Page 220 - Computational Fluid Dynamics for Engineers

208 6. Inviscid Flow Equations for Incompressible Flows

6-6. The NASA GA(W)-2 airfoil (see Table P6.2), which is a general aviation
airfoil designed by Whit comb of NASA Langley Research Center, is an example
of a supercritical airfoil. Supercritical airfoils were originally developed to delay
the drag rise Mach number in the transonic flow regime. It was later found that
airfoils of this type were also useful in the lower speed range of the general
aviation aircraft, and exhibited good high-lift capabilities. Their only drawback
is their relatively high pitching moment coefficient caused by the maximum
camber being located far aft along the chord line. With proper design, however,
this drawback can be avoided.
Table P6.2 presents the airfoil coordinates and Fig. P6.3 presents experimen-
6
tal data for a range of angles of attack at a chord Reynolds number of 4.1 x 10 .

Table P6.2. Airfoil coordinates for the NASA GA(W)-2 airfoil, c = 61.0 cm.
x/c (y/c) upper (ij/c) lower x/c (y/c) upper (y/c) lower

0.0 0.0 0.0 0.54954 0.08025 -0.03803
0.00199 0.00922 -0.00486 0.59950 0.07609 -0.03326
0.01246 0.02365 -0.01385 0.64946 0.01035 -0.02745
0.03747 0.03957 -0.02196 0.69942 0.06305 -0.02107
0.07494 0.05230 -0.02904 0.74938 0.05446 -0.01460
0.12490 0.06323 -0.03528 0.79933 0.4476 -0.00851
0.17485 0.07080 -0.03769 0.84929 0.3417 -0.00357
0.24980 0.07857 -0.04353 0.89925 0.02296 -0.00086
0.34971 0.08357 -0.04508 0.94921 0.01112 -0.00143
0.39967 0.08441 -0.04475 0.97419 0.00497 -0.00377
0.49958 0.08294 -0.04149 0.99917 -0.00143 -0.00720
1.0 -0.00164 -0.00732

1.6
C l 1.2

0.8
0.4

0.0
-0.4

-0.8 V * i i i < i i i i I I I i J • • i i » i » i i i i r i i
-12 -8 -4 4 12 16 20 24
o,deg.
Fig. P6.3. Experimental data for the NACA GA(W)-2 airfoil, R c = 4.1 x 10 6