In Rocket Project at San Diego State University, myself and 3 other members were assigned the task of designing a hybrid rocket motor. We were required to use gaseous oxygen as the oxidizer, solid acrylic as the fuel, and a standard 53 mm convergent-divergent nozzle to accelerate the hot exhaust out of the combustion chamber. It was also mandatory for this design to have a safety factor of 5. To meet this requirement, we had to calculate the internal pressure and temperature of the combustion chamber, given that gaseous oxygen would be flowing in at 60 psi. Once we found the internal pressure and temperature, we had to calculate the hoop stress on the cylindrical acrylic fuel to ensure that it would not explode during the reaction. As a further safety precaution, we decided to encase the entire acrylic cylinder in aluminum, since the solid acrylic could melt away from the baseplate at extreme temperatures. To prevent leakage, we made a 3/8 NPT hole for the oxygen inlet on the anterior baseplate, and an O-ring gland for a 1/16 O-ring on the posterior baseplate. We used 4 threaded rods to compress the motor between the two baseplates.