Answer Happy

a) Determine the value of the propellant temperature sensitivity coefficient Op, if the pressure inside the combustion chamber changes for 10% (positive change) when initial temperature changes for 40% (positive change)? [8 marks] b) A sounding rocket has the following characteristics: initial mass mo= 250 kg; mass after solid rocket motor burn-out mb=180 kg; payload + structure without solid rocket motor = 160 kg; solid rocket motor burning time tb= 3.5 s; average solid rocket motor specific impulse Isp = 2400 m/s. . . Determine: i. ii. iii. iv. = V. = vi. Propellant mass (mp) [2 mark] Propulsion system initial mass (mops) [2 mark] Mass ratio of vehicle = mp / mo [1 mark] Propellant mass fraction (propulsion system) = mp / mops [1 mark] Propellant mass fraction (rocket) = mp/mo [1 mark] Propellant mass flow rate m [2 mark] Thrust (F) = Isp. m [1 mark] Initial thrust/weight ratio = F/Wo [2 mark] Final thrust/weight ratio = F/Wb [2 mark] Initial acceleration ao = F/m. [1 mark] Final acceleration ap = F/mp [1 mark] Total impulse (Itot) = F. tb [1 mark] vii. = viii. ix. X. xi. xii. =