06. Static Stability

Nd787 C5 L4 A06 L Static Stability V2

Static Stability

When we talk about aircraft stability, we distinguish between static stability and dynamic stability. This short article does a good job explaining the difference.

Note on equations used in this video

The equations presented in this video are a bit of an oversimplification. For example, the equation you saw for the rolling moment looked like this:

L = C_{L_{\beta}}\bar{q}Sb\beta + C_{L_{\delta A}}\bar{q}Sb\delta A

In reality, the rolling moment also depends on p, r, and even the rudder deflection \delta R. A more complete version of this equation would be:

L = \bar{q} S b \left [ C_{L_0} + C_{L_\beta}\beta + C_{L_p}\frac{bp}{2V} + C_{L_r}\frac{br}{2V} + C_{L_{\delta A}} \delta A + C_{l_{\delta R}} \delta R \right ]

These additional terms are generally small compared to the terms in the simplified version presented in the video.