pchapman

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Posts posted by pchapman


  1. The Stylemaster and Starmaker manuals are one and the same. I was just now told this by long time poster Beatnik, who owns a Starmaker among his large collection of vintage gear.  (The manual that has been around a long time in pdf form is only labelled Stylemaster; I hadn't thought of opening that.)

    Stylemaster.pdf

    • Like 1

  2. Quote

    The rib design in those Phantom paragliders are really interesting.

    It makes sense as part of the evolution of ribs. Starting out as solid ribs, with a few round holes knotknifed into them. The holes then become more rectangular, or a set of thin vertical slots to allow the rib to transfer loads along the weave of the fabric. With diagonal loads being taken by tapes sewn on from the line attachment points.  As computer aided design expands, more and more excess material in the rib is removed.  One can't go too far with a plain rib as soon one would have a thin strip of material on a bias, on the 45 to the main threads, that will stretch when loaded or ravel even with hotknifing. So one would need strips of material built to work along the diagonals. (Not sure how the Nova Phantom paragliders' diagonal ribs work.) ("crossbracing" in skydiving = "diagonal ribs" in paragliding)

    If the production methods could be made to work without adding ridiculous cost, for great structural efficiency, each rib or diagonal reinforcing rib could end up as a bunch of bifurcating, cascaded threads or mini-lines. 

    A 2D version is sketched below just to convey the idea, but obviously these could split spanwise as well to act as crossbracing, whether they could attach to the upper surface at any point or have to join into some sort of reinforced seam. Then it becomes more like organic structures from nature, thin structural members going everywhere instead of a few heavy structural beams of simplistic design.

    In skydiving, having ribs that aren't just a bunch of holes might be useful for controlling inflation though.

    Some more thoughts on some diagonal variations plus spanwise load bearing tapes, from a while back I think, can be seen at http://www.laboratoridenvol.com/paragliderdesign/V-H-ribs.html

     

    image.png.af37a49c5290297e8f8a4e2f86bc293e.png

     

     

    • Like 1

  3. What Skylark is doing looks nice. The crossbrace design reminds me of the Atair Onyx of around 2002 - one over-hyped canopy even if some aspects were inventive. Two sections on the bottom surface become 4 sections on the top surface.

    Atair onyx.jpg

    • Like 1

  4. I would hope someone has done a more recent scan, but attached is the best I have from what has floated around. It is a crappy but readable OCR scan from a rigging manuals library in I guess the early 1990s.

    It still shows and states stack-packing only for the reserve, although pro-packing is allowed for the main. Yet Precision must have been one of the first to do reserve pro-packing showing how to do it on a VHS video sometime at or before 1990. So this is definitely not one of those cases where 'you must follow the manual'...

    Precision Raven.pdf


  5. Interesting to see in that document some of the background to the situation. So a bunch of people in the industry were talking over the years-- Sandy Reid (RI) with Eric Fradet & Bill Gargano (Airborne Systems) & Henri P. (Sunrise) for example. Interesting that Sunrise Rigging licenced Eric's MARD. [Edit: took out half a sentence as I mixed two companies up.]

    CAVEAT: My take on this is just as someone skimming over everything, with a bit of time to spare, not any sort of lawyer understanding the patent system or going over every claim word by word.

    Eric's patent claim isn't at all what one would think from a quick look. We might think: "Hey, Eric's MARD uses a pin with a grommet or similar, in all sorts of possible variants as seen in his patent drawings." In casual discussion over the years, that's what you always hear, about "Eric Fradet's pin system MARD".

    Then we look at RI's system, with a metal device that hinges to let the RSL line release when pulled in a certain direction, not using bridle slack or grommets. Seems totally different, not obvious or like pin systems.

    But the actual claims in the detailed wording of the patent seem to be much broader, as presented in the lawyer's letter.

    The patent doesn't talk initially about pins, but just a connection between RSL system and reserve bridle! So it seems to claim ANY attachment mechanism between RSL and bridle.

    (Where the claim also includes other necessary background stuff -- of course it has to function as a MARD, staying attached or disconnecting depending on the situation.And the system has have the usual skydiving parts, like a main and reserve parachute and a way to stow the RSL.)

    It's almost like all those drawings of various pin & loop & grommet designs are just there as camouflage, and to show off some possibilities. Those are covered in 20 other claims, but are minor if the claim #1 covers any RSL to bridle connection.

    But if every connection is claimed, so how does Eric's patent not infringe on the Skyhook?

    Well, I have only skimmed the Skyhook patent, but its claims are all about the hook & slot thing.

    So is it a situation where Booth got the patent on hook & slot MARDs, while Eric basically then got a patent that covered everything else no matter how clever? (Except say the Mirage TRAP, because as packed, there is NO  connection between RSL and bridle. Weird but clever.)

    (Eric's patent does mention the Skyhook in the Background section, saying it isn't ideal because in the case of a total malfunction situation, the Skyhook doesn't disconnect as quickly as it should, potentially delaying the reserve opening.)

    If you have time Mr. Fradet, I sure would be interested to know the explanation. Patents can be very complex and opaque to the layman.

    Eric's patent: long patent URL for Eric Fradet's MARD
     

     


  6. That classic Dual Square report dates from 1997. I can add a Jim Cowan (CPS) presentation from the PIA in 2013.

    Maybe someone else can keep moving the data closer to the present...

    (As I wrote in 2014 somewhere on dz.com: "The document's value seems to be that it goes into more detail about actually flying two-outs that one usually sees. He also adds the case which is neither biplane or side by side but is "in between", and also adds partial deployment of the 2nd parachute. The document doesn't cover landings. ")

    9 Dual Deployments - Jim Cowan.pdf

    • Like 1

  7. There were plenty of discussions back in the day about the accident, back on newsgroups. One of the very very few collisions between jumpers and planes (other than the one they jumped from!). You can find discussions archived in google groups.

    The NTSB put the blame on ATC but had to also put it on the pilot of the jump aircraft. Unfortunately in reality it is basically impossible for a jump aircraft to spot other aircraft below, and pretty hard for skydivers in modern skydiving to do so. It didn't help that the parachute symbol -- a warning and not a prohibition of flying through the area - was more or less blue printed on blue on the sectional map. 

    Things get messy with all the different factors involved in how airplanes and skydivers are kept separated, and how both sides still somewhat rely on the occasionally fallible big sky theory.

    The short NTSB report

     

    Quote

    Probable Cause The National Transportation Safety Board determines the probable cause(s) of this accident to be:FAILURE OF THE AIR TRAFFIC CONTROL (ATC) FACILITY TO IDENTIFY AND PROVIDE THE REQUIRED TRAFFIC INFORMATION TO THE JUMP AIRCRAFT BEFORE RELEASE OF THE JUMPER(S). A FACTOR RELATED TO THE ACCIDENT WAS: INADEQUATE VISUAL LOOKOUT BY THE PILOT OF THE JUMP AIRCRAFT

     


  8. Ok, I'm not super clear on business terminology of mergers and sales, but:

    If Sandy owned the company outright, does he now own a share of Sunpath/RI?   If not, if he SOLD his company and got some retirement bucks out of it, it was a sale.  If those who have ownership of Sunpath, now own RI, well, that also shows a sale.

    Even the RI  FAQ on the deal includes "1. Why is Rigging Innovations being sold to Sun Path Products?"

    It may be a sale yet still be an effective merger if both teams continue to largely run their own domains, but with gradual co-mingling of staff and processes over time -- best person or process for the job stuff, even if there's a bit of "here's the new way we do things according to Sunpath".   Its not like all sorts of spare Sunpath staff will likely be flying to immediately to Arizona and kicking RI people out on the street. Yet what happens down the road when RI gets absorbed into the S. Carolina Sunpath, who knows.

    Companies often talk of mergers even if one was sold to another, to indicate both teams are valued and are expected -- for now -- to continue to contribute in their own ways. A merger in operations but not actually so in ownership.  To what degree it really ends up a merger in the long run varies a lot. 

    I'm willing to stand corrected, but it looks like a sale, could indeed also be called a merger for the short term, but it seems like Sunpath will be firmly in charge in the long term.

    • Like 1

  9. 9 hours ago, mark said:

    Aerodyne Smart reserve:  porosity check after 10 jumps or 20 packs, but no boxes.

     

    And in newer manuals, Aerodyne upped the number of packs to 40 before a porosity check, at least matching PD on that side. Just noticed that change myself.

    Easy for people to forget Aerodyne requirements as they are buried in the manual.

    They also have always required a porosity check if the canopy was immersed in water.

    (One can of course also get into the argument whether 'the currently published manual sets the rules' or the 'manual that came with the canopy sets the rules' or one may choose from both.)

    [Reference: a Smart manual from 2011 current in 2013 said 20, the manual current in Feb 2020 but from 2015 says 40.]

    • Like 1

  10. It looked in one photo I've seen, like he had two rocket deployed parachutes on his rocket vehicle (as for recovery of ultralight or other very light aircraft) and one deployed on takeoff. Some quote in the news  mentioned the rocket rubbing somehow on the launch ramp. While some interference is possible, I'm wondering if it was just poorly designed in some way, that the G forces on launch caused the deployment rocket to be initiated. 

    The steam rocket he used only produces thrust for a few seconds.  A big bottle of superheated water plus a nozzle basically.  Which means high G's right at takeoff, rapidly lowering thrust (although somewhat compensated by the mass of the vehicle going down), and then just coasting up to one or two thousand feet.    Seems a bit of a sketchy system to get decent altitude -- although if applied correctly it can work for smaller flights. (E.g.  Evel Knievel Snake River jump - also with parachute issues -- or the more successful later re-creation by Eddie Braun.) 

    If Mike did have two chutes, why was the second not deployed? Who knows what condition he was in after the high G takeoff (with a jolt when the canopy started to inflate then ripped off), or whether all parts of the second recovery system were still intact.

    His 2014 flight vehicle did fly although some say he wasn't actually in it. That vehicle deployed the recovery parachute at high speed and shredded a lot of panels, being held together only by an intact lower lateral band. But the video I saw showed no landing and if he wasn't in it in the first place, not a problem. 

    His 2018 flight had 2 parachutes, the first being activated a few seconds after apparent finish of thrusting but still during what seemed pretty high speed upwards flight. That seemed to be a very poor choice of timing. Still, the canopy survived. Later when low on the descent he seemed to realize the descent rate of the whole vehicle under canopy was pretty high so he fired off the 2nd parachute. The 2 canopies pulled apart into quite a Y-configuration but slowed him down a bunch in just the last couple hundred feet of descent. He got through the landing with some back injuries but how serious they were is a bit unclear.

    I only know any of this from watching a few videos and reading a bit online. Hard to find much technical info on his vehicle & flights.

     

     

     


  11. The company said: "The unit has been visibly damaged from the client, the soldering are not the original ones as well the battery has been changed even if the unit has 4 jumps only."

    It is as if someone at Parasport doesn't realize that unit was ever sent in for repair by their own folks.... when clearly they should have some history from its serial numbers and see that it is a problem unit.  Do they have a poor database detailing their products shipped? Or tracking of customer issues? Especially with them having changed the serial number? Or is it a dumb employee who didn't use the databases correctly?

    Hanlon's razor: " Never attribute to malice that which can be adequately explained by stupidity"

    So is their decision final or is there still a chance to explain to them how they messed up?

    • Like 1

  12. 2 hours ago, airnutt said:

    check out the incident with very low cutaway with injuries at Eloy, I watched this from the beer truck area, except for the last 500 feet, my beer was empty, but I'll bet this guy was glad he had a skyhook or something similar.I'd say they're worth the couple of extra bucks.

    While we all can fuck up, maybe the original poster isn't going to be a total idiot and mess with a malfunction for 44 seconds (as was stated in the Eloy thread). Which is well beyond the sort of mess ups most of us are subject to from time to time. Or the poster isn't willing to bet $350+ that he'll be such an idiot in the next couple years while he has the rig.

    I also question whether adding something worth $X to a rig is really going to add $X to the sale price. MARDs are becoming more and more 'normal' as more brands get them but I don't think not having one is yet making gear hard to sell at reasonable prices. But I don't know the used gear market well. The price for the MARD in this case is also going to be more than $350; it will be that plus disassembly, shipping and assembly.

    The original questions still stand, about how the market prices MARDs in used gear.

    • Like 1

  13. The static line was made of some heavy tubular webbing or something like that, good for likely thousands of pounds of load. Note that this was a direct bag static line setup, rather than static line extracting a pilot chute or whatever those systems were like.

    The student gear used an SOS system, so when the student pulled the emergency handle, it cut away the main too. The main canopy fell away at some point, rather than staying in the bag at the end of the static line. (What with the odd angles involved, I guess friction on the risers, despite being released at the 3-rings, could have extracted the canopy from the static line bag.)

    As for do's and don'ts, the obvious lesson is to close any main container correctly to avoid bad things happening (freefall or static line), and that any 'pin check' (such as by an instructor) look for proper routing of the bridle.


  14. In the end the closing loop ripped out of the rig (maybe distorting the plastic in the flap enough for it to do so). The static line stayed intact.

    From my 2009 post after it happened at the DZ I was at:

    " It is thought that the tab of the static line went into the heavy dacron closing loop from the right instead of the left, which is not normal DZ procedure. [Packer error, not caught by instructor] Still, it was a surprise that the static line actually locked up on itself in some way, rather than just causing a hard pull for a moment while it rotated back to the right orientation. I've never heard of the DZ ever having anything like this happen before in its many years of operation. "

    The question of hook knives always comes up. The DZ aircraft 'always' had a hook knife, and the instructor happened to also normally have one. But his got lost the previous week or something, and someone doing maintenance on the plane moved the big hook knife in the plane shortly before. While some will say 'The instructor should have checked for the knife!', it is one of those things people don't check all the time as it was standard DZ equipment on the plane. (Did you check for the fire extinguisher in the airplane the last time you boarded?)




     

  15. 2 hours ago, ChrisHoward said:

     Any unit more than 8 years old will automatically get a battery change if it is returned to the service center for any reason.

    But you can't hold that policy against them, as that's only one part of it: If the batteries are replaced between 8 and 12 years, and no mandatory replacement until the unit is expired, then the batteries are considered good for 12 years.

    So yes Chris Howard, for someone to say 10,000 jumps is a "standard" is using too strong a word for it. Nevertheless, as Gowler pointed out, the expectation in the industry is many many years without a battery change for most jumpers.

     


  16. 8 hours ago, mbohu said:

    There is therefore simply no one making any decisions of any consequence whatsoever. There can therefore be no moral or immoral action. Every action is simply an effect of the simple combination of physical laws and prior states of matter. "Morality" is meaningless and non-existent. (or the meaning of the word has to be completely redefined)

     

    You kind of lost me there. While I'm not getting the subtleties, it feels like one is saying, "Everything is just atoms and sub-atomic particles... so nothing matters... everything we do is just movement of atoms or electrical signals and stuff... our existence and lives are all just irrelevant to the universe."

    Um yeah, that's all true.

    But that's doesn't make morality any less real as a concept. Religion or not, every society ends up trying to have some form of morality, which is a concept about fairness, justice, not causing harm, and whatnot. Pain may just be a mind's manifestation of electrical signals, but that still doesn't make it generally good for one human to torture another to death. (Whether or not a particular society suggests it as a reasonable punishment for some crime.)

    I think I can bow out here and leave anything more to deeper philosophers.  

     

    • Like 1

  17. On 1/7/2020 at 7:27 PM, mbohu said:


    But, there is one logical problem, I think Atheists*) have, and I haven't seen this addressed very well:
    If you look at it in terms of the source of one's moral values, there really is nothing in atheism that one could base one's moral values on.

    Going back to one  of the original question:

    It is still better to have the opportunity to try to be moral, that be in the situation that some Christians seem to be in: They may crow about the morality built into their belief system (confusing as it may be). But sometimes it seems that their being moral is only because of fear of punishment -- "Don't do this or you'll be condemned to hell for eternity!"  Which is kind of like a kid saying, "The only reason I don't beat up my little sister is that my big brother would beat me up!"  Which is saying you would be a nasty bully except there's someone else there to bully you, God. As opposed to actually choosing to be moral and not a nasty bully.

    So if you can be a good person who is Christian.... you can also be a good person outside of those confines.

    And since Atheism isn't an organization with meetings or membership cards, I don't have to apologize if some Christian nutter says, "But whattabout that serial killer or that dictator... he was an atheist!" 

    And there's the issue that some religions' morals are pretty messy and disputed, with reference to ancient and contradictory texts from which people have argued just about anything. But the same discussions over what is "right" could be made without references to some ancient book that refers to bizarre tales from thousands of years ago. I'm obviously thinking of Christianity here, what with the issues over the centuries of things like whether homosexuality or owning slaves is evil or not. Organized religions did serve some purpose in having shared goals for societies, but it didn't make their decisions on what is good or evil necessarily any better than the choices made by people within other religions or who were skeptical of the local religion.

    • Like 1

  18. I'm not familiar with what originally came with Northern Lites.

    I have an old 2 pin Northern Lite I use for accuracy and other jumps. Back in the early 2000's when assembling it, some parts were missing. So I put in a 357 Magnum reserve PC, as that was a commonly available generic reserve PC (before the single-loop-through-the-PC era), and have stayed with that.
    I tried packing it using a nice strong Vector PC but the spring was so strong it kind of distorted the whole pack job, given its old 2 pin design, so I didn't proceed with that. 
    (Note though that I'm in Canada using our rules, so I'm flexible with mixing and matching, not worrying about TSO's or any company's approval.)

    • Like 1

  19. No slider? Ouch.

    On the other hand, I do wonder just how much effect the slider does have, as the openings are rather hard in my very limited experience...

    (Single keel that is. Dual keel is nicer all around.)

    • Like 1

  20. What is acceptable probably depends a lot on the DZ's conventions.

    Lowest step:    I and others filmed for years with no sight without issues.
    At first one has to check how the cameras are pointing relative to the helmet and one's eye gaze up or down, with some checking of video to make sure one isn't consistently low or high. But after a while it becomes natural to fix one's gaze at the right angle. I even did some 4-way video that way, although if one is filming at narrower zoom angles a better sight might be useful.

    Next step up:     Others used a mark on their goggles. Commonly used was a stick-on ring of paper -- one of those reinforcements for 3-hole punched paper holes. It is out of focus being close to the eye but that provides a good "see through" ring. 

    Next step up:     The cheapie ring-sight as suggested above by IJskonijn.