Assignment – 2014 Kul–34.3250 Airplane Aerodynamics Assignment Preface In this work we use the vortex lattice method to calculate the aerodynamics of a given wing in subsonic flow. The wing is a straight tapered wing and it has sweep angle and twist but no thickness. The individual initial values are given in table 1. Work The purpose of this work is to study how wing twist affect the aerodynamics of a wing. According to given individual initial values a student must also study the effect of wing taper ratio or sweep angle. Use the given initial values in your calculations. Calculate results using 20 x 12 panels (span x chord). You get panel method computer program (Mathcad worksheet, in Finnish) from the Noppa page of this course. Wing twist First examine an untwisted wing. Calculate the lift coefficient CL of your wing, lift coefficient distribution, moment coefficient around y-axis and the induced drag coefficient. Calculate also the length of the mean aerodynamic chord. Calculate the same case for some other angle of attack and calculate C L ,  0 , Cm_0 , and wing aerodynamic center in per cent of MAC. Calculate again the same values for a twisted wing. Twist is linear and t= -3°. Define the induced drag coefficient of the twisted wing in the three term form as seen in eq. (7.5) in the course theory paper. In other words, define the coefficients C0, C1 and C2. They can be defined by calculating the wing at three different angles of attack and using the CL-and CDi -values to form a set of equations. Thus you need to perform one additional computation. Compare your coefficients to figure (7.1) in the theory paper and to your results of an untwisted wing. Discuss the effects of wing twist on induced drag, stall characteristics, and the structural weight of the wing. The assignment is submitted as paper submission in the form of report. The email-submissions are not permitted. The submission deadline is 3.12.2014 by 15.45, which is also an exam requirement for the exam in 16.12.2014. If the submission deadline is not met, the next deadline for attending the next exam (2015) is one week before each particular exam. The assignment must be fully written and calculated when submitting. If there are still errors in the assignment, those must be corrected and the assignment must be re-submitted. The assignment must be approved by the assistant by 31.1.2015. The assignment is submitted in the letter box with the correct course code in the entering hall in K4-building. Kul–34.3250 Airplane Aerodynamics RT 24.10.2014 Assignment – 2014 Only one of the following parameters must be studied pointed in the individual initial values. A) Wing taper ratio Repeat the previous calculations of untwisted wing for wing taper ratio values of =0,2 and 0,3. How does the taper ratio affect the lift coefficient distribution and induced drag coefficient? B) Leading edge sweep angle Repeat the previous calculations of untwisted wing for wing sweep angle values of =45° and =55°. How does the sweep affect the lift coefficient distribution and induced drag coefficient? Finally, this study is for everybody: The effect of the number of panels Repeat the calculations for one case with a coarse paneling (J=16, N=9) and (J=10, N=6) to see how sensitive the results are. Does the initial paneling seem sufficient? Table 1. Individual initial values. Op. No 291165 296937 83783P 48551H 80425V 36751F 225856 350776 84723C 350501 69242H 466259 52671D 50331A 69577W 84818C 50366U 401191 S (m^2) 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 A 8 9 10 10 8 6 9 7 6 8 8 7 6 10 8 6 9 9 b (m) 28,28 30,00 31,62 31,62 28,28 24,49 30,00 26,46 24,49 28,28 28,28 26,46 24,49 31,62 28,28 24,49 30,00 30,00 Pyörrehila Lambda Nuolikulma 0,33 36º 0,42 30º 0,4 30º 0,42 32º 0,38 29º 0,4 35º 0,44 37º 0,38 32º 0,35 26º 0,4 26º 0,44 27º 0,43 28º 0,38 42º 0,38 34º 0,4 26º 0,39 32º 0,32 44º 0,36 42º Alpha 3,9° 2,9° 2,9° 3,2° 2,9° 3,9° 3,9° 2,9° 3,5° 2,9° 3,9° 2,9° 3,2° 3,9° 2,9° 2,9° 3,9° 3,9° Ma 0,3 0,3 0,3 0,3 0,3 0,3 0,3 0,3 0,3 0,3 0,3 0,3 0,3 0,3 0,3 0,3 0,3 0,3 Suure B A A B A A A B B A B A B B B A A A Kul–34.3250 Airplane Aerodynamics RT 24.10.2014