twists on a reserve, and mine is loaded barely over 1:1, but I have had to chop a twisted up Stiletto. Question is, are line twists on a higher loaded reserve always recoverable, or can it spiral you in? Is the "spiraling in under line tiwists" a function of wing design (highly elliptical) or wing loading (highly loaded)? I'm thinking it's the former, but I've got no experience with highly loaded, twisted reserves. I would hope any reserve would fly straight with line twist until you could kick out. Who's got some info?

Share this post


Link to post
Share on other sites
>Question is, are line twists on a higher loaded reserve always
>recoverable, or can it spiral you in?

They can spiral you in, but it is unlikely. Jumping a less-loaded reserve is one way of helping ensure this does not happen.

>Is the "spiraling in under line tiwists" a function of wing design (highly
>elliptical) or wing loading (highly loaded)?

It is both. I've line twisted a Sabre 120, but it was a lot easier to line twist my Safire 119. And line twists are the first step towards an unrecoverable spiral. Some canopies just like to do it - I once jumped a Diablo that would wind up if you didn't release the brakes quickly.

>I would hope any reserve would fly straight with line twist until you
>could kick out. Who's got some info?

Most will if they are reasonably loaded and working normally (i.e. a brake didn't fire during opening.) The best way to see how reserves will react is to jump one as a main; both PD and Aerodyne are willing to send out demo reserves.

Share this post


Link to post
Share on other sites
Quote

Quote

***What's the point of having an RSL if you're going to disconnect it?:S

Quote

I was trying to find out if a spinning main and consequent unstable body position would likely induce a spinning reserve, and if you had altitude to spare if it would be worthwhile to get stable before deploying reserve. Anyway some good resolute answers to that. Thanks for clearing it up.

I've got simliar questions about line twists on reserves. I've never had line twists on a reserve, and mine is loaded barely over 1:1, but I have had to chop a twisted up Stiletto. Question is, are line twists on a higher loaded reserve always recoverable, or can it spiral you in? Is the "spiraling in under line tiwists" a function of wing design (highly elliptical) or wing loading (highly loaded)? I'm thinking it's the former, but I've got no experience with highly loaded, twisted reserves. I would hope any reserve would fly straight with line twist until you could kick out. Who's got some info?



John,

Part of it is aspect ratio. A higher A/R canopy, like a 9, will be more likely to spin up than a low A/R canopy, like a 7 cell. Also, I believe the H/P 9 cells have a a steeper trim angle then 7 cell reserves.

Sparky
My idea of a fair fight is clubbing baby seals

Share this post


Link to post
Share on other sites
All square reserve canopies are packed with three intentional line twists, just below the slider, for TSO drop testing. They must be "fully open and functioning" within 3 seconds for a "normal sized" sport reserve. This requirement should weed out designs that are susceptible to line twist induced spirals.

Share this post


Link to post
Share on other sites
Thanks to all for the info. I can think of few things that would suck more than being under a spiraling, line twisted reserve that wasn't kicking out. It's food for thought when you're picking out a size for your next reserve. I like to remind people that you might very likely be off the DZ and might not even be awake when you land your reserve. IMHO, a little bigger is better. It's cheap life insurance.

I like what Bill said about the intentional line twists for the drop tests. When people start loading the reserves too far above recommended levels, problems can crop up that were not seen during testing and certification.

Share this post


Link to post
Share on other sites
Quote

I can only hope the "market" doesn't drive the manufacturers to make "tiny" high performance reserves, similar to mains. We all ought to be at least slightly conservative when it comes to our "last chance" parachute.



Skydivers have never been known to be overly bright when it comes to making their rig 4 oz. smaller.

Sparky
My idea of a fair fight is clubbing baby seals

Share this post


Link to post
Share on other sites
>I can only hope the "market" doesn't drive the manufacturers to
>make "tiny" high performance reserves . . .

When I started skydiving, a PD150 main was for people with a deathwish. Now Tekno 98 reserves are popular because they can be squeezed into a rig the size of a loaf of bread.

One thing that I wish more rig manufacturers would do (I know you do this) is to offer rigs sized for sub-100 sq ft mains and larger reserves. That way skydivers are not tempted to get a rig to fit their main, and a reserve to fit their (tiny) rig.

Share this post


Link to post
Share on other sites
Quote

One thing that I wish more rig manufacturers would do (I know you do this) is to offer rigs sized for sub-100 sq ft mains and larger reserves. That way skydivers are not tempted to get a rig to fit their main, and a reserve to fit their (tiny) rig.



There are several who do. Mirage comes to mind, as wel as VSE (Infinity).
----------------------------------------------
You're not as good as you think you are. Seriously.

Share this post


Link to post
Share on other sites
Quote

It's an odds game and a skyhook changes the odds, no I wouldn't plan on relying on it but I might chop lower if I knew I had a skyhook.



That's an incredible contradiction you got going there. Sounds to me like you are counting on the skyhook.
Shit happens. And it usually happens because of physics.

Share this post


Link to post
Share on other sites
Of course you know the "market" has already driven canopy makers to make UNSAFE reserves (as far as the good/safety of the sport) when it comes to reserve choices. When I worked for a company that builds reserve canopies, I was asked many times "what is the right size reserve for me?" and my answers hopefully made people stop and think a little bit. A reserve that can't land you with only minor injuries with NO input from the jumper could very well be the reason you live the rest of your life crippled. It must be taken very seriously that your AAD might open your reserve because you are unable to. Do you really think that a sub-100 ft. reserve, loaded at 1.5 or 1.6 is going to set you down gently with the brakes still stowed? Or still with some line twists in the canopy? Remember, if your AAD fires, your reserve will be well under 500 ft. when it opens. I also remember hearing Manly Butler (who certainly knows his stuff) saying that he doubted "very seriously" if some of the tiny reserves could actually pass all the tests for certification, specifically in the total velocity requirement. It seems that a loophole in the certification is in how one accurately measures that total velocity.

Share this post


Link to post
Share on other sites
The "total velocity" requirement of TSO C-23d has been removed from the draft C23e, mainly because no one could make a reserve that anyone would buy (because of pack volume), that actually passed that requirement. I'm not primarily worried about a reserve safely landing an unconscious jumper, because no reserve can guarantee that. I'm worried about a reserve that might open in an un-recoverable spiral, because of something as simple as body position or line twists.

Share this post


Link to post
Share on other sites
Quote

The "total velocity" requirement of TSO C-23d has been removed from the draft C23e, mainly because no one could make a reserve that anyone would buy (because of pack volume), that actually passed that requirement. I'm not primarily worried about a reserve safely landing an unconscious jumper, because no reserve can guarantee that. I'm worried about a reserve that might open in an un-recoverable spiral, because of something as simple as body position or line twists.



How long do you think it will be before canopies are manufactured under C23e?

Sparky
My idea of a fair fight is clubbing baby seals

Share this post


Link to post
Share on other sites
Quote



"Options till impact"
"Keep pulling handles till your goggles fill up with blood"

I live by them.

Anyone got any others?



Yeah.
1: If all else fails 'grab the grass 'cause it's the bounce that kills'.
2: Pray.
3: Flap arms.
4: Blow hard (or suck if you are on your back).

Seriously. If things are bad you'll try anything but best NOT to let it get that bad.


Get out, Land on a green bit. If you get the pull somewhere in between it would help.

Share this post


Link to post
Share on other sites
Quote



I'm worried about a reserve that might open in an un-recoverable spiral, because of something as simple as body position or line twists.



If you are under a spinning mal and have the altitude then a slight delay after the chop to get stable before the pull would help. If you don't have the altitude then the next stage after pulling silver is (as I was taught) ARCH (or recover, same thing) as this will help stop the body spinning as the reserve deploys reducing the risk of twists etc.

One bit of advise I would give everyone is to relax & enjoy it, the more you worry the more you tense up & the more tense you are the more likely you are to cause a problem.


Get out, Land on a green bit. If you get the pull somewhere in between it would help.

Share this post


Link to post
Share on other sites
Quote

I'm not primarily worried about a reserve safely landing an unconscious jumper, because no reserve can guarantee that. I'm worried about a reserve that might open in an un-recoverable spiral, because of something as simple as body position or line twists.


I share your concerns, too, and I agree that the only "guarantee" is that you "will" land; but even with a jumper able to fly the reserve, things like off-dz landings, forced downwind landings, etc. are still why I always advise enough square footage over you to help lessen the risks of landing injuries.

Share this post


Link to post
Share on other sites
Quote

If you are under a spinning mal and have the altitude then a slight delay after the chop to get stable before the pull would help.



Who told you this, and WHY is this being perpetuated??? :S:S:S:S

Please take a look at both the actual, practical and EMPIRICAL EVIDENCE that has indeed shown differently. I am getting tired of seeing and "hearing" people continue to say this, when it has been so clearly, and REPEATEDLY dis-proven! >:(

This is exactly the type of mentality that will cause a low-timer to hesitate, and work on getting stable after cutting away from a spinning mal for the rest of his life!

Puh-leeze people, if you have an RSL in this situation ...don't worry about it, do what you have to do. And if you jump without an RSL & find you have been flung bodilly spinning from under a chopped spinning main, sure ...if you can very nearly INSTANTLY snap stable, go for it. Otherwise, PLEASE, grab & pull that silver handle. DON'T FIGHT IT!! -It may end up instead becoming the very last thing you do.

-Grant
coitus non circum - Moab Stone

Share this post


Link to post
Share on other sites
>a slight delay after the chop to get stable before the pull would help.

The only time I would ever advise this is if you have a premature opening and a resulting malfunction, say at 12,000 feet. If you pull at your normal opening altitude (an opening altitude that takes into account time to deal with a malfunction) do not take the extra time to 'get stable.' If you have pulled at your normal opening altitude, then you are already close to burning through your decision altitude; that's not the time to cut away and take a delay.

Share this post


Link to post
Share on other sites
Quote

Quote



I'm worried about a reserve that might open in an un-recoverable spiral, because of something as simple as body position or line twists.



If you are under a spinning mal and have the altitude then a slight delay after the chop to get stable before the pull would help. If you don't have the altitude then the next stage after pulling silver is (as I was taught) ARCH (or recover, same thing) as this will help stop the body spinning as the reserve deploys reducing the risk of twists etc.

One bit of advise I would give everyone is to relax & enjoy it, the more you worry the more you tense up & the more tense you are the more likely you are to cause a problem.



1. Pull
2. Pull at the right altitude
3. Pull at the right altitude while stable

Maybe you should leave giving advise to the instructors.

Sparky
My idea of a fair fight is clubbing baby seals

Share this post


Link to post
Share on other sites
Quote

Maybe you should leave giving advise to the instructors.



Agreed.

To all of the low-timers reading this thread, this is one case where I beleive jump numbers mean something. MJO Sparky has 2500+ and LiveLifeGoJump has a little over 200. Who do you trust to give advice that may save your life one day?

-
Jim
"Like" - The modern day comma
Good bye, my friends. You are missed.

Share this post


Link to post
Share on other sites
Quote

...and have the altitude then a slight delay after the chop to get stable before the pull would help. If you don't have the altitude then the next stage after pulling silver...

Quote


1. Pull
2. Pull at the right altitude
3. Pull at the right altitude while stable

Maybe you should leave giving advise to the instructors.


Alrighty, now I'm a little puzzled.
Unless I'm misreading something, you all appear to be saying the same thing.
Sparky listed rule (3) and Billvon and LiveLifeGoJump have suggested there can be circumstances where rule (3) actualy applies.
Why the fuss over LiveLifeGoJump's comment ?

-
No 'mericans were harmed during the making of this post.

Share this post


Link to post
Share on other sites
Quote

The only time I would ever advise this is if you have a premature opening and a resulting malfunction, say at 12,000 feet.


A slight tangent, but am I right to think that even in a case of high altitude cutaway (12,000ft), it is preferable to go for the reserve while at sub-terminal fall rate?

"For once you have tasted Absinthe you will walk the earth with your eyes turned towards the gutter, for there you have been and there you will long to return."

Share this post


Link to post
Share on other sites
Quote

Quote

...and have the altitude then a slight delay after the chop to get stable before the pull would help. If you don't have the altitude then the next stage after pulling silver...

Quote


1. Pull
2. Pull at the right altitude
3. Pull at the right altitude while stable

Maybe you should leave giving advise to the instructors.


Alrighty, now I'm a little puzzled.
Unless I'm misreading something, you all appear to be saying the same thing.
Sparky listed rule (3) and Billvon and LiveLifeGoJump have suggested there can be circumstances where rule (3) actualy applies.
Why the fuss over LiveLifeGoJump's comment ?

-




When you are talking about pulling the reserve after a low cutaway, you are already past the right altitude and taking the time to get stable in not such a hot choice. So that leaves "PULL". Don't count, don't look for the ground, don't think about missing your mother, 'PULL".

Sparky
My idea of a fair fight is clubbing baby seals

Share this post


Link to post
Share on other sites
Quote

it is preferable to go for the reserve while at sub-terminal fall rate?



I've had a terminal reserve opening, it was certainly quick but not as brutal as you might expect. Either way, I'm here to talk about it and that's all that really counts.

-
Jim
"Like" - The modern day comma
Good bye, my friends. You are missed.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

0