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  1. #1
    Join Date
    16th November 2012
    Location
    Michigan
    Posts
    190

    Newbie Question, How fast is too fast for a HPR?

    Hello Everyone,

    My question for the day is "How fast is too fast for a cardboard rocket with a plastic nosecone?"

    A few days ago I was running openrocket on my Big Nuke and I was curious, How big of a 54mm motor can I put in this rocket?
    Questions isn't how big of a 54mm load I can afford, but how big of a motor can a cardboard rocket handle before it shreds in mid air.

    I put in the sim a K1440 and a warning came up,
    "body calculations may not be entirely accurate at supersonic speeds"

    After thinking about how cool it would be to send my 9 pound rocket to 6000ft at Mach 1.31 at top speed, "would it shred?" came to my mind.

    So many my question shouldn't be How fast is too fast, but How fast can you go before it shreds in to many pieces.

    Your thoughts are welcome.. horror story are welcome as well.

    ~Russ N8RSH
    Team H3 Rocketry
    NAR 94760 L3

  2. #2
    troj's Avatar
    troj is offline Wielder Of the Skillet Of Harsh Discipline, Potentate of Perilous Pans TRF_ADMIN.png
    Join Date
    19th January 2009
    Location
    In a house
    Posts
    14,290
    The answer is...."it depends"

    Construction makes a significant difference. It also makes a difference if you've reinforced the airframe in any way.

    -Kevin


  3. #3
    Join Date
    23rd February 2009
    Location
    Northern NJ
    Posts
    4,958
    Loc 5.38" tubing can handle an M.
    I'd be more concern about fin attachment; thickness, vent hole size, and shear pins.
    My 4" x 78" tall 13 lb rocket just missed mach on an EX K 943.
    It did 6,200 ft.


    JD
    2016:
    NS: 12,571.6
    Flights: 10
    Motors: 17
    EX: 8
    Comm: 9
    ---------------------------
    2015: 32,195 Ns
    F: 38, M: 44
    ----------------------------
    TRA: 04486 L3
    METRA VP
    MDRA
    URRG

  4. #4
    Join Date
    26th August 2012
    Location
    Colorado Springs, Co
    Posts
    933
    The aspire can handle mach on a g77 (supposedly havnt tried my self yet)... and its a 29mm cardboard mindi with plastic nose... so i have to agree with troj... it depends...
    What goes up must come down... On top of school. :/

    My Fleet
    Patriot / 24mm Patriot / Ventris / Leviathan / Riptide / Baby Bertha / Vagabond / MoonDance / EPM-010 / QCC Explorer / Prospector / Magician / Mini Max / Mini Honest John / Hornet / Quark / TR-1027 / MINDI P MAN- 527 / Mini P-527 / V2 / Ambisagrus / AS1 Escort / Fenian Rising / Argent / Hi-Flier XL / Black Star Voyager / Aspire / Return to Flight Shuttle / Saturn V

    Current Build


  5. #5
    Join Date
    19th January 2009
    Location
    San Diego, CA
    Posts
    2,624
    An unpainted plastic AeroTech nose cone has been flown on a rocket which exceeded Mach 2.
    Bob

  6. #6
    Join Date
    17th September 2010
    Location
    Los Angeles, California
    Posts
    2,118
    Round abouts mach 3.5 or mach 4 on the high end?
    TRA #13945
    Level 1: 06/10/11 Level 2: 10/08/11 Level 3: 11/9/13
    Mega Squat 11.5" Squat

  7. #7
    Join Date
    9th April 2011
    Location
    Plano, TX
    Posts
    2,562
    My Nuke Pro did mach 1.3 with no issues with the plastic nosecone and no fiberglass anything.
    Jarrett Dorough

    Most people are average

  8. #8
    Join Date
    18th October 2011
    Location
    Washington State
    Posts
    324
    Q; My question for the day is "How fast is too fast for a cardboard rocket with a plastic nosecone?"

    A: c + 1

  9. #9
    Join Date
    6th June 2011
    Location
    San Diego. CA.
    Posts
    6,434
    Quote Originally Posted by DavidQ View Post
    Q; My question for the day is "How fast is too fast for a cardboard rocket with a plastic nosecone?"

    A: c + 1
    Or it teleports back from the future already built on your workbench...next to the kit. Thus destabilizing the World Event Timeline as we know it and from that all of Humanity and our decendents on other planets. A good wormhole can make such a bad day. Instead,a small donation to the World Domination Machine to help convert 97.89% of the known population into rocketeers is better. Or just keep it below c...
    TRA 2383
    Somebody told me I was on the watch list-I hope I get a Rolex.....
    The road to Hell is paved....you're welcome.
    I can't remember the last rocket I built, because I haven't built it yet.....

  10. #10
    Join Date
    10th February 2010
    Location
    Southern N.H.
    Posts
    3,885
    Quote Originally Posted by fyrwrxz View Post
    Or it teleports back from the future already built on your workbench...next to the kit. Thus destabilizing the World Event Timeline as we know it and from that all of Humanity and our decendents on other planets. A good wormhole can make such a bad day. Instead,a small donation to the World Domination Machine to help convert 97.89% of the known population into rocketeers is better. Or just keep it below c...
    You forgot about the Flux Capacitor and the Jedi Mind Meld!

  11. #11
    Join Date
    19th January 2009
    Location
    Hole in the wall near Savannah, GA
    Posts
    7,357
    The Vulcan Mind Meld is more effective.
    Chute Happens!!
    NAR 86940 L2
    TRA 12270 L3 09-01-12
    KF4GUL
    TeleTubby Fan, Unofficial King of Namby-Pamby Land:tongue:

  12. #12
    Join Date
    28th December 2011
    Posts
    575
    Your Aspire came with a PNC? Not mine...

    Quote Originally Posted by Bubba02STi View Post
    The aspire can handle mach on a g77 (supposedly havnt tried my self yet)... and its a 29mm cardboard mindi with plastic nose... so i have to agree with troj... it depends...
    -Chr$
    NAR 79536 L1
    Vice President - Superstition Spacemodeling Society Section 506 www.sssrocketry.com
    SAM 0488
    "Prefers Plastic Nose Cones"

  13. #13
    Join Date
    5th August 2010
    Location
    Pleasantville, Ia.
    Posts
    226
    Quote Originally Posted by Pantherjon View Post
    The Vulcan Mind Meld is more effective.
    Frickin trekkies , theyre everywhere !!! lol Ever been to the future birthplace of James T Kirk ? Ck out Trek fest annual festival in Riverside Ia.

  14. #14
    Join Date
    18th October 2011
    Location
    Washington State
    Posts
    324
    Ever been to the future birthplace of James T Kirk ?
    No, but I have been to the future home of Starfleet Headquarters.


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