RiggerLee

An I beam canopy is one that is built with a top skin panel, a bottom skin, and loaded bearing ribs at the ends of the cell, and a non loaded rib in between. There have been other designs but that's what you see now in the majority of canopies. So imagine the cell. You have the loaded ribs at the end and the non loaded in the center and the panels stretched horizontally in between. Two types of distortion. Pressurize it and the top and bottom skins bulge out like a balloon between all the ribs. Ribs stay straight and vertical unless they are an end rib in which case they bulge as well. The distortion is a product of the ratio of the height of the rib to the width in between each rib. This distortion gets worse as you go back towards the tail and the rib gets thinner. Thats why you see sub ribs between the main ribs near the tail on newer canopies to try to thin out the trailing edge and reduce drag. Second type and what we are referring to here. Again imagine the ribs are vertical supports. Remember the fabric is soft. When the wing produces lift that fabric wants to move upwards between the load bearing ribs. It wants to compress the canopy span wise by folding it back flat lifting the unloaded rib till the cell is compressed. This reduces the volume of the cell. The pressurization of the cell does not like that wanting to maximize the volume. These are the two forces seeking a medium. The amount of distortion in the wing from this is a product of the ratio of the lift across that cell and the pressure ratio in that cell. So whats this ratio? it's basically dynamic pressure, Q, .5RoV^2. Ro=density V=velocity magnitude squared, to lift. Lift is Q*CL*S, CL= coefficient of lift of the wing, fixed number, S= surface area generally a fixed number but in this case it's actually going to shrink a bit as the canopy distorts. Cl=A*AoA, A is a slope it's how the lift changes with AoA. We're kind of simplifying all this but in the end even with high induced G loading, like coming out of a dive, you can basically say that the ratio of the internal pressure to the lift of the wing is linearly related to the AoA. And so the loss of lift as you lose span width and surface area of the wing is related to AoA of the wing. Now think about the cross braced canopy. The diagonal ribs support much of the load of the cell. They prevent the cell from drifting upwards. Analogy. Ever seen a cable bridge like in Nepal. Its just cables with a bed and more cables for the hand lines. It's a big bow. Always will be. Now think about a suspension bridge like the golden gate. Road surface is flat no distortion because those big cables support the vertical load on the road surface. Their curve is a product of those forces. There is still horizontal force supported by the anchors at the ends but the road stays pretty much straight. Same thing in a cross brace. As long as the pressure ratio stays below the angle of the angle of the diagonal rib the cell will not distort upwards. So there is a limit to how wide you can make your cell related to how tall your rib is. Fortunately most of the lift is being produced at the front of the canopy where the cell is thickest. Think about it a bit you'll see it. That's a little dumbed down but every one else should be able to follow it. Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

You know, the interesting thing about cross braced canopies is that they are better low speed airfoils. I know that sounds strange as they are used on the fastest canopies around but that's actually the point. What allows people to jump canopies at those high wing loading's is that they are better low speed wings. It's about how the wing behaves as the AoA increases. The wing inflates because the inlet is near the stagnation point with the highest pressure on the wing. That dynamic pressure wants to inflate the wing. The lift produced by the wing actually wants to collapse it. That's why cells bow upwards on an I beam canopy. It's trying to flat pack it self in the air. The inflation pressure fights against that. The distortion is related to the ratio of the pressure to the lift. As your air speed reduces and the dynamic pressure lowers relative to the lift the distortion becomes more pronounced. The canopy gets smaller. Example when you are in breaks and slow the canopy. You can see this as the front of the canopy narrows on landing when you flare. Basically it's in relation to your AoA. So right at the point when you need to canopy to perform it's best it's at it's worst. In a cross brace the canopy is now less dependent on the inflation to support the load of the cell. The diagonal ribs carry the load more efficiently and the the compresive force is reduced. The canopy is less distorted and flies more efficiently. This is going to sound strange but the best place for cross bracing is on an accuracy canopy. I can see it now... five cell cross braced accuracy canopies ruling the world meet. Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

PD built the Excalibur in some larger sizes. Does any one remember the largest that they built? Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

A few things make more since now. There was... I think this was the double fatality, canopy collision. The camera helmet was knocked off one of the jumpers heads. DZ was like, Oh well. One of the jumpers went out and searched through the field all day till he found it so we could know what happened. The DZ was pissed. They gave him so much shit over that he was almost band from the drop zone. At the time I didn't understand why? Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

I'm wondering about the liability angle. So if there is an injury or a fatality and the DZ shoots video of it, would the DZ own it? In a civil suit would the family have access to it? And could they use it as evidence in the trial. Who would own it? The student may have commissioned it but if the drop zone doesn't deposit the check who owns it? Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

I've never heard of any one "demilling" a canopy before sale for any type of liability reason. The military started doing that as a policy at some point. I bought a bunch of canopies at an auction once and they made me sit there with a pair of sesores cutting the lines off before I could take them out of the ware house. Generally people, or at least I, tend to be upfront about the age, wear, and condition of the gear from the very beginning in a sale. Why waist time? Their going to see it at some point any way. Why blow all that money shipping it back and forth. And if they can't be trusted with basic maintenance they don't need to be buying it any way. A car is do for an oil change. Are you going to drain the oil out of it before you sell it for liability reasons? Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

I think there is a little more to the history then that. Coatings on lines have been hit or miss over the years. Think back to when things were TSO'd. We had nylon lines then Dacron. I think Kevlar was the first "high tec" line we had. Didn't last long enough for mains but they were trying to use it on reserves. I believe it was kevlar that they had trouble with. Was it the early ravens? The coating would stick together if it got wet. Lines would come out in a clump. I seen to recall that they had some trouble on some braided nylon line as well? Been a long time since I thought about this. So what did you see in the next round of reserves? Untreated lines. Didn't the swift+ have untreated lines? And PD reserves. They came out around then. And Strong reserves. All of these things came out in about the same time frame and it was fashionable at the time to use uncoated line. Re testing is a bitch so they've stuck with it. I've also had them argue that there are advantages to it or at least potential down sides to coatings. Questions of consistency. Coating prevent fibers from sliding and might reduce ultimant strength. If you ask them they will give you an answer but I think the truth has more to do with what was going on in the industry at the time when these first designs were developed. Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

I also favor a front mount. I'm not sure I'd say that it's any less complicated. The point is that they are all significantly more complicated and involve fundamental changes to your procedures which is how almost every one gets into trouble jumping them. People have killed them selves pulling handles out of sequence. Doesn't the USPA require a C license to do an intentional cutaway? Seems silly since it could happen on their first AFF but as odd as it sounds intentional cutaways are more dangerous then emergency ones. It's the gear. It's more complicated and it's not what you've been trained to use. The latter could be corrected but you're talking about adding that complexity to ordinary rigs for ordinary jumps for an infinitesimal, or at least very small increase in safety. How many actual reserve malfunctions do you have a year? Now raise your hand if you know some one that has died doing an intentional cutaway... My hands up. You can jump a third canopy if you want to but it's not worth the price. Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

Size, bulk, weight make it a point of diminishing return. There are also issues of routeing of risers and bridles. You can have three canopies. We do things like that for test jumping. I have a rig I test jump with. I have also built systems for tirshes for canopy relative work. Bumper cars with parachutes. Some times they get tangled up and the ability to deploy a round reserve on a long bridle can be helpful when your tumbling to the ground in a mass of nylon. But in any normal circumstance all of this is just way more trouble then it's worth. Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

Face Palm... Do you really have to ask that? Think back, or have you never jumped one? You get a pass if you've never jumped a tempo. Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

I don't recall a life time on a tempo. Some riggers have a personal standard. If it's a closet queen with relatively few repacks on it it should be in good shape. It's not really an out dated design. For example it's a newer design then a PD reserve. They're perfectly good canopies. Do you happen to know if it's a "R" or an "L" model? Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

How do you feel about being a test jumper? It's really hard to build up enough test jumps on a design before it goes to market. Keep in mind that there will be numerous iterations in the design over the course of it's development. All have to be tested and when you move on to the next change it all starts over again. So when they say that they have put x0000 test jumps on this canopy that may be split over x0 iteration of the design. Some of those changes are small, some not. And then there are all the different sizes. The honest truth is that no manufacturer, even PD, can really afford to truly adiquitely test their designs prior to release. Until it's out in the wild with thousands of people jumping it every weekend you're not really going to know the full story on it. If you buy a new canopy design you are a test jumper. I for one enjoy shit like that. If this makes you uncomfortable do not buy a canopy that has been on the market for less then 24 months. In this case with such a small/new manufacturer selling to such a small customer base, Brazil vs. America, it will take even longer and when they make changes, not uncommon, the real clock starts over again. The designs of such a small company may never truly mature at least not for years. Having said all of this. I would be first in line, but that's me. I would be volunteering to help with their test program before they ever went to market. I'm not saying you shouldn't consider their canopies. I'm just saying, realize what you are getting into. And if you want to have a local manufacturer you need to support them. That includes buying and jumping their prototypes. Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

That would be called CRW. And yes you can do that. The front risers carry most of the load and we would fly front riser trim flying wings an extended period of time on the big diamonds. There are tricks to how you do it... it also helps to have large forearms. The rear risers are much easier to pull. You can pull them with no problem. But the best way is to reach up and, kind of twist your arms around them. You reach up to the inside rather then the out side and kind of twist your forearm. You can put a couple of inches of trim into the riser with very little effort. Your arm is strong that way and you have advantage. You can hold that forever. Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

I think the only time you might see that is with highly loaded very steep trimmed canopies. Pulling on the rear risers, kinda sorta, trims the canopy flatter. In theory it's flattening the trim of the canopy and improving the glide with out decreasing your speed as much as riding in deep breaks. You're actually distorting the canopy quite a bit if you pull to far on the rear riser so if you're trying this be subtle, an inch or two. With a really highly loaded canopy that is penetrating into the wind you might improve your landing point by trimming the canopy slightly flatter. You might see this with the really steep ground hungry canopies. A lot of the swooping canopies are very steep and very ground hungry with high decent rates and are well bellow best glide angle. As to the second half of his comment, that is exactly right and it goes double for small aggressive canopies. If you are long and running down wind to get back to the DZ in high wind you are much better off reducing your decent rate as far as you can and letting the wind carry you back. This is doubly true for small ground hungry canopies. Their glide is shit. The only chance they have to make it back is to hang in breaks reducing their decent rate as far as possible to let the wind help them back. Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

I used to see things like this and just assumed that it was a joke. I couldn't imagine that some one could be so disconnected from reality. Until one of these guys wondered into the shop one day. He had flown in with his friend who was a pilot. I'm sure there are some stories there. His friend just kept shaking his head. He had had no more luck educating him over the years then any one else. Nice guy but he was a no shit flat earther. Had an answer for every thing. We were standing next to a 34 ft long rocket and he was explaining how it's all a hoax. It was surreal. I swear, we need some Darwinism to clear some of the dead wood out of the species. I don't know what we're becoming. Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

One of the major rigger in the area refuses to pack canopies older then twenty years. If it's old enough to drink he wont pack it. I can understand him taking a hard line on this because I know who some of his costumers are. He deals with a lot of older pilot rigs and honestly we've been letting them scrape by way too long on some of those. So he put his foot down and made them start replacing canopies. And honestly, that was a good thing on some of those rigs. I'm easier going and prefer to make the judgement based on it's condition. It's hard to tell these guys that their shit is shit and grounded. Somebody packed it before. It's been good for the last fifty years. What do you mean you wont pack it? So although it's harsh and often unfounded I can understand him drawing a hard line. It also doesn't hurt that he's a gear dealer. And although he's made a lot of sales off this I'd like to think that that wasn't his motivation. I honestly think he just got sick of arguing with crusty old pilots. Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

So no more royalties? https://www.epictv.com/media/podcast/fastest-bra-removal-cutaway-system-%7C-base-girl-ep-4/252315 Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

In regards to LaBlanks lecture on elliptical wings and plane forms. The first thing you have to understand is that the theoretical optimum of an elliptical wing is actually a theoretical optimization of an elliptical lift distribution span wise across the wing. This is to reduce the induced drag component of the wing to a min. In theory the most efficient way to do that is through the area of the wing. He touches on all the trade offs in his lecture. As to the difference in taper in the leading vs the trailing edge. What he fails to mention in relation tto that is the fact that the aerodynamic center of the wing is not at the center of the cord. This is why you see a lot of wings, like the spit fire, with greater taper on the leading edge. When you model an aircraft, this is kind of an old school discrription but very relevant to WWII, you look at locations of CG, wing AC, and tail AC. From this comes your basic stability. Looking closer at your wing. you examine it as a span wise line through the aerodynamic center of each wing section. Each wing section can be reduced to it's lift and drag and moment acting through the point of it's aerodynamic center. Generally a point 1/4 of the way back along the cord line. So you talk about the 1/4 cord point of that wing station. So let's design a wing. I take a straight line and and decide how big and how long and in this case how elliptical I want the wing to be. That gives me a span width and cord of the wing. That plugs into all of my stability equations and I can design the plane. Fine. So I go to build it. Well the 1/4 cord point of each rib arranged in a straight line gives you a wing with 3 times as much taper on the trailing edge then on the front. You get a Spit Fire wing. That is what an elliptical wing looks like. It doesn't have to be this way. You can build the wing symmetrically. But what you are doing is warping the wing. Reducing it to the span wise line of lift, that line is now bowed. Now you can do some interesting things with this. It could affect where the center of lift is for example, under certain conditions. Let say in a side slip. Is the wing is swept back, which is kind of what we are talking about, then you will have more lift on one wing then on the other. This can affect the yaw/roll coupling. It affects how the aircraft turns and behaves dynamically in yaw and roll. Same thing in a canopy. Even a bit more so. Keep in mind that the wing of a canopy wants to sit above your head stable at one point. But if you think about it each section of the canopy wants to sit above your head at it's own point based on it's own angle of attack which is dependent on induced drag of the wing and its individual effective angle of attack. Also keep in mind that a canopy is totally dependent on it's yaw pitch relation ship to roll into a turn. I've talked to people trying to model canopy dynamics and they have had at most moderate success. They've been hard pressed to get a model that matches even the most basic perturbation in a canopy. So their model in theory looks great. They are getting pretty good actual test data now when they jump it but the two don't match up. So it's still kind of in the voodoo phase. Lots of test data, lots of experience. They know what the variables are and pretty much what they do but to try a new design they pretty much have to build it. I don't know any one successfully predicting the dynamic behavior of there designs by computer model prior to test jumping the way we can with a rigid air frame. Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

First off, rarely have I seen some one injured by jumping too large of a canopy. That's not an absolute statement but skip the esoteric arguments about swooping and longer vs shorter recovery arcs or other nonsense where people are arguing for the safety of a smaller canopy over a larger one. I'm a small guy. I started jumping when canopies were a lot bigger then they are now. You don't know shit about backing up in wind. The smallest canopy we had in a student rig was a 288 Manta. I was 135 lb at the time. Here's the real truth. Backing up is not that big a deal. Your canopy can fly in a cone. From where ever you are in the sky your canopy can fly to any point in this cone radiating out from the point you are at. We're skipping turning radius and things like that. I'm talking basic flight planing. The angle of that cone, that's your glide angle. Now when the wind blows, that cone leans to one side. Imagine taking the center line of the cone and moving it from right below you and pulling it down wind. A horizontal slice through the cone will still be a circle but the center of that circle is along this wind line. So you can still fly 20 mph through the air but the wind is backing you up 10 mph so one side of your cone looks a lot steeper then the other. These speed just add/subtract from each other. You can still fly in just as large of a cone as you always could. You have just as much control as you had before but the cone that you can fly in from that point in the sky is skewed along the wind line. If there was no wind you would still be limited by this same cone. You can't out fly your glide angle. The cone is no smaller then before. It's just slanted along the wind line. Once you understand this there is no or little difference in flying in wind. Backing up simply means that the wind is faster then the airspeed of your canopy. One side of the cone now has a negative slope. The cone is just as large. You still have just as many options as before, they are just behind or down wind of you if you prefer. None of this is a problem. The spot is just longer. And the spot is really no more critical, it's just in a different place. Wing loading. Does not, for the most part, change the slope of the cone. Same glide angle, you just fly faster. That higher descent rate means that the wind pulls the center line of your cone less. You can penetrate better in to a slightly higher wind. This is all fine in theory. There is one real difference in flying with wind. There is one fact that becomes important and is affected by canopy size. You don't have to fly in full flight. You can slow the decent of your canopy. depends on the canopy, but it really doesn't improve your glide angle that much, in deep breaks your glide angle goes down, but you can slow the descent rate enough for that to become dominant in high winds. YOu can slow your decent rate enough that you can let the wind carry you back along the wind line from long spots. The cone is now stretched into an ellipse reaching out to the down wind. So in a since you have more options in wind then you have on a calm day. Spots are actually much more forgiving and the stronger the wind the more this is true. Larger canopies can do this way better then small hot rods. That ability also allows you to hang above the other canopies and vertically stage, delay your landing while other smaller canopies fly down and land to reduce the level of traffic you are flying in. So backing up is not a big deal. There are other thing that you should be much more aware of and concerned about in wind. The wind speed isn't as bad as the gust.The differences between the high and the low are more important and more dangerous then the average wind speed. Say your canopy fly's at 20 mph and stalls at 10 mph. I'm just pulling those numbers out of my ass so don't put any thing on them. If the wind were 20 mph gusting to 30 mph then each gust would, when it dies take you almost to your stall point. So under canopy the wind gust pushes you backwards, you feel the canopy pull backwards and move behind you then the gust dies and so does your airspeed and the canopy seems to surge forwards in front of you. Gust are not instantaneous but they can be a big deal for slow flying, low wing loading air craft, Ultra lights, Paragliders, and Parachutes are prime examples. This is one example where a higher wing loading/ smaller canopy can be advantageous. With their higher speed the gust is less of a factor. It's a smaller percentage of their over all speed. Answer, Keep the canopy flying fast. Don't fly in half breaks. Don't slow modern canopies down. They like the pressurization. The other thing you should be scared of in wind is turbulence. Rotors coming off a building, like a hanger, can go a LONG way down wind. They are killers. This is some thing you should be afraid of. Be scared. You don't know me but when I tell you to be scared you'd better be wearing diapers. The proper reaction is to piss your self. Seriously, this is what to be afraid of, not backing up. Look for clean air. I don't care how far you have to land off or how far you have to walk. Look for clean air and long wind lines. this will save your life. So that's the best explanation and advice I can give you with out busting out math on you. Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

Just got back into town and was catching up when I saw this thread. As to it being out dated. I was base jumping my Pegasus on the trip. I think their is more to it then just direct vs flair. Some of the early canopies had a vertical tape rather then v reinforcing the rib or no tape at all. Strong actually tried cutting ribs on the bias and sewing a vertical tape to it allowing the fibers to convey the load to that tape. So their were big changes to the quality of the airfoil as canopies evolved. A good example was the Raven. One of the big changes from the Raven to the Super Raven was the change from one vertical tape to a V. They also made some panel changes. But there is a notable difference in performance. If you look down on them from above the old airfoil is much bumpier then the later one. Dijango/glide path/flight concepts went through similar changes. The Peg had one vertical tape. Early glide path flares were just attached to the bottom and could pull lose. Later glide path or flight concepts canopies, I don't recall when they made the change, The flare is sewn onto the bottom of the rib but that tape is continuous. It forms a continuous V on the rib and comes down and makes the attachment point. Later they played with a shorter flair with a wider tape angle. But the bottom line is that, like other companies, as they got better support on their rib their air foils became smoother. And the canopies flew better. Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

As the Prop Turns. Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

What is it? Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

That was what I thought but then he started pulling out all this math on hit probability with area effect weapons and round count per kill, etc. He was making a pretty good argument based on rate of fire vs. hit probability for aimed vs unaimed fire. He was basically saying that even though his rate of fire was, I'll just make up numbers, 6 times higher, that the hit probability is so much lower that the over all number of casualties was lower. And that's with a proper gun. The groupings, control ability, with a bump stocks is so bad that at 300+ yards their really is no aiming, even less then with a normal full auto weapon. By the way we were just doing some test on control ability with some comp/flash suppressors that we are working on. So this morning we were doing slow motion filming of muzzle deflection firing our class 3 AR full auto. Set up right it really can be very control able. In comparison a bump stock, I owned two and sold them at a gun show last weekend, is not very control able. You can not hold a group tight firing a bump stock. So I maintained that with such a tightly packed target aiming was less relevant but he made a good argument based on real numbers for aimed fire and that he was an idiot for using a bump stock. Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

I am curious. Has any one seen a breakdown on the injuries? Last I heard 59 people died. Did they all die from bullet wounds? I would expect there to be deaths from trampling injuries in a large crowd like that. Of the 500+ injuries treated, How many of them were GSW? I was talking to a friend the other night and he was arguing that the bump stock(s) saved lives. That if he had fired a normal rifle with a scope and just did aimed fire that he would have killed more people. I was arguing that it was a tight packed crowd and aiming was irrelevant. Apparently the army has done studies and has found that their is a remarkable amount of empty space in a crowd or group of men. These are question that were addressed when they first started studying machine gun fire from WWI onward. Their's actually math for area weapons like machine guns and rounds per kill. The numbers are way higher then you would think, number of rounds per each kill. To be clear. Regardless of how exactly they died I do still attribute their deaths to him. Firing into a crowd is a terror technique just like yelling "FIRE!" in a theater. I'm just curious what the break down was. Lee Lee lee@velocitysportswear.com www.velocitysportswear.com

Real or not it certainly made for a good movie. Lee Lee lee@velocitysportswear.com www.velocitysportswear.com