Letting PRODAS calculate the chamber volume based on the propellant cavity is very powerful. Our example projectile has the propellant modeled for that purpose. It has already been done but since it is so easy and useful I am including an overview of the process.

The powerful propellant component has been modeled using a common practice that Arrow Tech engineers use that is nothing more than copying and pasting other elements. Basically once the projectile and case have been modeled the propellant cavity definition just becomes available by copying and pasting elements and toggling whether they are voids or not. In other words the inside diameter of the case becomes the outside diameter of the propellant cavity. Also the outside diameter of projectile or ignitor elements that are within the case become voids in the propellant component. Here are the basic steps.

• Model the Case
• Model the Basic Projectile
• Model the Ignitor
• Copy all Case elements that are voids and interface the propellant
• Paste these elements and make them the Propellant component
• For each of these new elements toggle the Void property to "No"
• Similarly you can copy interfacing elements from the Projectile and ignitor
• Paste these elements into the Propellant Component.
• For each of these new elements toggle the Void property to "Yes"

For Our example the propellant component has already been defined. It is made up of nine elements. You can walk through the elements and their corresponding elements in the Case, Propellant and Ignitor to see the result. An example of a void element and a non void element are shown below.

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