B3. The initial weight of a single stage rocket is 500 kN, of which 420 kN is fuel. The weight of payload weight is 40 k

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B3 The Initial Weight Of A Single Stage Rocket Is 500 Kn Of Which 420 Kn Is Fuel The Weight Of Payload Weight Is 40 K 1 (526.13 KiB) Viewed 62 times

B3. The initial weight of a single stage rocket is 500 kN, of which 420 kN is fuel. The weight of payload weight is 40 kN and the structural mass of the booster is 40 kN. It is launched vertically from the surface of the earth. It burns fuel at a constant rate of 3 kN/s and has a constant exhaust speed of 3 km/s. Assume that the average value of the gravitational acceleration is 9.6 m/s² and the rocket start from rest. (a) Determine the average thrust of the rocket engine to burnout. (4 marks) (b) Determine the time of burnout. (2 marks) (c) Determine the speed at the burnout. (4 marks) The rocket is redesigned and a two stage booster is used. The payload weight is the same (40 kN). The weight of fuel is 420 kN fuel and is stored in stage 1 booster (300 kN fuel and 30 kN structural booster mass) and stage 2 booster (120 kN fuel and 10 kN structural booster mass), respectively. The fuel burn rate and the exhaust speed are still the same. Assume that the average value of the gravitational acceleration is 9.6 m/s2 and the rocket start from rest. (d) Determine the speed at the first burnout. (4 marks) (e) Determine the speed at the second burnout. (4 marks) (f) Compare the performance of single stage rocket and two stages rocket using the above calculation results. (2 marks)