RiggerLee

By the way. If you are going to see patches on a sleeve of a jumpsuit. Find a post bed. It's awesome. You'll never want to work on a jumpsuit with with a flat bet again. Sew a patch on an elbow. No problem. Lee

To clarify in the example given we are looking at between 1000 to 2000 lb of snatch force depending on fuel burn off acting on a 65 lb bag. That's why the 80 lb. The locking shows are also made of 1 inch tape. I was thinking more of the bundling of the lines. Tieing them with a light cord at about 12 inch intervals before showing. Since we have eight main risers with a short split to 16 we bundle in 4 groups every 24 inches then then the full bundle in between for a tie every 12 inches. On smaller canopies I've seen them do it in right and left then the full bundle. I was wondering if the larger tandem reserves with non cascaded lines would justify the effort. But I think as things trend small it will be unnessisary. Watching high speed it does make a difference. You can see the bundle deploy. The ties hold through line stretch. The main bundle spreads and you can see the slider splitting the 4 sub bundles as it comes down. Way more orderly then the chaos of a normal deployment. But I have to tell you it sucks. My ass gets sore setting on the floor tieing all those lines. Lee

I haven't looked at the numbers but I've seen friction knots on both. And yes that totally anecdotal. Working with larger canopies we do see some interesting things. I think the first question is the quality of the staging of the line deployment. As canopies get bigger and the bulk and mass of the lines gets larger how they are retained becomes more important to a clean deployment. For example we wound up using 80 lb. Break tie for the line shows. This canopy has 15 cells and 7 non cascaded line groups of 1000 lb line. Which basically adds up to a metric shift ton of line. We also tie the line bundle. Actually we do it twice. Once in four bundles then in one big one. Total pain in the ads but if you look at the really high speed footage of the line deployment it makes a big difference. Some times I wonder if tandem canopies are large enough to justify that effort? I think it's border line but as tandems are trending smaller I think the problem will get better not worse. Lee

I had not seen that video. I'm surprised he lived through it. I would have expected the decent rate to be higher. I guess he was lucky the canopy was not more asymmetric. The one I remember was back in the day and he died. I wonder what the gs were with double line length? Lee

This idea has come up once or twice. I remember one conversation about the value of dacron lines in mitigating hard openings. We use screamers the folded in half and zigzagged kind in some of our designs. It kind of comes down to the amount of kinetic energy absorbed. Force times distance. The bottom line is that the magnitudes are just to high. You just can't make a meaningful difference in the overall opening. But it can effect some things. Openings are not one smooth curve. The canopy is lifted to line stretch and you can feel a sharp jerk when all that momentum runs out of line. Depending on the snatch force size of pilot chute high speed that can be a painful high but brief spike. It can be the highest peak force in an opening. But it's generally followed by a much larger bell curve of some type. In a square it's mostly determined by the slider and at what speed it loses its dominance over the opening. The area of this second curve is just too large to be affected by a small amount of elongation. So the peak of that first spike is within the realm of something you could effect but the main opening just involves too much kinetic energy. Dacron lines play a different role in creating higher friction to slow the timing and decent of the slider. That is meaningful. More so then their elongation. That and improved staging from the rubber bands having a better grip on them is where their reputation really come from. I've changed my mind over the years. I do think that there is value in risers breaking to control super high peak forces. It's not a common occurrence but I've seen fatalities that I attribute to opening shock. It's not a fun idea but there is something to be said for a fuse in the circuit. Maybe type 6 risers weren't such a crazy idea after all. Lee

Sex swings are more often solid saddles then split saddles. Both exist but split saddles are much harder to climb into and almost guaranty a face plant if you fall forward out of them. So I don't think it would be limited by that otherwise it would push the date up to the 70s. There have been female jumpers forever. At least back to the barn stormers in the 20s. Lee

I know that we have some pretty good historians of the sport here. When did we start using hanging harnesses for training? The question came up today of how long have skydivers been using hanging harnesses for sex. As improvised sex swings. I was guessing around ww1 but I was trying to remember the details of early harness design. Does any one know how far back the practice goes? Lee

Variations of this idea have been in discussion forever. I remember them all the way back to the otter crash at Paris when I was a young jumper. All of them were better then what we are doing now. None of them have gone any where. Do you think any manufacturer wants his harness to officially be part of the restraining system? There are a lot of hurdles in the way of a new idea. Lee

First to be clear. I think what you mean by bi cell is that there are two sections to each cell instead of three. One vertical unloaded rib inbetween the loaded ribs. Like a normal canopy. That would put both diagonal ribs running to the same seam. Well that's kind of over kill to support that seam. This would of course work but it's not very efficient in terms of the bulk of the canopy. Turns out that a 7 cell 3 section is more efficient bulk wise then a 2 section 9 cell. If on the other hand you ment a 5 section cell with 4 diagonal ribs per cell then I can tell you that there is an issue with the vertical rib between the diagonal cells. They build nice long bridges like that all the time but that vertical member has to be able to withstand compression to really work properly. There is kind of an inbetween. There is at least one design out there by... Airborne systems? They make the unloaded rib shorter. So the bow, the support, is all in the bottom skin. The top is smooth, all the top skin seams at the same hiath. The individual skins still inflate and how but no distortion as the unloaded rib shifts upwards. Basically the same thing you get from a crossbarace with out the bulk. PD played with it as well but felt that it didn't give them enough rigidity. But that is some thing that is out there in a "bi" cell. Lee

At normal operating speeds, with full fuel exaustion, the absolute slows it down to about 100, the openings are about average, 3 g. So pretty soft. Early shut down can double the mass of more. So the terminal goes up. You can be dealing with four times the kinetic energy on opening. If it's a flat shot, like a guidance failure, you can be going fast horizontally. If it's high enough it will wait a few seconds to let it slow down before deploying the main. Lee

Strong c1200 cargo canopy. 1200 sqft 15 cells. A,b,c,d,e,f,g lines. grommet spacing can't really be wider then the cell so you wind up with an inner and outer set of grommets to allow three cells to inflate with the slider up. It gives you the area you need to deccelerate the payload before the rest of the canopy opens. You wind up with four grommets front to back in four rows and six on the back edge for break lines. They extend the back edge of the slider and have there own slider stops to increase its area. You actually have eight primary risers that give you inner and outer on each side. They Y near the top front to back to allow the slider to come all the way down, accommodate those four grommets in each row. 16x7 noncascaded 1000 lb lines and 6 primary break lines 2000 lb split to 12 attachment points. So ya, it's a beast, 68 lbs of joy, but I've seen it survive 20,000 lb opening shock. Lee

It astonishes me that some one would ask a question like this here or that we would try to answer it. Don't people go to the dropzone any more? Don't people drink beer any more? This is the sort of question that should be answered standing around the hanger after the last load. People sould just show you or as the very least a green bottle should buy you a full lesson. I'll give you a hint to make a continuity check easier. You don't always have the ability to hang it up where you can easily see the routing. If you are doing it on the floor flat on its side. You can start at the canopy and load the lines of the riser into your fingers separating then on your hand and walk that whole group back to the riser. You can also use a course comb. Load all the lines into it in order at the canopy. Use a second comb from the top to lock them in place. You can even secure them with rubber bands on the ends as you walk it back. It's some thing I learned working with larger more complex canopies. With like 124 lines 60 ft long. 16 risers and 22 grommets in the slider. Try line checking that by your self. Lee

Above reply is probable the best answer is probable the best. I'll bet that it's really not that fun when taken as a whole. Stop and think about the logistics of trying to fly it. You really need a tail gate. The awkwardness of it. The complexity of integrating the wing... Yes they have made some spectacular videos. I'll bet he doesn't go out and make 10 jumps a day with it just for fun with his buds. if you really want to do this don't let any one tell you that it's impossible. In comparison to building a kit plane it's a rather small project. Don't let any one tell you that you need 10,000 jumps to fly it but 500 wing suit jumps probable wouldn't hurt.I You could do this if you really wanted to but if this is your sole goal. I think you will become disenchanted pretty quickly. Skydiving is a broad community that offers a lot and this is about as nitch as you can get. Lee

The comment about Indian woman is kind of an inside joke about Mandy. for a while we seemed to be getting a lot of tandem students from India. She was by far the smallest tandem master so when the Indian family's would show up she would get the small Indian woman. She was absolutely convinced that they could not arch. They always went fetal on her. She was convinced, and she had more empirical evidence then any one I know, that Indian woman were genetically, culturally incapable of arching and would always go fetal on exit. No other group exhibited this phenomenon. Indian woman can not arch. Just ask her. She'll tell you her self. Indian woman are the only cultural/racial group that can not skydive. Lee

Back in the day shipping weight on a tandem rig with harness was 60 lb. I'm curious what the newer smaller rigs are weighing in at now? Mandy looked almost ridicules wearing those big strong rigs. I'm wondering if the smaller rigs would be any more ergonomic, better suited to some one with a shorter mlw, maybe narrower? Or are they still being built on the same long wide patterns? Your also liable to get stuck with all the small Indian woman... And we all know how they are. Lee

They have been working on it for over thirty years. Can't really get around the ratios of the the size of the rings to their guage and the thickness of the webbing. Mini rings are really just too small. There are the aerodine rings which are a substantial improvement. Not quite as good as large rings but so so much better then any mini ring riser. The substantially reduice the internal stresses between the second and third ring. And consequently the load on the loop. I think the reduction in internal stress is the most important part as i have seen risers fail at the tape for the third ring. We've actually pull tested... well everything trying to build 20,000 lb releases. So we've actually pulled all of these peaces of hardware and designs to destruction with load cells. 15,000 lb webbing is exciting when it lets go. Some of the hardware send pieces flying when it snaps. The aerodine rings were some of the best. If you are curious their failure mode is that they bend wrapping around the main ring rather then snapping but you have to build a kevlar riser to have enough strength to make them do it. Lee

It looks like what you have there is just an attached bag. That's normal on there retract pilot chute systems. I'm not seeing a "flag bag" in your pictures, that is also a thing. Flight concepts builds a flag bag on the bottom skin. Flag flies between the canopy and riser. So if it's just the attached deployment bag. This is something they often do with retract, not to be confused with collapsible pilot chutes. The cord bridle runs through rings inside the canopy. When you pack it you pull out the bridle you compress those rings, making sure the fabric is clear. On opening the rings spread retracting the bridle so that the pc is sucked into that grommet and nothing trails behind the canopy. It's a CRW thing. The bag is attached so that the weight of it done not pull the pc and bridle out of the canopy during a wrap when the canopy is collapsed. If it is lose the bag will swing around like a bolo and wrap around things. That's what a lot of companies have gone to tail pockets. To pack it you first need the proper length cord bridle. Attache it to and route it through the internal rings. When you pack it clear the fabric. You had to fold it so that the grommet is at the top. Pull the bag around the canopy and close just like any canopy. Bridles tend to be short. You might want to go to a pullout. But you may need a cord extension because the base of the pc will actually be pulled into the grommet. Call Red, he will walk you through it. Lee

Interesting. I wonder what the speed range is in that thing. It would be interesting to have a wind tunnel in which you could text dynamic control. So instead of just. Changing the angle of a model and measuring forces of pressures to directly test flight control systems... Lee

I have no idea how this got so complicated. I'd just do it. There are some basic rules like don't use a slider with grommets significantly wider then your cell. Depending on the length of your stabilizers your slider should not be setting on your bottom skin when packing. If it's so much wider that it's just crumpled on the bottom skin the fabric will not be holding the grommets up the lines till they slide low enough to lift the fabric off the bottom skin. Only then will the wind be holding it up. That's a fairly extreme limit but I have seen people make that mistake. Don't people futz with there gear any more? Lee

Actually the coolest stuff was done back when we were known as Armadillo Arospace. if you search around on you tube for some of the old stuff that they used to do there are some great videos. th ey did a lot of lunar lander type designs. They played with a number of fuel combinations. They played with a lot of peroxide. They were making it in bulk distilling 90% in Russels garage by the barre l. 200 gal is a lot of go juice. Then they did a lot of bipropelle my work injecting different fuels into the chamber with the superheated decomposed peroxide. Think black arrow. Later won one of the lunar lander challenge and went on to do some other NASA contracts. Lee

Leaving tomorrow for the desert. Next flight will be on Saturday 10/26. If you look on the Exos Aerospace Face book page there should be some type of live stream Sat morning. It will probable get off some time between 11:00 and 12:00 MT. Last one was... entertaining. Read that scary as shit. I'm hoping that this one will be much less exciting. We had a short but very good hover test. Simulator is looking much better. I'm feeling pretty good about this launch. I'm hoping this one will make altitude with no problems. Lee

Ground hungry... I wouldn't list the Spectra as being a particularly ground hungry canopy. There are certainly other canopies out there that are steeper trimmed. Keep in mind that any canopy that is designed to land easily and be forgiving on the flare will have to have an excess of flare authority. It has to be trimmed a little steeper to have the ability to increase it's CL to give you that powerful flare. If you were to fly a flatter canopy, one with a flatter glide, less ground hungry, you would find that the flare is some what less forgiving. I actually prefer flatter canopies and the way you generally land them is with a little extra speed. Even just a bit of front riser, so in a since you trim it more nose down, ground hungry, to get an easy landing out of it. One thing that was noticeable about the specter, is the way it pitches front to back. It was noticeable on landing as you descended in to the stiller air near the ground. When you passed through a wind shear between two layers. Think end of the day as the ground cools off and the ground winds die but the wind is still blowing a couple hundred feet up. Well there is a wind sheer as you drop from one layer to the next. Some of your airspeed goes away. Interestingly the larger the canopy is for you the more noticeable this is. 5 knts is a larger percentage of your air speed and when that head wind dies you are 5 knts slower. The canopy wants to correct that. It wants to speed up. It feels like it takes off surging forward and down toward the ground. Flaring dosen't seem to help because the canopy is pitching forwards and can not make lift to support you till it pitches back above your head. The larger the canopy and the longer the lines the more dramatic this can be. You see it with student canopies. They induce it all the time. If you make a small turn with a break, the canopy pitches back and then when you let up on the toggle the canopy surges forward. Not a lot but enough to ruin your flare. Worse is the student that flares high and then decides to let up because miss judged it. When he tries to flare again the canopy is well in front of his body. These are more dramatic examples but the same thing happens when you come in to land. If the wind drops off you get a surge in the canopy. Some canopies do this more then others. Line length is one factor but I think the airfoil also plays a part in it. It really depends on the pitch stiffness of the canopy. I don't understand all of it. But it's noticeable in the specter. You might try a Triathlon. They are not as prone to this. Back when these canopies came out they were neck and neck and we had jumpers that went back and forth between the canopies. It was the same market. They loved the specter but had noticeable more trouble landing them under some conditions that they had no problem landing their Tri in. I would not categorize a specter as a bad canopy you just need to learn to land it. Under those conditions I like to carry a little extra speed, front risers, or a small turn but hook a bit high. The idea being to to have a bit more speed when you enter that still air. You could also barrow a saber 2 from some one and give it a try. They also have a forgiving flare. Or go up a size. But with the specter I think it may just be a mater of learning to reconise the wind conditions. Or just use it as an excuse to hook that bitch down wind on the last load of the day. That way the wind sheer acts in your favor. Or at least that's my excuse and I'm sticking to it. Lee

The difference in wing loading is not that great. Large canopies like that fly very well and will accommodate the weight easily. You'll probable find it to be just slightly more responsive. The differences when you down size are not directly related to wing loading. I know it's the number that we use but there are other factors like line length that also factor into how the canopy behaves. That's why 1.1 on a 150 is not the same as 1.1 on a 107. It's been an issue for small girls that get pushed into buying a smaller canopy because it's the "right" wing loading for her. If you could some how graph it, control response?, call it what you will it would look like a down wards turned hockey stick. That's a little misleading because I would not say that small canopies fly badly or control badly. I've had a lot of fun over the years flying small canopies but they can be a hand full for a young jumper. It's the difference in flying a highly loaded, heavy, air craft and a short coupled one. That refers to the size of the tail in respect to how far back it is. It makes it sporty, think Pits. So although you might fill the tanks and all the seats on a cessna and be over grouse, it's still a cessna. A Pits on the other hand, might be at the same wing loading but it is a very different airplane regardless of how heavy the cessna is. So that's part of why I don't think you'll have a problem down sizing. Not only is it a small change but you are well away from the bend in the hockey stick. Lee

Well, since it's adjustable... Sorry, couldn't resist. As I recall the finger trap starts just past the grommet. and is short only about .75 inch. Then it runs out the other way 180 off from the loaded part of the loop. So it's tied at the washer. Washer on the inside of the pilot chute. comes up through the side grommet. Across the top of the hard cap. Turns and goes down through the center grommet. Just past the grommet is where the finger trap will be. It goes down and forms the loop. Comes back up and enters the finger trap, 0.75 inches? exits the finger trap. comes up through the grommet. Turns 90 deg. away from the side grommet. Exits from the soft cap through the little hole. Pull on that lose end to tighten. Tuck under the soft cap. Don't you have the manule? All of this must be in there. This is just memory from way to long ago. Lee

I hope you got that fabric for free. It totally saturated my screen and caused strange artifacts around the edges. Hideous. Lee