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Everything posted by sundevil777

  1. sundevil777

    Diff between RW & Competition jumpsuits

    The important thing is to call the mfg with your measurements and let them help you decide how to get a fall rate that will allow you to easily play with others. Nobody flies best when having to fly near the upper or lower limit of what they can do.
  2. sundevil777

    Main Pilot Chute Question

    It may be that the kill line is too long, so it isn't collapsing enough, allowing it to grab enough air to twist. That is the theory anyway that some will propose.
  3. sundevil777

    Can You Install a Skyhook Into any Rig? How?

    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.
  4. sundevil777

    Can You Install a Skyhook Into any Rig? How?

    Not just the Jav, it is also available on the Icon and Vortex. Maybe others also, come on people!
  5. sundevil777

    Lubricating the 3-ring loop

    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?
  6. sundevil777

    Audibles with adjustable volume?

    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.
  7. 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.
  8. sundevil777

    Audibles with adjustable volume?

    It is wise to be concerned about damage to your hearing, but wind and airplane noise are also damaging. I prefer the noise filter type earplugs such as these: Many threads can be found on the subject, and reports of hearing your audible more easily with all forms of earplugs is I believe always true.
  9. sundevil777

    Fuel per jump

    Electric plane thread
  10. Dacron lines thread Dacron lines ought to be considered.
  11. sundevil777

    Boeing 757 hard landing in the Azores

    Ha! “Were they really able to buff out all the damage”
  12. sundevil777

    Full-face helmets

    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.
  13. sundevil777

    Hurricane to Cool openings

    I don’t understand your comment about it being so big.
  14. sundevil777

    Full-face helmets

    Are you trying to be a troll?
  15. sundevil777

    Full-face helmets

    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.
  16. sundevil777

    Full-face helmets

    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?
  17. sundevil777

    Full-face helmets

    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.
  18. sundevil777

    Softest opening canopy

    Quite right! Dacron just works well, and not just because it is able to absorb some of the shock:
  19. sundevil777

    Abnormal Closing Loop Wear?

    I always withdraw the pull up cord when there is no tension on the closing loop. I put my thumb on the loop during the final pull through the final grommet, when it is pulled through farther than needed as the pin is inserted, and withdraw the pull up cord with virtually no resistance force at all. This has resulted in a closing loop that still looks absolutely new after about 90 jumps. I think that if you can't pull the closing loop through farther than needed to accomplish what I've described, then the loop is too tight. Others may think it means my loop is too loose, but I don't think so. So often I see people pulling their pull up cord very fast through a very tight loop, and even if they situate it under the pin before withdrawal, I think the potential for needless wear is great. The modern, wide pull up cords with heat-sealed edges at the ends I think are particularly harsh on closing loops. The old-school gutted 550 cord were much gentler I think.
  20. sundevil777

    Full-face helmets

    Quite right. One would think that if the G4 was such an improvement, Cookie would be advertising about it, with graphs and videos from the tests and such. I would expect that skydivers being the tech wonks that we are, we would eat it up. Many more people would be replacing their G3 if there were solid data to back up the improvement. We are left to wonder if the numbers actually are impressive. The standard to which the G4 complies might result in 50% less g loading, or 5% or who knows what? That standard may be no more ambitious than the old DOT motorcycle helmet, which was not at all ambitious.
  21. sundevil777

    Full-face helmets

    Back when dinosaurs roamed the Earth, motorcycle helmets had their first (I believe) impact standard in the US issued by the DOT. Many years later, a private organization issued the Snell standard because it was recognized that helmets could, and should be much better. The Snell standard was much tougher to meet. At some time in the future, we may conclude that the standard to which the G4 complies is inadequate. It would be wrong to say that standard provides insignificant protection just because a better standard might exist. I only wanted to know how insignificant a G3 is compared to the G4. Is that somewhere in the deluge of documents?
  22. sundevil777

    Full-face helmets

    I also have a mech eng degree. I haven’t spread any bad, life threatening info. Please take it easy, I didn’t think curiosity would evoke such a reaction. Someone might actually know the answer to how well the old vs new helmet compares. It definitely will be better than nothing.
  23. sundevil777

    Full-face helmets

    It depends on what you mean by meaningful. You are speculating.
  24. sundevil777

    Full-face helmets

    There is no misunderstanding of how helmets work. The point I would make is that without data, we don't know if the liner for a G3 is 0.1% or 1% or 10% as effective as the shock absorbing material used in a G4.
  25. sundevil777

    Full-face helmets

    Without test data to compare the performance of a G3 vs G4 vs no helmet at all, we are speculating on how negligible the impact protection of a G3 or any other helmet is. Maybe we already have the data to make that comparison?