Containing a payload.

Discussion in 'Low Power Rocketry (LPR)' started by FlyingMonkey, Nov 3, 2019.

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  1. Nov 3, 2019 #1

    FlyingMonkey

    FlyingMonkey

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    Almost done with my first payload rocket.
    Main tube and fins are modeled after the Bertha. Except I went TTW to a 24mm motor mount. Then strapped on the Apogee boosters.

    Question is regarding the rockets nose cone and how to keep it in place during flight. I know most people use a friction fit on LPR but I sized the payload tube to fit a glow stick. Kinda heavy, so I'm concerned that a friction fit might come apart. Should I use a screw or will a tight fit suffice?
    Not concerned with the aerodynamics of a screw head. Wasn't trying to build for max performance or anything.

    Also... I had intended to attach a kevlar cord to the motor mount but managed to forget when I glued it together a year ago lol. Looking for ideas on how to still accomplish that. One idea was to attach cord to a coupler and shove the coupler down into the rocket. A little late to try the replaceable method I had been using on my other builds. Any recommendations would be great. Thanks!

    Thanks!
     

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  2. Nov 4, 2019 #2

    STEMdad3

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    I can't remember the diameters off the top of my head, but you should have at least 3/16" between the motor tube and the body tube? We had some older Estes rockets that we built before we started using the replaceable kevlar method. I found a 1/8" x 12" long drill bit on Amazon for a few bucks, believe they are called aircraft bits or something like that. Turning the bit BY HAND and parallel with the body tube, we carefully drilled up through the centering rings on the motor mount, inserted a coffee stirrer cut to length, and held it in with a dot of epoxy on the back centering ring. We could run our replaceable kevlar through the coffee stirrer and loop it around the back end of the motor tube. Not as pretty as adding it during the build process, but it worked really well.
     
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  3. Nov 4, 2019 #3

    Rex R

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    I would suggest a 2-56 machine screw through the tube into the nose cone shoulder.
    Rex
     
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  4. Nov 4, 2019 #4

    FlyingMonkey

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    I guess I could still try that. I have the drill bit. In my mind I was worried about not gluing the other side of the tube but that really shouldn't be a problem.
     
  5. Nov 4, 2019 #5

    FlyingMonkey

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    Thank you!
     
  6. Nov 4, 2019 #6

    David Schwantz

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    This is in an 18mm tube. I mounted a small piece of ply with a slot against the tube side. Kevlar will go through the slot. Use a piece of music wire to pull it through and you can either tie a loop and run it back through itself or pull it all the way through mmt and tie a big knot that will not pull through. this way it is secured and still removable.
     

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  7. Nov 5, 2019 #7

    BABAR

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    If you don't want to use screws.....

    Sinlge a piece of cellphane tape around forward (nose cone) end of the payload section.

    Same thing at the base end of the nose cone.

    This supplies a "backing" so later piece of tape don't pull of your paint.

    Put the rocket together, put a single layer of type overlapping the nose cone/payload joint.

    For everything but heaviest payloads, this should be enough for each flight. You can easily remove the outer layer of tape, leaving the underlying layer for the next launch.

    Caveat, the tape will break down under UV light over time, but should last a while.
     
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  8. Nov 9, 2019 at 7:21 PM #8

    FlyingMonkey

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    Another great idea! Thank you!



    I did manage to drill and install a tube for my replaceable kevlar cord. I tend to over think things lol
     

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