sundevil777

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Posts posted by sundevil777


  1. 1 minute ago, gowlerk said:

    Spoken as the true Airtec lover and defender you have always been here. Two points. Airtec no longer requires, only recommends 5 year servicing on the new units. Which means that almost no one will bother, making one of your points moot. And the other thing is that the demand for used AADs far exceeds the supply. This makes buying a new one the cheapest option on a per year cost basis.

    My point about getting a used unit applies not just to Cypres. I understand that the used market is tight. Sometimes the per year cost matters less than the "right now" cost. For some, the desire to have a predictable cost (warranty that lasts) is important.

    I am a fan of the Cypres, but will be considering others when I need to replace mine in few years. The competitors definitely have some advantages, as I have mentioned. I even bought an Astra way back when I returned to jumping after several years away. Fortunately others persuaded me to reconsider and I was able to return it. Back then the only other choice was the original version of the Cypres. The exchange rate at the time allowed me to buy it at perhaps the lowest price ever.

    • Like 1

  2. The cypres does have the benefit of being in warranty for the entire lifetime if you get it serviced as recommended.

    The mars has a 2 year warranty. If the battery on a mars does need to be replaced, even though the mfg says it should last 15 years, it would presumably not be done for free. It is great that it shows the remaining battery life left, and it also shows the pressure the unit is sensing for confirmation to a local barometer. If that pressure check is not within the recommended tolerance, then presumably fixing the unit would not be free.

    Of course the 15 year warranty of a cypres comes at a cost, and most never need to get their AAD fixed at any time during their life. I think we should acknowledge the trade-off when discussing cost comparisons.

    Another point worth acknowledging is a Cypres can seem to have no problems at all, no problems during the start-up self-test, and then when SSK does the full series of tests including accuracy/resolution at the fire/no fire limits, high/low temp, vibration, etc it fails to meet the original standards and requires repair before returning to the customer. Does this mean it would have necessarily failed to save your life if needed? No, but it does mean that the mfg is not comfortable with the self test being the only check on the proper function of the unit, and for very good reason - some fail! The self test can't check things to the same extent as can be done at the factory.

    The self test cannot simulate a jump (simulate the pressures on the transducer) to test the entire system, and cannot test it in harsh environmental conditions. It just is a partial check of the health of the electronics.

    If cost for an AAD is critical, then getting a used unit is also worth considering. If a used unit is bought at the right price, then the cost/year should be about the same as if buying new. I hear finding used units at the right price is the challenge.

    • Like 1

  3. 1 hour ago, massis said:

    then I revert to my original statement: there's no way i could pull out my loop far enough to easily hold it down with enough to spare so I could take out the pin and put it back in. I need to hold a fair bit of tension on the pullup cord (or packing tool) in order to have enough loop available to get the pin through...

    It might be easier than it seems, if you haven't actually tried.

    Unnecessarily high closing loop tension is common.


  4. 1 hour ago, massis said:

    I know that technique but found - in my limited experience - that even then the loop wears faster. However I never considered using the pin to pull the loop out a bit to reduce the tensions, which I assume now sundevil was talking about.
    I originally imagined him pulling the loop out far enough so that you can place a finger on it to keep the tension of the outer end and remove the pullup cord and then insert the pin, which made very little sense :-)

    You are correct, while I'm holding down on the loop with my thumb, the pin can be taken out and reinserted (there is no reason to want to do that), and of course the pullup cord can be removed with no wear on the loop.

    I do not "use the pin to pull the loop out a bit...", I just use the pullup cord to get the loop out far enough to allow the pullup to be removed without any friction.


  5. I would be more concerned about losing it from the occasional combat RW encounter. The mag and Grellfab also protrude so far, which makes interference with the mud flaps while looking to the side under canopy worse. 

    I love the https://chinmount.com/ alternative. I haven’t seen anything so low profile, so inexpensive, so well made, and can be used on a Kiss helmet. The ability to dislodge, and break or cutaway is superior to the mag IMO.


  6. 2 hours ago, massis said:

    I'm going out on a limb here and say that if you can pull your loop so far through that you have enough spare to do that, your loop is WAY too long and will have far too little tension on it to be safe.

    When I was in AFF they told us that if your hand didnt hurt after packing and you weren't nearly crying when closing the final flap, your loop is likely too loose. While I do now think that's a bit of an exaggeration, I do see the importance of having a tight loop, which means pulling it through the final grommet more than 1/2" is probably way to loose.

    I understand your comment about the loop being too long, but no need for concern. It doesn't need to be much past the final grommet for the technique to remove the pullup with zero tension to work.


  7. 2 hours ago, massis said:

    I guess you're holding it wrong then. Gripping the packing tool with 4 fingers hurts a LOT less than wrapping the pullup cord around your hand and pulling. Mainly because the stress on your hand is focused in the most outer spot where touches your hand, while the packing tool can distribute the force nicely across 4 fingers.

    On top of that, the round cord is much smoother to remove from the loop with the pin inserted, causing less wear on the loop in my experience. After 60 jumps my loop was good as new.

    I was holding the pack tool as you describe, and I still say it is less comfortable than an ordinary pullup.

    I can agree with you that the spectra cord will wear the closing loop less than a typical pullup used in the normal way, which means withdrawing the pullup when full tension is on the loop/pin. I withdraw my pullup while there is zero tension on the loop, because while the loop is pulled through with extra to spare, I hold my thumb on the loop against the grommet until I get the pullup removed.


  8. I can’t understand the benefit to the pack tool, such a small diameter it hurts more than using a wide pull up cord/ribbon. Even those seem fancy to me, for I grew up using gutted 550 cord. I’ve started using that again the last couple weeks.


  9. 1 hour ago, Bkleven7 said:

    The Vortex is DOM 2018 so hopefully it’s pretty easy to retrofit. 

    Definitely would still plan to cutaway at away at the same altitude with or without one. Nonetheless based on what I’ve researched skyhooks seem to have all advantages and no disadvantages if you’re planning to use an RSL, which I am. 

    My question was more if installing it would affect the TSO of the container as a couple of commenters mentioned. My thought process is...Tens of thousands of rigs have been manufactured without a skyhook, and the cutaway/RSL system has worked well for decades. I wouldn’t want the installation of the skyhook to be sketchy/complicated and interfere with the more essential and standard features of the rig. Not sure if retrofitting it on a rig that wasn’t initially meant for it could lead to it threatening the more standard safety features.

    The "affecting the TSO" that was mentioned was only related to the hypothetical case of having someone modify a rig to use a skyhook. You can stop thinking about that completely.


  10. I wonder if the L&B Solo has adjustable volume?

    If we want to go old-school, then of course the original dytter that few have ever seen was definitely not adjustable for volume, and the paralert from Steve Snyder (even less likely to be recognized) was also not. I think the old time-out was fixed volume.

    Every other type I know of is adjustable.


  11. I think the value of lubricating the inside radius of the 3-ring loop where it contacts the release cable is important and underappreciated. Of course lubing the cable in general is important, but I think a substantial part of the overall force to pull a release cable is due to the drag right at the loop, and applying lube to the loop is a subject worth addressing.

    The attached pic provides some evidence to support my claim. Mr. Booth used it many years ago in a thread where he advocated the benefits of the traditional, large 3-ring system over mini rings.  The different graphs were intended to show how pull force varies with the load at the loop, with the different systems having a different mechanical advantage (and some effect from inconsistent construction affecting mechanical advantage) which results in different loads at the loop.

    While on the subject of reducing pull force, we might as well touch on what I think is now widely accepted that silicone lube is best instead of some type of oil or other product. I think the gel type silicone grease, such as the cypress loop grease is better than the spray type. Other threads have devoted a lot of discussion about food grade silicone sprays, but the gel makes more sense to me. Please correct me if I am wrong.

    Perhaps there would be fewer instances of hard pulls and only one side released if lubing the loop were standard practice. I can't remember it being emphasized in all my years. I put the gel grease right on the inside radius of the loop, what do you think?

    pull_force_comparison.JPG


  12. If the handle is pulled somewhat slowly, or without maximum effort, I think there is a natural tendency to feel the cable moving gradually and then stop when a change in the level of force required to move them occurs. This change of force happens when one side releases first. The length of pull required to release the 2 sides are slightly different - intended to release the side with the RSL last to prevent reserve deployment if a lazy pull is done. The jumper would hopefully recognize that only one side is cutaway and complete the pull. I think it is not reasonable to expect the cable lengths to be just right so as to prevent one side releasing first, therefore the lengths are setup to make the RSL side last.

    The way to prevent the issue is to apply maximum effort and distance of pull - the expression used to be "punch it". The training to sweep the cables free is I think a recognition that students can't be trusted to punch it all the way out. Every time I've activated a release system, whether capewells or a 3-ring release, I've never had a sense of how much force was actually required because I punched it like my life was on the line.


  13. 14 hours ago, meat.missile said:

    Where do you get this idea that I can’t back it up with facts? Are you really so ignorant about helmet construction that you can’t understand how the G4 will protect more than the G3? 

     

    A good example is saying wood is a better insulator than glass. We don’t need to see numbers to know it’s true. 

     

    Of course we understand the G4 will perform better, but you insisted the G3 has negligible benefit, insignificant. Decide which.

    Of course wood is a better thermal insulator than glass, but it is not insignificant. 

    Engineers worth anything don’t think like that.


  14. 8 hours ago, Maddingo said:

    It's an elliptic canopy so it is quite normal. Even my Volt turns a lot and it's a semi, also why are you on such big elliptic canopy? How much jumps do you have?

    I don’t understand your comment about it being so big.


  15. 2 hours ago, meat.missile said:

    Try commenting in good faith. 

     

     The pro tech would be better than the G3, but I’m not sure how it compares to the G4. 

    Are you trying to be a troll? 


  16. What is so magical about that standard? I am certain that a tougher standard could be written, that would provide more protection that would help in some scenarios, and that would require a heavier, bulkier helmet to comply. The standard is a compromise, but you don’t seem to see it that way. I have no doubt that it performs better than the G3, but to assert that not meeting the standard makes the protection provided insignificant is not correct. This is not how engineers should analyze problems. I was sure we could have an interesting conversation about the new helmet, but this is really tiresome. 


  17. 2 minutes ago, meat.missile said:

    When you have a fundamental understanding of a subject you don't always need to see the numbers to know the general outcome. 

     

    Anyway, found the reference to the standard from chuting star.

    "The XPS 72-600 is a Skydiving and Windtunnel Helmet standard used for the G4. The impact testing is the same as the EN966 standard for drop height and conditioning prior to impact (5.47 m/s at roughly 1.6 meters). The impact must be less that 250G. The XPS standard also requires a SNAG test, while the EN966 does not. The XPS requires the chinstrap to be on the exterior of the shell so that a line cannot pass up the inside of the helmet, while the EN966 does not. The EN966 is a Hanggliding helmet standard and also has a penetration test, while the XPS does not require a penetration test. However, Cookie has tested the G4 helmet for penetration according to EN966 and it passes with "great results," says Cookie."

    Knowing the general outcome is very different than so confidently asserting the G3 provides insignificant protection as you have defined. You are not the only one with an engineering/technical background. The info you provided does nothing to clarify how much better the G4 is. It would have been very easy for Cookie to let us know how much improved their new helmet is, but they did not. Quoting the new standard's test setup and pass criteria gives us nothing with which to compare the G3. Quoting what the old DOT motorcycle helmet standard was does nothing to inform us of how well it compared to typical helmets that were common before the standard.

    Most engineers I think would not make such assertions without evidence. Why are you so determined to defend your position. I really don't understand. Can't this be discussed without insults?

     


  18. 11 minutes ago, meat.missile said:

    Dumb, just dumb. 

     

    Standards are a pain. To add some more info, XP S 72-600 is EN966 + some stuff relating to snag resistance. But as far as impact goes, it is the same. (I can't find my source on that, but I'll keep looking for it.)

    You assert "insignificance" without any data to compare the performance. I have no doubt the G4 performs better than the G3. Without data to back it up, your assertion that the G3 protection is insignificant as you define it, is unworthy of an engineer.