What makes modern amateur rocketry so different from the days of "October Sky" in the 1950's and 60's is the personal computer. Today, amateurs can test their rocket and rocket motor designs on their personal computers to see if the designs will work before a single part is built. CP Technologies was one of the first company to develop and bundle rocketry software together for amateur rocketry. Unlike software offered by other companies, our software has been extensively tested in the amateur and professional environment. It has been used to successfully design small rockets like those used in beginning Rocket Camp classes (left) and large rockets such as the SHARP S1 sounding rocket developed under NASA contract (right).
In the old days, the amateur had to experiment with different chemicals to see what may be a good propellant. Even if they found one, they could never be sure of the performance. Those days are over with the software program, Chem *. It calculates the performance of virtually any solid, liquid or hybrid propellant combination. Simply input the propellant ingredients and Chem * calculates the combustion temperature, propellant density, C-star, specific impulse and a lot more.
Most amateurs are using solid rocket composite propellant like that used in the Space Shuttle solid rocket boosters. This propellant is not only safer than the propellants used in the 1950's and 60's but has a very predictable and repeatable burn rate as a function of chamber pressure, i.e, burn rate = (c) * (Chamber Pressure) n. While it is not yet possible to calculate the values of c and n without testing the propellant, our Burnrate * program makes the task of determining c and n a lot easier. All the amateur has to do is obtain a few burnrates for their propellant at a couple of different pressures and plug those values into Burnrate *. The software does the rest and determines the correct values for c and n.
CP Technologies has three software packages then enable the amateur to design their solid rocket motor to work without fear of structural, thermal or ballistic failure. The amateur starts to design their motor using Fpred *. It is a simple to use program that simulates the entire burn of a solid rocket motor and shows the pressure-time and thrust-time curve for the motor in a graphical format. You blow the motor up on your computer, not on the test stand. Fpred * has been used on motors as small as one inch in diameter and as large as 18 inches in diameter with over 800 lbs of propellant. In all cases, it has accurately predicted the performance of the motor. Fpred * handles a variety of propellant grain designs including straight cores, segmented (Bates), c-slot, moon and end burner grain patterns with eroding and non-eroding throats.
Once the motor design is set ballistically, it is time to check it structurally. Our STRESS spreadsheet will tell you what wall thickness is required for the rocket chamber as well as the required thicknesses for the motor bulkhead and nozzle plus a lot more. THERM * is used by the amateur to determine the ablation and temperatures in nozzles, exit cones, bulkheads and chambers. It can calculate the throat erosion of your nozzle. If you are going to be flying a rocket that goes at supersonic speeds, you will want to use the aerodynamic heating option on THERM *. It calculates the heating of nosecones and the rocket body during flight and determines the ablation and temperatures within the parts as a function of time.
To help the amateur design their rocket, CP Technologies offers three software programs. For a rocket to be stable in flight the center of pressure needs to be aft of the center of gravity. Of course, this is useless if the amateur doesn't know where the center of pressure and center of gravity are on their rocket. CG-Calc * determines the location of the center of gravity on a rocket before it is built. The user simply inputs the weights of items on the rocket and their location and CG-Calc * does the rest. CP1 * determines the center of pressure. Once the rocket is designed to be stable, the next question may be, "How high does it go and what will it do in flight?" Flight * simulates the trajectory of the rocket and outputs the information in a variety of graphical formats such as altitude, velocity, acceleration, dynamic pressure, axial compression on the rocket and pitch as a function of time. Flight * and Fpred * are designed to work together so that the motor you design in Fpred * can be imported to Flight *.
Note: The * symbol after the software title indicates the software is copyrighted by CP Technologies.
Click here to see a copy of the software manual
Periodically, the list of chemicals available in CHEM is updated so you have more ingredients to use in your propellant formulations. The list of propellant ingredients for CHEM Version 3 is in the file "pepcoded2.daf". The list of chemical ID numbers and their chemical names are in the files "Idnum.txt". We will also be adding more chemical species and reactions (jannaf2.daf file) to make CHEM the most accurate propellant thermochemistry program available to the consumer. Future updates to these files will be free and available on this page.
March 13, 2007 - There are no updates for CHEM at this time.
If you bought the "How To Make Amateur Rockets" bookset a long time ago, your software is out of date. CP Technologies offers previous bookset buyers the opportunity to upgrade their entire software package for only $9.95 which includes mailing within the United States. If you bought your bookset from CP Technologies, you may want to upgrade. To see if you have the latest versions, check the table below.