Simple rocket simulator
One rocket must at least produce a thrust equal to it's weight.
A rocket must push the payload, the structure and the fuel and oxidizer not already used.
A rocket must pass through atmosphere at either :
High speed and high drag
Low speed and high use of fuel and oxidizer to counter gravity.
The best thing for ordinary people is to use a
spreadsheet to build a model, like :
Excel Simulation of a one stage rocket going to LEO
But you can have a quick glimpse with this simple simulator :
Enter the parameters of the rocket motor here :