Exam sample 202324

Pagina 1

AIRPLANE PERFORMANCE AND DYNAMICS A.A. 2023/24 – XXX EXAM TERM – XXX, 2024 Teacher: C.E.D. Riboldi General Rules  The delivery must be clearly marked with the SURNAME, NAME and STUDENT PERSONAL CODE at the top of the sheet, in this order and all written in capital letters.  The sheets must be written using a pen, not a pencil.  Graphs and drawings must be readable and complete  THE MAXIMUM NUMBER OF PAGES FOR ALL ANSWERS IS THREE (i.e. one front, one back and another front) Questions 1. Consider typical Sizing Matrix Plot curves for the take-off for a jet aircraft a. introduce and describe the corresponding analytical expression b. plot lines corresponding to different of the take-off parameter, clearly indicating the trend of the constraint line on the plot for increasing values of that parameter 2. Consider the equation for the stability derivative 𝐶𝑀𝐺𝛼 for the two-surfaces model of a standard configuration back-tailed aircraft 𝐶𝑀𝐺𝛼 = 𝑎𝑤(𝜉𝐴𝐶𝑤 − 𝜉𝐺) + 𝜂𝜎(𝜉𝐴𝐶𝑡 − 𝜉𝐺)𝑎𝑡(1 − 𝜀𝛼) + 𝐶𝑀𝐺𝛼 𝑓 a. describe the expression by stating the identity of each symbol in it and the meaning of the three terms appearing in a sum on the r.h.s. b. comment the sign and the corresponding contribution to static stability provided by each of the three terms on the r.h.s. for a standard back-tailed aircraft c. show how to emend the expression above when the aircraft is flying a pull-up, by suitably introducing on the r.h.s. a term related to the longitudinal relative density 𝜇1 = 𝑊/𝑆 𝑙𝑡𝜌𝑔 (skipping all derivations). d. please answer directly (Y/N): is an aircraft featuring a traditional configuration always statically stable in the longitudinal sense during a pull-up maneuver? 3. Considering propulsion forces, with the help of qualitative sketches and analytic definitions, discuss a. the sign…