The objective of this paper is to study theoretically and experimentally the effects of different design parameters on hybrid rocket motor (HRM). HRM propellant constituents are Polyethylene (PE) with Al powder additive as solid fuel and gaseous oxygen (GO2) as oxidizer. The study has been extended to cover the important phenomena such as throttling operation, exhaust flame (plume) and the results are given in the form of tables and graphs for quick and easy analysis. The effect of several design parameters on system performance under consideration was investigated. These parameters are the fuel grain port-diameter, oxidizer mass flow rate and Al powder additives. Focusing on the use of Al powder weight percentage additives to formulate, improve the regression rate and performance as compared to conventional hybrid motor (pure PE+GO2). Regression rate of hybrid fuel grain was enhanced by addition of Al powder. Adding up to 7.5% gives the best performance as regression rate increases by 90% and chamber pressure increases by 40% compared to basic configuration (0% Al). The present work is to aid the designer to carry out optimization of HRM to increase the combustion efficiency and to better control the operating parameters.