brettski74

People still manage to get it wrong, and it's nothing to do with complacency. For one thing, there's parallax error. This can be mitigated with numerous wind direction indicators spread around the landing area, but then you have the problem of light winds that may be in different directions in different parts of a large landing area. Compound this by the fact that the winds may change between the first and last canopies opening and landing. If you can't safely land your canopy downwind in light winds, you have the wrong canopy. Consider a canopy control course or upsizing. As I've said before, I prefer a clear, ground based, human controlled indicator for landing direction in the main landing area, as it seems to be least prone to confusion, but if the rule is first man down, you'd do well to follow the rule. If not, you may be warned, grounded or if you're really unlucky, the victim of a collision on final.

??? The turbulence you speak of is created by the skydiver falling through the air. If you're talking about building a wind tunnel to simulate freefall, you want laminar flow in the tunnel. An ideal freefall simulator would create no turbulence in the flight chamber until someone got in there to fly. In the real world, you get some turbulence near the door at the very least, but most modern designs do their utmost to minimize turbulence in the flight chamber due to the machine itself.

I currently am jumping a Samurai 136 with a PDR-160 reserve, so my reserve is bigger than my main, although I must admit, when I first bought it, my main was a Sabre2 170, but everything else I've put in that container has been smaller than the reserve.

I think there should be another option - a manual, ground based indicator. This could be as simple as someone holding the tetrahedron or a large movable arrow on the ground. One dropzone I used to jump at had a large canvas triangle on the ground in the main landing area to indicate the landing direction. It was set by the DZSO in accordance with the winds. Sometimes we would end up with a downwind landing direction, but that didn't happen very often and was generally always fixed for the next load. On the upside, there was never any doubt as to which direction your should land in the main landing area. On the downside, it relies on a dedicated person to set the landing direction for every load. Wind direction can work well when winds are not light/variable and there are adequate wind indicators spread throughout the landing area, although even at it's best it's never ideal. First man down can also work well, but once confusion begins, it quickly turns into a clusterfuck. Not everyone sees the first man land, so then they have to rely on whoever they do see landing. The best methods would require everyone to be obtaining their landing direction from the same source.

Without looking at the particular incidents you're referring to, there are several reasons why this could happen. Parachute equipment can malfunction. eg. reserve snivel, streamer, etc. Electronic malfunction. eg. incorrect barometric sensor data, incorrect zeroing of device Incorrect device configuration. eg. incorrect offset, inadvertent offset/zeroing due to travel while device is on Firing parameters were not met until at a lower altitude. eg. low cutaway, low aircraft exit. An AAD is a backup device. Like any device, it can fail or be misused as can the reserve canopy it deploys. Read the manual. Know how it works. Be aware of its limitations. Never rely on it to save your life. It may just do that in an emergency, but if it does, you were lucky. Saving your life was your job.

I have a V348 which has had in it the following canopies: Sabre2 170 (brand new) Sabre2 150 Samurai 136 Triathlon 135 Hybrid Vision 140 Safire2 139 All have been perfectly fine. The reserve in all cases has been the same PDR-160.

The measures aren't that heroic. We have a rag-tag bunch of hackers across the world that manage to hack firmware on most popular devices within a short time of their release and they don't have a budget to do so. If someone were paid to do that full-time, the time required would be much shorter. Of course this raises moral and legal questions, but I still don't see where the heroism is required.

See 419 Eater. No skydiving scams, but plenty of information about messing with scammers if that's what rocks your world.

How is the ladder strap secured? From the photos it looks like it's just the one bolt at the back, so I'm assuming that it's just floating in the channel over the top. Does this mean that flexing in the ladder strap can allow the visor to rattle up and down, or is there perhaps tension in the hinges to limit this? Maybe it would be easier if I could see one but at the moment I'm imagining that a force applied to the visor from beneath the chin would lift the visor and flex the ladder strap on top by some amount. Are they already released, or if not, when are they expected to be released into production? How is the visor replaced? I haven't looked at how the havoc works, but I'm assuming that there are just some screws and/or clips in the helmet body to allow replacement of the clear plastic visor.

That's quite a cool observation. I remember talking about the lag time between input and response in Brian Germain's canopy course, but I didn't quite put it together like that until now, or maybe I've just forgotten about it in the 18 months since I did the course. Either way, that's something else I'll have to make a point of remembering.

The two main factors that can cause turns are asymmetric speed/drag and bank angle on the wing. Asymmetric speed induces turns not unlike a tank, which also tends to produce a kind of skidding turn through the air. This may be hard to visualize, but think of a snowboard or skis turning and throwing snow off to the side as you turn. You can notice this to some extent by watching how the pilot chute trails behind the canopy. Bank angle causes a turn by changing the direction of the lift from the wing. When the wing is banked, the lift vector gets a sideways component that causes a change in direction of the wing. When you pull on a toggle or rear riser, this induces greater drag on that side and it's the asymmetric drag/speed which results which is the dominant phenomena. This asymmetric drag induces a turn as the side that is pulled down slows down. Because the inside of the wing is going slower than the outside of the wing, it also loses lift. The reduced lift on the inside of the wing subsequently induces banking in that direction also. If you pull both front risers, the canopy tends to speed up, however, if you only pull one front riser, the speed increase this can create on one side of the canopy is negligible. I'm not sure, but it may even slow down that side of the canopy. I haven't really had the chance to see how the airflow over the wing shifts during such a maneauvre. The way I think about the aerodynamics, however, is to assume that the bank angle is the dominant phenomenon causing the turn. I pull down the nose, inducing a bank angle at the nose, which starts the turn. As the turn progresses, the speed on the inside of the wing reduces while it increases on the outside, which further enhances the bank angle and increases the speed of the turn until equilibrium is reached. Finally, harness turns pull down one entire side of the canopy. This induces a turn by bank angle alone, so the mechanism is somewhat similar to that from front risers, but less aggressive. In a harness turn, the pilot chute should always be straight behind the canopy just as it is in straight flight, regardless of the turn. This is because the airflow over the wing will be straight and clean, rather than skidding sideways a little like it does when using rear risers or toggles to turn.

Nothing on TV tonight? I guess this thread could provide entertainment. Try the search feature. You'll find lots of debate and discussion about various AADs pros and cons, various malfunctions that have occurred with different units over the years and the implications of them. You'll also find a lot of pointless arguing over trivialities, anecdotes and personal preferences. For the record, I have a Vigil 2, but I'm not entirely sure that I agree the design philosophy of the manufacturer, but they've improved over the years. I like Airtec's (ie. CYPRES) design philosophy better, so if I was buying a new device, I'd probably be changing away from Vigil, but who knows what will happen between now and then. Maybe they'll impress me some more.

A new fabric currently offered as an option by Aerodyne on their canopies. According to their information, it is stronger, thinner, lighter than regular fabric. It also has some self-healing properties when it comes to minor punctures - you can kinda pull out the puncture and make it air-tight again. I've tried it on a test swatch of the material. It's been discussed before on here, such as here. You can also do a search for zpx to find more discussion about it, or check out the aerodyne website.

I'm wondering if anyone has ever converted a regular triathlon for CRW by relining with red, non-cascaded A lines and having the retractable pilot chute rings sewn onto the top skin. I wouldn't normally consider such a thing, but one of our newer jumpers is buying a rig which has a triathlon 135 in it. She doesn't want it and she's getting the rig at a good price so she may be willing to give it to us at a price that still makes sense after you factor in the costs of re-rigging it as a CRW canopy. We already have a few triathlon 135 hybrids and comp CRW canopies for CRW and another one would be handy, but is such a conversion even worth considering if the money part of the equation works or are there other considerations that I'm not thinking of?

Until the cat lands and runs away with your new pilot chute attached. Now you need to build another pilot chute and find another stray cat.

No gear rental. That's what a slot costs here. It used to be $35, but then the Ontario government converted over to HST, so an extra 8% sales tax got whacked onto just about everything and jump prices went up to $38 as a result. When the Canadian dollar was weaker against the USD, it wasn't so bad, but not with the CAD hovering at or just under parity, it's a little more sucky. If Frontier had a turbine, I suspect that they would be a very busy dropzone. I you're renting gear, you'll be paying closer to $60 or more.

Yeah - most aircraft accidents involve the plane hitting the ground, so thank for the ride up Mr Bus Driver, but I'll make my own way back down.

Yeah - I saw that, but I was meaning "you" in the figurative sense, not literally you. Stay safe.

Well said, although the OP did come out swinging. At the end of the day, the seller can choose what methods of payment they wish to accept and what methods they do not accept. You can jump up and down and complain that the seller should accept your preferred method of payment but at the end of the day, if it's a popular item, you're just going to lose out. There's little incentive for a seller to invest time and money in supporting additional payment methods when they can easily move their stock using their currently supported methods. I had similar problems years ago, but rather than complain about, I adapted my methods to allow myself to more easily trade with others. If the OP wants to compete with other buyers in the marketplace, he too will need to adapt. PayPal is not too hard to set up and much more widely accepted method of payment than Western Union. Regardless of how secure you feel it is for the seller, if the seller doesn't accept it, you're just going to lose out again and again.

Like I said before, a safety call is made to protect you from injury or worse. If the $38 slot is worth more to you than not jumping to avoid injury, you don't sound very smart to me.

You should count yourself lucky that there's even a chance of the DZ covering the plane ride if you choose not to jump. You're a trained skydiver. You have eyes and other senses to see what's going on before you ever get on the plane. You can see if there's weather moving in. You can see if winds are getting sketchy. In the case of forgetting something, who's fault is that if not yours? As has already been said, you are not paying to jump. Jumping is free. You are paying for the ride to altitude. You will find few dropzones that will cover a fun jumper's slot due to weather or any other issues for not jumping. At most places, if you get on the plane, you're paying for your slot. In fact, at most places, if you're on the load sheet at the gear up and go, you're paying for your slot. The safety call you made to protect your life. You only get one of them. The safety call had nothing to do with the $38 you'd already spent to get to altitude. Brettski :)

Nice photo. I've never seen streamers on a canopy formation before. How/where are they attached? I'm assuming that the formation is completed first, and then the streamers deployed. It'd be cool if there was some video of the build to watch.

I never said it wasn't possible to fly your canopy under the next group. I said it was unlikely if you started out with adequate separation at exit and everyone involved kept to their own airspace in freefall. Of course it's possible. It happened. The question is what factors may have contributed to that problem and may need to be addressed in avoiding such problems in future. Avoiding flight up or down jump run immediately after deployment will help, but so will avoiding movement up or down jump run in freefall and adequate separation to start with and canopy flight alone is unlikely to be the sole contributor.

There are a few. The universal mount adapter is a reasonable start providing a standard 1/4"-20 thread and provides about as good a mounting platform as any Sony product without an enclosure. There are also a couple of enclosures available, including VHoldR's waterproof case and another skydiving specific box made by 2K composites, but regardless of the availability of more appropriate mounts, we do need to make it clear to people that despite the existence of better mounting options, the normal considerations for flying camera still apply, regardless of it's smaller size.

I'll say it again, under most conditions, if you have adequate exit separation, it is simply not possible to fly your open canopy underneath the next group before they deploy. The canopy simply doesn't have sufficient forward speed. The exception to this is if you have a large difference between winds at exit altitude and deployment altitude, then it may become possible. Taking a simple example case of no winds, 85 knot jump run, 20mph canopy air speed, 7 seconds between groups, jumpers fall straight down and track 200' from centre at break off. If we have two jumpers in adjacent groups tracking towards each other, they're deployment positions are still 600' apart. In the 7 seconds it takes the second jumper to get to deployment altitude, the first jumper could fly about 200' closer to his deployment position, but that still leaves them 400' apart. The distance can get smaller as you increase the upper winds (or more correctly, the difference between the upper and lower winds), however, the difference has to get pretty significant before you start to get people over top of open canopies - like about 40+ knots difference. That could happen, but I can't recall any time I've seen that and considered the ground conditions as jumpable, so at best, I'm thinking that is rare. Could avoiding flying up/down jump run immediately after opening mitigate these risks further? Sure it could. Is that something I'd want to rely on? No. Who knows what direction your canopy may be flying in if you're kicking out of line twists or some other correctable canopy issue. If you're finding yourself opening above other canopies, you need to look at the exit and freefall to resolve the problem.