pchapman

Sounds like the mainstream police forces investigated many of them, figured out what really was happening, and the mainstream media reported it. It is unfortunate that sometimes people lie and try to deceive other people. Even a president may do that, a dozen plus times a day. But yes it is annoying that the nature of the media, social media, and web based 24 hr news reporting is that things can blow up so quickly before there's time for more investigation & analysis.

Adolf had days like that too. Such strength of character!

Man, what a busy body you are. The thread is about the holding area. You move it down to the pattern. Then you talk about stuff at 300-100 feet. Then you talk about people coming out of their hooks, which could be 50-5 feet. Would you like to divert the discussion to talk about turbulence in the stratosphere too? Winds on Mars? You just spout random stuff about turbulence, thermals, wind shear, whatever. It's more dangerous during a turn! No, it's more dangerous when you come out of a turn! It's all dangerous! Won't somebody think of the children! (Yes there is some sensible stuff hidden in there within the confusing stuff but it's all rather mixed up together and out of any reasonable context.)

The NeXgen actually started to be produced July 1, 2013. (A relevant document was labelled "AERODYNE_NEWSLETTER02_nxgn". I haven't checked whether this is now up on the web at their site.)

Ah, work hard to enrich yourself, breaking the law whenever you think you can get away with it, screwing over anyone you feel like (especially the humans one considers unworthy), lie left and right, hate your fellow man, and the list goes on... In it for himself and the Devil take the hindmost!

I'll expand on what Rob mentioned: Nobody should get hung up on a particular number. Various ones get bandied about. For a typical low speed cambered airfoil in skydiving, at moderately high angle of attack as in typical flight, it might be 80%, but that's just a guess. Based on having done undergrad aero engineering, but not having actually calculated anything for a particular situation & airfoil. (Who knows, maybe 60% is better for an airplane at cruise, which is typically at a fairly low angle of attack, as airplanes tend to cruise much faster than their stall speed, so the wings doesn't have to work as hard to provide enough lift to keep the plane up. Less 'bite' into the air needed.) It may be best just to say "most of the lift comes from the front, upper part of the airfoil", than quoting one number. Since attachments can no longer be uploaded, I'll have to resort to links: https://www.mh-aerotools.de/airfoils/images/velo6.gif A reasonable example would be the airfoil in that link, which is at a moderate angle of attack. The graph shows velocity ratios from front to back on the airfoil, top and bottom, but that basically translates into pressure ratios. That is whether the pressures are higher or lower than the ambient pressure. The difference between the upper and lower lines is the lift. The bottom surface has low speed, higher pressure air, so it does get a 'push' upwards. The top surface has higher speed, low pressure air, especially towards the front. Most of the area between the lines is above the value of v/V=1, so that's the contribution from the upper surface. If the angle of attack goes even higher, then that front upper surface line is even peakier, spiking upwards more. The front of the airfoil is working especially hard, up closer to the stall. All that lift at the front top of the airfoil is why we use airfoils and not just flat surfaces. You can fly a barn door, but there's not nearly as much lift, and there's a ton of drag. Airfoils are the magical way to get a lot of lift for not much drag. (Things are a big different at small scale and low speed, so don't dump on insects for having simple flat wings. Viscosity & Reynolds numbers and all that.) As an example of comparing angles of attack, see: https://i.stack.imgur.com/f7wHm.png It's a bit messy, but shows pressures on top and bottom for three different angles of attack. At low angle of attack the wing isn't 'working hard' so the upper surface isn't providing much lift anyway. As the angle of attack increases, there's some more upward push on the bottom, but a lot of lift is added at the front of the upper surface.

[edit: ninja'd by wolfriverjoe] Actually Rush, the snopes article comparing Obama and Trump on the campaign finance issue is instructive. Snopes isn't perfect but they try to be a serious, balanced source. See https://www.snopes.com/news/2018/08/22/election-law-violations-compared-obama-2008-vs-trump-2016/ The Obama situation was mainly some sloppy paperwork here and there in a billion dollar (ouch) campaign, missing some reporting deadlines, having some wrong dates attached, and missing 48 hour notices for a couple million in donations. All pretty minor stuff given the size of the campaign but the FEC takes it seriously and expects the paperwork to be right. A quote from a former FEC chair, discussing what makes a campaign finance issue criminal (as Cohen pled to), versus just civil (as for the Obama campaign):

That was actually a useful contribution. From a right wing but not totally nutso site. Differing opinions from former FEC chairs as to what actually constitutes a campaign finance violation, and what the penalties have historically been. Doesn't change Trump's endless malfeasance and lying, but good to put things in perspective.

Wings Boost has a metal pin. So which one were you thinking of? (Quite a few variations out there to keep track of...)

That sounds like what I expected. It's hard to know what forces might be set up in the system without a lot of testing. Indeed the red lanyard for the Skyhook system was set up to be a weak link in the chain -- strong enough to work as the MARD almost all of the time but break in case of some weird high force situation. I wonder what the strength of the bungee is. The ultimate strength would likely be largely from the sheath. But there isn't just a particular Mil Spec style bungee out there? If I were building the thing, I'd want careful control of the bungee loop source and material and stitching, so that a bungee good for 200 lbs (or whatever it actually is) didn't get replaced by a low quality one that's good for 100 to 150 lb depending on batch. It does look like the bungee is sewn into the RSL, and not a loose part, so it isn't something a rigger would easily mess up by trying to replace. Mxk's suggested tests sound good to try 'just in case' although I see that you would argue that those situations shouldn't happen: The 'pulling 180 degrees' opposite test would be interesting, although it shouldn't happen unless the MARD somehow hung up on something. Once the rig opens the MARD should be free (or only lightly restrained to a rig flap as many are), so that if one tries to pull the PC end of the bridle back 'against' the MARD, the MARD will just rotate as needed so the folded bridle acting as the pin will always pull straight out of the cloth loops. The 'fold the MARD in half' case is also interesting to test. If the MARD can still disconnect without much force in that situation, then it isn't a problem. Even if disconnect forces went up, some could argue whether a disconnect is needed at all when the RSL is pulling super hard. Normally people expect MARDs to disconnect if there's any light force from the PC end. Yet they also don't want it to disconnect when chopping from some weird vertical-axis spinning mal (ie, helicopter style, not a smooth spiral canopy-on-horizon) just because the PC bounced around while the RSL & main were starting to extract the reserve bag just fine. Is a MARD supposed to disconnect at 0 lbs, or 5 lbs, or is a higher value allowed in cases where it is far less than the RSL end's force? Still, the 'folding MARD' thing could be tested. Even on the ground with a car coming to the end of a long slack rope. Maybe the MARD is light enough that even in the case of an explosive main opening just as a cutaway is performed, giving say a 20g or whatever acceleration to the MARD, it will either not fold the material, or is one of the extreme cases that will break the bungee as the deliberate weak link. I'm just winging it here; thinking through all the possible failure cases of MARDs is tricky.

Made by the Democrats?? As people noted even at the time, that suit was up to her & her lawyer, a hard hitting but weird guy.

If I'm getting it right, compared to a system like the Wings Boost, this uses bridle fabric in place of a steel pin, and a bungee in place of a piece of line. That seems to be changing towards materials that are higher friction (the bridle) or weaker & perhaps more variable (bungee). While the subtleties of any issues with MARDs can be difficult to see, I'd like to know the rationale for changing things in this way.

As best I know,there is a rule, but it is hidden away in the PFF Instructor manual, where section 2.3 on minimum acceptable standards states this about any student entering the PFF program: "Student has made 1 jump (IAD, SL or TDM) or 20 minutes of wind tunnel under the supervision of a trained PFFI before undertaking the PFF jump program" Not something one might have heard unless one actually took the PFF Instructor course. Anyway, this is getting into more detail than needed about how the Canadian system works. As I said a waiver is possible, and there are also USPA affiliated DZ's in Canada who may use the AFF program. So things vary DZ to DZ.

I think in the US the standard is to do AFF from the start. Plenty of people here can correct me if that's wrong. (Although the USPA is now getting into tunnel before AFF rules.) In Canada the standard is a little more conservative. Normally you do 1 jump of some other type, whether tandem, static line, or IAD, before taking the PFF (our version of AFF). That's to cut down on the people who get totally brain locked, by exposing them a perhaps less intense skydive first. (We've also long had rules on using the tunnel before PFF. Tunnel trained students can go straight to PFF.) The one-other-jump-first rule is in effect waiverable though the CSPA, so there is the occasional DZ that goes straight to PFF for the first jump.

I don't recall the exact sequence of events, but I looked stuff up to summarize: - Oct 2005 - Skydive Atlanta - first lost tandem student, the one who was paraplegic. It seemed then like a one-off, special case. - May 2006 -- Aerohio - second lost tandem student, the more pear-shaped one. Strong came out with their Y-mod after that, and made it mandatory by the end of 2006 or 2007, I don't recall exactly. Things seemed quieter for a while, until hanging-grandma went viral: "In May, 2011, 80-year-old Laverne Everett went skydiving in Lodi for her birthday" UPT then came up with their Y-strap modification, and with bulletin #2013205 made it mandatory by the end of 2013. Tom Noonan in 2013 summed things up:

"Tortoise, what's that?"

So, there was the Super Swooper Tandem than morphed into the SST Racer, which became the Racer. For the old timers, how did the "Struggle Struggle Thump" moniker originate? And in what era? Was there any fundamental issue? Or a tendency to over tighten the pop top to make it look neat? Looking at old bulletins, one serious reserve-related one that I see has to do with installing the type 12 buffers within the freebag, as someone had to hand-assist reserve deployment when because canopy fabric got caught up with the reserve closing loop & grommets in some way. That was in 1984. And in '76 there was a change to the way the reserve ripcord housing was tacked -- I think it might bend too tightly over the shoulder for some shorter people for example, which could make for a hard pull. By the mid '80's I'm guessing, that was "peak Racer"?? Photos old bigways would show something like 25% plus of the rigs with pop tops...

Racer wars again! Although every statement here could be endlessly debated, here's my grab bag of reasons why Racers are not popular: 1. First off, when a set of gear is less popular, there are fewer to be seen and fewer dealers…. So the average skydiver isn’t likely to consider buying one. Especially if there aren’t well known jumpers out there to push the brand in popular disciplines. 2. Racers used to have safety advantages that other rigs didn’t. Like much better reserve pin protection and main deployment handle protection, or a better reserve pilot chute launch. But other rigs have more or less caught up. One can argue the details, but other rigs are considered decent these days. So there’s little incentive now to go for something a little out of the ordinary. (It probably doesn’t help that most Reflexes are retired and few TSE Teardrop rigs are seen in North America … full pop tops of any variety are nearly unheard of.) 3. Racers are a pain to pack especially if not every rigger is used to dealing with Racers. They can be done efficiently... but if 1 in 100 rigs you pack is a Racer, it can be a real bother. 4. Nowadays with near universal AAD's, it costs a couple hundred bucks more to equip a Racer because of the two pin system. 5. Racers were slow to innovate with modern riser protection. Although they have good stuff now, for quite a time when their popularity declined, I seem to recall they were pretty much the only ones with "all that old fashioned 1980's velcro". Other rigs innovated, Racers were slower to change, even if the owner said “We got the design right the first time.” (Mind you, a ton of new velcro can be more secure than a bad tuck tab design, even if it chews risers and lines up.) 6. Bizarre closing loop system. In some ways, having an adjustable loop is really handy and smart. I like it. Although some riggers get worried about having their seal on the rig,when a user or some other person could mess with the pull force after the rig leaves the shop. The worst is changing the loop. All that hand tacking of the loop and hand tacking of the pilot chute cap. It's like something from the 1960's in the military. Heck, some rigging instructors are all about "Change reserve loops every repack!" these days... They clearly aren't thinking about a Racer. (Nor can Airtec and Parachute Labs even agree on the best loop setup system -- a free loop in a channel or tacked down?) Changing a loop shouldn't take 1 1/2 hours or whatever, including building the loop. (Ok, I'm sure some of the riggers out there can do it faster.) They need to have some neat quick attach system for the caps -- heck, cheapo Wings rigs manage to have a clever design. 7. Reserve speed bag with all the elastics. I can’t even buy a traditional safety stow type freebag from Parachute Labs any more. Yeah, the speed bag is supposed to work, but I’m not sure everyone feels all warm and fuzzy about the design. Traditional free bags still work fine. 8. In general, the company owner is inventive but notably fixed in his opinions, sometimes counter to the industry. Sometimes that’s good and leads to innovation, sometimes that’s bad, as it can slow changes being made or make the rig seem weird. So the average jumper might be OK with some innovation that’s different than the industry. (different cutaway cables.) Or they might be a little wary (speed bag freebag). Or the company seems unusually fixated on something, as if their Type 13 harness design is the only true, safe design in the industry. Or there’s the endless defence of the two sided RSL – Even though a regular RSL is actually available, that would make the average jumper happier about the rig. If they think they have the better answer, but it is something skydivers are wary of, make it an option rather than turning people off with it. And I'm saying this all as a Racer owner. Got one cheap years back and have done various mods to it.

Not sure of the skydiving relevance but I wasn't aware of that paragliding incident. A popular paragliding forum doesn't have any answers yet. Who knows what the standard of equipment was at that particular place in India. No emergency chute carried either, apparently. Carabiners in paragliding have long been known to have certain limitations. Now maybe you know this, but just to give background for the thread: If the 'biners are aluminum they are more likely to get cracks from rough handling or scratches that make them fatigue damage and breakage. So many pilots went to heavier steel 'biners. And the snap gate system sometimes allows repetitive strain on them because when under less load, the closed snap gate doesn't always actually get loaded. So the 'biner acts more like a "C" shape rather than a closed "O" shape, and cycles of stress fatigue it. We don't usually deal with carabiner style hardware in skydiving...

You mentioned such hardware 'had already been credited with saving a life'. In what way was that said to have happened? (That was in the Vector Digital camo thread which got into leg strap hardware stuff more appropriate here.)

Ah, I see, it's like god and Jesus. The meaning of things is whatever you interpret it to be, and whatever happens was meant to happen, all part of his plan, visible only to the True Believers.

As an outsider I'm like, boohoo, some of those dumb Americans get so butthurt about the flag thing. Flag waving Americans, indeed. Gee, like I need the flag to remind me. What? I always thought it was the ARMENIANS who landed first on the moon. Now I'm told it was the AMERICANS. The lander descent stage built by Grumman should still be there doing fine on the moon. The flag has probably disintegrated from the UV light... (Not quite practical to follow the flag code about "when it is in such condition that it is no longer a fitting emblem for display, should be destroyed in a dignified way, preferably by burning." )

Regarding Westerly: So how is a high puller supposed to see the first down? He might be well be a mile away at 5000 ft when jumper #1 is about to land. (It might not be impossible to spot the jumper, but much of the high puller's focus during the first minute of canopy flight might have to be looking carefully at the DZ area, to the detriment of anything else they might be doing.) So I could see that someone just follows the prior jumper when approaching the DZ, expecting that everyone else has gotten into the correct pattern.

Yeah one has to be fast in the transition. Maybe going from 'hands pulling down rears a few inches' to 'hands another foot lower' in a split second, so that one doesn't let the canopy dive in between. So it does mean being comfortable with one's normal flare, and having a good feeling how much the toggles need to be pulled down at any part of the flare. One does have to be quick and decisive about it. Whether that in particular works, willl depend on the energy available. I'd practice starting with the rears, but not attempt to fully level out. One might find after levelled out at 3 ft high, that one doesn't have enough energy left with the toggles to give time to begin to drop down again, and then flare out level at zero feet. So I'd rather (if new at this) start pulling out on rears, but transition to toggles fairly early, without being fully level. Keep more energy for the toggle flare after. (While one doesn't want to end up flared too high and slow on rears, of course one doesn't want to fail to pull out level before hitting the ground, so there's a balance to be found...) As one practices, one will see how much one can do on rears while still having enough energy left with the toggles.

Well the original poster might well now a competitive canopy pilot, or have left the sport years ago, since this is a thread resurrected from 2004.