# Angle of Attack influence on Adverse Yaw

we are analyzing an aircraft's lateral-directional control characteristics with self-made code. We have observed that the aileron's influence on the body axis yaw moment is quite sensitive to the angle of attack.

My question is if this makes any sense or if there is something wrong.

For Alpha = 0°

For Alpha = 5°

Edit: our model analyses the effects of the individual effects we simulated in CFD, relying on the superposition principle. For every component (including the ailerons) the following operations are made:

$$$$\label{eq:decompforcas} \begin{bmatrix} F_x \\ F_y \\ F_z \end{bmatrix} = \begin{bmatrix} \cos{\alpha}\cos{\beta} & -\cos{\alpha}\sin{\beta} & -\sin{\alpha}\\ \sin{\beta} & \cos{\beta} & 0\\ \sin{\alpha}\cos{\beta} & -\sin{\alpha}\sin{\beta} & \cos{\alpha} \end{bmatrix} \begin{bmatrix} -qSC_D \\ qSC_Y \\ -qSC_L \end{bmatrix}$$$$ $$$$\label{eq:momentodocomponente}\begin{bmatrix} 0 & l_z & -l_y\\ l_z & 0 & -l_x\\ -l_y & l_x & 0 \end{bmatrix} \begin{bmatrix} F_x \\ F_y \\ F_z \end{bmatrix} + \begin{bmatrix} -qScC_l \\ qScC_m \\ -qScC_n \end{bmatrix} = \begin{bmatrix} M_x \\ M_y \\ M_z \end{bmatrix}$$$$

• You use the same reference length for all moments, which is uncommon. Normally, c$_m$ is multiplied with l$\mu$ and both c$_l$ and c$_n$ are multiplied with wingspan b or ½b. The adverse yaw over AoA looks wrong but without the code and the CFD results I cannot tell you why. Jul 31 at 17:56
• You're right about the reference length. I missed that when writing the equations, but it is done right practice, thanks! Jul 31 at 18:28