riggerrob

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Posts posted by riggerrob


  1. 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

  2. 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

  3. 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.


  4. 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


  5. 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.


  6. 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.


  7. 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!”


  8. 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!


  9. 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

  10. 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.


  11. 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

  12. 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

  13. 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

  14. 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

  15. Flex pins are the most idiot-proof way to close static-line rigs, but they are not perfect.

    When I maintained the gear at a S/L school, I always made sure there were a few spare closing loops and a few spare flex-pins and encouraged packers to replace them at the first sign of significant  wear.

    Key point: flex-pins and closing loops are cheap, but airplane tails are expensive.

     

    For tools - as important as hook knives - wise operations double-up or triple-up.


  16. Cypres 1 should have retired from Canadian DZs a long time ago because Airtec put a 12 year life on them. Airtec quit building Cypres 1 early in this century.

    Similarly, Canadian skydivers are expected to maintain their gear in accordance with manufacturers' instructions. That includes all Service Buletins, Special Inspections, etc.


  17. This morning, as I put on my shirt, a button fell off.

    When I picked up my brief-case, the handle fell off.

    When I tried to turn the door handle, it fell off.

    Now I am afraid to pee!

    • Like 1

  18. Canada has few rigid rules about gear life beyond those specified by manufacturers (e.g. all Cypres 1 AADs should have retired more than 15 years ago). Also review service bulletins.

    This is really two separate issues.

    Fortunately, most parachutes wear out before they fall out of fashion.

    The more complicated problem is when gear remains in service long after it has fallen out of fashion. For example, round reserves should only be worn by POPs who have already landed a few dozen round main canopies. I may have started jumping round canopies - during the 1970s - but my last round landing was in 1986. If you ask me to repack a round reserve today, we will share a laugh!

    If you ask me to repack a round reserve made during the 1980s, I will explain that I no longer have the tools to test for acid mesh …. and the nearest museum is in Langley.

    An even greater problem is when junior jumpers want to jump older gear without understanding the limitations. For example, I have advised several skydivers about the dangers of loading Micro Raven 120s more than 1 pound per square foot because no one was loading mains that heavy when Ravens were introduced (circa 1984).

    As for free-flying with pre-1995 gear, that is just plain dumb because there are far too many opportunities for stuff to blow loose when wind hits it from weird angles.

    In conclusion, the simple answer is don't jump gear more than 20 years old. The complicated answer is that some 30-year-old gear is still airworthy, but you need a history lesson from a grumpy, old, grey-bearded master rigger to understand the limitations on older gear.

    • Like 1