billbooth

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Everything posted by billbooth

  1. billbooth
    I have no data about malfunction rates vs. age of Dacron lines on sport canopies.
  2. billbooth
    That number is true.
  3. billbooth
    As I've posted before, hand deploy pilot chute release to line stretch should take just over one half of one second. Any longer or shorter, and you've got problems.
  4. billbooth
    In the last few years, we have filmed dozens of spinning cutaway tests on the Skyhook system. On a few of these tests, we have recorded rotation rates up to 360 degrees per second, post cutaway. What's worse, is that the relative wind, right after cutaway, is often "horizontally" across the jumpers body. On a standard RSL, this would result in uneven line lengths at line stretch. Combine line twists with uneven line lengths, and you might just get a spinning reserve canopy. As noted above, post cutaway spin rates that high are rare, but they would give me pause before jumping a standard RSL with a very high performance canopy. The Skyhook solves this problem placing the reserve canopy, not into the relative wind, but right where the main was a half a second before, directly in line with the jumpers body. So, even if you have a twist or two, you will not be spiraling from uneven line lengths.
  5. billbooth
    I designed this RSL 25 years ago in response to problems associated with the conventional ripcord-cable-through-ring method. It is still the only RSL system that does not damage the reserve ripcord cable each time it is used. However, it was not an attempt to build in a "ripcord stop". The Velcro joint on the reserve top flap and static line lanyard, should allow the static line pin to rotate, and the reserve ripcord eye to slip off, before the pin is anywhere near the housing. I never patented this improved RSL, and have always wondered why more people haven't "borrowed" it. As it turned out, this design, along with the Collins' lanyard, was absolutely necessary for the Skyhook system to become operational.
  6. billbooth
    I hope you're right.
  7. billbooth
    I have made many "facing each other tandems" with experienced jumpers, and see no safety problem. However, I see a large potential safety problem with "wuffos" facing the tandem instructor...they are free to grab all your handles (or arms) at any time. Relative Workshop's position is that the primary and best purpose of tandem is as a training aid, and therefore do not recommend its use for anything else. However, what you may consider "training" is left up your "good judgment".
  8. billbooth
    I think that "zero" stretch lines are a bad idea on tandem canopies. An unstable, 170 mph opening could be fatal with no stretch lines...especially if the passenger is an 85 year old grandmother. (4 people have died from opening shocks on solo rigs with "zero" stretch lines in the past two years.) It could even damage the harness. (Parachutes de France had two harness failures with Microlined tandem canopies.) Tandem rigs are commercial vehicles, so comfort and safety for the passenger is our number one consideration. A smaller, lighter rig will always be secondary. "Zero" stretch lines are perfectly fine if you have a canopy which never opens hard...no matter what you do to it. However, I know of no such canopy.
  9. billbooth
    They have been modified to a simple hand deployed configuration for jumpers that weigh over 300 lbs. But these are no longer tandem rigs.
  10. billbooth
    A tandem rig is different than a sport rig. Therefore, you need tandem training to safely jump a tandem rig. That is company policy. I am not aware of any FAA policy about this. This begs the question...why would you want to jump a 45 pound rig if you didn't have to?
  11. billbooth
    It has been done. Two small, beautiful blonds, on the front of a very happy tandem master. My favorite picture, however, was a "tandem" Christmas card, with a father, mother, 5 year old daughter, and her teddy bear...All in a row. I say "favorite" because it was not done in the US. It was also not very smart. The military now carries up to 1,000 pounds on our tandem equipment, so theoretically, you could go with a 200 lb. tandem master, and EIGHT 100 lb. women. Please don't try this at home.
  12. billbooth
    In the beginning, I actually tried TM up front, as well as passenger up front, facing TM. The latter is a lot of fun with an attractive member of the opposite sex, but TM behind student, both facing the same way, is the only way to go. (Anyone for a side-by-side?)
  13. billbooth
    My new Spectra ripcord is "stiff" enough to thread easily through our stainless housing with no tools. It is only about 14" long, and with no pin on the end, I doubt it will ever tangle with a deploying canopy.
  14. billbooth
    Years ago, before hand deployed pilot chutes, when every jump was a spring loaded main pilot chute deployment, I had my main ripcord ripped out of my hand, and entangled in my main canopy lines, 3 times in about 1,000 jumps. That's one reason I can think of to throw your handles.
  15. billbooth
    In a previous draft, the ripcord/static line test was 600 lbs. That was changed to 300 lbs., but apparently the conversion to metric was not done in both cases. This document went through so many changes in the 5 years I was associated with it, that I'm amazed it makes any sense at all. By the way, the qualification test sequence it contains has never actually been run, so we don't know yet if the gear we now use could actually pass. TSO C-23D had tests that made it nearly impossible to build gear that anyone would actually buy. That's why we had to do it all over again. Apparently, we will never learn that we should actually test the tests BEFORE we submit the document to the FAA. It's so hard to fix problems afterwards.
  16. billbooth
    Hey! How about putting the reserve up front...in its own separate container. Wow! That way, if you had a reserve total, you could just pull it open yourself.
  17. billbooth
    We don't plan to change the upper weight limit for the Sigma 340 main. Technology has improved enough since the 370 was introduced to make the 340 equal or better to it in every way, while packing a little smaller. Test jumpers say it flares just as well as the 370. However, nothing is set in stone yet.
  18. billbooth
    I didn't mean THAT kind of grass. Honest!
  19. billbooth
    As I pointed out to Derek Thomas, owner of Sunpath. The Super Bowl will not be played on Astroturf this year. To be authentic, they should have used real grass.
  20. billbooth
    Hold it guys. We already settled this issue...25 YEARS AGO. Hand deployed pilot chutes won. Live with it.
  21. billbooth
    The Relative Workshop is now ISO (very different, and much harder than TSO) certified. "I" can't even make any changes without getting permission from at least 3 other people, and then filling out about 10 pages of paperwork.
  22. billbooth
    Good point!
  23. billbooth
    Very simple advice: Take the time to learn how your gear works, and inspect it before every jump. Someday it will save your life. I am always amazed that SCUBA divers spend much more time inspecting their gear than most skydivers do...and total equipment failure in SCUBA usually is not a problem.
  24. billbooth
    Most "stiff" rigs are caused by too much reserve canopy packed in the top of the container.
  25. billbooth
    This is just one of the reasons why it is a bad idea to link the drogue release with the cutaway handle. It always lowers the reliability of the cutaway system. However, metal cutaway housings are not easily crushed. Most packing weights I have seen would not do it.