mark

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Everything posted by mark

  1. mark
    Usually the skirt of the canopy and the apex are at the same height when the pilot chute is cocked. Are you saying you have 4" slack in the center lines when the pilot chute is cocked? Mark
  2. mark
    Send me your mailing address. Sometimes the battery cover cracks. Let me know, and I can include one of those. Also let me know if you need the springs. Mark
  3. mark
    Even when our sport was growing fastest, most students did not progress beyond a few jumps. Since licensed jumpers do not use ground-to-air radio, should student radios be eliminated? Mark
  4. mark
    By "wind" we usually mean the speed of the air relative to an observer. The 300 mph jetstream wind in this discussion is the speed relative to an observer on the ground. The ease or difficulty of exit from an aircraft is dependent on the airspeed of the aircraft, that is, the wind with respect to an observer in (or on!) the aircraft. If the aircraft airspeed indicator shows 80 knots, then you'd feel 80 knots of wind, and it would feel the same even if you were making a downwind run in a 300 mph jetstream. Unless, of course, your airplane stalls on a downwind turn, the wind blows on the back of your canopy when you fly downwind, etc. Mark
  5. mark
    I'd like to do a little reading about CAT and jetstreams, as they pertain to objects falling at skydiving speeds. Google has not been my friend. Can you point me to a good reference? Thanks. Mark
  6. mark
    I've taken the liberty of rearranging your post to put the assumption first. I've tried to find a a source to confirm the assumption, but the best I've been able to get to is a crude cross-section showing isotherms and isotachs, but nothing so detailed as to say "200 feet." How thick would the boundary region need to be for the delta-V to be in the range routinely found in speed skydiving? Mark
  7. mark
    I agree. Although the FAR requires riggers to seal the rigs they pack, the regulations do not specify what is to happen to the seal after a rig is in the owner's possession. We trust owners not to screw with their harnesses, so why wouldn't we trust them not to screw with their reserves? Mark
  8. mark
    Flight Concepts reserve, packed by/for Silver Wings freefall demo team at Fort Benning, Georgia. MEL (posts here with same name) participated in the investigation. You could PM him for details, but the bottom line is to RTM to ensure you use exactly the manufacturer's packing method. Odd that this doesn't show up in dz.com search. I thought I read about it here. Mark
  9. mark
    Most sport/student rigs are limited to 254 pounds and 150 knots. That's 254 pounds fully equipped, what you would weigh if you stepped on a scale just before boarding the airplane. Some newer rigs are limited to 300 pounds. I don't know of any rigs other than tandems that are rated for more than that. For ASC's student rigs to be legal for your body weight, they would need to be certified for use at around 320 pounds, figuring your weight at 280 and your equipment at 40 pounds. What harness/container systems, what reserves, and what AADs (student, expert/pro, or tandem) do they say are they using? Mark
  10. mark
    In my Icon Harness Container Packing Manual (TM162, Edition 05-2005) on page 34: "Warning: never use slider bumpers on the reserve canopy." Mark
  11. mark
    I see plenty of PD reserves in Icons. Mark
  12. mark
    Except for reserves packed in Aerodyne Icons, of course. The packing instructions explicitly forbid use of slider bumpers. Mark
  13. mark
    Further, no regulation calls out 4.75# seal thread. Since the pull test is done without a seal, one might plausibly infer that once the owner has possession, it would be okay to remove the seal for safety. The FAA trusts airplane owners not to screw with airplane components, so why not trust rig owners? You're right -- it does get MEL stirred up! Mark
  14. mark
    My "knee plate" is 6" across. Not much use for kneeling on, but allows good compression when I use a crank. Whatever plate you use needs to be wide enough to span the pilot chute spring coils. I don't mind when I see other folks cranking without using any sort of plate. I make good money replacing stiffeners and grommets they damage. Mark
  15. mark

    Astrology

    mark replied to Broke's topic in The Bonfire

    You're welcome. And you're right, I should have included the attribution. Mark
  16. mark

    Astrology

    mark replied to Broke's topic in The Bonfire

    I travelled with him on the astral plane to Atlantis and gazed upon the Tuaoi Stone. Cayce was a fantastic prophet, a seer of the future. Some of the things he predicted were simply amazing. For example, in 1958, the US discovered the death ray used on Atlantis. Also, in 1968 all of China converted to Christianity. Who wants to know more, and who wants simply to believe? Mark
  17. mark
    FAR 105.43(c) addresses only required AAD maintenance, not installation. No AAD manufacturer can approve or disapprove the use of its product in any rig. The company can arbitrarily say "no" if it wants, but it is hardly the final word. Any harness/container manufacturer can approve or disapprove the use of an AAD in its rigs, and can restrict approval to certain brands (i.e. Rigging Innovations: Cypres or Argus only) or configurations (i.e. Mirage: Vigils approved only with newer-style cutters). As Sid knows, AC-105-2c outlines procedures for alterations in general, and is most useful if the product is an orphan or if the rig manufacturer doesn't have an approved alteration procedure or configuration. Mark
  18. mark
    Most students do not progress beyond the first few jumps. An SOS system (one handle to cut away the main and pull the reserve) allows simplified emergency procedures at a time when students are overloaded with new information, at the cost of slightly increased hazard for the few students who need to make the transition to separate handles. Mark
  19. mark
    Must be a really big light bulb. Mark
  20. mark
    Thanks, Mirage! I needed a ripcord overnight -- and you came through. The FedEx guy pulled in while the load was manifesting; Tim made the load with a new ripcord. Timing couldn't have been better. Great customer service, a hallmark of a great company. Mark
  21. mark
    1-715-684-3416 for those dialing from phones without a Twin Cities area code.
  22. mark
    No, he didn't. You were the one who started the headwind tangent, in the first reply to the original post. On any canopy, including a Velocity, if the headwind equals the brakes-released airspeed of the canopy, then increasing the forward speed of the canopy (by using front risers) is the only choice for covering ground. Are you (even) familiar with the term "ad hominem?" Mark
  23. mark
    Sometimes there's a little silicon gel on the underside of the closing loop plate grommet. Shouldn't affect the pack job at first, but could wick down to the knot over time. Doesn't sound like that's the case for you. I bought a batch of pre-made loops once. There was so much gel that some squeezed out while I tied the knots; the knots would just roll off the end of the loop. Since you are making your own loops, this doesn't sound likely either. You might try using the Aerodyne Icon knot/washer method, which traps the knot under part of the loop and is more resistant to slipping. Mark
  24. mark
    Amen. Mark
  25. mark
    A rather opaque post. If prices will not be governed by supply and demand, how will prices be determined? There is a barrier -- more of a low hurdle -- to entry in the form of FAA certification, but is there anything else that prevents there being a free market? What prevents an East Coast rigger from going to the L.A. area and getting rich by charging $50 for a $35 pack job and undercutting those eeeevil price gougers who are getting $75 from willing customers? Or is the barrier the shame that East Coast riggers feel about asking a price that might compensate them for their time and allow them to pursue rigging as a profession? What experience of other countries might predict what will happen? Mark