Abstract: The Optimal design is an important part of the CAD for solid rocket motor. This method is conducted by computer and is much better than traditional parameter selection by hand. It can also shorten the design and improve the calculating accuracy significantly.Based on the overall goal of tactic and technical demand of missle, the selection of optimal parameters of solid rocket motor is obtained through numerous calculations.In the existing optimal design material of rocket motor, the calculation of surface burning is always avoided and some simple shapes of solid grain (one dimension and two dimenicons)are adopted. In this paper, an investigation of optimal design of the three dimensional solid grain (finned tube solid) is introduced. An example is given and its result is satisfactory.

Key words: Optimal design, Finnecl tube grain, Solid rocket mctor, CAD