riggerrob

Members
  • Content

    17,329
  • Joined

  • Last visited

  • Days Won

    6
  • Feedback

    0%

Posts posted by riggerrob


  1. Parachute Industry Association Technical Standard 102 says that reserve canopies are supposed to be shipped with: bridle attachment (relevant with round canopies), canopy, suspension lines, connector links, deployment devices (e.g. slider) and manual.

    Military Specifications say that packing data cards travel with the reserve canopy. This is partly because containers wear out long before canopies. 

    If in doubt, send photocopies of packing data cards with second-hand: canopies, AADs aand harness/containers.


  2. Traditionally we have used dry-cleaning fluid or Woolite.

    Since traditional dry-cleaning fluids are considered nasty, petroleum toxic waste, I have never used them.

    OTOH I have hand-washed a hundred harness-containers with Woolite, warm water and a scrub brush.

    I have even washed a few rigs in an industrial washing machine. Wrap hardware in rags (& tight rubber bands) to prevent it from ruining the inside of your washing machine.

    Hang your rig - to dry - for 3 or 4 days.

    Finally, spray it with (lawn furniture grade) Armourall to prevent new viruses from sinking in. Allow Armourall to dry over-night before delivering it to your rigger to repack.


  3. Strong Para-Cushion Seat packs still pack the same way as the original Pop-Top chest packs, but all other skydiving Pop-Tops (Racer, Chaser, Tracer, Teardrop, Reflex, Excalibur, etc.) have evolved beyond recognition.


  4. DPRE guy, that 15 or 20 year life limit was a subtle reaction to the acid-mesh problem of the 1980s. That makes the youngest suspect round canopy something life 35 years old! I quit packing suspect canopies a decade ago and no longer have the tools to test for acid-mesh (bromocreasol green).

    When I rigged for Butler and Para-Phernalia, they refused to service any of their gear more than 20 years old. After 20 years in the Southern California desert, most parachutes were faded, frayed and filthy! 

    Closet queens raise far more complex questions. The biggest difficulty is for younger riggers is finding manuals, service bulletins, etc. for rigs that fell out of fashion before the internet became fashionable.

    When in doubt, work to the tightest standard.

    Lawyers are sneaky bastards who will distort the slightest variation in your work to make you look guilty. They also cheat widows and wounded. Starve lawyers by keeping your work above reproach. Always be able to point to a specific page in a manual to reinforce any rigging decision.

    When in doubt, work to the tightest standard. 

    • Like 1

  5. I have jumped at more than a dozen small airports where gliders, power planes, skydivers, etc. all gracefully shared the field.

    Separating gliders and skydivers starts with understanding each other's flight patterns.

    Since jump planes rarely carry more than 2 hours worth of fuel, they need to refuel after every 3 or 4 flights. Skydiving flights vary between 5  and 30 minutes depending upon how high they climb and how fast they climb. Minimum jump altitude is usually 3,000 feet with the top end being 12,000 to 14,000 feet or before they need to start breathing supplemental oxygen. Dependence on supplemental oxygen depends upon how many minutes they fly above 10,000 feet MSL.

    Jump pilots report their intentions two or three times per flight. First as they roll onto the active runway for take-off. Then a 2 minute warning. "Jumpers away!" And some jump-pilots report after the last jumper has landed. All these reports are broadcast on the local airport frequency, plus calls to appropriate air traffic controllers.

    Skydivers exit directly over the target or upwind. If upper winds are strong, they may exit two or three miles upwind. Exiting down wind of the target is silly since few parachutes can fly back to the target when surface winds exceed 15 miles per hour. Since modern jump pilots use GPs to navigate to the exit "spot", spotting errors are are these days. Jump runs are typically flown facing into winds aloft, but might be modified depending upon local ATC patterns or to avoid over-flying hazards like lakes or mountains. Jumpers are still responsible for "looking before they leap" to confirm that no airplanes are flying underneath them.

    Typical freefalls last 30 seconds or a minute, though wing-suiters may fall up to 5 minutes before opening their parachutes. Standard opening altitudes are between 5,000 and 3,000 feet AGL.

    Once open, parachutes are just low-performance gliders with a rate of descent about 1,000 feet per minute and lift to drag ratios around 3 to 1. Parachute rides last 3 to 6 minutes from opening to landing. Standard parachute landing patterns are just smaller versions of rectangular power plane landing patterns. Patterns start at 1,000 or 1,500 feet above the target and conclude with landing into the wind.

    Skydiving targets are marked with cloth panels, etc. that are visible from 3,000 feet or higher. Targets are usually on the same side of the runway as the skydiving school and only a short walk from the boarding area. Skydivers often board the plane near fuel pumps. Smoking is strictly forbidden near fuel pumps and airplanes.

     Like glider tow-planes, piston-pounding Cessna jump planes have to be careful to avoid shock-cooling their air-cooled engines. 

    For example, when a skydiving school opened at Dunnville, Ontario, they modified the traffic pattern so that all airplanes flew their landing patterns on the north side of the airport, while parachutes flew on the south side of the airport. Skydivers were told not to cross the runway below 1,500 feet. Better skydiving schools post maps/aerial photos beside the reception desk with cleanly marked traffic patterns. Visiting jumpers are briefed about local patterns before jumping at a new airport.

    If skydivers land on the wrong side of the runway, they are told to look both ways before walking across the runway. Skydiving school management will warn offending skydivers once or twice. The third offence includes encouragement to "jump elsewhere."

    Skydivers tend to be more social than private/glider pilots and many devote their evenings to drinking and bragging about their last skydive. Open alcohol is strictly forbidden before the jump plane takes-off for the last flight of the day (aka. the sunset load). If your airport, neighbours or town have a noise curfew, explain the curfew during your first meeting.

    Better behaved skydivers clean up their pizza boxes, beer cans, cigarette butts, etc. before the next morning's class arrives.

    Skydiving school management is responsible for keeping their operation clean and neat and reminding skydivers of traffic rules, curfews, etc.

    • Like 3

  6. 20 hours ago, gowlerk said:

    I like the idea of a harness that keeps the student six feet away! It reminds me of the old joke about the blind jumper and the seeing eye dog.

    We could always to civilian tandems the same way soldiers do tandem bundle jumps: threaten to kiss the student. As they run off the ramp, follow a few metres (yards) behind and let a static-line deploy your drogue.

    If you worry about light-weight students free-falling above you, just hang a water-barrel off them and drain it under canopy to reduce landing speed.

    Can I get a patent on that concept?

    Hah!

    Hah!

    • Like 1

  7. Dear HPC,

    The Vector 3 was an almost completely new design, with many improvements over its Wonderhog, Vector 1 and Vector 2 predecessors. 

    Over the last 25 years, I have seen a variety of small, cosmetic improvements to Vector 3, Micron, Sigma, etc. generations.

    What improvements would you like to see in Vector 4?

    • Like 1

  8. Back when I worked at RI, if you could pick the complete rig up - off the floor - by the bridle, the closing loop was too tight.

    Truth be told, no-one can close rigs that tight by hand. 

    Even with a variety of tools, I might be able to pull 40 pounds (pull-up cord) to close a tight reserve, but reserve ripcord-pin pull force rarely exceeds 22 pounds. I really struggle to close a reserve too tight to pass the 22 pound test. ... as per Federal Aviation Administration Technical Standard Order C-23B and all later versions.


  9. Another option is the V-ribs patented by Carl Yarbenet decades ago. They had no bottom skin, but a complete top skin. Each suspension line was attached to a pair of ribs that branched off (roughly 45 degrees)  up to the top skin. Pairs of ribs were sewn together along the bottom. From the front, it looked like a top skin, with triangular ribs spreading loads to half as many suspension lines.

     

    _____________________

    \       /   \        /  \        /   

       \/           \/          \/

        l            l           l

        l            l           l 

        l            l           l


  10. Only end ribs need to be made of ZP fabric. With internal ribs, the more porous the better.

    I am so old that I have jumped canopies sewn before cross-porting was fashionable. cross-ports primarily vent air sideways to help end cells inflate. XPs also help end cells re-inflate in turbulence.

    If you only care about structural loads, you could make internal ribs from mesh.

    A few years back, University of Alberta teamed up with a fabric specialty company (was it Altair) to custom weave structural ribs so that individual threads aligned (fan-shaped) to distribute loads perfectly from line-attachment points to the top skin. High-priced racing yachts have been flying custom-woven, 3D curved sails for more than a decade. As computer-driven weaving looms become more wide-spread, we will see more custom-woven ribs.

    The other new technology is through-stitched stand-on-top paddle boards. Currently they are only made constant thickness, but we can expect to see variable thickness SOTPBs in the next two or three years. Once TS technology is perfected, we will start seeing through-stitched mass-production canopies and a few years later diagonally woven, variable thickness canopies. Internal threads will be so thin and along so many different paths, that it will be impossible to stick your head inside to inspect the interior.


  11. On 3/9/2020 at 1:56 PM, mark said:

    Yes, for rigidity the optimum angle for the cross-brace is about 45 degrees.  By contrast, think about the lack of effectiveness of cross-bracing at the tail.  Some canopies cross-brace just the forward part of the cell (Icarus NEOS, for example), and some canopies add false ribs at the tail to keep the as-flown shape closer to the as-designed shape (PD Valkyrie, for example).

    Those extra tail ribs "sharpen" the trailing edge to fine tune down-wash flowing off the trailing edge.

    The most efficient trailing edges are sharp or squared. The least efficient trailing edges are rounded.


  12. The other day, I got into a heated debate down at the Royal Canadian Legion.

    I yelled “All lawyers are assholes!”

    From the far end of the bar: “I resent your remark. I am an asshole!”


  13. Yes pchapman,

    I meant to say that GQ Security USA later published a 15 year life on their reserve canopies. This was around the same time they exited the skydiving market.

    I don't remember if GQ ever published a work-around for acid-mesh.

    Eventually Manley Butler got FAA approval to test suspected canopies for acid-mesh and perform tensile tests to confirm that they retained full strength (40 pound pull on F-111). I have tested close to 1,000 round reserves in accordance with Butler's methods. But those were only a temporary solution to get pilots back in the air until they could buy newer canopies made with certified (acid-free mesh).

    By 1992, Butler was refusing to repack any pilot emergency parachute more than 20 years old. After 20 years flying in the Southern California desert, all PEPs were faded, frayed and filthy.

    But that was a long time ago. I no longer stock tools to test for acid-mesh. Now, if you bring me a 1980s vintage round canopy (now almost 40 years old), I will chuckle and refer you to the museum in Langley.

    Hah!

    Hah!


  14. Dear HPC,

    I would really like to see some updates to the Javelin. Yes, I know that they made a bunch of detail changes in 2000 and again when they added Skyhook, but the reserve pilot chute cap is the same diameter as when 26' lopos were fashionable as reserve canopies (circa 1984)! As Javelins get narrower and narrower, it is increasingly difficult to stuff all the pilot chute fabric under the cap.

    Meanwhile, Rigging Innovations went through a variety of wide-cap pilot-chutes, but needed to introduce the narrow cap "Stealth" pilot chute to make the smaller Talon 1s and all the subsequent Flexon, '94 Talon, Talon 2, Aviator, Voodoo Curv, etc. deploy gracefully.

     

    Sun Path could also learn a thing or two about ringed harness and pin cover design.

     

    Do I sound biased? Yes! The years that I worked for Sandy Reid were some of the best years of my life!

    • Like 2

  15. That collision reminds me of a pair of similar incidents over Hemet, California during the 1990s. Our pilot transmitted the usual warnings on the local airport frequency and he was talking with military air traffic controllers at March Air Force Base. We turned on jump run at 10,000 feet over the Hemet, California Airport. Our pilot told me to open the door of our Cessna U296. I saw a Bonanza maybe hundred feet below us and slightly to the right. If I had jumped, I would barely have missed his left wing tip. So I told our pilot to go-around.

    Hemet airport also hosts a glider operation, so transmitting pilots are supposed to monitor the (uncontrolled) Hemet Airport frequency as they fly overhead.

    The second time, we were jumping over the old dz to the south of Hemet. I jumped out with my tandem student and turned to face our video-grapher. A Fairchild Metroliner roared past behind the video-grapher. The video-grapher never saw the Metroliner. Afterwards, our pilot told me that the last thing he heard was an angry air traffic controller reminding the Metro pilot that he was cleared to descend AFTER the March VOR! The VOR is a good ten miles west of Hemet.


  16. If you decide to chamber-test an FXC Astra AAD, you need a test chamber and a test light.

    You can use the same test chamber as you did for FXC 8000 and 12000 mechanical AADs.

    The test light is a special item best bought from the FXC factory.

    If you have to buy all that test equipment, you will lose money. Just tell the owner to buy a more modern electronic AAD that is still in production: Cypres 2, Marrs, Vigil 2, etc.

    • Like 2

  17. Dear pchapman,

    Generally, the manual that was in print - when the canopy was manufactured is the best source.

    If a later version of the manual sets tighter standards, then work to the tighter standards.

    For example, initially GQ Security set no life limits on their reserves, but after the acid-mesh scandal (1980s) they set a a 5 year life on canopies.

    Pioneer also published a similar "shorter" canopy life on their canopies suspected of having acid-mesh. Both GQ Security (USA) and Pioneer exited the North American skydiving market circa 1984.

    • Like 1

  18. Forget about resale price. At best, the MARD will make it sell quicker.

    You need to be alive to sell this rig a couple of years down the road.

    A MARD slightly improves your chances of surviving the next couple of years. The way to improve your 2020 survival chances is participating in Safety Day refresher training.

    • Like 1

  19. We are all anxious when we jump.

    The only skydivers who are not anxious are stupid. Stupid skydivers don’t survive very long.

    As a junior jumper, your challenge is to convert your anxiety energy into “safe” routines, like studying the winds, planning your landing pattern before boarding the airplane, pin checks, looking over your shoulder before turning, etc.

    • Like 1