• Content

  • Joined

  • Last visited

  • Days Won

  • Feedback


Everything posted by riggerrob

  1. Yes, Wing-loading is the dominant factor. If you loaded a Raven at 1.3 pounds per square foot, you would complain about the abrupt flare. The second factor is line length. Any canopy smaller than 150 square feet gets “twitchy” .... er .... quickly responsive. If you worry about line twists, abrupt flares or being too responsive, you bought too small a reserve.
  2. A few hard landings are enough to start cracks in the airframe. Combine that with thousands of cycles during training flights, it is little wonder that trainers don’t fall apart more often!
  3. riggerrob

    How Green Is My Skydive

    Another brilliant analysis by Brian Burke
  4. ——————————————————————————————- ..... having worked in 3 different parachute factories and done a bit of ‘boutique’ manufacturing myself ..... may I offer some insight? Skydiving is a niche market and it is based on custom production of uniquely-coloured and sized, certified components. Ergo, manufacturers offer a bewildering array of options. I often thought that best way to simplify the order process would be to start with a default list of options: narrow main risers, dive-loops, brightly-coloured Velcro-less toggles, mini 3 Rings, brightly-coloured cutaway handle, steel reserve ripcord handle, RSL, Cypres pockets, BOC, thread through leg straps, medium width leg pads, loops to attach free-fly bungees, etc. all based upon last year’s production. Sizing prediction is more complex when you try to match different canopy pack volumes to different harness-sizes. Add in custom colours and there is little incentive to pre-cut fabric. Compair this to the personal computer industry which sells huge volumes of stock parts. Manufacturers of “custom computers” can afford to stock thousands of the most popular components and merely bolt them together at the last minute. As for retailers pre-paying for production slots ..... That can dramatically reduce wait times for customers. Up until the cut-date, they can add or delete options. If the retailer has not specified options before the cut-date, they risk getting stuck with only two options. They might receive the ugly-coloured, oddly-sized rig left over from last year, or they might receive a medium-volume, basic black rig with a medium-sized harness. From time-to-time, manufacturers offer discounts on semi-stock rigs. They pre-build a stack of basic black containers in a few of the most popular sizes. The only colour option might be the mid flap .... that is traditionally sewn on last. They sew harnesses 3/4 of the way and wait until the customer specifies length and width before sewing the hip junction.
  5. Under-ambitious air traffic controllers and overly-ambitious airport management. As Vancouver International Airport gets increasingly busy, they require jump-planes to phone ahead to reserve a time to enter Class B airspace (above 3,000 feet over Pitt Meadows. The second problem is overly-ambitious local air port management. When they got the money to extend the main runway, they decided to do upgrades during the 2017 summer/dry season ..... which is also the skydiving season. The main runway is 08R-26L. Previously - when jumpers were in the air - the Pitt Meadows control tower shifted all traffic to the main runway: 08R-26L, but with renovations, all traffic and was shifted to runway 08L-26R. Unfortunately, the parachute landing field is directly under the approach to runway 08L-26R. In a rather sneaky move - last winter - the airport banned skydiving when runway 18-36 was being used for take-offs and landings. The parachute landing field is close beside runway 18-36, separated only by a taxiway and a few dozen metres of grass. In the 11 years I worked there, I only saw a handful of skydivers land on that runway. Unfortunately, 2017 winds were more frequent from the north or south. In 2017, the DZ was prevented from flying so many days that the business was no longer profitable. I was on the last Navajo load: 23 September, 2017.
  6. What sin were you accused of?
  7. WingBug was just introduced at Sun ‘N Fun. It is a portable pitot tube that can be quickly attached to ultralight airplanes via a GoPro like mount. WingBug can be linked to a (cockpit mounted) computer tablet via Bluetooth. WingBug also records key data for download after you land. You would need specialized software to determine glide ratio (airspeed over rate of descent).
  8. Call Pete Swan (near Lodi, California) or Mel Lancaster. I have a written copy of a falcon line specs ..... if that will help. How big is your Falcon?
  9. I wear a similar knee brace made by Donjon. It helps stabilize my knee after (permanently) tearing 3 ligaments in my left knee. To avoid entanglements, I always wear it inside my jumpsuit. Few students even notice that I wear a knee brace.
  10. As an aside, several antique (built 1947) Repunblic Seabees have been retrofitted with LS1 engines from Corvettes. While Seabees are sluggish seaplanes with their original 200 hp Franklin engines), 300 hp LS1 dramatically improved performance, while dropped fuel consumption by 40 percent!
  11. I got over my fear of airplane crashes years ago. Sadly, that fear has been replaced by a new fear of lawyers who can drag out lawsuits 9 years after a crash.
  12. Frappe hats were only one step in the development process leading to modern skydiving helmets. Early show jumpers (1920s) wore un-padded leather helmets borrowed from pilots (of open-cockpit biplanes.) Leading up to WW2 a variety of padded motorcycle, football and tanker helmets were developed. During WW2, a few specialized helmets were developed for static-line paratroopers, but their steel shells were primarily designed to slow shrapnel. Post WW2, state-funded skydiving schools - in France - developed a variety of progressively lighter cloth and leather helmets, leading to the 1960s-vintage, padded leather frappe hats. During the 1970s, freefall formation jumpers experimented with a wide variety of ways to lighten gear, including trading their Fiberglas motorcycle helmets for lighter, padded leather frappe hats. Frappe hats became fashionable as lighter, more reliable, softer-landing square Parachutes dominated the market during the 1980s. Frappe hats dominated skydiving until freefall formation teams started turning 20 or 30 points per jump (early 1990s.) Then the fear of getting kneed in the face by a team mate drove the trend to full face helmets. Modern full-face skydiving helmets are too thin to accommodate much shock-absorbing padding, but they keep the wind off your hairdo and provide plenty of pockets for electronic gadgets and the mandatory camera! Hah! Hah!
  13. To summarize: most of taboos against double-stowing were invented when bulky Dacron lines were fashionable. Now that bulky lines have disappearred from most DZs we need newer methods to stow lines. Stowing methods vary with THICKNESS of lines. All the tandem ma its turrets have invented different solutions to a common problem: line slump/dump. Strong added an Anti-Line-Slump flap - secured with bungees. If you use fewer than (factory recommended) 3 bungees - or bungees that are too long - openings get harder. Both Parachutes de France and Jump Shack added extra (standard-sized) locking stows. Extra lock it stows reduce the risk of any single failure dumping lines or letting the canopy out of the bag prematurely. UPT tandem d-bags can be packed with three different sizes of rubber bands: standard, double-wide and triple-wide. Even though UPT discourages them, standard rubber bands work well with the skinny Spectra or HMA lines in Icarus canopies. I always double-stow those. UPT recommends double-wide rubber bands on civilian tandems and triple-wide on military tandems. Hint: military tandems often start with 500 pound barrels.
  14. The Stingray prototype, inflatable airplane flew a few times in May 1998. It was built by the Swiss company Prospective Concepts AG to demonstrate their inflatable structures. It was called Stingray, because it resembled the fish when seen from above. From the front it resembled a typical ultralight with an open tubular fuselage supporting the pilot, engne(s), motor and wing.
  15. In Canada, the USA and most European Union countries, the repack cycle - for ALL skydiving reserves - is 180 days. In colder countries, this becomes once a year. This usually becomes a mad rush the week before the skydiving season opens, which explains the 6 reserves in my apartment, all due for repack.
  16. Your's is a common- and well-understood - problem for skydiving students. We did not understand the problem u til tandem was perfected during the 1990s. It was also a 1/100 problem for static-line students. Sounds like you started your tandem jump under-nourished. Then adrenaline rapidly burned most of your blood sugar. After opening, you relaxed and low blood sugar made you feel faint. Dehydration and low oxygen at 14,000' can exacerbate the problem. Fortunately, your problem can be controlled by diet and anxiety control. I encourage you to concentrate on lowering your arrousal levels during subsequent tandems or tunnel time. When you are alert enough to steer a tandem all the way to landing (coached by your tandem instructor), then you are ready to jump solo.
  17. The accident involved a tandem jump from a Brazilian-made Embraer Bandierante airplane. Bandierante is a low-wing, light twin sort of like a Beechcraft King Air 99. Aircraft GPS did not contribute to the accident. The tandem accident occurred on a South Pacific island, maybe Fiji (?). A detailed account is in the "Incidents" forum, a few years back.
  18. ------------------------------------------------------------------------ May I disagree? It is possible to load a fabric structure in compression, buy only if internal (air) pressure exceeds external loads. Just look at s car tire. For aeronautical applications look at the experimental Goodyear Inflatoplane or more recent Swiss Stingray. Canopy ribs (or through loops in reserve containers) allow you to tailor the inflated structure thinner than a sphere. Similarly, the latest fashion in stand-on-top paddle-boards is inflated with hundreds of drop stitches to maintain a flat profile. In a few more years, we will be able to jump drop-stitched canopies with waaaaaaay smoother top skins than are possible with the ocaissional rib.
  19. Air locks are also cut on the bias, so they provide some diagonal stiffening near the leading edge.
  20. Yes, cooling with ice is very helpful. When I went for knee surgery, the doctor told me to buy a knee cooler gadget. Basically, you put blocks of ice and some water in an insulated box, then pump the water through hoses and a soft pack pressed to your knee/shoulder/wherever it hurts. The cold immediately slows swelling, spends recovery by two or three weeks and reduces your dependence on pain pills. On the subject of pain pills .... avoid Tylenol because it can damage your liver.
  21. I have never allowed a student to video his own jump because: I feared he would bash me in the face with his camera. I feared that he would take $&@?! ..... er ..... poor quality video. I feared that he would be distracted by the camera. I feared that he would drop the camera ...... and injure someone on the ground. As for the TI's not putting his thumb though the reserve ripcord: poor form. OTOH - if he wore a camera on his left hand - He would have missed great footage of the reserve deploying. As for copyright ....... better DZs offer refunds for "camera failure" and refund the student. Similarly, if outside video shows potentially litigious behaviour, the student gets a refund, but the outside videographer still gets paid. The vidiot gets paid on the condition that video never a goes public. As for whether $&@"?! lawyers can subpoena video evidence? Yes, $&@"?! lawyers can convince a judge to subpoena any type of evidence. There are slimy ways to avoid or delay providing evidence. For example: the last time lawyer suggested subpoenaing me to testify against a DZO, I counter-offered with "dumb insolence." He never asked me to testify.
  22. Yes and no. Yes, the bridle will still pull the pin out with either routing. BUT No, the main container will not open because Velcro still holds the side flaps closed. Only new Velcro is strong enough to hold side flaps closed, but it is still a risk.
  23. Striping open Velcro (on the pin cover) was the primary reason Wonderhogs routed bridle from top to bottom. Now that Velcro has disappearred (from pin covers) there is less need for ripping open the pin cover. Most modern main containers open just even when the pin cover stays closed.
  24. Yes, I wrote that old post before Precision introduced their R-Max series of reserves. Since then I have jumped a tiny R-Maxonce. I forget the exact size, but I loaded it to the corner of the weight and experience chart. That was when I weighed 5kg lighter than today. That R-Max opened and turned fine, but stalled when I pulled toggles below my bottom ribs, so I flared slightly less than that and enjoyed a soft, one knee landing. Bottom line: R-Max fly fine when loaded more than 1/1 and are strong enough to survive opening at the corner of their loading chart.
  25. 20 years is a realistic time to retire harnesses and containers. After 20 years, containers and faded and frayed and have been surpassed by newer technology. OTOH Reserves are protected by containers and can last decades longer, especially if they are rarely deployed. 20 years was also an excuse to ground reserves that have been surpassed by newer technology: Spectra suspension lines, span-wise reinforcing and wing-loadings more than 1 pound per square foot. The last major revolution in skydiving gear occurred around 1990. Performance Designs introduced the first reserves designed to be loaded more than 1/1. Since then, a dozen other reserves have been designed for wing-loadings exceeding 1/1: Amigo, Angelfire, Optimum, R-Max, Smart, Tempo, etc. For the last few years, PD has been testing their old reserves and the majority pass factory tests (porosity, tear strength, etc.) and are factory-certified to return to service. 15 or 20 years was also an excuse to ground round reserves that were built during the 1980s and suffered from acid mesh. Many of those round reserves were packed into pilot emergency parachutes and their containers are badly faded after 20 years. As for rumours about defective Tempos? HAH! I have packed hundreds of Tempos and have "saved" more than a dozen skydivers. Only one complained about UN-commanded turns on a Tempo 250, but he was the same guy who complained about UN-commanded turns on his main because he had not adjusted his main lift webs evenly (adjustable student harness).