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Roadster 0-60 times calculated with cold gas thrusters

Discussion in 'Roadster 2020' started by George S. Bower, May 13, 2019.

  1. George S. Bower

    Joined:
    Jan 22, 2016
    Messages:
    176
    Location:
    Tonto Basin, Az
    We have a computer model of the Tesla Roadster. We calculated the forward thrust provided by the cold gas thruster, then added that thrust to the forward thrust from the front and rear axles and re calculated the accel times.

    I figured a specific impulse of 60 sec. Thats a bit lower than wiki quoted for an N2 cold gas thruster
    Cold gas thruster - Wikipedia

    I then jst used the eqn: F= Isp times the mass flow rate
    Specific impulse - Wikipedia

    I figured a 100 lb of compressed air (mostly N2) dischardged in 5 seconds for a mass flow rate of 20 lb/sec

    so F=60sec times 20 lb/sec=1200 lb thrust

    Then I used our perf program for the roadster and just added 1200 lb forward thrust and also a calc for 2400 lb of added forward thrust (dump the 100 lb of air in 2.5 sec or add another tank and thruster).

    Slide2.JPG


    So 0 -60 times for the single thruster decreased 0.3 seconds
    and around .5 seconds for the dual thruster

    Our basic program shows a total forward thrust supplied by the front and rear axles of around 6400lbf.
    So to put the thruster amount in perspective, It's 1200 lbf on top of 6400 lbf....a 19% bump.

    Pretty crude but it gives you a general idea of how much the cold gas thrusters are worth.

    If you spot any errors in the math let me know in the comment section.

    Thanks,
    George
     
    • Like x 1
  2. Pinot.Noir

    Pinot.Noir Member

    Joined:
    Feb 28, 2014
    Messages:
    658
    Location:
    Livermore, CA
    1.87 is more than fast enough for me. No need for the crazy thrusters.
     
  3. MSDadMich

    MSDadMich Member

    Joined:
    Aug 22, 2017
    Messages:
    100
    Location:
    Michigan
    Mr Bower,

    How many g's will one experience at max accel? Also, how heavy was the "payload" in your calc?
    Cool stuff :)
     

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