In essence I'm working on a design project and I'm specifically looking at takeoff analysis at the moment. I already have access to great textbook resources, but I'm struggling to determine the coefficient of lift $(C_{L_G})$ on the ground with flaps in take-off position for the following equation taken from Appendix K-4 of Synthesis of Subsonic Airplane Design by Torenbeek:
$$\frac{a}{g} = \frac{T}{W} - \mu - \left(C_{D_G} - \mu C_{L_G}\right) \frac{\frac{1}{2}\rho V^2 S}{W}$$
Similar equations can be found in other textbooks, but I haven't found any reference to how $C_{L_G}$ can be determined from airfoil data. Currently I'm considering just using the zero geometric angle (ie compensating for the AoA the wing is mounted at) coefficient of lift for the airfoil, but how would I then account for the position of the flaps?