动力机械和机身手册1(37)

曝光台 注意防骗 网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者

angle of attack, induced-drag coefficient,lift-to-dra~ ratio, and the drag. Assume
e - 0.95.
REVIEW OF BASIC AERODYNAMIC PRINCIPLES                  61
    Solution.   For the NACA 2412 airfo11,3 we have ao - O.lOtUdeg and Ccto -
0,0060. We have V = 160 km/h:44.44 m/s.
     From Eq. (1.52), we have
a = ~+
Here, we have to multiply the value of ao by 57.3 in the denominator because we
are given ao/deg.
     Substituting ao - 0.104, A - 6, and e -.0.95, we get a = 0.079/deg.
Further,
C~= p-: Vft,S
                                                                        2270.663 * 9.81
                             = ~  225~0 864*44.442*27.75
                          - 0.768
Then,
              CL
                                 ct = -
                              a
and and
0.768
= O 079
= 9.7203 deg
CDr = kC~.
   =( ~ )CZ
 0.7682
                                                                 7t6 * 0.95
                                        - 0.03294
                                      CD = CDO + CDi
                                                                         -. 0.006 + 0.03294
                                    - 0.03894
The drag is given by
                D - l2p'V2SCD
                                           =  ~ (1.225 * 0.864)44.442 * 27.75 * 0.03294
                            ~ 1129.3456 N
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62                  PERFORMANCE, STABIUTY, DYNAMICS, AND CONTROL
                                                    Example 1.2
     A two-dimensional wing was tested in a wind tunnel, and the pitching-moment
　
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