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RiggerLee last won the day on May 5

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  1. RiggerLee

    How much does slider size actually affect openings?

    Interesting. Taking a wag at the cell width of a 97 I would guess that it was about 21 inches. Allowing about an inch on each side for the inset of the grommets. That still makes the slider about 8 inches wider then the cell. The depth of the stabilizers also factors in. Some canopies have a stabilizer attachment on the B line a good bit lower then the A attachment points. I doubt that it's 4 inches on a 97. So for a 97 the front of the slider is probable setting on the bottom skin but not by that much. The back half of the slider will not be supported on the bottom skin and is probable doing most of the work of holding the canopy closed during the initial part of the opening. Doing more math, by the time you get to a 135 I'm pretty sure that the whole slider is fully engaged. None of it would be sitting on the bottom skin. So I can kind of see where they getaway with a universal slider size and I guess they add just a bit for the larger sizes to help hold the slider up an decelerate the jumper. That also explanes why there is a market for after market slider for their canopies. It leaves a good bit of room increase the width on larger canopies or play with the aspect ratios. Lee
  2. I used to print a t-shirt, "CAN I BE ON YOUR ASH DIVE?" DZ is not a place for thin skinned snow flakes. If words bother you what are you going to do when your friend bounces and you get his gooey stuff all over you? Say what is all that stuff? When I was a student I figured there would be a lot of blood but when peoples bodies break open it's all this clear gooey stuff that dries and looks kind of like thin snot. Any body know what it is? Lee
  3. RiggerLee

    Extreme engineering

    Don't get too hung up on a major or specialization. My experience is that if you are an engineer you are an engineer. What you study in school is just a starting point. You will grow into what ever industry you wind up in. Example, I'm working for a rocket company. We're rocket scientist. The head guy is an electrical engineer. My boss who does the engine development and got put in charge of recovery systems came out of the petroleum industry. I'm not sure about his degree if he has an engineering degree it's probable in mechanical? Another is just a blue collar guy out of the air gas industry. He does all of our cryogenics and most of the construction on the rocket. There is a contractor that is a dynamacist that I'm sure has aerospace degrees. But I think I might be the only person here at the shop that was an AE, aerospace engineering major and I'm the seamstress. Maybe that should tell you some thing about the viability of that degree path... If I was to actually give you advice, I'd tell you to study your math. Maybe even get a minor in it. Regardless of what your paper says, some thing general like mechanical engineering or EE or some thing more specialized like AE, there will be a place for you in what ever industry you presue. But just as an example. I'm working for this company as their parachute rigger. Thinking back on what I've used from school. Alot of my work with pattern sets and design uses a lot of protective geometry and differential geometry. Unrolling sections of surfaces out of 3d space in to 2d to form pattern sets. Reentry models goes back to my AE courses. I cracked an old Thermo text a couple of weeks ago looking at a problem we were having with our pressurization system. Analyzing INU data from drop test. People say that you will never use what you learned in school, I've found the exact opposite. Particularly the math. But more than that I find the things I studied in school just generally inform me of how things will behave. And I never actually finished my degree. Some time I wonder what else I would have learned. It was invaluable but it was also just a starting point and nothing more then a foundation upon which to start building your experience. What you learn afterwards is what your career is built from. Lee
  4. RiggerLee

    How much does slider size actually affect openings?

    I was going to suggest he cut a hole in the center of his slider with a coffee can but I figured people would give me too much shit in this day in age. Lee
  5. RiggerLee

    How much does slider size actually affect openings?

    I don't really understand your post. If you want to alter the openings of the canopy your packing technique is by far the easiest thing to change. Is this a new canopy or used? The first thing I would check is the line specs, particularly the break lines. Could it have been built with the wrong break lines? Did some one replace them between relines? Altering the break set depth is the next easiest way to alter the openings. The slider is the third option. How big is it supposed to be? Was it assembled with the wrong slider? Did some one, perhaps of a different weight or tracking habits change it out to slow it down? Changing it's size or it's ratio can alter when the canopy becomes dominant over the slider on opening. Between the three you should be able to get nice openings out of a canopy. Lee
  6. This is a good example of some one off the center of the bell curve where a larger or domed or flag slider could be handy. A better question is are the openings with dome sliders more consistent? That's a different question to whether they can fix a problem under those conditions. Let's say you plotted opening shock for a hundred openings. You get a bell curve. What we want is to avoid the out liers at the top end of the graph, they hurt. Their are a lot of decisions you can make in design, including slider size, that can shift that curve right or left. Keeping in mind that you don't want it to open too slow as well. Are domed sliders better? The question would be if they can tighten that bell curve. Make it narrower. Avoid the out liers at ether end. No more hard openings, no snivils, smaller standard deviation. There is no question that we can shift that curve right and left. That's what we have been doing with these after market sliders for years. We just needed a higher drag slider on some canopies for some jumpers. They will tell every one about how great it is because it fixed they're problem. That is not to say that it's a fundamentally better slider design. A problem we had with the canopies for our system here is that the manufacturer tryed to build the slider too big. It's actually more complicated then that, the damn thing has 22 grommets but the point stands. I built things like this for people for years but what I was doing was shifting the curve. I have no reason to beleve that it actually reduced the spread. So I can't say that a domed slider is fundamentally better then a flat slider. I can just get a bit more drag out of it. Lee
  7. RiggerLee

    Video and telemetry

    You might check out... https://dekunu.tech/dekunu-one#data They are Australian and no one can pronounce the name of the thing but it's an interesting unit. I was talking to them at PIA and it's a small INU with GPS, accelerometers, gyros, pressure transduicer etc. It's basically a little data logger but what is really interesting is the back end cloud software for analyzing and sharing the jump. Got a student? Let's see what your holding pattern really looked like. Where was every one relitive to that big way CRW formation as it built? How hard was that opening. I literally got mine yesterday so I have not had time to play with it but I cant wait to pull data out of it. You're supposed to be able to get the raw data from it as well. If you go to their web sight and scroll down to a video you can get some since of it. It's edited in with a lot of bull shit video like a toy commercial but there are shots of the interface as well. Looking forward to playing with mine. Lee
  8. Flat sliders are easier to build. You try to design some thing that you can build. You try to design the canopy so that you don't have to resort to things like domed sliders. There are some tandem canopies with slightly domed sliders. But you try not to have to go their. You'll see most of these things after market where people are trying to deal with a bad canopy that is prone to aberrant hard openings. Lee
  9. RiggerLee

    Thunderbow manual needed

    I never had a manual. What I remember is mainly about the crown lines. As I recall it splits into three sub bridles. You had to make sure that each of them was clear. From that point onwards I don't recall it being that diffrent from a PC in terms of flaking. I think their might have been some excess control line to be stowed at the cascade to take up the slack. I might be confusing that with another canopy. It was the coolest thing I ever jumped. Wish I could have hung on to it. As I recall the crow lines were the key thing in packing the canopy. Lee
  10. I doubt there is even a copy right much less a patent. Have any of them actually filed any thing? Lee
  11. That's a cool project. I may have to revise my opinions of the training in the modern rigging schools. Lee
  12. It depends on the complexity of the project. Having some thing to copy certainly helps. Coping peaces... you almost have to make pattern sets from them. Get the markings right. Order of construction. And then on the next one you're almost starting over from scratch. It's doubtful that they actually have any peaces in common. But yah, you could do it. You'd have to source all the materials and get good thread, etc. You could do it. But at that point I think some one could argue that the rigger is actually in business illegally coping other peoples suits. I really prefer the open source idea and the kit plane materials concept. You can buy plans for an ultra light. You can buy the materials kit for an experimental air plane. You can buy the parts kit. You can even buy the "quick build" kit. Lone Star could live again. Being here in the US is one thing. But lets say you lived in some back woods country or one with tariffs. Look at Quag and his canopy project. No canopy manufacturers in the UK and it's kind of pricey to buy one from out side of the country over seas. I'm surprised their are not more home grown builders popping up in some of these countries. Theirs another guy in south america. He's working on a pilot rig. It's hard to get them down their. Lee
  13. If you were to build something noncommercialy for your self, I think you would be fine. Copy rites and things protect the commercial exploration of a design. Or at least that is my understanding. I don't think any thing can prevent you from building things for your self. I think it could be argued that the rigger is stealing the design and selling it commercially if he accepts money to build it for you. Having said that. I could do some thing like this. I can do it because I have twelve different types of sewing machines lined up behind me and pallet racks of fabric to the left of me. So when I get board, yah, I do fucked up shit like that. But if even I set down and counted up the hours I had in one of these projects it wouldn't make since to do it. It's only practical if I'm idol and really board. Prices are getting out of hand. I think you will start to see more of this. Like the guys building their own canopies. Mostly for fun at first but once the idea gets around, who knows. I could see some open source drawings getting out and it turning into a little kit plane kind of thing. Then they will start selling quick build kits, here are the pre cut ribs and panels... Lee
  14. RiggerLee

    1 or 2 Pin AAD on 2001 Infinity?

    Their is absolutely nothing wrong with an honest question. Every one here will be happy to help you. Your questions tell us a lot about your experience level. Don't be embarrassed by that. We all start some where and the most important thing is that you are asking these questions. When we give you advice, like that you should spend some time with your local rigger learning about this or any gear that you are considering it's in that spirit of trying to help you. You need to sit down with him as he inspects it, takes it apart, see how it works, and how it's built. And their are limits to what you can learn on the internet. We will help you, There are good resources here but it's no replacement to working with it with your own hands. Your best resources are always the ones right in front of you. Lee
  15. RiggerLee

    1 or 2 Pin AAD on 2001 Infinity?

    Frankly if you know that little about it you should really get it sent to a local rigger to make sure it's the right rig for you. Their's more to this then just picking some thing out of an add column. Lee