A rocket motor shown schematically in above picture is case bonded type and has an inner motor case diameter of 12 cm. The length of each side for outer propelant grain is 5 cm and the length of each side for inner propelant grain is 4 cm. The propelant grain is shown in orange color.

a. What is the web thickness?

b. If average burning rate is 14 mm/s, what is the total burning time of the motor?

c. Perform your burning calculations and draw propellant burning area (take motor length as 0.8 m) burning time graph (assume that average burning rate is 14 mm/s).

d. What is the value of a, if propellant n value is n=0,4 and measured r= 14 mm/s at 80 bar?

e. Nozzlethroat diameter is36 mm. For the case of c*= 1450m/s, propellant density =1.8 g/cm³, motor length L=0.8 m, calculate the chamber pressure.

f. Based on the value calculated in "e", choose a case material and calculate the thickness of the cylindrical motor case?