pchapman

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Everything posted by pchapman

  1. Never was a member.... but when visiting Germany in the summer of 1992, I stopped by at the Lahr DZ one weekend. Put in a few jumps in until the airplane transponder went on the fritz and they couldn't climb high. The fellow in charge maybe took pity on a student roaming the country who had walked to the air base from the local train station, so he didn't charge me any club fees, and gave me free rig rental. Slept on a barracks couch. I think fuel was at military prices, not high European civilian prices, so DZ jumps were cheap compared to pricy jumps at civilian DZ's in Europe. So I got a sweet deal. After a hop and pop to demonstrate I wasn't a total idiot, I did a couple two ways, breaking off at 3000'. ("I mean, it's only a 2 way, why break off up at 3500'?") Looks like Volker Kock signed my log book, though I didn't jump with him. Peter Landry (at least once a Canadian Nationals meet director) also showed up. Rental / student gear was EZ Flyers with Mantas or the super sluggish Laser 288's. They had new Telesis rigs but they were temporarily grounded after some student a few weeks earlier had had a main riser catch under the reserve tray during a mal, leading to him spiralling in and being paralyzed. While I was there someone else renting failed to catch an FXC set to 2000' and came down under the main but trailing the round reserve, the diaper having held it shut. It was the best defended DZ I had ever seen: DZ ops were housed in a large hardened aircraft shelter, complete with siren and rotating beacon as the heavy blast doors opened. Very impressive... but then there's a little C-182 inside! They called it the Yellow Banana I believe. By 1992 after the end of the cold war, at CFB Lahr the F-104 Starfighters were long gone, the Kiowa helicopters were gone, and many personnel were off doing peacekeeping things in Yugoslavia, so it was a quiet place, only a couple years before the Canadian military bases in Germany shut down. I did take some perhaps illegal photos on base, as attached. I had also been to Germany a bunch of times as a kid -- Great fun in the cold war, with so much military hardware to see on the streets and in the skies. Note the "Panzer crossing" sign outside the main gate. That's all for my most minor of exposures to the Canadian military's German sport parachuting club! Cheers Rob.
  2. A lot of people are more likely to follow what they are told when they understand the reasons behind what they are told. There are plenty of dumb, incorrect, and arbitrary things that people are told in life, so backing an instruction up with some reasoning can be helpful.
  3. Although I haven't been in the aerospace industry a long time, I would think that aero engineering isn't the only way to get into the aerospace businees. Not everyone at the companies are doing computational fluid dynamics of air flows or calculating shear stresses in carbon fiber D-cell spars. There's plenty of mechanical & electrical engineering and software coding to be done. So there's a range of engineering fields to study which can be useful both in aerospace and elsewhere.
  4. It was NOT a taildragger, just a plane with a bigger / longer cowl & radial engine. Looked like a Nanchang CJ-6, something like that. The riding mower and the plane off to the side of the runway could be seen in a new news video. Not that any of this really changes the issues as mentioned in the first post. ( https://montreal.ctvnews.ca/video?clipId=2235845 )
  5. Thanks. I had only seen less complete English language news outside of 'la belle province'. On the video, the way Mario explains the lack of vision just at landing, suggests the plane was a taildragger, which makes the visibility issue a little tougher. Lessons indeed about communication at smaller & private strips where it isn't like ground service vehicles and planes are in contact with ATC.
  6. I almost confuse Donald Rumsfeld with Robert McNamara, every time I think of them. Seemed like top-down efficiency experts, who worked both in private industry and government. Both with documentary videos done later in life (by Errol Morris). Although as someone noted elsewhere, McNamara apparently did have doubts about his past, while Rumsfeld never conceded much.
  7. So are there no other requirements other than minimum distances to obstacles, for an LZ size? Eg, USPA (at least in my older 2018 SIM) shows 330 ft to an obstacle for a solo student. So can one open a DZ with an LZ that is a 661 ft circle? Is that sufficient or is there some other rule that would make the USPA say "Nope, you need to have a decent sized landing area, PLUS the 330 ft in all directions." (Mind you, as a novice at USPA rules, I can get into other weird musings about the BSR rules: Trees covering less than 32,292 sq ft are NOT an obstacle? A concrete runway is not listed as an obstacle? So you can put a student LZ ontop of a 100' * 100' forest surrounded by runways & taxiways? Either I'm missing something or the BSRs in this case are way too lax compared what any actual DZO would do.)
  8. The website seems to work for me. Even jumpshack.com redirects to them. Aha.... "plabsinc.com" works. "www.plabsinc.com" fails. Despite the latter being the link on their facebook page. Although even for the version that works, the intro page is blank except for a "Skip" link to the real page -- Maybe the first page had some deprecated Flash animation or something that is so, I dunno, 2005?
  9. Anyone can become a dropzone bum. It takes more work to get a decent job / career. Which can then pay for lots of skydiving. (Like TampaPete said.) Everyone likes the "right" to do whatever they choose in life. But young adults often can use a boost / support from parents to get an advantage, and that financial power does give them some leeway to impose conditions. One can argue about those conditions, but one can't always avoid them...
  10. Yes I meant "the whole point" in the context of skydivers using tunnels, as one of the reasons skydivers want to use tunnels. Rather than the obvious "The whole point of tunnels, which are commercial enterprises, is to make money for their owners". Even in skydiving I have seen waivers where one has to state that one is "fully recovered" from any injury. Bad ankle, dodgy shoulder? Doesn't matter, you can't do the first jump course unless you claim to be perfectly healthy, as the DZ doesn't want to play the role of giving expert medical opinion. I think we agree on the liability thing.
  11. It would seem silly to exclude people just because of prior injury. The whole point of the tunnel is to be able to check things out in a safer environment than in the sky. Obviously there are walls to smash into, but all sorts of people are advised to get tunnel -- like people with flexibility issues, physical disability, older age, returning from an injury, etc. Often that's about doing basic skydiving things like staying stable, basic belly maneuvers, and being able to pull, not whether they can join a 4 way freefly style team in the tunnel. Heck, one local jumper here in Ontario got free tunnel time from worker's compensation, because his screwed up landing that broke a lot of stuff, was on a working camera jump. He still can't lift one arm much above his shoulder but flies ok. To the OP: Anyway, it sounds like general purpose legal disclaimer & warning stuff. Contact your local tunnel to find out what they really think about working with someone with a prior shoulder dislocation.
  12. Tests have been done over the years but little by individual jumpers as opposed to companies. Just whipping this post off: While GPS data is easy to get these days, you would still need to do some analysis to get good data out of it. It is hard to find "no wind" conditions all the way up to altitude, so you are going to have to take data acquisition runs in different directions, ideally up and down wind, to help calculate out the wind's effect. Plus, for any observed rates of descents and airspeeds, you'll want to do all your tests in similar conditions to avoid density altitude effects messing up your numbers. At least if you measure on a similar temperature day (across the air mass and not just on the ground), and at similar altitudes, you could compare canopies, even if they are not the 'proper' numbers as one would have for an airplane. That is, airplane flight data is always adjusted to be what it would be at sea level, International Standard Atmosphere conditions (29.92"Hg, 15 deg C), that sort of thing. So if measuring canopy speed and rate of descent at 6000' on a hot summer's day, it'll be faster than if measured at 3000' on a cooler day, in a predictable way. If all this goes over one's head, then one isn't ready to do accurate comparisons of flight characteristics of different canopies. ... Still, it can be fun to go up and get a little data just for fun, comparing different canopies for some rough numbers. Back 15-25 years ago I did a bit of data collection on a few canopies of the era, using a calibrated anemometer, electronic variometer, and a whole bunch of data reduction (analysis) to take into account density altitude effects. So the canopy types are a bit old now! -- and I'm not including modern competition style swooping canopies like a Leia or Valkyrie. This is a very quick summary that I used in a canopy flight course I have sometimes given, to give people some "rough numbers": From my testing. (These numbers have been adjusted to sea level standard conditions... because that's how it is done in aerospace engineering for comparing airplanes in a standardized way. On a typical summer day at a typical dropzone, at a typical height above sea level when flying one's canopy, the air density will be somewhat less. The Glide Ratio won't really change, but the Airspeed and Rate of Descent will be a little higher.) - Glide ratio typically: (brakes off) 3 student canopy 2.5 medium modern ZP canopy 2.1 small canopy In partial brakes, my Icarus FX 88 at 1.9 loading went 2.1 to 2.8! (lowered the rate of descent a lot, while only moderately reducing the speed) (While big F-111 canopies might just get less glide angle with brakes, with less effect on their already slow descent rate) (Sabre 1 135 when adding brake: got only bit better glide ratio with a bit of brake, then a lot worse as one got into heavy brake). Different designs could be more efficient… e.g. a special experimental high glide ratio 11 cell 170 from PD over 20 years ago that I jumped = 4.5 glide ratio in slight brakes - Airspeed: (Bit more than Forward speed horizontally) 25 mph student canopy 46 mph small crossbrace @ 1.9 loading (Icarus FX) But: Deep brakes only 25 mph - Sink rate: 800-1000 fpm big canopy (13-17 fps) for students or novices (On the lower side of that for modern ZP student canopies compared to ones like F-111 Mantas) 1300 fpm Sabre 1 135 @ 1.25 loading 1750 fpm (29 fps) small crossbrace @ 1.9 loading (Icarus FX) In brakes any of those down to only 750 fpm (So one can have the case of an instructor under a crossbraced canopy, maybe not a modern competition style one, being able to almost stay with a student or novice flying full speed under their rental canopy.) Note that glide ratios are only partially affected by the design of the canopy itself. Certainly a fat Parafoil with giant nose openings will be draggier than a modern highly elliptical swooping canopy with small nose opening and crossbraces for holding the shape well. Much depends on the trim the designers have chosen, nose up or nose down. That's why many swoop canopies are so 'ground hungry', trimmed nose down for more speed to use for a long swoop & flare, not just floating around in the sky. Another big factor is jumper size relative to the canopy. Scale the same parachute design down, and keep the same sized jumper under it, and now that jumper is in effect a larger draggy object below the canopy, dragging back from under the canopy even more as the speed increases with a smaller canopy. I saw some manufacturer test data way back that certainly showed the effect: Same canopy design at the same weight had a much worse glide ratio as it scaled to smaller and smaller sizes. - The PD info in a youtube video that BMAC posted is good, comparing a Pulse and Katana 150 at the same loading. Note that it looks like the data hasn't been adjusted to sea level standard conditions -- it is just the data they got that particular day and speeds would be slightly faster than in my type of data. Still a great comparison -- You can see how with brakes set, the Katana and Pulse are only somewhat different. Pop the brakes and now the Katana is super ground hungry in comparison.
  13. Even if the camera isn't a snag hazard: a) national skydiving organizations often forbid cameras on less experienced jumpers (even if the person is strapped to an instructor) and b) there's no incentive for skydivers and dropzones to take away from their own revenues in providing video services to tandem students. It is what it is. Enjoy your jump. Hopefully you do get video. :-)
  14. Curiously, their current Vortex / Decelerator manual has no mention of, or instructions about the number of reserve pack jobs or any porosity checks. Then one can get into the arguments about "What instructions from a manufacturer are the official instructions a rigger must follow?" I'm sure many would argue that something printed on the reserve parachute itself constitutes an official instruction, even if "it's not in the instruction manual".... Does Parachute Systems currently answer messages or are they now completely gone, despite the website being up? For a while in the last couple years, various people around the web said they were still supposedly open for spare parts sales & manufacture but not whole rigs & canopies....
  15. "Survey says...", I mean, my old ParaGear says: Raider = 220 feet in their 9 cell range of canopies (unlike the Fury), supposedly 484 packing volume (although those numbers can be uncertain). If your rig is a Vector II, then attached is a pack volume chart. Although modern canopies don't always have volumes listed any more, so it isn't necessarily a great help in figuring out what modern canopy will fit in the rig. What you should be flying, both initially and as you get experience with ZP canopies, is a whole other thing. 09101 (Vector II sizing chart).pdf
  16. 'Bill von's' checklist is an oldie that still makes a fair bit of sense. Just checked and saw he first posted it in rec.skydiving in 2003, and on dropzone.com too, with more details: https://www.dropzone.com/articles/safety/downsizing-checklist-r32/ I'm sure plenty of jumpers haven't done most of the steps, so it isn't like the OP is the odd one out, but they are good things to consider. Mind you, just working on learning these sort of things have dangers of their own. (While not directly related, I recall a couple people breaking ankles at the local DZ while participating in basic Flight-1 canopy skills camps.) But to re-emphasize: in the OP's particular case, the knotted brake line might lock that brake line into having 'some brakes on', to a variable amount. Landing on rears with one brake partially set, preventing a full speed approach to landing, can become a lot tougher than doing it brakes free. That starts to be a whole new ballgame, and changes the equations when considering whether to land vs. chop. One certainly can also practice landing from a little bit of brake on approach, but that again adds risk in practice while trying to reduce risk in an emergency. The USPA SIM mentioned flaring from "slow (braked) flight" in a section on downsizing, or at least some years ago it did. Don't overdo it though, as it would be easy to run out of flare power if the canopy is slowed too much on the approach!
  17. Ouch. Hope you can still find it. Kudos to anyone like you willing to educate others after a screwup -- even if it was just a tiny, momentary lapse in focus. (I did something not quite the same but with similar effect once. Locked up one toggle but that side was still effectively at full flight -- So I was able to land the Icarus FX canopy with one toggle and one riser. Not a big deal even if such 'mixed controls' is not typically recommended. Was your canopy still braked a fair bit on one side, which would complicate any flare? I assume your canopy was more ground hungry / twitchier / more highly loaded than my early generation crossbrace.)
  18. shredvideo.com AI based, automates the editing, processing is on the DZ's computer, provides a web page link for the customer to download pics & vids, integrates with Burble manifest software, etc. Haven't tried it myself but saw it at a DZ I've been to.
  19. Yeah, I've been at a big Ontario DZ that mandates sliding landing (although accepts standups in high winds). But it does depend on the canopy a lot too -- Sigma canopies tend to be suited to sliding landings rather than standups.
  20. Fair enough if it was implied that the airbag was to be used for normal civilian application. But it looks like it is being marketed more to the military, for heavy loads / night / crappy landing areas. Some of the pics show a military tandem, trailing a kit bag on a line. Looks like the airbag is like a paragliding airbag, which have been around for a long time, self inflating from an opening at the front, but with the added design feature to be held closed in freefall.
  21. In any case I think we agree that one shouldn't forget to be ready to PLF, even if one moved on to also using sliding landings, a landing technique considered to be 'more advanced' (due to it being learned later, and being associated with cool canopies).
  22. Yes and no. I'm not going against you here but am putting it in a different way: I would say sliding is superior for high speed landings in a general sense-- but as you would agree, there are limitations, where PLF's are better. I'd far rather slide a fast downwinder under a crossbraced canopy, than PLF and go tumbling along. But there are those limitations: High vertical speed requires a PLF, and a PLF is good in rough terrain where you don't want to pile into a rock hard clump of dirt or whatever, while sliding with one's body down low.
  23. A lot of people slide in landings without any special jumpsuit additions. Things to note: - Certainly some landing areas get very hard or are bumpy, making the situation trickier. - Normally one tries to slide while twisted a bit to the side, trying to slide on one butt cheek. (Pretty much the 'baseball slide' if I have the terminology right.) Thus if you drop down suddenly a bit, or you hit a bump, you don't smack down straight on your tailbone or compress the spine as suddenly. It might still hurt, but the shock to the spine will be less. - Some jumpsuits actually have padding and not just heavy duty cordura or ballistic cloth on the butt area. But that tends to be pants for tandem instructors. And if the instructor slides or sits down, it tends to be without that twist I mentioned, due to having the student there. - Part of the sliding landing is to gradually transfer weight from the canopy to the ground. So if coming it at speed, some of the slide will be with legs out in front, sliding with one's shoes, without one's butt actually being on the ground yet. Eventually yes as one slows down, the side of the leg and butt will be sliding on the ground too. But one tries to delay that. - So padding can help, but it is more about technique than padding!
  24. To educate oneself more and try to understand the source of the issues better, to be a better informed consumer, before discussing it with the manufacturer? To piss off those who cry "Won't somebody think of the children?", I mean "Why didn't you contact the manufacturer first?" ?
  25. A tight yoke & shoulder area on the rig could make it harder to move your shoulder blade area back, which in turn restricts how easily one can reach in behind one's back. But that's just guessing so getting a buddy to watch & record pulls on the ground is clearly the way to go.