A hobby I have had since early childhood is the construction and operation of model rockets – both the pre-fabricated kits from Estes and home made designs.  Through a project that lasted from spring through fall of 2010, I took my model rocketry interests to the next level and developed an iterative solving rocket flight profile calculator using excel, and built a three-pad cluster-engine compatible modular electric launch system.

My model rocketry one dimensional iterative solver can calculate trajectory, and the following properties of the flight profile:

1.       Total Impulse
2.       Thrust Duration
3.       Maximum Altitude
4.       Maximum Velocity
5.       Parachute Deployment Altitude and Rocket Speed at Deployment
6.       Approximate Drift Distance After Deployment of Parachute (given a crosswind speed)
7.       Total Approximate Flight Time
8.       Descent Velocity After Deployment

These flight parameters are functions of the following design parameters and properties:

  • Air Density (assume constant)
  • Coefficient of Drag (approximate)
  • Rocket cross sectional (projected) area
  • Rocket mass
  • Propellant Engine Packaging mass
  • Two Stage / One Stage Designs
  • Engine Clustering (assuming we can only cluster the first stage of flight if using boosters)
  • Transient Thrust Profile of the ‘Estes’ model rocket engines

The calculator accounts for the following dynamics:

  • Changing rocket mass as propellant is burned (assumed a linear burn rate)
  • Changing rocket mass if a booster is ejected (including engine packaging)
  • Engines of form factor B through E (properties available from Estes: packaging mass, propellant weight, total impulse, thrust profiles, etc.)

My calculator is available for download, here.