pchapman

More than once I've gotten a message from someone who forgot that their settings are to not accept messages (and didn't enter other contact info). Then it is impossible, other than to spam a thread, to get back to them to tell them to "turn on your messages!". I wonder if the default behaviour could be changed, so that if someone chooses "no messages", they can still receive a message, but only in reply from someone they actually messaged. Other possibilities exist too to get around this conundrum.

I did

I think the answer is that the 150 ft level above takeoff arming isn't an instant thing. For example, there's the drawing in the manual saying that the plane shouldn't fly more than 100 seconds in the range + or - 150 from takeoff. Even that isn't totally clear, but the idea is that if one lingers for a long time at a pressure close to where one was on the ground, then it decides it is on the ground again. So if one is takes off on a plateau and lands in a valley, under canopy you'll pass from +150 ft to -150 in under 30 seconds even with a very slow canopy in brakes. The Vigil won't turn off, and would still fire if you then chopped but didn't pull your reserve (assuming you have time to accelerate fast enough). Also, the 150 ft no fire zone (which doesn't actually have a proper name from Vigil) above the set LZ height, still applies. As was said, that disarming is a different 150 ft disarming compared to the airborne mode turning off, and that level does move when setting a negative altitude correction. @skydivesg: Hope you're telling Vigil what kind of confusion can result from a combination of complex devices and manuals that aren't written carefully. We've got a bunch of posters here who are putting a reasonable effort into understanding things, and it is still taking forever for us to try to hash out a common understanding. Inadequate terminology is a problem too -- there are two different 150ft levels that don't have good ways to refer to them.

Thanks Ronny. I started a new Gear & Rigging thread in case anyone wants to talk about the Vigil 2+ specifically...

The Vigil 2+ has been announced but isn't on their web site yet. Ronny2 posted the first info I saw, a JPG of a Vigil letter, in another Gear & Rigging thread, but it deserves a thread of its own. Copied here as the link wasn't always working right for me. Looks like some decent changes, although further explanation will be needed of the details.

Ok, shorter: A steady headwind will not affect the climb speed of an aircraft. (Of course, with less ground speed, and same climb speed, the angle over the ground will be steeper.) A very sudden change in headwind will affect the climb rate for a short time, when the speed of air over the wings (and thus the capacity for lifting) suddenly changes, before inertia and aircraft stability have the chance to return the flight to normal. @ Di0: Kites are a different situation because you are anchoring them to the ground, allowing different forces to be applied to them. They aren't free to move with the air mass.

Then Vigil did a poor job in the manual. The manual says "The Vigil® releases at 840 Ft. (256 meters) and below till 150 Ft." It does not make clear that increasing the firing altitude with the "altitude correction", adjusts the 840 ft level, but not the whole 150 to 840 ft zone. Indeed since the manual tends to show the "altitude correction" to largely be about LZ's at different altitudes, one might guess that the 150 ft no-fire zone moves to follow the planned LZ altitude. So their manual is inadequate in describing the functions of their device. Let them apologize. So we have the situation for a jumper: If you put a positive altitude correction into your Vigil, which must be in steps of 150 ft, and you are landing at a landing zone 150 ft or more higher than takeoff, you will have no no-fire zone on the Vigil. If you apply the positive altitude correction in order to bump up the firing altitude in general, the no-fire zone will continue to be 150 ft above ground. (For the thread, note that Councilman says Vigil said the deactivation altitude does not change with a PLUS altitude correction. It is important to know that it does change with a minus correction ... otherwise one could have it inhibit the Vigil from every firing if one were landing 1000' low...) Edit: We need someone to get an official statement from Vigil, on their web site, describing how the altitude offset actually works, and its implications for jumpers.

Ah, like Alien Skin (TSE, Paratec), or Diamondback (Sunpath)? (eg http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=2724443) I don't know any details about such fabrics though...

If it is a 260, and a 229 is the maximum size for a non-custom order (as I see on the Icarus & NZAS sites)... then that does suggest there might be a scaling issue with that canopy. Scaling a canopy isn't just a matter of typing in a new size in the CAD/CAM software...

Have a set with me. 14.5 cm for the straight part, excluding the loop and tab at the end. Pretty short I'd think for PG harness & riser webbing I'd think (given that they are double wrapped).

To add to that a little: On the Vigil the correction for opening altitude and different landing zone are combined into that single "altitude correction". On the Cypres in contrast, there are two separate corrections that act in slightly different ways. I figure that initially, the Vigil correction was really only for special cases -- the manuals mention using it for a different elevation LZ, or having a hill close to the airport. Only in the last few years, perhaps, when people started wondering whether AAD firing altitudes are sufficient for reserve deployment, would people start thinking about using the "altitude correction" to set a higher firing altitude for general purpose jumping. Edit: Councilman24 added another post before I was done this one. Yes it does look like the Vigil method -- although it is a firing altitude adjustment -- is not quite as sophisticated, in how it treats the de-activation zone (before landing) when applying an adjustment.... To add to what was said about adjusting the Vigil for LZ differences, they also mention in the manual using the altitude adjustment "if there is a hillock near the drop zone." - so it is more than just an LZ adjustment, even if one might argue it isn't a great way to do it.

1. As pretty much noted already: Steady winds in themselves won't change descent rate, and gradual transitions between different wind speeds at different levels will basically do the same. 2. As pretty much noted already: Up and down drafts, whether thermals or just short term gusts, will of course change descent rate while affected by them, until the canopy is out of them and regains its equilibrium glide. Now the new bit, which is messy because I haven't had time to state it more succinctly: 3. Descent rate will however be affected by sudden wind shears, or by a horizontal gust. Consider an airplane flying horizontally that goes from a no wind condition to a sudden headwind. (Or some wind to more wind). One could equivalently have an airplane descending at a very shallow angle through some idealized shear layer, going from no wind to sudden headwind. In any case, since the airplane has plenty of inertia relative to the aerodynamic forces on it, and isn't a dandelion seed that almost instantly changes speed with the wind, the airflow over the wings will suddenly change. So the plane will go from some equilibrium cruise condition to suddenly having a higher airspeed through the air (with no change in ground speed.) The airplane has suddenly been given extra energy to work with. The natural stability of a normal aircraft will make it pitch upwards, trying to regain its original airspeed. Depending on the stability characteristics of the plane, it might just gradually and smoothly regain its original aispeed and horizontal flight path, or it might pitch up and down a few times in smaller and smaller increments until back to normal. Because the airplane caught the gust, it picked up the extra energy from the high speed air, and climbed. So it changed its descent rate from zero to a climb for a while until flying level again. This is the exception to the normal "wind doesn't matter" scenario: Usually wind changes are fairly gradual, or in the long run things even out with gusts from different directions, so then wind changes don't matter. But if a flying vehicle that creates lift is suddenly hit by a horizontal gust or shear, it will pick up energy that changes the descent rate. Similarly, if there's a suddenly tailwind, there's suddenly less airspeed for the wings, lift is lost, and the aircraft pitches down and descends faster until it regained speed. I used the example of an airplane flying horizontally or nearly so, because that simplifies the math. With a parachute that is descending at a significant angle, it gets a little messier and the results depend on a mix of factors. A horizontal gust from the front does increase the speed of the wind felt by the canopy -- increasing its lift suddenly, so that like an airplane it would tend to pitch up, slowing its descent rate until back at equilibrium. But on the other hand, because the parachute is descending, the gust also reduces the angle of attack. (Consider the extreme -- if the head wind suddenly jumped by 200 mph, whatever the canopy type in a normal glide, it would suddenly have the relative wind coming from above the chord line, "hitting the front top of the canopy" so to speak, a negative angle of attack.) The reduction in angle of attack will reduce lift and cause the canopy to start to drop and pitch down. (And if extreme enough reduction in angle of attack, have the nose collapse downwards.) So the net result of the horizontal headwind gust may be a pitch up and reduced descent rate, or a pitch down and increased descent rate, depending on the vector math of the canopy flight and gust. So the result is, like for the airplane flying horizontally, that a sudden horizontal gust (or dropping through a sudden wind shear) can temporarily change the descent rate of a canopy. SUDDEN horizontal changes in wind can thus affect the vertical speed of a canopy, creating temporary decreases or increases in descent rate, by temporarily increasing or decreasing the canopy's lift. Under a canopy one might get a thermal or upwards gust that makes the canopy pitch back and slow down until returning to normal. After hitting the up gust, you may then reach the end of it, or a downward gust too, and suddenly pitch down. You might feel pretty much equivalent motions if you hit a horizontal gust -- pitching up, slowing down, then pitching down, and speeding up, until all returns to normal. Edit: So to clarify, responding to the original post: No, when talking about different winds in general, or flying up or downwind. Yes, sudden gusts, even if only horizontal gusts, will change descent rate temporarily.

Anyone save it or able to retrieve from their browser cache to re-up? I only bookmarked it...

One wonders if anyone is building triangular foam mounts, similar to the chest strap mounts of the 80s...

Their fundraising site says: Anyone know any details? I'm used to the idea of trespassing just being a fine under provincial Civil Law, but that's in Canada, while in the US I guess there is more of criminal trespass . What did they supposedly steal, other than altitude?

My DZO in Canada is a by the book kind of guy, and takes photocopies of our UPT tandem rating cards when we do our yearly instructor review. So you can still send UPT your $25 along with the form signed by a tandem system owner, your FAA medical info, etc. and they'll give you a card. (I'm not sure what we do here in Canada for the medical: I personally have a Canadian Class III medical for flying, but I think some people just put down "N/A" since the form specifically asks about an FAA medical.)

Another 'terrain issue' example: A year ago my DZO upped the firing altitude on the rental gear by 150', due to the combination of somewhat higher ground in one common upwind direction of the DZ (100' higher?), and this concern about realistic deployment distances. (They're actually Vigil 2's on Pro mode, using the "altitude correction" which is both their landing zone and firing altitude offset, and bumps the altitude from 840 to 990'). On the waivers he also recommends all jumpers to set their AAD's up by a similar amount. I don't think most jumpers have bothered, but some may have.

Ah, so he has a criminal violent streak too? (Just because we're all dumbasses at some point, doesn't make him not a dumbass for something he did.

Just a little update on what I wrote before. First, I think the ideas others have posted are great, that some of the traditional problems with ripstop are probably: a) attracting grit that wears the canopy at or under any peeling edge of ripstop b) adding stiffness to the canopy, so that small patches create localized areas of increased stress on the canopy, which may become important for aged canopies where the fabric strength is already low Twardo kindly sent me some of his 27 year old ripstop tape, which I did a couple tests on: 1. The glue showed no signs of acidity in a bromocresol test. 2. As I had seen in Poynters, some old ripstop is much heavier than modern ripstop, with a wider box pattern, much like some early parachute fabrics. One F-111 style ripstop tape ripped at about 43 lbs, while the heavier, stiffer ripstop tape wouldn't rip at 65 lbs and that's as high as I wanted to go with my hand scale. (In both cases, using 1" wide test pieces) 3. The glue on the old ripstop tape had somewhat worn out, so it wouldn't stick well to canopy fabric, making it impossible to do some other tests with the old ripstops. Just for fun, and unrelated to ripstop tape, I did a couple tensile tests on the top skin of a Stiletto that had 3200 jumps on it before being retired because of repeated rips happening at the topskin seams. One area would only go to 25-27 lbs before tearing, while other bits went to 32-33.

It is funny how much more casually we treat mains than reserves. Sure, reserves are our last shot, and we want them to have extra strength for some high speed, unstable deployment, so there is a difference. No doubt about that. But one could jump a 22 year old 1992 Sabre 1 all day and not be worried about it blowing up, even if it opens hard. (The exception would be if it were filthy and sun-faded.) Or the same with some 1980s F-111 canopy. At times in recent years I've had a 1988 Maverick 200 in my backup rig as the main and used it regularly. That canopy was certified both as a reserve and main. As long as the top skin isn't getting faded, or worn from kneeling on it, I have no worry about it blowing apart on opening.

Canada! If you're at a CSPA DZ, you follow CSPA rules. Wear two parachutes. But no TSO is needed (except for official Demos into urban areas - gov't rules). But elsewhere there's no gov't law about needing 2 parachutes. I'm not in touch with the BASE community, but I'm surprised there doesn't seem to be more BASE rig wingsuit activity here by Americans. (Although there are differences between North American mountains and the Alps, such as infrastructure in the valleys.) As for air traffic control, it all depends on the class of airspace whether one can just go jump, or have to broadcast the jump on radio, or have to actually coordinate with ATC. (@ Riggerrob: Sonic from the Ranch in NY does market the BASEr actively. He's at the Bridge Day gear show every year for example.)

Re: Firebird Maybe they are getting their ideas from the paragliding industry which they are also part of. In North America there are no specific rules on paragliding gear lifetimes, but in Europe there sometimes are, depending on the country, such as a life of 15 years for an emergency parachute. There tend to be more rules about mandatory checks of the paraglider itself too, every few years at a dealer, again depending on the country. While it has become popular to look down on 20 year old reserves, a large part of that had probably been because it used to be that 20 year old reserves were often antiquated designs (e.g., rounds, overloaded Ravens, reserves without spanwise reinforcement). Now that we are getting 20 year old PD reserves, I wonder if attitudes will change... (Although I'm not sure what kind of results we'll see when more go in for a porosity test after their 40 boxes are full.)

Whether or not this is an April 1 thing, it is in some ways really half-assed looking. Not clear to me where the carabiners are hooked to the harness of the 'instructor'?? Or where is there any hip attachment, which would greatly add to safety and be easy to rig up. Looks like the connections are a couple snap gate biners per side (not even locking biners), and a what looks like a paragliding reserve parachute swivel (which not everyone would recognize, and not many skydivers would have on hand). Even with a light weight girl it would be hard but not impossible not to exceed the weight limit for the container & reserve, although perhaps they were betting on non-terminal operations only. Lastly, Kroops goggles? The elastic bands on those are crap because they wear out so fast! Looks dangerous to me...

Both Cypres and Vigil manuals say to turn the AAD off and back on at the takeoff location, if your LZ is at a significantly different elevation than the takeoff. Any offset for LZ location is retained for the Vigil, and for newer Cypres'. (Older Cypres before about 2006, required the offset to be entered each jump.) All Cypres' have a "dropzone offset" for different takeoff and landing altitudes. The newest Cypres' (Jan 2013+ for manufacture or maintenance) also have an actual "User-selectable activation altitude" just for changing firing height above normal ground level. I would guess that this is response to criticism that their activation height of 750', chosen back in about 1990, is too low for some people nowadays. The Vigil only has the "altitude correction" which is for a landing zone offset, NOT specifically designed for adjusting firing height above ground (even if it is sometimes used that way). Adding to the complexity, remember that while the Cypres disarms at 130' when coming down, the Vigil does not. (That 130' doesn't change if setting the Cypris's user-selectable activation altitude) And the Cypres requires a climb to 1500' to arm, while the Vigil needs a + or - change of 150' to arm (no matter what altitude correction is used). At least, that's what I think I'm reading in the manuals... A fundamental problem with the user interface with both designs is that one can't tell exactly what the AAD is thinking when you are on the ground. ("Does it think we are at the ground here at the takeoff point, or does it think we are airborne or something?") However, one might get a clue if watching a Vigil closely during climbout, for the 3 red flashes when Activation Altitude is reached.

Addressing the thread in general, the USPA SIM is a great reference, but for two-outs I'm not sure that it has the best possible information. At the least, what to teach for two-outs is up for debate. For example, for a biplane, the first thing the SIM says to do is to unstow the brakes of the front canopy. Jim Cowan says don't release brakes, and the CSPA says don't release brakes. (The latter acknowledges Jim Cowan's work as one of its sources). For side by side, the SIM says either (a) disconnect RSL & cut away, or (b) fly using the brakes of the dominant (more overhead & larger) canopy). The CSPA and Jim Cowan say to use the inner rear risers to turn. 'Always Push, don't Pull'. EDIT: I now see what the SIM might be based on, given that they are heavier on releasing brakes and flying with toggles. In a previous thread on this topic I noted that the Dual Square Report presented at the PIA in 1997 mentioned flying the front canopy in a biplane, or the dominant canopy in a side by side, with gentle toggle input.