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Solving Rocket Launch Equations in matlab

  1. Apr 18, 2013 #1
    1. The problem statement, all variables and given/known data
    A Super Loki rocket (http://en.wikipedia.org/wiki/Loki_(rocket [Broken])) is used to launch a small
    payload to above 100 km altitude in a sub orbital flight. Ignoring atmospheric resistance, find the
    apogee using both numerical and analytic techniques (solve the differential equations given in
    the lecture notes). Use the specifications given below.
    Payload mass (unpowered 2ndstage)
    6 kg
    Thrust (constant until burnout–kilo-Newtons)
    18 kNt
    Launch (take-off) mass
    29 kg
    Burntime
    2.1 sec
    HTBP solid fuel specific impulse
    238 sec
    At the end of the 2.1 sec burn, the payload is explosive bolt“ launched” to coast to apogee. This
    does NOT effect the calculations.




    2. Relevant equations
    Basically my question is what differential equation am I to use to solve this? I'm using the equations give here
    http://exploration.grc.nasa.gov/education/rocket/rktpow.html
    I solved the problem analytically already so I have a general idea what the answer should look like.



    3. The attempt at a solution
    I attempted to use ode45 to solve the equation dvdt = -F/M but the ode solver gets an error with the time step I'm using.
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
    Last edited by a moderator: May 6, 2017
  2. jcsd
  3. Apr 18, 2013 #2

    SteamKing

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    Staff Emeritus
    Science Advisor
    Homework Helper

    Are we supposed to guess what you did? You still must show specific work, rather than say, "I did this. It didn't work. What went wrong?"
     
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