New Year's Day Project: Rocketception

Discussion in 'New project ideas' started by JoergS, Dec 27, 2013.

  1. JoergS

    JoergS Administrator

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    Yepp, the 48 hours of legal fireworks fun in Germany are fast approaching. Last year I exploited them with fire crackers, this year my attention shifts to rockets.

    I want to make a launch tower for fireworks rockets. By law those rockets can not exceed 100 meters, most won't even reach 60 meters. I am thinking with a launch tower of 2 meters height and 60 lb of a draw, I can add 60 or 80 meters easily.

    The idea is to shoot them up when the rocket is just about to begin the acceleration phase through it's fuel charge.

    60 meters "fuel"
    + 80 meters "rubber"
    = 140 meters total height

    So I cock the bands, light the fuse, wait until the sparks begin to sputter, put my foot on the launch pedal and send the igniting rocket skywards! Hopefully my rockets will dominate the town's sky this year.

    Should be cool.
     
  2. slingpit

    slingpit Slingshot addicted

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    So is it possible to see your firework in Hattingen????
     
    Last edited: Dec 27, 2013

  3. JoergS

    JoergS Administrator

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    Depends on the length of your neck!

    There is the "Sauerland" and the "Rhön" between Hattingen and Burgkunstadt, both sizable mountainous formations. Any mutant giraffes in your ancestry? :)
     
  4. slingpit

    slingpit Slingshot addicted

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    Wait,i've a look at my family tree. No mutant giraffes. But i'm sure ,that there is a vid coming up. :-D
     
  5. BeMahoney

    BeMahoney Builder of things

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    Will you give a try at igniting the rocket,
    then shooting it up directly, to let it reach
    those 60 meters and THEN use its own engine
    on the climax?

    (Of course when you know how long it takes to let
    the fuse start the rocket engine, of course)

    Greetings,

    Be
     
  6. JoergS

    JoergS Administrator

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    How could I NOT try to optimize the height? That is half the fun, after all...

    soooo wicked


    hahahahahahahaaaaaa!
     
  7. AngelicScars

    AngelicScars MILF of the board

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  8. Withak

    Withak aka Whitehawk!

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    I used to build and fly model rockets as a young buck. Just last year, I build several for my daughter's school to have some fun with. It never occurred to me to try and give them a slingshot 'boost'. That's a very interesting idea. I'm looking forward to the video.

    On a side note, one of the rockets I built, I painted red with black dots like the colors of a ladybug, then added some nice ladybug stickers and coated it all in poly to keep the finish intact. It flew very well, but my daughter threatened a tantrum if I ever tried to launch that particular rocket again. It is 'special' to her and doesn't want to risk losing it. After I agreed, the next rocket I launched, I put in the most powerful engine I had, and that rocket went way off course during the extended descent - it was recovered, but damaged by the tangled mess of clutter it landed in. The look she gave me told me she was right to not have me launch the ladybug again :)
     
  9. JoergS

    JoergS Administrator

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    You know, in theory it should not make a difference WHEN you pull the trigger on the slingshot part, as long as the rocket is

    a) no longer accelerated by the rubber bands, and
    b) still flying SKYWARDS

    when the powder charged acceleration kicks in.

    Theoretically if the charge ignites just one cm above the muzzle of the launcher, then the rubber based speed will be still very high, say, 60 m/s. The acceleration of the charge will simply start from there (a running start so to speak), reaching a much faster top speed. It will burn out sooner of course.

    If the charge ignites at the peak of the throw, then the speed will be almost zero and the acceleration will start from there. The top speed will remain slower, but the charge will be ignited later and therefore burn out later too.

    Mathematically, if we leave air resistance and so on out of the equation, both strategies should lead to the same maximum height.
     
  10. BeMahoney

    BeMahoney Builder of things

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    How it´s NOT supposed to be (but I like it :) ) :

    [ame]http://www.youtube.com/watch?v=Yi-b1YVql-w[/ame]


    [ame]http://www.youtube.com/watch?v=oASOlN2DO9c[/ame]
     
  11. VWscooby

    VWscooby Senior Member

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    I had number 9 happen to me when using a Skybird bird scaring rocket. Never ran so fast in my life!

    Looking forward to seeing this one. Slingshots and explosives, what a combo!
     
  12. Alukuchen

    Alukuchen Senior Member

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    Sending the rocket skywards with a crossbow and letting it rocket back to the ground would be fun! :D
     
  13. Withak

    Withak aka Whitehawk!

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    My friend lit and knocked over a saturn missile battery one year. When it fell over, it ended up pointing straight at me. They started launching immediately. I think I ran faster than I had run before as well! Perhaps we need to try firing off fireworks at the folks in the Olympics. Maybe they'll set some new records.

    On another note. I have a feeling mixing fireworks with slingshots is going to get me into trouble with my wife. No fireworks that can move more than 6' (2M) along the ground, and definitely none that fly or explode are allowed here - we are highly restricted when it comes to fireworks. I can have all the guns I want, but I can't be trusted with a firecracker or bottle rocket. The thought of launching at least some sparkling balls would be fun. We are allowed crackling balls that are about the size of a .68 cal paint ball. You're giving me bad ideas Joerg, bad ideas.
     
  14. Withak

    Withak aka Whitehawk!

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    On another note, I would think Number 9 would make you Number 2 ;)
     
  15. Flipgun

    Flipgun Well-Known Member

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    I think the speed of the inertial launch is irrelevant, because the impelled speed will be the same. BUT! The inertial launch will elevate the impelled launch point. If the rocket will ascend X from ground level, then it will also ascend X from the higher point generated by the inertial launch and the cumulative altitude will be the sum of the two.
     
  16. Arturo Borquez

    Arturo Borquez Administrator

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  17. JoergS

    JoergS Administrator

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    Why do you think so?

    Don't you believe in running starts in general?

    Keep in mind a rocket accelerates for about four seconds total. It is not a single short thrust, but rather a slow build up of speed.
     
  18. Jeremy

    Jeremy Senior member who totally rocks a pink Scout! Pink

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    Oh how I miss the Sylvester Feurwerken. My two favorite times in Germany, Christmas and New Years.
     
  19. Flipgun

    Flipgun Well-Known Member

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    A running start would will provide the mass an inertial advantage that decreases to zero after a certain point. When the propellent begins to burn, the acceleration will exceed the inertial advantage making the running start
    irrelevant. But when you combine the altitude given by the slingshot with the distance the rocket will travel as it burns, that will be a significant advantage in altitude. Much as if Joerg1 lit his on ground level and Joerg2 lit his on top of a tower. Bullets fired from a flying plane don't move faster than those from a grounded one.

    MythBusters anyone?
     
    Last edited: Dec 28, 2013
  20. BeMahoney

    BeMahoney Builder of things

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    Supposing Jörg´s got a parachute..

    ... I suggest to mount that whole contraption to a let´s say
    red Dodge RAM. ..

    Next stept is plain to see:
    The truck is rubber-launched (even into a low orbit maybe?)
    on the climax, Jörg will then rubber-launch the lit rocket.
    With a little aiming, hitting the moon is easy then! - problem solved!

    ..and of course, Slingpit, me and the others around can watch
    in real time.

    Ain´t that a sweet idea? (it is to me!)

    Be

    (Just fooling around, I´m not drunk. ;) )