Penguin 1: Supersonic Ice Cream Sandwich (Build Thread)

Discussion in 'High Power Rocketry (HPR)' started by Nodroc, Jan 21, 2020.

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  1. Feb 20, 2020 #31

    Nytrunner

    Nytrunner

    Nytrunner

    Master of Rivets

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    Ah! That's simpler, but time consuming. A rough paint job will still get pushed past Mach. But it sounds like you want every ft/s you can get.

    The trick is surface preparation. If you can feel it, you'll see it when painted. Sanding starts at 220, prime, fill indents/divots/scratches/pinholes (bondo spot and glazing putty, the red stuff not the 2 part), sand ~320 or 400 grit now, repeat till smooth. When primed surface is as flat as you're willing to get it, paint. Follow the instructions to the letter as far as recoat times and environmental conditions. Spray cans or airbrush is up to your skill/resources. When fully cured, wetsand increasing grits 600, 1000, 2000. Some folks use a polishing compound at this stage.
     
  2. Feb 21, 2020 #32

    Pariah Zero

    Pariah Zero

    Pariah Zero

    Gravity’s Plaything TRF Supporter

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    For super sharp taped lines, get some fine line tape (used for auto paint). Great stuff.

    One trick (though a bit thicker & heavier): spray a light coat of clear over the masking tape between colors. Read the directions, make sure the clear works with the color. The clear will seep into any cracks/crevices in the mask you missed, and when you remove the masking, the lines will be sharp.

    You could also use a clear coat when all finished - the process is similar to prime/sand cycles, but with clear coat. Shoot clear, sand it flatter (but not into the color), shoot more clear, sand... That way you aren’t cutting into the paint as you sand over masked lines. The trick there: is the extra smoothness of the clear worth extra weight? Your call.

    Unless you intend to pay a pro to spray clearcoat, stay away from automotive “2k” clear. That stuff is pure poison in liquid/spray form. Pros have the safety gear. It’s expensive.
     
  3. Feb 29, 2020 #33

    Nodroc

    Nodroc

    Nodroc

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    Again, I appreciate all the advice!

    Today's update involves some renderings of the GoPro securement system I've got going on for the AV bay.

    As I had said before, I wanted to develop a system such that I didn't need to take the rocket apart to put in my GoPro Hero5 Session.
    GoPro AV Cross Section.JPG

    Here we can see generally how this system will work. With cuts in the coupler and switchband, the GoPro will be inserted into the housing attached to the AV sled. Once the camera is inserted, a cap is placed on top of the GoPro face and screwed in (screw holes have not as of yet been included in the model but will be in each corner).

    GoPro AV Half Fillet.JPG

    Here you can see the cap that will be placed to hold the GoPro in place. My initial design of the cap only had fillets trailing up to the top and down to the bottom. As I thought about the design however, I imagined there would likely be better airflow if the entirety of the cap were filleted. So, accordingly, I added fillets around the entire region as seen below.

    GoPro AV Full Fillet.JPG

    I'm curious as to what this will do to the aerodynamics of the rocket. Am I correct in saying the last design would better? Would it be beneficial to create a dummy cap to place on the other side of the coupler for more even air flow? Let me know your thoughts!
     
    FlyBy01 likes this.

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