pchapman

Highly doubtful it's as high as +18. That would be quite remarkable for a well designed rigid wing. http://www.grc.nasa.gov/WWW/K-12/airplane/foil2.html Without trying to get too far into airfoil discussions, I'd say 18 degrees is not totally unrealistic. Foilsim (your link) does seem to show a very early stall if the output is set to Surface Pressures. Just about anything seems to show a stall at 10%. But if one selects Lift vs. Angle, more realistic results occur. E.g., for something vaguely resembling a skydiving canopy, how about 18% thick, 4% camber. Max lift is at 14.75 degrees geometric, but because of the camber, zero lift isn't attained until -3.75 degrees. Thus the total aerodynamic range to the stall is 18.5 degrees. However, the graphical part of the display still shows separated flow over much of the airfoil. The problem is the graphics are crude and pretty much suddenly switch from attached to separated at, you guessed it, 10 degrees. For another source, there's the classic book Theory of Wing Sections (by Abbot & von Doenhoff). For a similar NACA 4418 airfoil: 14 deg geometric to maximum lift, zero lift at -3.5, thus a full aerodynamic range of 17.5 degrees to the stall. So I'm just saying that 18 degrees, isn't totally out of whack when talking ideally about an airfoil. Although that is without the limitations of a 3 dimensional fabric wing, where the performance wouldn't be nearly as good -- and that you're right about. (One could still argue about what exactly defines the stall, and whether FoilSim is really doing a good job at predicting stall behaviour...I'm skeptical... it is a notoriously tough thing to do well even without the most advanced aerodynamic codes.)

While opinions will vary, here's one way that I think riggers may gain experience: Most DZ's have some sort of a loft / rigging room. There may be a chief DZ rigger one can do some work for, or maybe the DZ could use another rigger to help out when the regular one(s) are too busy. Rigging for the DZ, at the DZ, seems an easier way to "get known" than trying to start off with taking experienced jumpers' rigs home to pack -- unless you already have a good circle of friends a the DZ who trust you. Besides, you have to get a bunch of repacks done under supervision to get your rating. So unless you go to some all inclusive American-style rigging course, you need to form some sort of relationship with a local rigger. Years ago, I got my required repacks in by apprenticing essentially free at a local rigger's shop. A newbie rigger may be more likely to be trusted if he's been checked out on say just a couple types of student gear, which are often less demanding to pack than the greater variety of experienced jumper gear. (An experienced jumper with a PD 113 in a Javelin is more likely to complain about bulk distribution and loop length than a student renting a Vector II with a PD 235 in it.) Slowly he'll get more chances to pack experienced jumpers gear, with ideally some supervision at the DZ. Being in some sort of a rigging loft with exposure to more equipment and other riggers' knowledge is also a lot better for skills development (and customer safety) than being alone at home with your shiny new seal press and not much else.

I thought ( dare I say remember ) that the rings team used Vectors. You're right. The cover of ParaGear #54 (attached) shows the rings jumpers all had Vectors. (The photo credit says "Kent, Crabtree, Sanders" - somehow their photos must have been pooled or shared.) The Racer thing might have been just for the CRW / accuracy folks. Who knows.

I don't know what the current thinking is, so I'm wondering what the opinion is about what to do when teaching about emergency dive recovery, to prevent ground impact while in a turning dive. The standard recommendation always seems to be to level the wing (canopy) first, to enhance the ability to pull out, by getting the lift vector working directly upwards instead of being angled and contributing less vertically. I don't like that as the SOLE answer. While that could well be appropriate at slightly higher altitudes, at very low altitudes there might be too much time wasted in rolling wings level before starting the pull out. I heard Brian Germain also isn't happy with the roll-level-first idea - more on that later. Part of the problem is that people don't typically have practice in asymmetrical toggle flares from a turning dive. They might be able to turn quickly, or apply both brakes quickly, but trying to flare sharply while trying to level out at the same time just isn't practiced much. In such cases, if the person is very low, it may be best to focus on first flaring hard, even if the canopy is still in a turning dive. Then the person can start applying some more outside brake to level the wing. Ideally there would be both a flare and extra outside brake to level the wing, all at the same time. Naturally if one brake is to be pulled down more than the other, one can't do a 100% flare first. One brake has to end up down further than the other, or at least lead the other brake as the toggles come down, even if both end up at 100% in the end. The idea of flaring and turning at the same time is in some of those "downsizing checklists", things to become comfortable with on one's canopy before downsizing. But (without checking them right now) I think the exercise is mostly designed as an avoidance maneuver, not a dive recovery maneuver. The difference: -- avoidance: start wings level, do a flared turn off to the side (and, whether the canopy stays banked or is re-levelled, the rate of descent has to be taken out to permit a soft landing) -- dive recovery: start in a diving turn, do a flared turn to level out in roll and rate of descent So even the turn & flare practice for avoidance maneuvers doesn't translate precisely into the skill needed for dive recovery. As for Brian Germain, I recently read that he also likes the idea of not automatically trying to level the wing first. E.g., from his site: [Quote] Turning too low is the preliminary cause of many injuries in our sport. Unfortunately, most canopy pilots assume that bank angle must be eradicated before arresting the dive. This leads many to waste valuable altitude in the process of leveling the wing. In situations with very little altitude remaining, this may delay the collective brake application until it is too late. By rehearsing a transition to zero decent while still in a bank, the pilot becomes accustomed to applying the toggle on the outside of the turn as a learned instinct, reducing the chances of a turn leading to serious injury. Also: [Quote] Arrest the dive as quickly as possible by sharply applying the opposite toggle as well as the inside toggle; the inside toggle is not applied until the two are matched in the degree of input. When the toggles are matched, a short stab of collective brake pressure is usually all that is needed to achieve level flight. I am confused by his wording in that last paragraph. For example, what's the difference between "matched" and "collective brake pressure"? Both sound like they apply to brakes being at the same point. Maybe it is just me, but his choice of words seems poor. Either way, I think his overall point is clear -- one should be able to both flare and turn at the same time. I just think that if one isn't well practiced in doing so, one might not be able to accomplish that accurately and quickly. In such a case is better start with a quick flare (which one can do instinctively), and then add some turn.

Everyone's memory differs! I'm just reporting what I read. In late '88 a Canadian on the Olympic jump, Eileen Vaughan, wrote an article for Canpara magazine. While she could have gotten erroneous information too, this is what she had to say: ==== "Our only misadventures included one Korean malfunction on a practise jump. After his cutaway and reserve opening he landed in the stadium under his Firelite. Unfortunately, members of the media only saw his cutaway main fall to the ground and assumed it was a person. The rumours were rampant for two days that someone had been killed, though no one bothered to verify the fact. One U.S. media group went so far as to send a report back to the U.S. that a Golden Knight had been killed. That generated several reassuring phone calls to confirm that there were no problems. The other mishap occurred one windy day when 5 CIP jumpers got caught concentrating too much on flying the formation and not on accuracy and landed out of the stadium (National Accuracy Champs, mind you). No, I wasn't one of them. A few red faces on that one. This also generated some media." ==== Eileen was one of the national accuracy champs who participated to do non-contact CRW stacks. The other two groups among the skydivers were the champion RW teams who formed the Olympic rings in freefall, and a group from the Korean army. Each of the freefall rings was made by a different RW team: the Golden Knights, Tag Heurer (France), Coors, Air Bears, and Mirror Image. The jumpers had apparently all been offered Pursuit mains (in the required Olympic colours) / Firelite reserves / Racer Elite containers at a good price, so I imagine that was a combo many had. Edited: Jerry Baumchen mentioned how a rings team member said there was no malfunction... if Eileen is correct, then the team member is correct only that there was no mal among the rings teams. Edit #2: What the hell, here's some more from the scanned article: ==== "Over the next 6 days we made 19 practise jumps from 3 U.S. Army Chinook Helicopters (plus a few spares as are usually required). We made all but 6 jumps into the main stadium with the others made onto an open DZ at the Kwangnaru Yatching Centre in Seoul. We all preferred the Olympic stadium as you can imagine, and that's where the reporters were. Flying past the upper edge of the stadium and getting lots of lift and turbulence while trying to perform a "non-contact CRW stack" really got the adrenaline pumping. Most of our jumps looked more like tight accuracy stacks but we still had our work cut out for us in making the jump of Olympic standard. Fortunately, working with the best jumpers in the world make it possible, even with some language barriers. For our first two days of practise, each group worked separately, with long delays between each part of the show. We then progressed to the intended routine of each group landing immediately after the other to work on our timings for the show of only 7 minutes and 30 seconds (or so). In order to fit in with the rest of the ceremonies show, we had to make the timing perfect. Each jump was videoed and critiqued for effect and timing. We had to perform given any weather or wind, so we varied our exit altitude from 2000' to 4000'. The Rings Team worked with a range of 2000' to 11,000' with modifications. At 2000" they would hop and pop like us and the Koreans, to fly only a canopy show. At 3500' they would drag out each ring separately. At 6000' or over they would go for the whole Olympic Rings formation. These guys were hot, as they completed a 20-way, (in fact a 32 or 33-way with a couple alternates sliding in) from 5500'!! Lots of yahooing after that one. Being the lightweight on the CIP load, I was usually of top of the stack, which was a beautiful view of the group and pattern that we flew. The first of the yellow ring guys would be right on my heels for landing or even land a couple before me, so I had to keep an eye out for them on their opening. The days were long due to delays and holds for air traffic, other people using the stadium, and endless briefings and debriefings. We usually made 4 jumps per day from 7:30 a.m. till 8 p.m. with a break for our daily "western" lunch of cold cheeseburgers and warm Cokes. Soon we were offered a vegetarian option of 3 doughnuts and an apple. " ==== (Emphasis mine on the good old school RW altitudes!)

Yeah, I see what you mean, that's the old problem with regulators: It's hard to regulate well if you know less than the people you are regulating about some very specific topic. Would I say OK? In my ideal world, if I were the FAA guy involved, I'd set up conditions that would remove most risk to persons and property on the ground, and require the applicants to present documentation demonstrating that they were taking reasonable steps to create a favorable outcome. I wouldn't issue a document that would imply that their particular stunt plan was "safe" for the participants. I would issue a document allowing the group to engage in aeronautical activities in a certain time and place with specific exemptions for particular regs, and be satisfied that those concerned were voluntarily accepting risks, while others in society would not be harmed. (I wonder what the regs were in "the old days". There were the Cliff Winters airplane stunts, some involving low altitude parachuting in the 1950s in the US. FMI: http://www.parachutehistory.com/men/wintersc.html Or, in a relatively more recent era, there was stuntman Jim Bailey in Hawaii in 1981, hanging from the bottom of a plane to try to skid along to a landing in an armor plated suit, who fell to his death when his support hook released early. I saw the disturbing video on TV years ago, and it is out on the web too. So in the past there have been bizarre ways to get yourself killed, that have been in the purview of the FAA.)

I do like seeing stunts. But one can distinguish between different varieties of stunts. Some may be carefully set up a such and don't harm others, while are more like BASE dayblazing that cause problems for other jumpers. As for the legality, what has always troubled me is that, at least at the surface, the FAA just doesn't seem to make exceptions to the skydiving rules. Even in the field of aerobatics, heavily regulated as with most aircraft operations, airshow pilots can get low level waivers if they can demonstrate reasonable skill and experience, to fly aerobatics down low at airshows. I wonder how hard it would be to ask for a waiver to do 400' BASE rig jumps from aircraft at airshows? Please correct me if I'm wrong, but it doesn't sound likely. Given all the different airshow acts out there, there would be a market. And it isn't as if professional airshow performers (and aerobatic pilots in general) don't get themselves killed regularly. It is not as if the FAA regulations on skydiving equipment & altitudes apply only at airshows or within 2000' laterally of any person or structure, to avoid harm to the rest of society. One can fly a plane right down on the deck, legally, if well away from persons and structures. (Although regulations on maintaining the aircraft still apply). While I don't know the regs that pertain to the latest chuteless jump, if it wasn't done within the law, I somewhat doubt that he had much opportunity to do it within the law if even he tried.

How would you make them? I'll just reply to that, and not the issue of whether the original poster needs or should used webbed gloves. Webbed gloves can be much simpler to make than regular gloves, if one has access to materials. The skydiving ones I have from the early 90s are pretty much just a layer of heavy spandex style material on top of a layer of leather like material. Then it is just sewn around 3 sides and around the fingers as if one traced around one's stretched hand. There is also an all Spandex cuff that complicates things a bit. I've seen another brand that is more like cycling gloves in that the finger tips are open. Less area, worse when cold, but better for grabbing things. I experimented with the webbed gloves a few times for style sets, beginning to sit fly (way back in the sit suit era), and tandem video. No fun when dealing with toggles and risers for a small crossbraced canopy these days.

It has also been pointed out that a reserve is not pulled slowly 'from a standing start'. There's some force to remove the handle from its pocket (not measured), then it may move easily for some more inches until the slack in the cable is taken up. Then the momentum of ones arm moving all of a sudden yanks on the pin. The pin even gets the chance to move a bit before the slack is taken out of the seal thread, and that force is added. There may also be some effect from the dynamic friction while the pin is moving, being a bit less than the static friction to get it started. So the forces one apply can easily be quite a bit more than static pull tests indicate. The Great Bearded One (Bill Booth) mentioned some of that kind of stuff in threads 491650, 144383, and 942674. (Use the search function too, Hackish!) Now I bet a fair number of reserves are packed with pull forces a little bit higher than the 22 lb maximum. One tends to get that with some super tight pack jobs. A day's cooling off period tends to bring the force back down again so in practice it doesn't become an issue. And a rigger can get a feel for what is on the tight side but reasonable, vs. ridiculous and on the way to ripping the Cypres loop while packing.

[Old thread but the topic is right.] I've been at a DZ where instructors do give a cutaway command, although the emphasis all through the static line course is that the student makes the decision. WHEN NOT TO CUT AWAY A related issue is when not to cut away. If a student has a mal but doesn't deal with it and gets low, at some point one will want to make sure the student doesn't cut away. This can be an issue both at DZs that give and don't give cutaway commands. No more calls for a cutaway if they're spiralling through 500 ft under a lineover. My DZO seems to have a point that at such a time, it's pretty much a case of having to lie to the student. The idea is to reassure the student, have them prepare for the landing roll, that sort of thing, as if it were all very routine. Nothing is said about any emergency, that might invite a chop at 200 ft when they finally notice the ground approaching quickly. TERMINOLOGY Instructors at the DZ are careful about terminology when using the radio. Usually the instructor would say something like "Use your Emergency Handle!" (as it is a one handle system), being very clear of course about which student is being addressed. The instructor might instead say, especially if the student isn't responding, "Look, Grab, Pull!" because those are the words the students learned while practicing the motions during the first jump course. Instructors never use those words for anything else, to avoid confusion. Many many years ago, an instructor must have told a student something like "pull your right toggle, come on, pull, pull!". The student only registered the "pull!" idea and cutaway, thankfully high enough for the reserve to open. GETTING FOOLED EVEN WITH CAREFUL USE OF TERMINOLOGY Recently an instructor was dealing with a student who was not particularly responsive to the radio. While normally students are addressed by "jumper #1" etc., we have their names recorded as a backup. In this case instructor tried to get the student to respond by using his name: "Luke, Luke!" You can guess what that sounds like. From under a good canopy, the student chopped. Again, they were plenty high enough to get under a good reserve. It's hard to anticipate every eventuality...

Which brand of gear was that one?

If you've got 'em, post 'em. Or at least give us a gist of the type of thing to watch for. It's a big book so errors are possible. I'm curious how obvious the errors are. If they are obvious to even a newer skydiver, then perhaps it isn't that bad a problem. The nature of the errors may still say something about whether other ones lay undiscovered, and more likely to trip up a new or experienced rigger.

[Note: Thread applies to CANADA] I'd go right to the CSPA's Coaching Working Committee (CWC) site. The page is http://www.cspa.ca/cwc/relativework.htm It is a little confusing that some of the best stuff on the CSPA site is "hidden" under the CWC section. CoP study guides and info on all Endorsements are at the CWC site. The blueplanetweb site mentioned in post #3 seems to be a development site for the CWC stuff?? The page mentioned is almost identical but bit shorter than the one I mentioned. I can't tell which site would be most up to date at any given time, but the official one would be the CWC one. So the CWC page on the 2 way RW endorsement does list what is to be done on the minimum five jumps. However, the list still still requires some interpretation by an instructor. At my DZ (the 'other Toronto one') we've got charts for this sort of thing, taking the CSPA guidelines as a starting point to create a curriculum. Spread the word about the CWC site -- it isn't perfect but is useful and not as widely known as it should be!

No issue with propacking that I know of. I think flat packing is done simply because it works fine for big old F-111 style canopies, and because propacking large canopies can get awkward. Propacking may even make it easier to apply certain nose & tail treatments, like rolling the tail a lot, if that is one's preference. (For those taking Parafoils to terminal, it seems that everyone has different packing variations anyway, to try to get a decent opening.) While I've flat packed my Parafoil, I know a fellow with thousands of Parafoil jumps who propacks his all the time.

Regarding the rocket activity: This is just like skydiving operations having other pilots flying overhead, oblivious to the skydiving activity. The DZ may be frustrated because they have already done everything correct with the FAA, when it comes to NOTAMs etc. But additional effort is necessary to "get the word out" into the local flying community about the hazard. Send notices out to other airports to put up on their bulletin boards...

Are there particular concerns you can mention, whether or not the the risks turn out to be valid? A major one would be how well a particular design operates under heavy load.

Thanks Ryan, I have left a message for the DZO suggesting he can contact you, if for whatever reason he isn't getting the payment issue resolved. I don't know any of the details.

Fun to check the logbooks. Not exactly a typical progression for me: -- jump 41 first set of own gear: used Racer & Titan 265 -- circa jump 600, 11 years later: different used Racer & Sabre 135 (hey, the Racer was cheap and as a rigger I could make some changes) -- circa jump 770, 1 1/2 years later: same Racer & Icarus FX 88 (But due to doing a lot of accuracy on another rig, I only had 32 jumps on the 135 before going to the 88) Currently 1950 jumps. (I have accumulated some other odds and ends but the above has been my main gear.)

I know a DZO who decided to try accepting Skyride certificates because he didn't know the whole controversy, not being a big internet user himself. He has accepted maybe a dozen students arranged through Skyride, and now can't seem to get them to pay him for the jumps the students made... (Now that jumpers found out and filled him in on the story, he's no longer planning to do any business with Skyride... except hopefully get what he is owed.)

I'd like to know what the real strength of chest strap adapters are, whether the one for the 1" webbing, or the traditional wide-webbing MS70101 design. Although they are somewhat wimpy pieces of metal, they are much maligned as everyone keeps quoting the 500 lbs number. "Rated strength" does not tie in directly with ACTUAL STRENGTH. It's all a bit mysterious and I've never gotten good answers (or found them in DZ.com searches). RATED STRENGTHS have different safety factors depending on the standards for that type of item. For example: -- Webbing: Poynters suggests that a rated webbing strength is the minimum at which the webbing would break. If there is not more to the story, the manufacturer would make sure that for any variation in material and manufacture , their webbing will break at that strength or somewhat higher. There is no extra safety margin built in, above the quoted strength. (I'm discussing the new webbing alone. It's another matter how it is used, given stitch pattern strengths or UV and mechanical wear) -- Rapide quick links: The loads listed on them are Safe Working Loads, with a 5 times factor to the Breaking Load. The Proof Load that they must withstand without permanent deformation is half of the Breaking Load (or therefore 2.5 times the quoted Safe Working Load) -- Parachute hardware: (At least for the US style milspec hardware) Poynters #1 is vague. It says that hardware is proof loaded, and that there is a 100% safety factor. So I guess but don't know that if hardware is quoted as "500 lbs" then it is supposed to hold 500 without permanent deformation, but also to survive 1000 without actually breaking (if the load is applied in the intended manner). If this is correct, then it suggests that in the quoted scenario, then the stitch pattern of 900 lbs max may actually be fairly well matched to chest strap hardware that could well go to 1000 lbs before failing.

Kefran: Regarding "don't play the 'YOU'RE A DUMBASS ...' with me ok?" Riggerrob was probably curious because you wrote "my certification as a tandem camera will allow me to follow them in the sky". Your profile shows your home DZ to be in Canada, at a CSPA affiliated DZ. I don't know of any certification required in Canada to allow anyone to do tandem videos. Educate me. You were simply being called out on something that someone probably believed to be inaccurate. Perhaps the DZO has a strict procedure to qualify people to do tandem video, or likes to closely follow manufacturer's recommendations regarding RW with tandems, or perhaps English isn't your first language. But you still say you have a certificate: "regarding my certificate i really don't have to show it here ". True, but we may not believe you if you don't, and we may still be curious what certificate is required to film tandem video. I seem to be missing mine...

The stalled chute is not the problem. It won't overtake the jumper so to speak. The issue is coming out of a stall, where a sudden reinflation with zero brakes applied can cause it to shoot forward to the horizon and result in slack lines. This is more of a problem if the canopy was either well stalled for a long time (completely collapsed and vertical speed has picked up a lot) or the canopy had just swung far back as the jumper has entered a stall in a very dynamic manner. Proper stall recovery technique is advised. I can't recall whether anyone has managed to gift wrap themselves with a skydiving canopy, although dropping into slack lines could easily cause problems. Who knows, you might be able to do it if you tried. More likely with a high performance parachute would be to get an opening that isn't on heading, which when combined with lack of line tension, would result in a spinning diving line twist situation requiring a cutaway. (With much lower drag, long lined paragliders, grift wrapping has happened.)

Billvon's reply gives a perfect example of what I was writing about -- a simple looking thing to do (a launch with just a little 4 ft drop) turned out not to be so simple. So to have a high chance of success with no scary moments, someone doing a building launch should be very comfortable with paragliding or ground launches. Otherwise they may not instinctively recognize the precise position, orientation, forward speed, pitch rate, lift, drag, etc. of the canopy at the moment of deciding to go over the edge... Just my opinion.

I'm usually at a fairly large static line DZ with FXC's on their gear. I don't recall or recall any talk about any unintended FXC firing over the last 5 or more years. (The exception was one FXC that went bad and fired while the student was flying around at normal descent rates.) Student AAD's are turned off in a descending plane. When the DZO was looking at expanding the range of rental rigs available, I did a few test jumps with a bag of 3 FXC's. I couldn't get any to fire when doing toggle spirals at a 1.3 wing loading on a Sabre 135, but two went off at 1.4 wing loading. (However, I only did a single jump at each wing loading. In the spirals I was trying to achieve by feel the fastest possible descent. ) The tests gave some assurance that even for a lowly FXC, even when trying hard to fire them, it can take quite a high wing loading to get that to happen. I don't have the FXC firing specs in front of me but another post by an experienced rigger suggested 40+ fps (approx 28 mph).

CanuckInUSA had a good and detailed reply. I'm not current in paragliding, but in that sport cliff launches are generally considered to be dangerous and not normally done. The sharp corner tends to cause turbulence and odd wind gradients, and the sharp corner also means a launch is more of an all-or-nothing deal than the usual launch down a slope. If someone were launching off a building, I'd suggest they should to be really comfortable kiting their particular canopy in turbulent conditions, whether for forward or reverse inflations (facing back at the canopy to see it better while inflating it). It should be easier for a low aspect ratio skydiving or BASE canopy compared to a high aspect ratio paraglider. Being really familiar with ground launching the canopy off other slopes too, would help in gaining that split second awareness of what the canopy is doing and how to control it. Kiting and launching canopies, and dealing with different winds, is a real skill, that takes time to acquire. Still, who knows, maybe one doesn't need all that kind of practice to accomplish a successful building launch. I just don't know.