Apr 24, 2012, 3:33 AM
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SIGMA rig: premature container opening questions
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OK, so I understand that SIGMA container is superior to other tandem containers in a way that if the main container opens, the drogue is automatically released, preventing the out-of-sequence deployment. That has been the feature marketed quite heavily over the years and it makes a lot of sense (especially, when you examine the 'tandem fatality list' prior to Sigma introduction...).
The question is: who experienced this feature 'in action', meaning container opening and autiomatical drouge release. I would like to hear some first hand accounts of some thankful users :-).
And the second question: did anyone experience out-of-sequence deployment on Sigma? (I cannot see that happening, but still...).
The container closing loop and where the drouge anchors for drouge fall are one and the same. So a broken closing loop or a pulled handle without the drouge saftey pin in place will open the main container and release the drouge chimney. I would hesitate to say it automatically releases the drouge because it may not have been deployed yet and you could have it ball up in the pouch and horseshoe.
Check your closing loops and the pin. I have seen the pins come unseated after they were packed! Gear checks and heads up packers.
This is kind of off topic but I have a question about the patent on the Sigma drogue release. Is the use of a drogue chimney and main closing loop integral to the drogue release completely patented to UPT and the sigma rigs? It is obviously the best system on the market for tandem main closing and no one else uses it. For example, the new strong tandem rig is more modern than the Sigma but it still uses a 3-ring release on the drogue.
This differs from the 3-ring release on main risers. Although it was invented by Bill Booth, all containers now use it, but I bet there is an agreement in place and some royalties paid. So is UPT not licensing the drogue chimney design to anyone else but is okay with the 3-ring patent being used by all?
This is kind of off topic but I have a question about the patent on the Sigma drogue release. Is the use of a drogue chimney and main closing loop integral to the drogue release completely patented to UPT and the sigma rigs? It is obviously the best system on the market for tandem main closing and no one else uses it. For example, the new strong tandem rig is more modern than the Sigma but it still uses a 3-ring release on the drogue.
This differs from the 3-ring release on main risers. Although it was invented by Bill Booth, all containers now use it, but I bet there is an agreement in place and some royalties paid. So is UPT not licensing the drogue chimney design to anyone else but is okay with the 3-ring patent being used by all?
From what i remember when BB designed the 3 ring, he released it openly and people made copies of it that were "subpar". I dont think he is open to making that same mistake again.
Except I was the cameraflyer with a whole bunch of lines coming at me...
Everybody had missed the bag lying on the floor on exit.
The tandemcanopy opened fine in the end, and yes the drogue was pulled out of the pocket before the TM could do it himself, he was going for it right out the door. By the time the canopy had passed me, the half linetwist was gone as well.
From my point of view, it kinda looked like a direct-bag staticline type of jump.
the new strong tandem rig is more modern than the Sigma
In what way?
In reply to:
This differs from the 3-ring release on main risers. Although it was invented by Bill Booth, all containers now use it, but I bet there is an agreement in place and some royalties paid. So is UPT not licensing the drogue chimney design to anyone else but is okay with the 3-ring patent being used by all?
The 3-ring patent expired approximately 13 years ago (20 years after its invention). I believe, Bill Booth had been charging other manufacturers 6 dollars for every rig using the 3-ring release system (1 dollar for every ring). I am talking about solo rigs, not sure about the tandem drouge release 3-rings.
For example, the new strong tandem rig is more modern than the Sigma but it still uses a 3-ring release on the drogue.
my guess why the strong TNT still uses a 3ring drogue release is related to the KISS principle: Keep it simple sweetie (or keep it short & simple). its easy to inspect and more or less fool-proof and maintenance free.
also from what I have seen you can have some substantial wear on the drogue attachement of the sigma inside the chimney...
some risk for out of sequence deployment exists with sigma if the drogue release pin is not seated properly. To seat the pin, fit the pin into the closing pin, and then pull the handle that would deploy the main. This will seat the drogue release pin in the closing pin. Sometimes this is not necessary but sometimes it is very necessary.
OK, so I understand that SIGMA container is superior to other tandem containers in a way that if the main container opens, the drogue is automatically released
incorrect. Read my post above. The best you'd get when the main container opens would be partial drogue bridle released (and then hopefully? the drogue released from the BOC pouch). Whether or not the dbag would extract the drogue from the pouch would depend on the drag of the dbag and the force needed to pull the drogue. You could end up with the drogue being pulled or you could end up with a horseshoe.
The sigma is designed with the drogue release pin in place preventing (if the drogue release pin functions normally and not malfunctions as per my post above) the main container to open. If the drogue is pitched then the drogue release pin is pulled and allows for the main container to be opened when the time is right with the handle (on either side of the TI).
(This post was edited by 5.samadhi on Apr 26, 2012, 7:17 AM)
Sigma drogue release. ... no one else uses it. For example, the new strong tandem rig is more modern than the Sigma but it still uses a 3-ring release on the drogue.
This differs from the 3-ring release on main risers.
Not by much. Strong uses mini 3-rings on their drogue risers, but a large (size "0") on the bottom of their drogue bridle.
All the other tandem rigs use 3-Rings for drogue releases: later Vector 1, all Vector 2, Strong Dual Hawk, Parachutes de France, Racer, etc. The basic dimensions still come from Relative Workshop's 1998 manual on 3-Ring risers construction. The biggest difference is that most drogue releases have an extra grommet to accomodate a double-ended white loop and two release cables (similar the "Universal" cutaway system available on Studnet Dolphins).
Precision's tandem rig also uses the 3 rings, FWIW.
What rig is that?
I don't think it's out yet, but a dude can't remember his name, stopped by our dz with it. It looks like a wings with vector parts sewn to it. Sigma for the win again. I don't get why people buy any other tandem rig brand new.
I think the Sigma rig is a really great rig and better than the Dual Hawk or Vector 2, but it still has it's own set of issues IMHO. Precalapsing the drogue in a bag lock situation there may not be enough drag to release the risers after a cutaway. Also the line used for release the main that is attached to the blue and orange golf ball shrinks, and over time will shrink enough to allow canopy deployment without pulling the handles (yes this is a wear item that needs to be monitored). All that said I still like them better than the others IMHO
(This post was edited by TheCaptain on Apr 26, 2012, 3:00 PM)
Precision's tandem rig also uses the 3 rings, FWIW.
What rig is that?
I don't think it's out yet, but a dude can't remember his name, stopped by our dz with it. It looks like a wings with vector parts sewn to it. Sigma for the win again. I don't get why people buy any other tandem rig brand new.
The TSO application just got filed for it... It looks like a Wings tandem rig would (anyone care to guess why? ).
Anyways, its a brand new system but I see no improvements that would warrant people even changing to them from SDH's, much less going from a SIGMA to them.
the sigmas do have there own issues.. I wish the golf ball strings were a little longer to account for shrinkage and the bungee a little stronger. The golf balls don't always retract all the way and I get worried about the them snagging on the 3rd loop of the toggles during aggressive turns.
the new strong tandem rig is more modern than the Sigma
In what way?
In reply to:
This differs from the 3-ring release on main risers. Although it was invented by Bill Booth, all containers now use it, but I bet there is an agreement in place and some royalties paid. So is UPT not licensing the drogue chimney design to anyone else but is okay with the 3-ring patent being used by all?
The 3-ring patent expired approximately 13 years ago (20 years after its invention). I believe, Bill Booth had been charging other manufacturers 6 dollars for every rig using the 3-ring release system (1 dollar for every ring). I am talking about solo rigs, not sure about the tandem drouge release 3-rings.
Its more modern in that it has been on the market for less time and is a newer product. Sorry if it was unclear.
So is that how patents work? 20 years and anyone can use it without royalties? I don't know when the Sigma came out, but so is it then possible that other companies could use the drogue chimney design after the patent expires?
the sigmas do have there own issues.. I wish the golf ball strings were a little longer to account for shrinkage and the bungee a little stronger. The golf balls don't always retract all the way and I get worried about the them snagging on the 3rd loop of the toggles during aggressive turns.
So, because the golf ball lines are too short, they wont always retract, you think there's better out there?
IMO, nothing is perfect, but the SIGMA is the best we have (that I know of) and I look forward to the day when I can say that about a new rig.
(This post was edited by theonlyski on Apr 26, 2012, 4:58 PM)
I think the Sigma rig is a really great rig and better than the Dual Hawk or Vector 2, but it still has it's own set of issues IMHO. Precalapsing the drogue in a bag lock situation there may not be enough drag to release the risers after a cutaway. Also the line used for release the main that is attached to the blue and orange golf ball shrinks, and over time will shrink enough to allow canopy deployment without pulling the handles (yes this is a wear item that needs to be monitored). All that said I still like them better than the others IMHO
I want to learn more about the Precision tandem rig... stays closed even if the loop is snapped and the reserve clears the dorgue apparently
2c from a kid half way through the Sigma course...
That's because they put a hesitator loop on the main as well. If the closing loop snaps, the hesitator should keep the main in the container if the drogue isn't set.
But, that's if the packers use them, I can see them breaking a bunch and packers just not replacing them.
so there is a system that - in the hypothetical situation of the closing loop breaking - leave with a potential horseshoe. did any such incident ever happen and was it documented in any way? no one has anwered this question so far
then there is a system that uses a dual closing loop and another with a hesitator loop on the main, both preventing the initial questioned situation.
as i am not familiar with the tandem racer, can anyone answer how they solve this scenario?
For the record, the Racer Tandem system also has 2 pins to open the main (one releases at drogue toss, and the other at drogue release). So the Sigma is not the only system that prevents premature main openings (or out of sequence main deployment). You can't get the main out unless you've tossed the drogue first. No drogue = No main.
I don't get why people buy any other tandem rig brand new.
Some reasons without thinking too much
1. Some people don't like Sigma main 2. Some people don't like the Skyhook 3. Some people prefer different location of the drogue att. point. 4. Some people don't like the idea of shipping the spare parts overseas especially when they need them for yesterday. 5. Some people want a tandem rig that will go way over 1000 jumps without major repairs ( this is subjective because some tandem masters will find the way to ruin the gear even if it's made of steal and concrete, but in general tandems like NEXT and Atom will last longer than the Sigma.......I'm talking from personal experience here ) 6. Some people prefer a pop top or semi pop top design.
There's gear out there for every taste and preference. Saying that this or that is "the best" or "the safest" gear is just a bit overreacting.
I want to learn more about the Precision tandem rig... stays closed even if the loop is snapped and the reserve clears the dorgue apparently
2c from a kid half way through the Sigma course...
That's because they put a hesitator loop on the main as well. If the closing loop snaps, the hesitator should keep the main in the container if the drogue isn't set.
But, that's if the packers use them, I can see them breaking a bunch and packers just not replacing them.
I've seen the test jump pictures. The drogue is out.... I don't know sqwat about tandems...I'm assuming the main container is staying closed because of a three-ring configuration or a second loop. I would like to better understand this. See attached picture. Edit to add: Could it be the attachment location?
In regards to why someone would choose a rig over Sigma...I'm hearing price point.
(This post was edited by ManagingPrime on May 4, 2012, 8:49 PM)
I've seen the test jump pictures. The drogue is out.... I don't know sqwat about tandems...I'm assuming the main container is staying closed because of a three-ring configuration or a second loop. I would like to better understand this. See attached picture. Edit to add: Could it be the attachment location?
I've had the rig in my hands, though I'm not sure they would like me to post any pictures of it.
The container is held closed by a flex pin (kinda like on the SDH) and a safety stow of drogue. The drogue is attached via a 3 ring (basically in the same location as a SDH)
There are things that IMO aren't going to put it above the containers on the market, but only time will tell. I'm just a rookie TI/Rigger. What do I know?
The safety stow does keep the container closed if the main closing loop breaks. I jump tested it myself about a month ago.
As for wear, it doesn't show much if any wear under normal conditions. I don't think packers will skip this important step, as it only adds seven seconds to my pack job.
One thing I noticed during the testing. If the closing loop breaks and the safety stow is used to keep the container closed, the bungee shows a little wear. I'm advising people to replace it then.
Let me know if you have any questions about the rig.
No, it is other way around. You can't open main conteiner without throwing the drogue first,..
Absolutely, totally, dead wrong. If you reach back and grab a hand-full of bridle instead of drogue then that bridle will fully extend about two and a half feet behind you, release the safety pin which prevents that out-of-sequence deployment, and then totally allow you to open your container (without the drogue out) when you start pulling golf balls.. Granted, you would have to be an idiot to not do a complete systems check after throwing your drogue and not sensing that "slowing down" feeling, but I can promise you as an instructor that I have seen this happen on a guy I was evaluating.
I was told to look over my right shoulder to visualy check for drogue inflation, and this is what I always do.
Such practise should eliminate bridle pull followed by golf ball pull,...
Also during my TM training we did 1 jump when drouge was thrown on 3000 meters (jump was from 4000) to feel different speed when it is not inflated. It is hard not to notice that something is wrong no drogue scenario.
That's an odd one for sure... Did they not notice that it wasn't a plastic ball they grabbed??
It also do happen that student tandeminstructors forget to set the drogue and never or to late realise their mistake. (Hint, if you see the videoman in headdown in front of you, ...).
That's an odd one for sure... Did they not notice that it wasn't a plastic ball they grabbed??
No, he did not. He grabbed what he thought was the drogue handle and threw it, then completed his system check,. He did not actually spot his drogue (obviously) on "check drogue", but continued with his system checks all the way to drogue release altitude at 5000 feet. That's when the fun began.
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