Upscale Goblin

Discussion in 'Mid Power Rocketry (MPR)' started by John_461, Oct 14, 2019.

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  1. Oct 14, 2019 #1

    John_461

    John_461

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    With Halloween coming up, I thought it would be the perfect time to build another Goblin or two. But since I can’t leave well enough alone, I upscale mine to a bt-60 air frame, a stock Estes nose cone, and 1/8 ply fins and rings on a 29mm motor mount.

    She’ll get a couple of shakedown flights this weekend on an F23fj and maybe a G77r. Then the fun starts. I’m thinking a G138t is in her future. OR sims it to mach 1.25 and 3800’

    Recovery will be a 16” nylon parachute and a chute release to make sure it comes down in this time zone. 31F49070-A7B6-45C3-ACF1-CB7BB007D804.jpeg
     
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  2. Oct 14, 2019 #2

    Nytrunner

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    What did you do to reinforce the fins?
     
  3. Oct 14, 2019 #3

    John_461

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    They are through the wall. Glued to the motor mount with titebond 2
     
  4. Oct 14, 2019 #4

    Nytrunner

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    They look a little high aspect ratio for that speed, but good luck regardless!
     
  5. Oct 15, 2019 #5

    Arsenal78

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    I wouldn't push it past an F. While the fins will hold, Estes BT60 is quite flimsy and will have a very high chance of crumpling. I would've suggested doing it out of LOC tubing if you wanted to punch it.
     
  6. Oct 15, 2019 #6

    Nytrunner

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    The Star Orbiter has survived quite a few things folks throw at it with a 29mm mount.
     
  7. Oct 15, 2019 #7

    Rainmaker

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    Agreed, I fly my stock Star Orbiter on Gs all the time, and the length would be more of a problem if it was an issue.
     
  8. Oct 15, 2019 #8

    John_461

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    This little guy only weighs 4.9 oz, and only has 5" of body tube that isn't re-enforced by either the motor mount or the nose cone shoulder. Even at 55G's, we're only talking about a maximum 8 pounds of vertical pressure. My only real concern is the shock wave created by the nose cone as it breaks the sound barrier buckling the body tube.
     
  9. Oct 25, 2019 #9

    John_461

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    She flew Saturday on a F23FJ. Nice flight, but it broke the rubber band on my ChuteRelease and it took a while to come down. Luckily there wasn’t any wind and it only landed 200yrds away.

     
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  10. Oct 25, 2019 #10

    Nytrunner

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    I don't think that's likely
     
  11. Oct 25, 2019 #11

    Tyler P

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    I saw your rocket posted on facebook! Looks really nice! A nice flight, too!
     
  12. Oct 26, 2019 #12

    Bruiser

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    Well I missed the boat on having a Goblin built to fly this Halloween but I think I will have to start building one for next Halloween. I think I will do an upscale too maybe with a Pro Series 2" tube and nose cone.

    Anyway, is there a rocket I need to have built for a launch on Christmas?

    BTW, I dig the color scheme. What did you use on the body?

    -Bob
     
  13. Oct 26, 2019 #13

    Rocketjunkie

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    LOC Precision has Goblin kits in 2.6", 4", and 7.5" sizes :)
     
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  14. Oct 26, 2019 #14

    gldknght

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    1/8" ply non-fiberglassed fins going supersonic? I don't think that's going to work. If I was RSO and that came to the table, I'd definitely say "No!"
     
  15. Oct 27, 2019 #15

    John_461

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    I've taken minimum diameter rockets with balsa fins supersonic on a few occasions without issue.
     
  16. Oct 27, 2019 #16

    DAllen

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    2.6???????

    LOL WUT

    I can't find it on their web site.
     
  17. Oct 27, 2019 #17

    John_461

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    North Coast Rocketry has a 2.6" Hobgoblin.
     
  18. Oct 27, 2019 #18

    Rocketjunkie

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    Unfortunately, the Hobgoblin is not a Goblin and neither is the lil Goblin from Madcow. I don't see any current kits between the original and the 4". I expect LOC would kit one up if you called and asked.
     
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