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.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Canard Neutral Point

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**