In OpenRocket, how do YOU account for glue and paint?

Discussion in 'Rocketry Electronics and Software' started by Funkworks, Jun 24, 2019.

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  1. Jun 24, 2019 #1

    Funkworks

    Funkworks

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    It seems like I've used over 30 grams of glue in one of my recent builds, and that still leaves out the primer and paint. I see little point in weighing every single part if I have to override all of it with total mass and CG.
     
  2. Jun 24, 2019 #2

    Nytrunner

    Nytrunner

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    If I build a simple rocket that's straightforward, I'll just put the outline in OR and override the mass/cg

    If I'm building my own design or a kit for more performance and want accuracy, I'll input specific component weights, and, at the end, I'll make a Glue/paint/misc mass object to account for the overage and position that to match the built CG.
     
  3. Jun 24, 2019 #3

    neil_w

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    What models are we talking about, what kind of glue, and how much do you use?
     
  4. Jun 24, 2019 #4

    Keisling

    Keisling

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    I just weigh the finished sections (nosecone, booster, payload and ebay) with their recovery gear and electronics and then override the mass (including subcomponents) of each of these sections in OR. That get's me very close on the sims. I mark the CP calculated by OR with a sticker on the rocket and then use that and the actual CG to verify stability is good at the field.
     
  5. Jun 24, 2019 #5

    caveduck

    caveduck

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    I try really hard to avoid mass overrides since they obstruct tracking CG changes when you make part substitutions, and screw up the moments of inertia needed for computing flight trajectory in the wind. Instead I'll usually add a mass object for the main fillets, which can be several ounces in a large HPR model, and another one at the overall CG for paint. I did all this stuff pretty carefully for my L3 and ended up with the actual built mass within 20 grams or so of the OR calculated mass, with no overrides.
     
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  6. Jun 24, 2019 #6

    lakeroadster

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    I'm a glue-a-holic also.... ;)

    What I do is add "mass component's" in any area where there will be glue weight that is unaccounted for.

    We had a discussion about this on one of Neil_W's threads just last week.

    TLR Mass Components.jpg
     
    Last edited: Jun 25, 2019
  7. Jun 25, 2019 #7

    Banzai88

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    Simplest way for everything is to override the mass and cg. That way you're sure that everything is correct.
     

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