OK, I have two canard NP formulas.(adsbygoogle = window.adsbygoogle || []).push({});

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.

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# Canard Neutral Point

Can you offer guidance or do you also need help?

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