Revision to Tripoli Rule Regarding Wireless Remote Switches

Discussion in 'Rocketry Electronics and Software' started by Steve Shannon, Feb 4, 2020.

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  1. Feb 13, 2020 #721

    Charles_McG

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    Due to the nature of the drivers, the Proton shows all channels have continuity when the deployment power is disconnected.
     
  2. Feb 13, 2020 #722

    Nytrunner

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    If I recall one of the previous pages correctly, it wasn't Steve and the BoD's intention to make folks disassemble and prove they had a mechanical separation at the RSO desk (which turns every electronic flight into a cert inspection and increases time substantially), it was a safety ruling for folks to adhere to on their own. If the flier was to intentionally disregard that and "sneak one through", that's shameful and on them entirely.

    Making every electronic flight disassemble the bay for inspection for rule compliance almost sounds like protest via malicious compliance.

    And I'm surprised I haven't seen any risk analysis squares floating around yet!

    upload_2020-2-13_10-7-23.png
     
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  3. Feb 13, 2020 #723

    cerving

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  4. Feb 13, 2020 #724

    jbr

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    in the case of having switches to disable ejection charges whether it be disabling the power circuit or disabling the ejection charges themselves, I would request a roaming rso visit while I was assembling the ebay to get a prior rso approval

    the rso does not have time or resources to xray the rocket to trust that the switches do inhibit the charges
    the switches may connect to something else like gps or other devices

    the current ruling has turned me into a hardass requiring proof

    I can physically verify cp and cg, I have asked some flyers to pull the nosecone and show me the chute

    better to be a hardass than have a dangerous rocket
     
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  5. Feb 13, 2020 #725

    warnerr

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    If only tripoli had simply required that altimeters controlling any pyrogens be unpowered until on the pad rather than telling us how to do it this whole mess could have been avoided.
     
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  6. Feb 13, 2020 #726

    Charles_McG

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    I think they did. And that a number of us objected to their definition of unpowered.
     
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  7. Feb 13, 2020 #727

    jbr

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    I will remind the BOD that there have been cases of TAP and or L3 being revoked for a mentor/RSO that allowed dangerous practices to take place
    since this was because they apparently were not enough of a badass, I will continue to be a badass rso and not allow things that I view as non safe to happen
     
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  8. Feb 13, 2020 #728

    jbr

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    in a lawsuit if one happens they will sue TRA, the club, the RSO, and any others they feel are responsible

    I will stay being a badass hardass RSO to prevent law suites
     
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  9. Feb 13, 2020 #729

    Charles_McG

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    RSO is a thankless job. But not one in a vacuum. I think if an RSO were irrationally tough, their club would find other ways for them to contribute.
    So let us thank our RSOs, and our clubs.
     
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  10. Feb 13, 2020 #730

    FredA

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    Easy to say - hard to do.
    Unless they watched the rocket being assembled and/or know the intimate details of the build, an RSO needs to ask the right questions and then be able to trust the flier's answers to be accurate and truthful.
    How else do you do the job?
     
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  11. Feb 13, 2020 #731

    Speaknoevil

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    OK, I have to say something here as I feel this is going overboard. How about another suggestion?

    Today at many large launches the high-power flight cards have a line stating deployment type and a line/checkbox for tracking, where you check yes-no and jot down the tracker, maybe even the frequency. In addition, they often have a line for "electronics." In that case, it takes just a few more seconds to write down the name of the altimeter(s). Given that, why not at that same time require that the flyer disclose when/if they are using an electronic switch where they can state the name/brand and have a checkbox that says, "Are all electronics mechanically disconnected from power?; If NO, are all deployment charges mechanically disconnected?" The flyer then explicitly states that they have both considered and comply with that element of safety. And, as a flyer signing that flight card, it makes you well aware of your ultimate responsibility before leaving your pop-up to go to the RSO table. Another side benefit is that it may be another small step in Tripoli having an audit trail for flights just in case an insurance claim ever arises.
     
  12. Feb 13, 2020 #732

    Charles_McG

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    Attempting to ‘like’ more than once.
     
  13. Feb 13, 2020 #733

    Steve Shannon

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    That’s very good.

    We don’t want an atmosphere of distrust to pervade the rocket inspection process. Unfortunately, to John’s point there may be one or two who decide they’re not going to follow the rules. In every case the flyer is ultimately responsible for following the rules and flying safely. In those very few instances where the rocket inspector has good reason to suspect they’re being lied to they shouldn’t allow that rocket to fly. Usually a few calm questions can clear up any worries.
     
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  14. Feb 13, 2020 #734

    Speaknoevil

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    True, always potential for rebels and rule breakers, but as an RSO, I'd much rather review the flight card and seeing that is complete, then ask, "Where's your mechanical disconnect?" or, "How do you access your charge cutoff switch?"; then only reserving the "Unscrew those wing nuts on that bulkhead so I can see your battery wiring" to outliers.
     
  15. Feb 13, 2020 #735

    Steve Shannon

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    I completely agree!
     
  16. Feb 13, 2020 #736

    mikec

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    The fewer the rules, and the clearer and more well-motivated the rules are, the more likely people are to follow them.

    I'm a little disheartened by the zeal some people are expressing for adding new rules, new cert levels, more checkboxes, etc, to solve a safety problem I didn't think we had.

    I fly rockets for fun. I have a demonstrated track record for flying complex projects safely within the current system. I get more than enough rules and reviews in my day job in aerospace. IMHO we don't need more.
     
  17. Feb 13, 2020 #737

    cerving

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    Maybe all of this will lead to a TRA review of current launch safety procedures, in light of some technology changes (wireless/electronic switches, wireless launch systems, wireless altimeters,altimeters with wireless connections to the deployments, etc.) that weren't there the last time that it was done. That's gotta be a good thing.
     
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  18. Feb 13, 2020 #738

    jbr

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    seems like it would be good to have some standard flight cards to use
    with the standard questions on all of them, clubs can add any extra things they want
    I have seen many colors, sizes, different info asked, etc

    colors are a good issue and may be used to distinguish mod rocks from high power from research, etc

    the flight cards seem to need a lot more questions lately and some I have not seen space enough to put all the items in the rocket
     
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  19. Feb 13, 2020 #739

    Dugway

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    I've got to get better at drilling delays, it looks like I'll be flying a lot more motor ejection only flights!
     
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  20. Feb 13, 2020 #740

    Jmhepworth

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    I suppose it might be wise to take a picture of the wiring so I can provide some evidence that the switch is on the deployment side.
     
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  21. Feb 13, 2020 #741

    Steve Shannon

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    A block diagram should be more than sufficient.
    See you in a few months!
     
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  22. Feb 14, 2020 #742

    David Schwantz

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    So has this rule made pull pin switches illegal?? There is that one moment that the pin is pulled while you are assembling your AVbay. BP charges are in place and wired and you are installing the sled into coupler, tightening wing nuts on the rods and then you can install the pin into switch. But before this there is NO physical disconnet to the BP charges. So, now is a switch required that you can access through the switch band that is always "off" until after assembly?
     
  23. Feb 14, 2020 #743

    Steve Shannon

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    No, it has not. Put a terminal strip on your bulkplate and connect your charges after the avbay is assembled and your pull-pin is inserted.
    There’s never a good reason to take unnecessary chances.
     
  24. Feb 14, 2020 #744

    David Schwantz

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    On my larger stuff I do use terminals. But not a lot of room on a 24 mm bulkhead. What are other choices for small air frames ? On my first DD rocket, at the time I thought I went overboard and installed a rotary switch in front of the pull pin switches. This way I could isolate the batteries from the alt's, assemble everything, install the pin and then arm the rotary switch. Now I wish I would have built that on them all. Might just have to redo them.
     
  25. Feb 14, 2020 #745

    cerving

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    I don't use terminal blocks on the bulkplates... I just run a wire directly from the altimeter through a hole in the bulkplate, then twist-and-tape the igniter to it. Seal the hole with some putty and it's all good.
     
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  26. Feb 14, 2020 #746

    David Schwantz

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    I have never used twist and tape. But I assume that this will now need to be done after RSO insp and at the pad, or the approved area. So will the rocket now be presented to the RSO disassembled? I have one with a screw switch for a NC AVbay, it has a Quark in it. The RSO always dislikes when I approach with my NC off so I can arm the switch at the pad.
     
  27. Feb 14, 2020 #747

    g.pitts

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    Thank you for the pointer. Ordered from Mouser (only vendor I saw with stock for the config I wanted). These will be for an L3 project... once I get past L2. :D

    <edit> I checked Octopart and there are other vendors showing stock at the time of this post. </edit>
     
    Last edited: Feb 14, 2020
  28. Feb 14, 2020 #748

    g.pitts

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    ^ THIS is what Tripoli should be looking at, IMHO. There should be standardization around which combinations of probability and impact require mitigations to be put into place in the design, but that's a working group matter.
     
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  29. Feb 14, 2020 #749

    John Williams

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    Might I suggest that the board sit down with the vendors and some electronics engineers and have a through and well informed discussion about how the wireless products work , eggtimer, featherweight ect., And the reliability of those products versus the mechanical means and determine what if any is the extra risk of using these products and then make necessary changes by means of either additional certification or other options
     
    Last edited: Feb 14, 2020
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  30. Feb 14, 2020 #750

    g.pitts

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    Kelly, I personally have never seen a genuine JST connector that could be reversed without a lot of "persuasion" (wherein the user should think to him/herself, "hmmm this doesn't seem right"). Take a good close look at the connector you're referring to and see if there's a JST logo on it.

    Genuine JST connector on battery connectors is in the area circled (snippet from a black and white photo from JST product collateral):

    JST - Genuine.png

    Certain battery cables such as the ones in the photo above that I have purchased on Amazon and eBay lack the JST brand mark, so clearly there are a lot of knock-offs out there. All that said, wiring best practices (and hopefully common sense) would tell someone to wire both conductors of a two-pin connector system with the different color wire on each conductor of one end and matching colors on the mating end so as to provide a visual cue of how the connectors should properly align.
     

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