darkwing

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Posts posted by darkwing


  1. An appalling length of time and opportunity to fix the problem went by.

    It is interesting for me to reflect on the number of similarly bad decisions that have been made by pilots when I have been in the aircraft. It can be fun if you live through it, although it isn't always. One pilot I said I'd never fly with again, and I didn't. Another I should have told the same thing, but didn't. He's dead now, and took some with him. Nobody was surprised.

    -- Jeff
    My Skydiving History

  2. Only slightly off topic... I think I recall back in the 70s at Pope Valley DZ they had a bunch of mock rigs for the "Aqua Beech". The rigs were just military surplus backpacks. They had a mock door at the edge of the swimming pool for exit practice, especially 10-way.

    -- Jeff
    My Skydiving History

  3. I wish I did. That was some great film. I watched it many times. I'm pretty sure when I saw it it was either BJ's copy or Rande Deluca's. I don't think there were many copies. Possibly only one.

    -- Jeff
    My Skydiving History

  4. I built, from scratch, quite a few canopies, starting in the mid 1970's. That seems close to the design time frame you are in. My initial strategy was to copy an existing canopy. It was a 189 square foot foil, a very under appreciated canopy. It flew great. My teammates liked them too. Building a copy gives you a big advantage when you first jump a canopy you built.

    Later, after I was confident in my construction methods and skills, I started doing my own designs. There are some minor and major tricks to it, some of which have been mentioned above.

    I'll be glad to share with you. PM or email me and we can talk on the phone or Skype.

    -- Jeff
    My Skydiving History

  5. A long time ago I made a canopy with only a single riser on each side. So the slider only had two grommets and was shaped like a pointy ellipse. It was also domed. It worked fine, but I didn't really see any advantage, although maybe these days we could save lives if there weren't front and rear risers to do tricks with.

    -- Jeff
    My Skydiving History

  6. Historically it has often very difficult or impossible to protect the evidence or have qualified people inspect it. There are lots of cases where crucial information has been lost because the police took it, and refused to take advice on handling.

    I suspect these days things are often better, but there are still problems. Perhaps the most likely scenario is at a smaller, isolated dz which hasn't had a fatality before.

    -- Jeff
    My Skydiving History

  7. Back in the 70's in my loft we had a pattern to make a c-9 into a parasail. The D-rings on this pretty much make it look like that is what this one is. Still, it is probably jumpable as a main. If you put steering lines on it.

    -- Jeff
    My Skydiving History

  8. Glass would work, but I wouldn't recommend it for other reasons. When I built canopies I used a sharpie and could very quickly trace around a template made on almost anything that was fairly stiff. Then I would remove the template and cut with the hot knife. I think I had some templates made from tempered masonite (not transparent) and could cut those without tracing.

    I am a little curious why you need transparency? Pretty much any thing transparent is some version of plastic or glass. I don't know anything about high temperature transparent plastics. Part of the issue is how heavy your hand is with the hot knife against the template material. Cutting canopy fabric you can use a very light hand, but cordura and such require a heavier hand.

    Then there is the alternative of using a rotary cutter, much more expensive, but not hot at least. Generally used for stack-cutting. For one-off cutting I think a hot-knifed edge is better though.

    -- Jeff
    My Skydiving History

  9. I have jumped 5, 6, 7, 8, and 9-cell canopies. Some were add-on extensions to smaller canopies, and some were built that way. I seem to recall that I did some work for others that involved adding two cells to 5-cell canopies. It generally worked quite well. It wasn't hard to do, and generally was much cheaper than a new canopy. It could also be un-done if desired.

    -- Jeff
    My Skydiving History

  10. In 50 years your logbooks will be one of your most prized possessions. Not so for your protract.

    Log every jump. Each jump is a story. Tell it. Write down tail numbers from aircraft. Google them a few years later.

    It is very unlikely you will regret writing too much. Very likely you will regret writing too little.

    I have logged every jump since my first one, in 1973.

    -- Jeff
    My Skydiving History

  11. A note on soft opening canopies--ANY canopy can open very hard. I feel confident in saying that there isn't a modern canopy that hasn't hammered someone. I have a few hundred spectre jumps, and one was a crusher. I hung in the saddle a while after opening. After landing I just sat there a while.

    I recommend a Pilot as a solid performer, with very consistent, soft openings.

    Again, no canopy is immune.

    -- Jeff
    My Skydiving History

  12. It would be easy to put a bridle attachment on it. The opening shock might not be comfortable in the long run, but it seems very likely that packing technique and/or a new or modified slider could fix that too.

    I'm sure that PD has a good idea how many jumps it would take to degrade the fabric and the canopy performance. I wonder how many jumps they let their demo reserves get? Someone knows the answer to that. It would be a conservative estimate for the number you could expect.

    -- Jeff
    My Skydiving History