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  1. #1
    Join Date
    27th March 2004
    Posts
    521

    Giant Leap 3" Vertical Assault Motor Estimates

    I am in the process of picking my motors for my L1 and possibly L2 attempt for this kit. It's current in its "naked" stage, awaiting primer and for Mamma to pick the color scheme. One of the ways I got her to let me buy into HPR...

    anyway, does anyone that has THIS or a very similar kit have any motor/altitude estimates to share with me?

    not really wanting to start a "that motor would rock in that rocket" thread here.

    I have rocksim and could model it, but time and time just keep me from getting that done.

    thanks in advance,

    Jerryb


  2. #2
    Join Date
    18th January 2009
    Location
    SW Michigan
    Posts
    3,815

    Re: Giant Leap 3" Vertical Assault Motor Estimates

    The problem I have found with modeling larger rockets like this one is the weight and cg of the finished product. That can vary enough in just the building techniques to make a difference. If you can get a finished weight, balance it and get the dimensions of the fins and structure then it's a snap.

    (Psssst...by the way, if you are going to do all that it only takes another 10 minutes to model it in Rocksim. Don't worry about the materials for fins and the tubes just use the mass/cg over-ride function and it will get you real close.)

    -DAllen

    Dave Brunsting | NAR 85879 | TRA 12369
    L1 - 11/04/07, Three Oaks, MI | L2 - 7/25/09, Muskegon, MI
    Michiana Rocketry
    Notre Dame Rocket Team Mentor

  3. #3
    Join Date
    27th March 2004
    Posts
    521

    Re: Giant Leap 3" Vertical Assault Motor Estimates

    thanks for that idea... I have it close to completion... this kit uses an acme fincan, so I think that i have that component already in Rocksim. Problem comes in the weight of the stuff in the altimeter and the amount of epoxy i've added to the tail of this thing filling those enormouse gaps for the fincan.

    later
    Jerryb



    Quote Originally Posted by DAllen View Post
    The problem I have found with modeling larger rockets like this one is the weight and cg of the finished product. That can vary enough in just the building techniques to make a difference. If you can get a finished weight, balance it and get the dimensions of the fins and structure then it's a snap.

    (Psssst...by the way, if you are going to do all that it only takes another 10 minutes to model it in Rocksim. Don't worry about the materials for fins and the tubes just use the mass/cg over-ride function and it will get you real close.)

    -DAllen

  4. #4
    Join Date
    1st July 2010
    Posts
    537

    Re: Giant Leap 3" Vertical Assault Motor Estimates

    Giant Leap has several estimates on their Vertical Assult page. Mine weighed 7 lbs with motor installed and went to 4900 feet on a J275.

    Jim

  5. #5
    Join Date
    22nd December 2006
    Posts
    93

    Re: Giant Leap 3" Vertical Assault Motor Estimates

    Is your kit the Fiberglass version? I am going to build one and I have it modeled in RockSim. What is your final weight (without motor) and CG? I'm not at home right now but I can run some sims tonight.
    I can tell you that if put a Loki L1400 in it, it will go fast and high
    Matt

    TRA #11142 L2

  6. #6
    Join Date
    27th March 2004
    Posts
    521

    Re: Giant Leap 3" Vertical Assault Motor Estimates

    No, mine is the phenolic version. I didnt have the extra budget for the preglassed one. I've seen others fly, and they do get up there..lol

    can you email me the sim file if you dont mind?

    I'll put all the guts in it and weight it in a bit though. Its not primed, but paint shouldnt add too much at this point maybe an oz or two, not enough to effect the CG.

    thanks
    Jerryb


    Quote Originally Posted by SoCal Mad Matt View Post
    Is your kit the Fiberglass version? I am going to build one and I have it modeled in RockSim. What is your final weight (without motor) and CG? I'm not at home right now but I can run some sims tonight.
    I can tell you that if put a Loki L1400 in it, it will go fast and high

  7. #7
    Join Date
    19th January 2009
    Location
    Perth Western Australia
    Posts
    88

    Re: Giant Leap 3" Vertical Assault Motor Estimates

    I used a GLR FWFG Elipse weighing around 6.5lbs for my L1 & L2 certs using an I357T and a J420R respectively.

    The I357T-10 went to around 1400ft AGL and the J420R-14 went 3033ft AGL

    The elipse is not too disimilar to the GLR VA.
    Why Limit Yourself?

    TRA #11080
    L3

    www.cgngroup.com.au

  8. #8
    Join Date
    7th June 2010
    Location
    Sacramento, CA
    Posts
    28

    Re: Giant Leap 3" Vertical Assault Motor Estimates

    Does anyone have a Rocksim file for Vertical Assault 3? It would sure be a time saver.

    Thanks!

  9. #9
    Join Date
    31st December 2012
    Location
    Martinsburg WV
    Posts
    471

    Re: Giant Leap 3" Vertical Assault Motor Estimates

    IIRC, mine came out at just over 8 lbs fully loaded, got around 3100 feet on an I375GG.


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