rocket appropriate for D12-7?

Discussion in 'Low Power Rocketry (LPR)' started by bjphoenix, Nov 30, 2018.

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  1. Nov 30, 2018 #1

    bjphoenix

    bjphoenix

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    I found 3 D12-7 in my stuff and that means I need a new rocket to use them. My D rockets are more like the Estes Executioner, not appropriate for 7 sec. delay. I scanned some older Estes catalogs to find some that should use the D12-7 and found the Hi Flier XL with BT-60 airframe and 31" length. I'm thinking a BT55 airframe rocket would work also but might get that much more altitude and I don't want to lose it and have to build another. BT-60 airframe seems like the best compromise. The Sprint XL might also be appropriate although it doesn't list the D12-7 as a recommended engine. The Hi Flier XL is cheap enough that I wouldn't be too hurt if it punches through the clouds and doesn't come back.
     
  2. Nov 30, 2018 #2

    rharshberger

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    Estes Cherokee-D or the Semroc clone of it sold by Erockets.
     
  3. Nov 30, 2018 #3

    jlabrasca

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    Red Nova?

    https://bellevillehobby.com/product/estes-red-nova-model-rocket/

    The D12-7 was the recommended motor for the original Goblin. Looks like they recommend the D12-5 for the reissue. Wonder what changed to make the difference?

    https://bellevillehobby.com/product/estes-goblin-model-rocket/

    http://www.ninfinger.org/rockets/catalogs/estes75/75est18.html

    EDIT: Looked at the Estes website -- D12-7 is still recommended for the Goblin

    https://www.estesrockets.com/rockets/by-engine/c11-and-d/007236-goblintm
     
    Last edited: Nov 30, 2018
  4. Nov 30, 2018 #4

    MECO

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    I’m thinkin a 3 D12-7 cluster would be the way to go....
     
  5. Nov 30, 2018 #5

    kuririn

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    A recommended engine that has a long delay implies greater altitude, that is inevitable. Might be because it's a smaller, lightweight rocket, like the Goblin, or a two stager like the Extreme 12. By the way, if you launch the Goblin on a small field with a D12, it will go outta sight. Lost mine that way. Use a C11 instead.
    Does it have to be an Estes? Many other manufacturers out there. Here's a cheap two stager that can use a D12-7 for the upper stage, by Custom Rockets:
    http://www.erockets.biz/custom-flying-model-rocket-kit-galaxy-10058/
    Good way to learn about multi-staging. And about half the price of the Estes Extreme 12, and about the same price as the Goblin. But oh, so much fun!
     
  6. Nov 30, 2018 #6

    Rainmaker

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    I fly my Goblin with a D12-7, with as little wind as possible and a shiny metallic streamer about 5' long. Impressive flight Md haven't lost it in 3 attempts.
     
  7. Nov 30, 2018 #7

    kuririn

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    My flight was impressive as well, until the rocket started drifting over some houses and out of sight. How big is your field?
     
  8. Nov 30, 2018 #8

    GlenP

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    Last edited: Nov 30, 2018
  9. Nov 30, 2018 #9

    kuririn

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    And I would add to the aforementioned Semroc Cherokee D and Magnum Hornet, the Semroc Magnum Sprint, if you can find one. They all top out at around 1300' on a D12.
     
  10. Nov 30, 2018 #10

    Rex R

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  11. Nov 30, 2018 #11

    swatkat

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    Lazer Lance and Solar Warrior both do well on a D12-7.
     
  12. Nov 30, 2018 #12

    milehigh

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  13. Nov 30, 2018 #13

    Nytrunner

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    Estes Magician. BT-55, very sleek rocket.
     
  14. Nov 30, 2018 #14

    CoachSteve

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    I vote for the scratch build 2 stage - grab some D12-0s and you will get some altitude for sure and need every bit of that 7 seconds :)
     
  15. Dec 1, 2018 #15

    bjphoenix

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    The local club has a big field but I still prefer to keep them in sight.

    The last rocket I launched out of sight was a BT50 rocket on an aerotech SU F72. It was out of sight once the igniter lit. I don't think it launched, I think it teleported into another dimension. So I prefer to keep them in sight, at least just a tiny little bit.

    And thanks for the suggestions, I'll check them out.

    I have a clone of an Estes Apogee II (without the payload compartment). I haven't had the courage to launch it yet.
     
  16. Dec 1, 2018 #16

    sl98

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  17. Dec 1, 2018 #17

    jlabrasca

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    That's an interesting problem. I guess you need a longish and relatively light-weight rocket? Something that you will be able to see at the altitude from which it will safely recover on a 7 second delay.

    Just because I have an Open Rocket file for the Red Nova

    Screen Shot 2018-11-30 at 9.33.41 PM.png

    At 230 meters a 55cm long rocket would subtend a visual angle of about 0.13° (about 8 arcminutes). Depending upon the conditions, and the health of your eyes, this should be easy to see as it arcs over at apogee.

    With an A8 in the sustainer and a streamer, the Apogee II is a good small-field flier. From where we set up the pads, at our club LPR field, it is between 250 and 300 feet to the trees in pretty much any direction. The only time my Apogee II has gone out of bounds was when I used a Quest A6 in the sustainer. It was along walk to get most of it back (the ejection charge separated the payload section which ricocheted off a utility pole and disappeared into the understory).
     
  18. Dec 1, 2018 #18

    Woody's Workshop

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    Currently contemplating putting out a kit called Katana-D.
    Specifically designed and made for the "Mighty D" engines to maximize performance.
    Does not use TTW fins, but papered w/mounting tabs.
    If you have RocSim (I understand OR can open RS files) I attached the file.
    Over 2150' altitude, and still rising upon deployment on a 7 second delay at almost 20' per second.
    Very simple and easy design for small rocket performance junkies.
     

    Attached Files:

    Last edited: Dec 1, 2018
  19. Dec 1, 2018 #19

    bjphoenix

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    I found my Apogee in the closet recently, I forgot I even had it. It was laying there loaded with B.8 motors.
     
  20. Dec 1, 2018 #20

    kuririn

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