New Build. Have Questions.

Discussion in 'High Power Rocketry (HPR)' started by Valkyrie, Jul 9, 2017.

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  1. Jul 16, 2017 #61

    noffie79

    noffie79

    noffie79

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    One harness will connect to the Kevlar you attached to your motor mount and will run to your av/bay. The other will connect to the other end of your av/bay, run up through the payload (where your main chute will be) and attach to your nose cone.
     
  2. Jul 17, 2017 #62

    Valkyrie

    Valkyrie

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    I plan on a JL chute release. Was gonna keep the nose and payload bay connected and deplybthe main chute from there ?
     
  3. Jul 17, 2017 #63

    DavidMcCann

    DavidMcCann

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    This is my setup...for DD. 4 foot rocket man chute. No drogue..

    [​IMG]
     
  4. Jul 17, 2017 #64

    DavidMcCann

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    To use a CR, I'd just put one tubular nylon from the kevlar harness to the bottom of the av-bay, about two foot down from the av bay I'd attach the main chute, wrap it in the JLCR, and possible put a drogue in the area... Never flown a JLCR, so I'm guessing here.
     
  5. Jul 17, 2017 #65

    Valkyrie

    Valkyrie

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    Thats was what I was also contemplating.

    How are you making all the connections? Eye loops, overhand knots in the nylon line? I was gonna stitch eye loops in each end of the nylon and use small D rings. Or just slip them through each other. With the 4' chute how is the descent rate? Hard landings?
     
  6. Jul 20, 2017 #66

    Valkyrie

    Valkyrie

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    I want to do ejection tests. Problem is, I don't know how. I plan on using motor ejection as a single deploy set up and a JLCR. How do I rig the BP set up? How to set it off? I have plenty of black powder stuff as shoot and I hunt with a flintlock in the winter.
     
  7. Jul 20, 2017 #67

    DavidMcCann

    DavidMcCann

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    I use overhand knots and quick links.
     
  8. Jul 20, 2017 #68

    Steve Shannon

    Steve Shannon

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    Rig it by putting BP and an electric match in the charge well of an empty case.
    Set it off with a battery and a long two conductor cable connected to the ematch.
     
  9. Jul 20, 2017 #69

    CzTeacherMan

    CzTeacherMan

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    Ditto. I use my old Estes launch controller.
     
  10. Jul 20, 2017 #70

    OverTheTop

    OverTheTop

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    I personally prefer bowline knots if they are on the end of a harness. Good enough for mountain climbing, good enough for rockets :). A cable tie further guarantees that the knot will not untie unexpectedly.
     
  11. Jul 20, 2017 #71

    Steve Shannon

    Steve Shannon

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    Me too, before I built our club launch system. The first time I tried it I forgot that the continuity test passed so much current. A friend got a real surprise when the charge went off. It was plenty.
     
  12. Jul 20, 2017 #72

    CzTeacherMan

    CzTeacherMan

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    LoL! I know what you mean... First time I tested it in my basement with (luckily) just a bare e-match. When it popped, I just about popped myself....
    So, good tip to anyone using the Estes controller for charge testing: be prepared for the charge as soon as you put the key in. Doesn't always set it off, but be ready.
     
  13. Jul 20, 2017 #73

    NateLowrie

    NateLowrie

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    If I was tying knots these days I would agree. All of my harnesses now are kevlar with sewn ends. The sewn ends are much smaller and generally hassle free.
     
  14. Jul 21, 2017 #74

    Valkyrie

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    Ok and would you run the wires out of the bottom of the empty case?
     
  15. Jul 21, 2017 #75

    DavidMcCann

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    Just run it out of the vent in the booster. (Did I mention you should drill a vent in the booster?). Forget what size mine is
     
  16. Jul 21, 2017 #76

    dcullen

    dcullen

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    Actually about 5 years ago the climbing community recognized that the bowline increases the potential for become untied with respect to the figure 8 or retraced figure 8. The additional of a zip tie on the tag end of the rope would mitigate that potential, but increases the complexity.

    For climbers the bowline had been the choice because it is much easier to UNTIE follow shock loading (i.e. a fall). Since I rarely untie shock cords, I switched to a figure 8 mostly because it is more obvious if it is not tied correctly.
     
  17. Jul 21, 2017 #77

    dcullen

    dcullen

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    I've replaced the bulb in my Estes controller with a pinball machine LED bulb, easier to see and passes much less current.
     
  18. Jul 21, 2017 #78

    dcullen

    dcullen

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    Don't be like one of my students who tried to test a deployment charge without a motor casing in the booster. He was puzzled why his rather large charge didn't deploy the chute.
     
  19. Jul 21, 2017 #79

    Valkyrie

    Valkyrie

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    I have a 1/16" static port in the payload section. And I figured I would need something in the booster section also. So what size?
     
  20. Jul 21, 2017 #80

    Steve Shannon

    Steve Shannon

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    There are calculators out there and formulas, but I just do 1/8 inch for nearly everything.
     
  21. Jul 21, 2017 #81

    rharshberger

    rharshberger

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    Static Port or Vent, they are two separate things. Static Ports are used on Av-Bays to allow the altimeter to sample the air pressure and are meant to be of a certain size and usually at least 3 are recommended. Vents are just that, usually a single hole in a payload bay or airframe section to allow the air pressure INSIDE the rocket to escape as the rocket gains altitude rapidly which if not vented can cause the rocket to separate on ascent at either the booster section or nosecone.
     
  22. Jul 23, 2017 #82

    Valkyrie

    Valkyrie

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    I plan on doing the ejection tests soon. Maybe next week. I need a source for E matches? Also I weighted the rocket minus the motor as ready to launch at 1553g.

    Now I need to consider what motor is gonna work best to get an L1 cert.
     
  23. Jul 23, 2017 #83

    djs

    djs

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    Crazy Jim on the forum (blackjack73747373) or whatever the end number is, sells ematches.
     
  24. Jul 24, 2017 #84

    CzTeacherMan

    CzTeacherMan

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    Wildman sells them. He also sells them with an optional cardboard tube attached for ejection charge.
    http://www.wildmanrocketry.com/ShowProducts.aspx?Class=846&Sub=848
     
  25. Jul 25, 2017 #85

    Valkyrie

    Valkyrie

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    so I am trying to do a friction fit for the Bt and payload section. It's very loose but adding just one layer of tape and it will not go.

    Any ideas?
     
  26. Jul 26, 2017 #86

    MikeyDSlagle

    MikeyDSlagle

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    You can use strips of tape on multiple sides of the coupler or just one strip on one side. Run them lengthwise and remove narrow strips until you get the proper fit. I prefer to not use tape but still do on my Wildman Sport, it leaves sticky behind and has to be replaced on occasion; and on paper birds, it peels up part of the material when I remove it.

    OR

    Brush on some sanding sealer and sand smooth - repeat.

    OR

    Do the same with epoxy or epoxy with filler.

    I've used CA glue over sanding sealer before and it made a hard "plastic" layer that I was able to sand to fit. But only did it once, on accident, and haven't tried to repeat the results.

    Mikey D
     
  27. Jul 26, 2017 #87

    mccordmw

    mccordmw

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    I'll +1 this. In my last 3 builds, I've taken to brushing some laminating epoxy on the inside ends of the tubes instead of CA. Mix up a small batch, brush it on the end 2-3" and let it cure overnight. Gives really hard tube ends. However, they do get rough patches that swell up by a fraction of a millimeter which makes them too tight to fit the coupler. A quick, light sanding lets me tune the fit so it's as tight as I want it to be. Doesn't take long.
     
  28. Jul 26, 2017 #88

    MikeyDSlagle

    MikeyDSlagle

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    You can use strips of tape as guides to apply your epoxy as well, if you just wanted to make bands or strips on the coupler, that would help get close the thickness you need as well. Rough it up before you apply epoxy or put you some dimples or grooves.

    Yep. I've done the same except it took over 2 days for my epoxy to cure. Was frustrating, I have had pretty bad luck with laminating epoxy. Had some fillets that never would cure, day three I scraped em off and went back to my thick stuff,
     
  29. Jul 26, 2017 #89

    Valkyrie

    Valkyrie

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    I use CA to build up on my paper tube rockets maybe I'll try it here. I am still considering shear pins. The rocket is almost complete aside from paint. I'm gonna wait until I'm done with ejection tests to paint it. Hopefully I can get the rail buttons mounted this evening and the friction fit dilemma solved. After that she is a functional rocket. Then getting a sponsor to help me cert. and flying this thing!!

    I am considering a gloss candy candy apple red metallic paint. Maybe a gold switch band on the AV bay and call her the Iron Man!
     
  30. Jul 26, 2017 #90

    MikeyDSlagle

    MikeyDSlagle

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    I was thinking this was a paper rocket..I see now it is a fiberglass bird. What sections are you having problems with? I don't understand what you mean by bt and payload. You mean where the upper section connects to the coupler, the upper section to nose cone or lower section to the coupler? I use different methods of connection for all three.
     

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