Two dimensional lift drag data for the NACA 2412 airfoil with 2 percent camber (from Ref 12) may be curve fitted accurately as follows CL 0 178 0 109 0 00109 2 CD 0 0089 1 97E4 8 45E5 2 1 35E5 3 9 92E74 With in degrees in the range 4 10 Compare (a) The lift curve slope and (b) The angle of zero lif...

The lift formula is not quite linear in but a reasona ...

Two-dimensional lift-drag data for the NACA 2412 airfoil with 2 percent camber (from Ref. 12) may be

Question:

Two-dimensional lift-drag data for the NACA 2412 airfoil with 2 percent camber (from Ref. 12) may be curve-fitted accurately as follows: CL ≈ 0.178 + 0.109α – 0.00109α 2 CD ≈ 0.0089 + 1.97E−4α + 8.45E−5α 2 – 1.35E−5α 3 + 9.92E−7α4 With α in degrees in the range –4° < α < +10° Compare
(a) The lift-curve slope and
(b) The angle of zero lift with theory, Eq. (8.69).
(c) Prepare a polar lift-drag plot and compare with Fig. 7.25