Hard openings

[SSkydiver 0]

I jump a Merit 170 that commonly opens hard. Does anyone have any idea on how i can achieve softer openings other than seriously rolling the nose.

[Kris 0]

Quote

I jump a Merit 170 that commonly opens hard. Does anyone have any idea on how i can achieve softer openings other than seriously rolling the nose.

Rolling the nose doesn't work on all canopies, even canopies that are the same make & size will react differently.

Make sure you are properly rolling the tail. The rolls should be a nice, tight and thin, usually no more than 4 or 5 are required.

Keep control of your slider at all times. Make sure it isn't slipping down the lines while you are packing. Even an inch or two will get your attention on opening. Cloverleaf the slider and pull it out in front of the nose a few inches to help catch more air.

Do not push the nose all the way inside of the canopy to the tail. Just nestle it in a bit. Pushing it all the way back can bite you when the tail whips open and forcibly dumps the nose into the air.

Make sure your line stows are the proper size and tight in the bands. It should take 12-14 pounds of force to unstow your lines on the ground.

Have a rigger check your PC to make sure it isn't too big for your canopy. If the PC is too big, the snatch force will be higher and can lead to harder openings.

If all that fails, talk to a rigger about making a pocket for your slider.

Kris

Sky, Muff Bro, Rodriguez Bro, and
Bastion of Purity and Innocence!™

[ixlr82 7]

I have a Hornet 150 that was giving me very fast openings. I had heard about Hornets doing this so I was rolling the nose a lot. As soon as I quit rolling the nose and pulled the quarter of slider facing me out to catch more air I began having normal openings. Also tight stows. Way too many people have loose band stows.

__________________________________________

[rigging65 0]

Quote

Also tight stows. Way too many people have loose band stows.

Loose stow bands have nothing to do with how fast a canopy opens. That's an old skydiver rumor. If you don't believe it, ask some of the folks testing stowless main-D bags out there right now (myself included). They work just fine, trust me.

Stow bands are there to keep your lines in order and to keep them from getting tangled around themselves (or something else) during deployment...and there are other ways to do all this without bands.

Canopies open hard because they are not properly reefed before they complete their deceleration cycle during opening. This reefing is generally accomplished by proper slider size and making sure the slider is oriented to catch maximum wind during deployment. Trim and design of the canopy also play into the game, but they really aren't something that the average jumper can change. Slider placement and orientation are. Rolling the nose basically helps give the slider a head start in doing it's job by slightly retarding the speed at which the nose spreads as the canopy gets into the air.

It's all about the slider and proper airspeed on opening.

"...and once you had tasted flight, you will walk the earth with your eyes turned skyward.
For there you have been, and there you long to return..."

[Hooknswoop 19]

Quote

Loose stow bands have nothing to do with how fast a canopy opens. That's an old skydiver rumor.

I completely agree. I can get hard openings from a reserve packed in a main D-bag with tight stows and a soft opening with a Stiletto packed in a reserve free-bag with a velcro pouch and a safety stow. I have done both.

Same thing for PC size, collaspable PC's anyway. Once the canopy is out of the bag, the collaspable PC doesn't affect the opening. It does affect how quickly the line stows come un-done, but not how hard it opens.

PD says that tight line stows are a must, they also say Sabres don't open hard.

Hook

[MontyPyhton 0]

I absolutely agree:

In therory tight line stows are the reason for a slightly slower POD (compared to the Jumper).
But this would also mean, that the POD has a higher airspeed. And higher airspeed are a major reason for hard openings because the canopy will inflate earlier.

Quote

Same thing for PC size, collaspable PC's anyway. Once the canopy is out of the bag, the collaspable PC doesn't affect the opening.

I agree also.
This theory means that the bigger PC would cause in a lower airspeed of the canopy.
Hmhhh... tighter line stows are the reason for higher canopy airspeeds and a bigger PC's are the reason for slower canopy airspeed.
That is not logically.

Oh, i had forgotten another "skydiver rumor": The differences betwen dacron and micro lines...

[hookitt 0]

Quote

Loose stow bands have nothing to do with how fast a canopy opens

Line dump and Hard openings come hand in hand. Line dump equals out of sequence deployment If the locking stows also release prematurely and the bag comes off the parachute prior to line stretch. Loose rubber bands on a standard deployment bag and Line dump go together as well. So that's true in a sense. Perhaps an explantion or a picture on how the bag you mention prevents an out of sequence deployment is in order. I saw a picture of it a while back but don't remember where.

If I find it I'll post it.

(edit: the sentence in Italics)

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

[Hooknswoop 19]

I have have seen probably thousands of deployments on video, some of them very hard. I have never seen nor do I know of anyone with video of line dump. Line dump gets blamed for hard openings all the time, yet I have never seen it. The locking stows would have to come un-done and the canopy would have to come out of the bag and begin to inflate before line stretch in order for line dump to cause a hard opening. In extreme cases (locking stows far apart on a large D-bag, heavy lines, loose stows, and a very big PC) maybe, but I still doubt it.

Show me the video!

Hook

[rigging65 0]

Quote

Line dump and Hard openings come hand in hand

That's only true if the line dump results in the bag opening and the canopy coming out before the lines reach stretch...which doesn't necessarily happen just because a couple of the stows come out all at once.

The key is to keep the bag closed until the lines are at stretch, then let the cat (er...canopy) out of the bag.

Since most people use some sort of a stow band to keep the lines in order and some sort of stow band to keep the bag closed (using lines to hold the bands in place) it's easy to think of the bag locking stows as being just another line stow...but they're very much not. The locking stows primary job is to maintain canopy containment, it just happens to double as a line stow.

There are actually two separate systems working on your standard D-bag: A canopy containment system and a line stow system. These two systems happen to co-exist in the form of stow bands, but they needn't always. The reason why line dump can result in a hard opening is that Newton's Law states that as the bag is zipped out of the pack tray, the lines want to stay put. If the stow bands are loose and can stretch out of shape, the lines may slip out and stay in the tray, thus...possibly...allowing the bag to open (if the locking stows all slip). And then you have your hard opening. But, if you could keep from using lines to maintain bag closure, you might be able to eliminate (or greatly reduce) this phenomenon, since it's the mass of the lines that is really causing the problem.

The key to a stowless or 'bandless' bag is to keep the bag-mouth closed, thus containing the canopy, then to maintain the lines in some sort of order (no harder than stacking them freestowed and covering them up with a flap to hold them in place). This can be accomplished with tuck tabs very easily and securely. And, voila, no more rubber bands to maintain.

The upsides:
1) No bands to replace.
2) Faster to pack.
3) Some folks say this "centered-linefeeding" design reduces line twists...I don't buy it, but maybe.

The downsides:
1) The bag is now more limited to the size of canopy it will accept. Not having stow bands means the tuck tabs need to have enough (but not too much) tension on the to keep them in place. Bands, on the other hand, allow for some flexibility in how much volume the bag can actually hold.
2) If you overstuff the bag, you'll warp your tucktabs (just like on riser covers) and they'll become less efficient...not a big deal on riser covers, but potentially a huge deal on a D-bag.
3) This type of bag will be more expensive. It does take longer to produce, but mostly it's gimic-marketing.

I really like the design I've been working with and I think it's got some great qualities, but for the average consumer, I'm not convinced it's all the necessary. I'll keep jumping it on my own gear for the time being and see how it tests out, but I just don't see the cost-to-benefit reward to be all that.

It's a gimic...a cool gimic...but a gimic. If you want to stay out of line twists, stay symmetrical when you deploy, that'll take care of almost all of them.

"...and once you had tasted flight, you will walk the earth with your eyes turned skyward.
For there you have been, and there you long to return..."

[hookitt 0]

Quote

That's only true if the line dump results in the bag opening and the canopy coming out before the lines reach stretch...

I suppose I should have added the part about coming out of the bag. That's what I meant about staged. Proof reading and editing comes in handy.
-

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

[rigging65 0]

Quote

--------------------------------------------------------------------------------
Quote
--------------------------------------------------------------------------------


That's only true if the line dump results in the bag opening and the canopy coming out before the lines reach stretch...

--------------------------------------------------------------------------------


I suppose I should have added the part about coming out of the bag. That's what I meant about staged. Proof reading and editing comes in handy.

Yeah, I know what you meant.
Still, I don't think that there are all that many cases of "canopy dump" out there. I'm sure there are some, but there are always "some" of everything.

IMO, the reason to look at a stowless bag is pretty much just to be lazy. It's basically maintenance free, as long as you take care not to warp the tuck tabs...and I hate looking for a spare band during a jump day.

Read my lips L-A-Z-Y

"...and once you had tasted flight, you will walk the earth with your eyes turned skyward.
For there you have been, and there you long to return..."

[kallend 1,679]

For the first 500 or so jumps on my Stiletto 150 I had consistently hard openings, regardless of who packed it or how. I had a master rigger take a look, and he couldn't see any problem. Eventually I sent it back to PD. It came back after a couple of months with a new slider, and now it opens nicely every time.

...

The only sure way to survive a canopy collision is not to have one.