found a real super loki dart for sale.

Discussion in 'The Watering Hole' started by Zetoyoc, Mar 30, 2012.

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  1. Mar 30, 2012 #1

    Zetoyoc

    Zetoyoc

    Zetoyoc

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  2. Mar 30, 2012 #2

    MClark

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    I paid $50 for a Loki with the dart at a antique store in Phoenix. 600 is a crazy price.
    That one was static fired, had it benn launch it would be destroyed.

    Mark
     
  3. Mar 30, 2012 #3

    tfish

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    I have a spent(?) one in my shop. It has the forward closer cut off.

    Tony
     
  4. Mar 30, 2012 #4

    J Blatz

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    Tony-

    Yeah. Karl B has one too, I believe with the fwd closure still on. Of course these days he gets enough rocket at work to keep him busy I suppose.

    The one you have was a static fire...when AT had the contract the customer required that a couple out of each batch be static fired. That motor is just vicious - there is very little margin between it's actual performance envelope and the maximum strength of the case. Also, being case-bonded with a cast-in-place rubber "liner" the case gets extremely hot - the cases would glow cherry red at the nozzle end after firing.

    What would really be cool is to have the motor and the dart:D.

    Also, just remembered, that Karl's and yours are actually Viper 3A's.

    Jason
     
  5. Mar 30, 2012 #5

    tfish

    tfish

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    Jason, I was thinking of you when I was posting my reply. Now I now the history to it.

    [​IMG]

    Let me know the next time you'll be at BR. I never found the owner of that rocket you found a couple years back. The only good thing left to it was the 54/2560 case. I need to get it to you.

    Tony
     
  6. Mar 30, 2012 #6

    J Blatz

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    Will do Tony. Plan on coming out and flying a lot this year. Might even do some hybrids and get my L2 yet again. That 54/2560 would be nice for that...
     
  7. Mar 30, 2012 #7

    New Ocean

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    The O 25,000 would work as a decent simulation of this rocket.
     
  8. Mar 30, 2012 #8

    skybuster

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    Don't mean to sound like a complete moron here, but I've gotta ask. Were there metal parts on that? I thought you weren't allowed to build with metal components, or am I completely missing something here?
     
  9. Mar 30, 2012 #9

    chadrog

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    Lots of metal - These are actual research rockets, not hobby rockets.
     
  10. Mar 31, 2012 #10

    JStitz

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    I remember Mike Dunkle (APS..:duck:) Was firing these for NASA in Michigan on the Lake shore.
    I Don't remember if the breach launcher was permanently mounted there or not.
     
  11. Mar 31, 2012 #11

    New Ocean

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    Depending on when and what you fly, you can have some metal parts. Fins, motor case, retainers, hardware internal, nosecone tips... hpr has come to include lots of metal. That is logical because metal parts may prevent catastrophic failures, and is hardly more dangerous than fiberglass at 300 mph.

    Professional rockets like this are basically motors with fins attached. That is how you get good performance, and part of the reason why our rockets never go nearly as high given the same impulse.
     
  12. Mar 31, 2012 #12

    MClark

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    I think I have some forward closures, I will see if they are 4 or 5".
    The one in the pic is a S. Loki. The fins on a V3A are steel inserts.
    Mark
     
  13. Mar 31, 2012 #13

    tfish

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    Mark, The ID 3.834...you gonna make me fly this thing?

    Tony
     
  14. Mar 31, 2012 #14

    MClark

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    I have the casting tooling!

    Mark
     
  15. Mar 31, 2012 #15

    J Blatz

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    I defer to Mr. Clark. Maybe my memory has gotten a little fuzzy:D.

    Could be the endless loads of horse droppings I endure daily while selling cars to morons and dealing with co-workers of similar mental capacity has dulled my edge a little.

    Back on topic - Could it be reloaded? Maybe. Would it ka-boom? Maybe. I do not know how severely the temper of the aluminum is affected by the extreme heat of the original burn. But I will say this - I don't know any EX guys who would knowingly build a motor with the types of design parameters that this motor runs through...most everyone tries to stay well under 1K PSI. So maybe this case would be OK for that level of pressure.
     
  16. Mar 31, 2012 #16

    GDJ

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    Not a moronic question at all.

    Some clubs (like mine) will allow metal parts IF THEY CAN BE JUSTIFIED and using the metal parts are necessary for a safe launch and recovery, and some rockets that break the sound barrier do contain metal parts so they can be launched safely and recover safely (ie no core samples/lawn darts).
     
  17. Mar 31, 2012 #17

    MClark

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    I think the case is shot. The temper is gone. It is 2024 and in a soft condition it would pop at a really low pressure.
    You may be able to save the nozzle parts but it would be easier to just make new and know it would be OK.
    On that note the original Lokis when first produced the cases were made on a drill press. The ends are held in with roll pins, the ends of the tube were just as cut out of the bandsaw. So a big long lathe would not be required.

    Mark
     
  18. Jan 23, 2013 #18

    JDcluster

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  19. Apr 18, 2017 #19

    JackO

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    Did some digging... they were lucky enough to use a 2014 t6 aluminum, so they ran it at 1530 psi with a .083" wall, surprisingly decent safety ratio with a bursting pressure of 2900 psi. Assuming the burn (pretty certain) dropped the temper back down to T0 and that the lowest 2014 aluminum tensile strength I can find describes T0, your case has a bursting pressure of 1160 psi.

    So hypothetically, it's reusable, but 1160 psi isn't 1160 psi when the case gets warm. The nozzle is graphite with a steel retaining ring, so it's likely still in good shape if not slightly eroded. Unfortunately, that booster is not stable without the dart atop it so it will need some modifications.

    Here's some light reading: http://www.dtic.mil/dtic/tr/fulltext/u2/750796.pdf

    -Jack
     

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