Nose Cone

Looking at the graph below the ideal ratio of length to diameter 3. How long must a nose cone be if its diameter at the base is 3.5 cm long? A student sanded a nose cone which was 4 cm long and 1.5 cm in diameter. What pressure drag coefficient would this nose cone have? A student decided to increase the length to diameter ratio by designing a long nose cone. Explain why this would not be a good idea. Refer to the graph below and to friction drag.