
    At the first run of this program it is advisable to fill the form by example values and test the program with them. Press the button "Endburner" or "Coreburner", then start the simulation by hit on the button "Start".
    The form can be filled by your own values. It's necessary use the right, reasonable numbers which can be integer or real. Use a properly decimal separator, depends on your system settings. Then hit the button "Chart" for drawing a simple picture of a motor, "Start" for simulation.
    Take into account that the resulting graph is not exact, the simulation is only approximate, two-dimensional. Accurate three-dimensional simulation would be too time-consuming. The values from simulation are usually a little bit higher than by exact computing using ideal geometry.

    In the menu item "Grain" is the submenu "Bates". This grains with central hole are divided into segments. The segments are separated by spacers, which internal diameter should be set, by item "Spacer diameter" of a form. The grain may or may not burns at the ends. The reason for grain segmentation is a better, near-neutral thrust characteristic. Program makes possible to understand burning that grains and put them up. But I have to add that some propellants which burn at low temperature and ignite after a short delay like KN/sorbitol are not advisable for bates grain, at least without primer. On the surface among segments the ignition is delayed and the characteristic of a motor should be similar like with simple grain.

    Each grain geometry can be saved into a file, using menu "File", subitem "Save as". Later is possible to read this files, menu "File" -> "Open", and after eventual changes save them back by "File" -> "Save".

    After the program starts the propellant is not specified. Items "Specific weight" and "Burning speed" in the form have to be set, at least by the estimated values. It allows to program compute the weight of a grain and set up the time axis. Take into account that this is an average, constant burning speed. Real propellant burns by variable speed in the dependance of a pressure.

    Program allows to compute more graphs when the propellant is specified better. It is necessary to know the dependance of burning speed on the pressure, which is possible to get from measuring or by computing when the propellant is well known. Further is necessary to know the dependance of theoretical specific impulse and outlet velocity. This values can be computed, for example by program propep. Name of propellant and tabelated values are written in a file "shj.tph" where are some commented examples. It's possible to add more propellant which then appeared in the menu.

    In the menu "Speed", meaning is speed of a simulation, is possible to set item "Real". Then the burning simulation and it's visualization goes by real speed. Otherwise the speed is limited only by performance of computer.

    In re-runs with the same values the results are not exactly the same. The program don't make the exact computing but simulates the real proces which is not the same either.

    In case of KN/sorbitol propellant the results are a little bit "wild" especially when the area ratio is low. It is by it's non-standard characteristic. In real the motor working at low pressure burns unstable too.

    Graphs and computed values are theoretical, then well above real values. The burning is not ideal, the nozzle has optimum expansion ratio only for one area ratio and doesn't have 100% efficiency, there are thermal losses, frictional losses etc. According to my guess the real values are from the half to three quarters of theoretical in the dependance on motor construction and it's size.
 
