darkwing

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Posts posted by darkwing


  1. Some people are cutaway magnets. One such guy, experienced people would watch him pack, and just shrug, “yup I can see why he cuts away a lot”.

    A single cutaway in a thousand or two jumps doesn’t mean anything diagnostically useful. Someone cutting away several times in a few thousand jumps has something going on. It could be packing technique, maintenance problems, or experimental or particularly edgy gear.

    People commonly want something to blame every malfunction on, but not every malfunction has a blame-able factor. Remember, you are throwing a wad of fabric and strings into a turbulent, high speed air flow. Shit’s gonna happen.

    The reverse scenario, is worth considering too...for uncommon events (cutaways for people who have none of the aforementioned risk multipliers) there will be cases of people going much longer than average between events. That doesn’t mean (necessarily) that they have anything special going for them other than the luck of the draw.

    -- Jeff
    My Skydiving History

  2. Having a lot of experience building for the military market is a plus. Looking at the photos on the web site they have a range of models and sizes. Nothing about any of them looks exotic or innovative. I suspect they are very similar to many existing canopies, but you really need to have riggers and experienced jumpers have a look at them.

    You might ask them if you can demo the canopy. Or if a group of you can try it. If they want to break into the local market, then they should be eager to let people try them. Merely having good prices isn't enough.

    -- Jeff
    My Skydiving History

  3. what others said... But you can reline it, take out some reinforcements, put on a slider, re-do the bridle attachment, and generally make it lower bulk. A long time ago, like late 1970s we did that with a canopy from ParaFlite known colloquially as a baby-plane. We renamed it the "Scare-a-plane" and put some jumps on it. The bottom line is that it isn't really worth it, unless you just like messing around with rigging stuff and jumping a canopy that doesn't open or fly as well as a modern canopy.

    -- Jeff
    My Skydiving History

  4. I don't think any experienced jumper even thinks about breathing. I don't. If there is a problem I think it is anxiety related, which doesn't make it not real, it just means the solution is to convince yourself that there isn't a problem. At worst, that comes with a few more jumps.

    -- Jeff
    My Skydiving History

  5. I was on a 4-way team that had a guy more than 60 pounds (27 kg) heavier. He was also a tandem Instructor. I was about your weight. Yes, he wore a baggy jumpsuit, but you need to think more broadly. Are there some jumping situations where your size is an advantage? Yes. We did a lot of fun hybrid stuff over the years.

    -- Jeff
    My Skydiving History

  6. I built a bunch (dozens) of canopies many years ago. I figured for the first one, the best thing to do was copy what I considered to be the best flying canopy of the time (a 7-cell 189 foil). It required much more intricate sewing than others I could have built, but I wanted to get the sewing down before I worried about aerodynamics. I still recommend that approach.

    I did a lot of seat-of-the-pants engineering and even my very weirdest canopy flew very nicely. It was a flat-rigged, double-humped, 5-cell, whose first jump was the day Mt. St. Helens blew up. We were in the air, watching the giant cloud of ash and lightning come toward us. I built it out of super cheap, really crappy (tear strength of about 3 pounds) but lightweight fabric. I just hoped it held together for at least one jump, so I could evaluate its performance. It flew and landed quite well I put a small number of jumps on it and sold it really cheap to a teammate, who put hundreds (I think) of jumps on it. It is still in a box somewhere.

    One of the problems with you diving into 3-D fluid dynamic simulations is that so many little details such as deformities at line attachments, seam shrinkage, dimples in the top skin, inflation of cells, lines, the jumper, etc. are hard to model. Sure, you'd get some insight to trying a bunch of variations in an extremely complex parameter space, but remember, lots of people have been playing with this stuff for decades, and you might, but probably won't, stumble on anything that hasn't already been stumbled on. BUT, it is about the journey, not the destination.

    My advice, don't get bogged down. Just design and build and enjoy.

    Also, don't die.

    Jeff

    -- Jeff
    My Skydiving History

  7. I was there too. I have often wondered, over the years, if USPA went to the trouble of archiving and converting such historical videos. I competed in 4-way, and very casually in 8-way (I think, but maybe that was just in 1978) and would love to see video of any of the competition events.

    I'd think someone at USPA would quickly be able to supply an answer.

    -- Jeff
    My Skydiving History

  8. Please forgive me if I say that sometimes it is a problem with the hand of the operator. Light fabrics can require more finesse, especially on some machines.

    I'm not dismissing any of the mechanical comments made by you or others, but bringing up this issue, even if it doesn't apply to you, is worthwhile as a caution to other readers.

    -- Jeff
    My Skydiving History

  9. stayhigh

    Botched exits, kinda LO's fault.
    Taking too long at the door, definitely LO's fault
    People landing in high speed area, Not LO's fault
    People flying every direction, Not LO's fault.



    My take - In the sense that these things are all important parts of organizing --
    • Botched exits, LO's fault.
    • Taking too long at the door, LO's fault
    • People landing in high speed area, LO's fault
    • People flying every direction, LO's fault.

    This is not to say that there isn't some shared blame, but if the LO doesn't hammer these in, the LO has done a poor job.

    -- Jeff
    My Skydiving History

  10. When you design a canopy, one of the things you play with is the brake settings for deployment. There can be a wide range of behaviors with different settings, and the behaviors are not the same from one canopy design to another.

    The original thought was to prevent canopy surge, and to make canopies open better. It is OK to still view it that way. Just don't assume you know what will happen with a different brake setting than your canopy came with.

    -- Jeff
    My Skydiving History

  11. For a long, long time now I've thought it might be useful to just use a high porosity fabric, rather than port it. I certainly understand that a soft, uncoated, high porosity fabric might be harder to handle during manufacture, but it still seems worth trying.

    -- Jeff
    My Skydiving History

  12. airtwardo

    ***

    Two pin reserve with a Martin Baker handle & a last hope rope...could be one of several I can think of. ;)



    I used to own a Top Secret. The photos confuse me though. I don't recall they had a last hope rope on them or Martin Baker handles (which I still like more than most people). Either the handle shown isn't martin baker anyway, or my brains are scrambled ( which is likely).

    -- Jeff
    My Skydiving History

  13. "Mark the Narc"
    "Crazy Ed" (there are many Crazy Ed's in the world.
    "Ganja" (because his last name was Weed)
    "Maplehart," or "Dougie Maplehart" (neither was related to his real name)
    "Wragg" because when your last name is "Wragg" you have an automatic skydiving nickname

    "Pilot Error" for one of our pilots

    Four of the six above are dead. Maybe we should avoid nicknames.

    -- Jeff
    My Skydiving History

  14. About 10 years ago I tracked through a dispersed flock of white birds of some sort at about 4500 feet. Didn't hit one.

    Another time a teammate during a 4-way competition landed with some bird poop on the front of his jumpsuit. Never saw the bird. I imagine the bird had an emergency "evacuation" when my 300 pound teammate approached from above in free fall.

    -- Jeff
    My Skydiving History