RiggerLee

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RiggerLee last won the day on May 5 2019

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  1. I built my container for my first base jump. Did not build the canopy. You've got me beat. I remember later when I traveled to norway. I and one of the friends traveling with me were jumping ribs I built. The guy that was checking us in and giving us intro at kjherag kept asking me what type of rigs we were jumping. I kept saying that they were my rig. Finely he caught on. I built them they're My Rig. They didn't have a name so I just decided to name them My Rig. Lee
  2. One thought is the crotch. If it has booties, the tow to crotch measurement is kind of critical. The leg straps pull the crotch up tight and the length to the tow must make the booty tight. In a tunnel that can be based off the shoulder and the crotch can just float where ever it winds up. So the measurements can key off different things. This is just a guess. Lee
  3. I assume it's a 110 motor. Any thing out of a shop will be 220. It's a $100 problem. It's a light weight garment machine. I like them but it's $400 maybe $500 if it's 110 and the clutch is in good shape. Back in the day baught them for $300. Lee
  4. CSR is where it comes from but that's by the spool. Para gear or call up a manufacturer and hit them up for a couple of yards. Lee
  5. It does look good. I hope you had fun with the project. Your skill set is rounding out very nicely. I wonder if you realize how much you've learned in the course of all this and how far youve come with these projects. One thing I think you should look at. I don't know where you would find it at this point. It may not still exist but there was a series of threads on base jumper. They grew out of an accident at perion. It was a pilot chute in tow/pin pull hesitation? I don't think it was ever really resolved but it developed into a series of conversations about flap and cover flap designs. It dug into dimensions for pin clearance, rotation, pin orientation, orientation of the pin attachment to the bridle, even pin design and geometry. They did identify some potential failure modes. It's worth preserving if any one is smart enough to go back and find it. I think it was spread out over a couple of different threads. But the rig looks great. Now you need to go and start testing it... Do they still run a ferry from Newcastle to stavanger? Just a quick ferry ride to lysebotten and kerage. Lee
  6. None of that surprises me. I've thought about similar things my self. Toyed with the possibility of building base harnesses from ultra light weight spectra webbing. Never went forward but it would have to have been sewed with essentially a bunch of bar tacks. Sewing like that has been the norm forever in other industries like the climbing industry. If you look at there harnesses every thing is sewn with a but load of zigzag on some big pattern tracker. There is no question that this can be done but there are some trade offs. One reason the flexion held together so well was the rings allowing every thing to aline in shear. So with propper design it can be every bit as strong. In fact I think I can make an argument for it better distributing the load across all the fingers of the webbing and better transfering the load through the joint. But... Although it's a smaller needle it's punching that needle through that fabric a lot. It's a known wear issue. Climbing harnesses are considered disposable. They do not and are not expected to last a long time. Think about how old some of our rigs are. That kind of stitching tends to be subject to abrasion. The stitches tend to lie on the surface. Rubbing against rock can abrade them cutting the stitches across large areas of the pattern. I've seen the same thing with roofing harnesses. These things quickly fell apart. A four point sewn lengthwise in a thick loosely woven webbing sinks down into it. It's kind of self protecting. We built a set of roofing harnesses for one of the local skydivers that owned a roofing company. The Gestapo, I'm sorry I ment OSHA, had show up at his site and busted him for not having harnesses for any of his Mexicans. We built skydiver grade harnesses on our seven class. I think there legality may have been questionable. There is probable some kind of certification for fall protection harnesses. They were the the only ones he ever had that held up. All the commercial ones fell apart litterally. They were the only ones his workers would actually use. I find the trade offs in these questions to be fascinating. Lee
  7. Never did the staple thing. At least not for harnesses. I have used e thread mainly for really heavy stuff to avoid the thickness that glue could add. I was maxing out the lift on my seven class. I actually have a lighter walking foot with more lift that I can baist it with. One advantage of hot glue is actually at the other end of the spectrum. When you're sewing some thing light. I'll use the example of a riser end. Let's say you're sewing a riser of type 8. It's structural. You want it to be strong so sewing it on a harness machine would be the obvious thing to do right? Problem is that even though it's a webbing and very much structural it's still soft and light. Sewing some thing like that on a seven class is very problematic. It's hard to keep from shrinking it and causing point loading. There are a lot of solutions. Sew it some other way, like with a boat load of zigzag. Fold the webbing under again so you have three layers and a little more meat and stiffness to it. That's kind of an extreme example but it holds true in all which patterns. If the stitching is contracting it and can not elongate with the webbing under load then ether the stitches them selves break or they cause point loads in the webbing where the webbing will fail. One thing I will say for glue. It can make the layup stiffer and the the sewing more forgiving. That should not be discounted. Not to mention the fact that it is by far the easiest way to get the layup accurate, even, flat etc and to hold it that way all through the process. I was there in that big general meeting, a fly on the wall, lessening to the biggest players in the industry, like Mills, talk about this. Trying to move to clamps was a huge pain for them. They were optimistic that if they could get a set up that worked that production would pick back up. In theory it would save steps glueing. But most of all they just desperately wanted to keep there contracts. Lee
  8. How much do you actually need? If you need rolls you almost have to find some one local. I don't know any one there other then heathcoat. I might just call up a manufacturer. I used to do crw with Red at flight concepts in Atlanta GA. Really nice guy. He would probably roll off a few cells worth of fabric and sell it to me in an envelope or a small box. I hate folded fabric. You know if you could send hi. The drawings in a format that he could early use he would probably cut the whole canopy for you on his computerized table. Custom colors on fabric. You know is straight. I'd pay for that. And that would break down into a box small enough to ship across the water. Lee
  9. It's been a few years but I think that is the $100 machine. Must have been a 7. Just drop feed. That thing was small but a beast. We got a lot of work out of that little machine. Never knew the model. The plate was missing. Lee
  10. No direct experience with that machine. But I've often thought that a 7 class was a bit overboard for 5 cord. There are probable machines out there that could handle 5 cord. Make sure you check the lift. Base jumping harnesses are not that thick. You might be able to find a smaller machine that would have the lift that you need and could see through with 5 cord. I can't remember the model. But we had this really old singer. That we got out of a guys barn for $100. We just called it the $100 machine. He was using it to repair really heavy horse tack. Harnesses and shit for the horses. He was sewing with a heavy cord. No markings on the spool. Probably a dacron but it was damn near 5 cord. Single needle simple dropfeed. Looked like a miniature version of a 7-33. That was actually a really great machine. I wonder how small of a needle would carry 5 cord? If you didn't go bigger then you had to that would make it easier to punch the needle through on a smaller machine. Lee
  11. I'll expand on that with some caviots. Perfectly good model but like most models it breaks down when you try to extend it into the range where the systems behavior becomes nonlinear. That kevlar thread is actually stronger then the nylon tec 500. Sew loops at both ends of a peace of kevlar webbing one with the stronger kevlar and the other with nylon. Pull. The kevlar will break first every time. The nylon junction is stronger not by a little bit but by quite a lot. So on places that are protected and not subject to aerodynamic heating we use nylon where we can. The little bit of give in the nylon let's it share the stress more evenly over the stitch pattern. As you try to get more strength, more stitches, in a joint there is a point of diminishing returns where when you pull on it only part of the stitch pattern bears the load. So the pattern breaks progressively from one end to the other. This relates to the elastisticy on the webbing. It is exaggerated if there is a discrepancy between layers of webbing. Say there are three layers and you are pulling on the top layer. The bottom two layers are stiffer then the top layer. When the top layer stretches it loads the first part of the pattern those stitches break first. Some one once told me that a reinforcing, like a tape on a canopy, should have an elastic coefficient a certain percentage of the substrate to avoid point loads and shear forces between the two. In the same since the stitch pattern must have the ability to stretch and deform to match the material being joined. That is why it's advantageous for the stitching to be as far as possible angled relative to the load. Notice that most of the stitches in a 3 or 4 point are angled. When you pull on it the highest load points are at the corners where the side stiches are straight. This is actually less then ideal. In fact the straighter the stitches the higher the load at the points.. So there is kind of a minimum angle that you would like to maintain in the pattern. Therefore there is a limit as to how long you can make a three or four point or the number of points you want in a pattern. So if you want a larger longer pattern it can be better to dubbel or triple the pattern. Imagine two three points end to end. Now imagine the stitches continuing rather the turning where the points meet. Basically the pattern bounces back and forth from side to side of the webbing like a big zigzag. Think of the dot in the old pong game. Try drawing it you will have an over sew when you get back to your starting point to move to the next half of the pattern. You'll wind up with the same amount of over sew as you would have in an equivalent pattern. But a multipattern can be better then one long four point. The maximum length of the pattern tends to depend on the stiffness of the webbing. The most extreme example of shortening and widening the pattern would be to sew it in a diamond pattern like to sew the four point sideways on the webbing and I've seen this in some heavy load applications on nylon. They actually sewed it back and forth from side to side in a big square block. It defenintly let the nylon stretch but a don't favor this because I think you would tend to snap the webbing at the end of the pattern. But I have seen it done. Most extreme example I've run into. An early project I was given was to test seam designs for a prospective canopy. So I had to figure out a way to load seams to destruction in f111 and zp. Trickier then it sounds. Wanted to load a decently wide area. Clamps didn't work. When the fabric stretched under load the fabric it self would tear under shear at the sides of the clamps. Ultimately I wound up sewing leaves of wide webbing to the fabric to pull on. It was an interesting stitch pattern. Boxes, 3 points, 4 points won't work. Any thing with a straight corner would cause the same shear as a clamp and tear the fabric before the seam. It needed a smoother transition to the unloaded fabric. I wound up with a two point with the points in the middle of the pattern not at the edges let the fabric avoid that sudden shear load. I don't like to think about how many of those test articles I had to sew up. Lee
  12. I'll expand on that with some caviots. Perfectly good model but like most models it breaks down when you try to extend it into the range where the systems behavior becomes nonlinear. That kevlar thread is actually stronger then the nylon tec 500. Sew loops at both ends of a peace of kevlar webbing one with the stronger kevlar and the other with nylon. Pull. The kevlar will break first every time. The nylon junction is stronger not by a little bit but by quite a lot. So on places that are protected and not subject to aerodynamic heating we use nylon where we can. The little bit of give in the nylon let's it share the stress more evenly over the stitch pattern. As you try to get more strength, more stitches, in a joint there is a point of diminishing returns where when you pull on it only part of the stitch pattern bears the load. So the pattern breaks progressively from one end to the other. This relates to the elastisticy on the webbing. It is exaggerated if there is a discrepancy between layers of webbing. Say there are three layers and you are pulling on the top layer. The bottom two layers are stiffer then the top layer. When the top layer stretches it loads the first part of the pattern those stitches break first. Some one once told me that a reinforcing, like a tape on a canopy, should have an elastic coefficient a certain percentage of the substrate to avoid point loads and shear forces between the two. In the same since the stitch pattern must have the ability to stretch and deform to match the material being joined. That is why it's advantageous for the stitching to be as far as possible angled relative to the load. Notice that most of the stitches in a 3 or 4 point are angled. When you pull on it the highest load points are at the corners where the side stiches are straight. This is actually less then ideal. In fact the straighter the stitches the higher the load at the points.. So there is kind of a minimum angle that you would like to maintain in the pattern. Therefore there is a limit as to how long you can make a three or four point or the number of points you want in a pattern. So if you want a larger longer pattern it can be better to dubbel or triple the pattern. Imagine two three points end to end. Now imagine the stitches continuing rather the turning where the points meet. Basically the pattern bounces back and forth from side to side of the webbing like a big zigzag. Think of the dot in the old pong game. Try drawing it you will have an over sew when you get back to your starting point to move to the next half of the pattern. You'll wind up with the same amount of over sew as you would have in an equivalent pattern. But a multipattern can be better then one long four point. The maximum length of the pattern tends to depend on the stiffness of the webbing. The most extreme example of shortening and widening the pattern would be to sew it in a diamond pattern like to sew the four point sideways on the webbing and I've seen this in some heavy load applications on nylon. They actually sewed it back and forth from side to side in a big square block. It defenintly let the nylon stretch but a don't favor this because I think you would tend to snap the webbing at the end of the pattern. But I have seen it done. Most extreme example I've run into. An early project I was given was to test seam designs for a prospective canopy. So I had to figure out a way to load seams to destruction in f111 and zp. Trickier then it sounds. Wanted to load a decently wide area. Clamps didn't work. When the fabric stretched under load the fabric it self would tear under shear at the sides of the clamps. Ultimately I wound up sewing leaves of wide webbing to the fabric to pull on. It was an interesting stitch pattern. Boxes, 3 points, 4 points won't work. Any thing with a straight corner would cause the same shear as a clamp and tear the fabric before the seam. It needed a smoother transition to the unloaded fabric. I wound up with a two point with the points in the middle of the pattern not at the edges let the fabric avoid that sudden shear load. I don't like to think about how many of those test articles I had to sew up. Lee
  13. That's cool I'd never seen that on a pilot rig. I thought I was a radical when I ran a horizontal below the leg junction on a harness. That harness didn't have a container attached to it. It was worn under clothing and that lower band made it feel very comfortable and secure with out a back pad. The container was a separate jansport looking backpack. It also had no hardware on the leg or chest strap. You wiggled too it from the top. Lee