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I am building a rocket and need a way to predict the maximum altitude. Can someone send me some links or explanation?

Also, is there any way to measure the thrust of the rocket?

Thnx in advance.

 

  • 8 years later...

You're going to want to calculate the sum of your Propellent Mass m_{0} and Empty Mass m_{f}

Then you can create a test apparatus to get your Effective Exhaust Velocity and solve for \Delta v.

{\displaystyle \Delta v=v_{\text{e}}\ln {\frac {m_{0}}{m_{f}}}=I_{\text{sp}}g_{0}\ln {\frac {m_{0}}{m_{f}}},}

  • {\displaystyle v_{\text{e}}=I_{\text{sp}}g_{0}} is the effective exhaust velocity
    • I_{\text{sp}} is the specific impulse in dimension of time (In this case, it's proportional to the effective exhaust gas velocity.) 
    • g_{0} is standard gravity
  • \ln is the natural logarithm function
  • m_{0} is the initial total mass, including propellant
  • m_{f} is the final total mass without propellant

Check this post out for a general overview of how you could go about making the test apparatus to get thrust data.

With this data you can then calculate if a launch is possible.

From here you can use the Ideal Rocket Equation to predict the theoretical velocity of your rocket.

https://www.grc.nasa.gov/www/k-12/rocket/rktpow.html

 

Derivation of the ideal rocket equation which describes the change in  velocity as a function of the exit velocity of the rocket and the change in mass of the rocket during the burn.

 

I'm no rocket scientist, but this is where you're going to want to start. These methods aren't perfect, but will give you proximal results. 

 

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