Page 127 - Aeronautical Engineer Data Book

Basic aerodynamics 103
M1 (local)
M > M crit M > M crit
∞
∞
–1.2
–0.8
–0.4
–C p –C p
0
0.4
0.8
1.2
0 0.2 0.4 0.6 0.8 1.0 0 0.2 0.4 0.6 0.8 1.0
x/c x/c
∞
M >> M crit
Supersonic
–1.2 regions
–0.8
–0.4
–C p
0
0.4
0.8
1.2
0 0.2 0.4 0.6 0.8 1.0
x/c
Fig. 6.6 Variation of pressure deterioration (2-D airfoil)

6.7 Wing loading: semi-ellipse assumption
The simplest general loading condition assump­
tion for symmetric flight is that of the semi-
ellipse. The equivalent equations for lift,
downwash and induced drag become:
For lift:
VK 0 πs
L =
2
2
1
replacing L by C L / 2 V S gives:
C L VS
K 0 =
πs