OK, I have two canard NP formulas. One is: h_n = h_0 - [eta_s*V_s*(a_s/a)(1-foretail downwash)] Where eta_s = efficiency; V_s = tail volume; a_s = slope of lift curve for "tail"; a = slope of wing lift curve, foretail downwash is obvious; h_0 is MAC of wing (25% nominally) The other is: h_n = h_0 - H Where H = V_s*(foretail downwash) The second one produces a negative number, and is from a CalTech report. The first is from a model aircraft aerodynamics book. The first one lines up more with the regular tail eqn, but i get a positive, and it should be negative. In both formulas, the term after h_0 MUST be larger than h_0. Help!!! This is on a test tomorrow. I would like to know tonight so i can finish studying. BTW, I think eqn 2 is better, but i have no idea, i am a sophomore.