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  1. Oct 4, 2017 #21

    Twodeaddogs

    Twodeaddogs

    Twodeaddogs

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    Sometimes, manufacturers of the same aircraft did not help themselves or the maintainers; The Air Force I was in had Alouettes, Gazelles and Dauphin Helicopters and there were a few cross-compatible parts but some of those had different part numbers. The Gazelle manual even came with a list of French car part numbers for such things as door handles (Renault Five). Metric aircraft bolt numbering would melt your head compared to AN/NAS/MS hardware.
     
  2. Oct 4, 2017 #22

    ScaleBirdsScott

    ScaleBirdsScott

    ScaleBirdsScott

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    My simple system for design just breaks the aircraft into major systems, which mostly comes in handy for CAD workflows I use.

    Every aircraft gets a prefix code, such as "SB6F" or "SB36" and then is divided into the major system categories.

    From memory it looks about like this:

    100: General arrangements
    200: Fuselage
    300: Wing
    400: Empennage
    500: Controls
    600: Cockpit
    700: Powerplant
    800: Landing Gear
    900: Instruments and Misc Systems

    Then, generally I'll develop those X00 codes into 3-digit sub-assys, and do a 2-3 digit actual part number. So my assembled sliding canopy assy may be SB36-605

    A bracket in the downlink sub-assy of the Hellcat landing gear might be SB6F-804-06

    A rib in the standard outboard wing that is cross-aircraft compatible might be CP-308-212 (in this case it might be that I gave all ribs forward of the spar a 1xx number and all aft of main spar 2xx, so that they stay consistent per rib 'station'.)

    Of course the way I model a lot of airstructure is with master modeling, so the wing structure, from spars to ribs, might just be one mega file, which means I'm not even really naming individual part files for much of that. So the wing structure model might just be CP-801.

    I don't bother spending time trying to define what a part is via the codes, thus a bent bracket, bolt, rib, bulkhead, engine mount weldment, fiberglass fairing, all treated equally under this system. For now I don't see a major need to get that crazy with it. My main concern is looking at a number and knowing where the part belongs. Looking at the other part info will tell me what it actually is.

    Then in the actual general arrangement folder will be the master aircraft, sometimes sequenced into different configurations (such as trigear vs dragger, 5 vs 7 cylinder, etc) And then if I need sub-arrangements like a non-specific complete assy that has all common assemblies loaded and then is the base for the specific configs, I'll do that. So that might be SB36-101/103/106 etc.

    I have separate libraries and number systems for purchase parts. Hardware gets whatever code the vendor uses and gets put into that vendor's subfolder. Plenty of random McMaster or AN numbers.

    It works good for design when you're just trying to throw numbers down and a part may change from one to another. If a part ends up becoming used in more than one or two designs then it gets moved to the common parts directory, and if I scrap a design idea those assemblies are (supposed) to go into an 'old' subfolder to keep clutter down in the directories; or if it's a bunch of stuff that's definitely not being used it goes into the archive graveyard.
     
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  3. Dec 2, 2018 #23

    Atomic_Sheep

    Atomic_Sheep

    Atomic_Sheep

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    A little over a year ago I asked this question and to this day I still don't have this issue sorted. I have been thinking about it on and off and have made some progress in my understanding of the issue. I now have a better understanding of what you guys were talking about. At the time of your responses I was completely on a different page and all I was reading was chingrish to me. Principally I finally have a decent understanding about what ATA is all about although I'm by no means an expert on part numbering systems in general.

    I'm now contemplating what my best course of action is i.e. to follow ATA which would mean completely re-organising my files pretty much from scratch and re-build everything in CAD (Close to 1000 parts), or to go with my current folder structure with some minor amendments. My current folder structure works as follows:

    1. External
    1.1 Fuselage
    1.1.1 Fuselage
    (Then parts are named like "Rib")
    1.1.3 Antennas
    1.1.4 Doors
    1.2 Landing Gear
    (Then parts named like "Drag Brace", "Lever")
    ...

    2. Internal
    2.1 MIP
    2.1.1 Audio Select Panel
    (Parts that make up the Audio Select Panel named like "Audio Select Aluminium Backplate" etc)
    2.1.2 Altimeter
    2.2 Centre Console

    etc etc

    Presently the problem I'm facing is when I roll everything up into the final assembly I have duplicate files (not many so far, I've got 6 or so parts that clash), so to me it seems stupid to completely overhaul my structure to comply with ATA. The reason why they clash is obvious, nowhere in the file name do I have any mention of which higher assembly they are part of so if I have two Axles one for a landing gear and one for a control column, I'll get a clash, which is what I'm seeing. The simple solution is to rename the clashing parts with the assembly they belong to and be done with it. My naming scheme works on the principle of no two duplicate files per Windows Explorer folder (+relatively short and human readable file names) but that obviously doesn't guarantee no two identical file names overall.

    I can see the merit of organising everything by system as per ATA - the principal advantage would be compatibility with documentation which describes aircraft systems not my way of organising everything by location, but at the same time I don't see the merit of switching from what I have given the amount of work necessary. If you were me, what would you do?
     
    Last edited: Dec 2, 2018
  4. Dec 2, 2018 #24

    Aesquire

    Aesquire

    Aesquire

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    Do it your own way. Whatever logic appeals to you. Most government systems evolved for a different reason than you'd think over decades.

    Later, at leisure, feel free to change everything and anything you want to a common logic system. Or not.

    The trick seems to be to not reinvent the wheel, unless that is your goal.

    Bolts and other fasteners, where possible, use AN or other common nomenclature. Add a cheat sheet to simplify as a means to help, mostly yourself, and part/section breakdowns, again, to crosscheck yourself.

    Simple lists. Example, Rudder assembly. (6) AN4-12, (3) AN4-17 and So forth. A copy of the AN bolt spec sheet is part of the plan set. Ditto washers, nuts, etc. Cross reference to your made up part numbers.

    The trick is to document everything so you aren't confused, no matter how weird it gets and later, when it's all done, you can systematically impose order on the chaos any way you want.

    If 1939 Focke Wulf logic fits your needs, use it. NASA shuttle logic? Whatever.

    Then hand it to a reasonably smart friend and have them see if it's understandable.
     
  5. Dec 4, 2018 #25

    Atomic_Sheep

    Atomic_Sheep

    Atomic_Sheep

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    I think I'm going to stick with my way of doing it at least for now. Thanks everyone for the info :).
     
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  6. Dec 26, 2018 #26

    Jimstix

    Jimstix

    Jimstix

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    All the work has been done for you in the link listed in Mad MAC’s post #15.
    This is a detailed Work Breakdown System (WBS) that could be used in a commercial or military environment.
    However, here is one that I have used and is easy. The example here is for a wing rib part located on the forward face of the main spar. I will need one (or more) of these nose ribs on the left-hand wing and will need a mirror image part on the right-hand wing assemblies. The naming of the part is “What, Where, LH side implied, OPP if required”

    Traditionally, detail part numbering starts with -7 (odd) and -8 (even), each dash numbered part is shown in the BOM (Bill of Materials) in the lower right-hand side of the drawing. Also listed should be the material specification and heat treat condition (if applicable) and the next assembly drawing number. Each hyphen in the part number is spoken as “dash”.

    Example: Part Number 4-2-700-7/-8 OPP, Rib, Forward, LH Side

    First number is the aircraft model number, e.g., 4th model = 4
    Group number (Top assembly =1, wing =2, fuselage = 3, tail group = 4, power plant = 5, etc.)
    Assembly number = 700 (major assembly LH Side, in this case of the wing structure, -800 Assembly RH Side)
    Detail Parts: Left-hand side part -7, with the matching part on the right-hand side -8
     
  7. Dec 26, 2018 #27

    Jimstix

    Jimstix

    Jimstix

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    Correction : WBS is Work Breakdown Structure - not system

    Jim
     

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