ChrisHoward

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Posts posted by ChrisHoward

  1. On 4/23/2019 at 7:54 AM, branch said:

    I have resorted to packing with the d-bag upright and this solves the problem

    A side note to consider, extraction problem or not, pulling immediately out the door is begging for line twists. Even if you solve your extraction problem you should still consider taking a longer delay to generate the airspeed necessary to lift the bag quicker and cleaner than a 2 second delay will provide.

    P.S. I jump an RSK 1 and an RSK .5 and have found that overly tight configurations will cause the hesitation you are experiencing. Something I have noticed to be beneficial is to ensure your closing loop is tight, the tighter the better. This will keep the canopy compressed nice a neat inside the container until the pin is extracted at which point the container will relax some making it easier for the bag to lift out.

  3. 21 hours ago, Justincblount said:

    What? I heard Poynter's manual was peer reviewed. That was sort of my basis for considering it "the bible" of rigging.

    I don't know about "peer reviewed" but there is a long list of credits in the manual the Poynter gives recognition to.

  5. I'm confused. You asked for opinions on a big drogue to slow you down with heavy customers. Now you are complaining because you can feel the larger drogue doing its job?

  6. 9 cells support the weight better than 7 cell canopies of the same size (due to increased structure) giving them better flight performance and flare power.
    Also a number of popular tandem reserves were at one point a tandem main before being designated as only a reserve.

  7. 20_kN

    I am told that HMA is just the material name for a product called Technora. Does anyone know if this is true?


    Try using Google. It has lots of answers :-) HMA is High Modulus Aramid. Technora is a brand name of aramid line just like Spectra is a brand name for polyethylene line etc.


    20_kN

    Anyway, does anyone know the differences between Vectran and HMA as it related to skydiving? My understanding is that both lines stay in trim until the lines need replacement (unlike Spectra). So what is the advantage of one over the other? Why would one chose HMA over Vectran or vise verse?


    HMA offers reduced drag due to it being a thinner line than traditional Vectran lines, although some newer designs of Vectran braid are simliar in dimension to comparable HMA lines. Traditionally I would expect Vectran line to outlast HMA although some coated HMA lines are very resilient.

    20_kN

    I know that Vectran is less prone to spontaneous failure than HMA, but that's the main difference I know about.


    It is not that HMA is "prone" to spontaneous failure. It is that once it starts to appear visually worn it's near its end of useful life. Vectran on the other hand can look like crap for a long time before it finally gives up.

  9. mark

    I think the answer most probably lies in the design of the container corners. For most rigs -- Sunpath being a notable exception -- the container corners are wrapped to form a pocket that traps the bag..



    A little research today revealed that the Vector 2, Talon 2, and Racer manuals all say to rotate the DBag. No pocketed corners in sight on those old things. So the concept clearly pre-dates pocketed corners. The Talon manual even goes as far as to say "FAILURE TO PLACE LINES TO THE BOTTOM OF CONTAINER COULD RESULT IN A PILOTCHUTE IN TOW".
    So that leads me back to the leverage argument. Of course I could have just made a phone call and asked instead :-)

  10. mark

    ******but wouldn't leverage be the major factor?



    Absolutely. The correct orientation of the bag gives the PC the advantage of leverage to rotate the bag upright breaking the friction before lifting the bag.

    I'm not sure this is correct. If it were, Sunpath would greatly prefer bag-grommet-to-reserve-bulkhead/bag-mouth-to-BOC for all its models, including those whose manuals recommend grommet-to-pin.

    You can't argue with physics :-) Levers have been working for 1000s of years :-) You can of course argue the necessity of that leverage.
    Can you please link the manuals you are referring to? It may very well be a concession they have made for their own reasoning (the Aurora doesn't count). The Javelin manual on the SP website clearly states "rotate the bag".
    Another easy way to tell that your DBag isn't meant to be packed grommet to pin is simply the size of the bag in that configuration. Bags are built to fit containers, changing their orientation will mean that the bag dimensions no longer match the container dimensions. If the depth of the bag is greater than the height of the side wall then packing it grommet to pin is obviously not the way it was designed to be packed. Square peg round hole.

    Edit: As you noted, this has become more of an issue as containers have become more compact with pocketed corners etc. I have also noticed that containers with higher side walls and more rigid boxed in dimensions suffer more here than softer containers with shallow pack trays.

  11. Cloggy

    but wouldn't leverage be the major factor?



    Absolutely. The correct orientation of the bag gives the PC the advantage of leverage to rotate the bag upright breaking the friction before lifting the bag.

  12. Westerly

    I know someone who figure-eights his entire lines into the tray and only uses the locking stows. That's excessive IMO, but he claims it works. If you go too overboard (e.g. more than 3-4 feet) though it's possible the lines could blow out of your tray on opening and get stuck on you, which would be bad.



    Do not do this. The danger is not that the lines "blow out" of your pack tray. What happens is that your side flaps blow into your pack tray and tangle with the coiled up lines. Lines half hitching around side flaps have resulted in fatalities. So again, do not do this, use some form of line control.

  13. melk

    I have a wings and i leave the dbag in with the lines toward the back of the container which seems the most logical to me, but I often see people roll it down toward the bottom and have yet to get a reason why



    The best reason I was ever given is that on deployment the PC twists the bag into the upright position, breaking the friction of the bag vs container, then begins lifting the bag out of the pack tray. If the bag starts out in an up right position the PC has to break that friction and lift the bag in 1 motion which is obviously more effort for the PC (think shearing forces vs pealing forces). Sure people do it, and sure it works, but it can cause weird deployments in overly tight containers.

  15. IJskonijn

    So with the restriction that no markers can be used anywhere, even on non-loadbearing parts, what are other ways to more easily differentiate lines into the different linegroups are possible?



    Simple. The length of the line is the single easiest way to identify a line group. A's being the shortest to D's being the longest. Colours are irrelevant.

  16. andrewjschutz

    ***Frankly if you know that little about it you should really get it sent to a local rigger to make sure it's the right rig for you.


    I thought it was a much better idea to get the information myself instead of blindly taking it to rigger for them to solve.

    The best learning experience could be to simply take it to your local rigger ;)

  17. mark

    There are a few manufacturers who have retroactively established life limits for their equipment. Those life limits are not legally binding, and violating them will not lead to FAA certificate action. But there is additional civil liability exposure from choosing not to follow manufacturer recommendations (recommendations, not legally binding instructions). Some riggers choose to accept the additional exposure, and some do not.

    --Mark

    edited because no spell check



    They have done no such thing. That would require an Airworthiness Directive, but you already know that. Pulling support for their equipment is obviously their choice, one that I can understand, and an obviously effective way of phasing out older generations. But to try and dump the onus of grounding gear onto the field rigger with the implied threat of civil liability is definitely a sore spot for me. If they don't want their gear out there anymore then They should ground it.

  18. Bob_Church

    Speaking of 20 years, there's some other rule in their. A rigger who was packing my rig let me know that this would be her last time because the reserve would be over 20 years old then. But it wasn't a problem with the reserve, it's just that she couldn't. She was letting me know that a different rigger would have to start packing it after this.



    In the USA? Sounds more like she was saying that she "won't pack it anymore", not "she can't". I have definitely told customers that they are welcome to find a different rigger that is willing to continue working on their old junky equipment that I was no longer willing to maintain.
    Edit: There is no rule to my knowledge that would allow one rigger to pack something that another rigger could not based on age.

  20. mark

    Riggers that graduate from such courses are authorized to pack rounds and yet they don't, at least until they choose to get training they are not legally required to have.



    I'm skeptical. I do not believe that the vast majority of riggers go and seek additional training in things they believe they are capable of. Yes, a good rigger would realize their limitations and take it upon themselves to further their education. But in reality guys are out there taking money for whatever comes in the door because they are permitted to do the work.

    Edit to add: I agree with Lee, to some extent. I would like to see skydive back mounted reserves and PEPs separated. Both of them being considered "Back" is just silly.

  22. It makes a noticeable difference in freefall. Openings are good, a little more drag but still better than the higher airspeed openings of a 250lb passenger on a 54inch. Great for what you are suggesting. As someone else mentioned they do try to sneak out of the BOC due to their extra bulk.

  23. It depends on what is causing the throttle body to become "Dirty". Cars have an emission system known as a PCV valve that vents the crank case gasses into the air duct which then flows through the throttle body and back into the engine to get burned up. When the PCV valve goes bad more than just gas escapes the crank case (read oil) which then leads to a dirty throttle body and air system. You noted that the MAS is "upstream" from the throttle body (most likely right at the airbox?), the problem as I see it is that when everything gets gummed up oil starts to drip back along the air intake after the car is shut off. This would then lead to MAS failure. I have seen air filters totally soaked with engine oil from this exact problem.
    P.S. I am not a mechanic, just a guy with tools. I have never seen the car you speak of and have no clue about it. I have had bad PCV valves in several different vehicles that led to oil in the throttle body and airbox.
    P.P.S. Cleaning a throttle body is easy to do yourself. Degreaser and a toothbrush. Another symptom of a dirty throttle body is irregular idle.

  24. Bye_gravity

    On the page it clearly states that MARD will need maintenance every 3 cutaways which seems like a big hassle.



    I suspect this would be because due to its nature the "lasso" could cause friction burns on itself and possibly other components.
    For the record the red lanyard on the Skyhook has been known to break and the lexan covers are susceptible to damage too so that system is hardly maintenance free either.