# How much is alpha induced angle?

I know that alpha induced rise with increasing AoA but how much is alpha induced in reality ,are we talking about 1-2 degrees or more?

The induced angle primarily depends upon the following:

• Coefficient of lift
• Aspect Ratio (AR)
• The correction factor $$\tau$$ (needs to be accounted for if the wing platform is not an ellipse. If the wing platform is an ellipse, then $$\tau=0$$)

All three are related the with the following equation: $$\alpha_i[\text{rad}]=\frac{C_z}{\pi AR}(1+\tau)$$

The table below provides the values of $$\tau$$ for a rectangular wing.

You can use these values and NACA Report 824 to calculate the actual induced angle of attack for a rectangular wing for any possible airfoil.

For instance, using $$\text{NACA} ~65_1-412$$ airfoil at $$\alpha_{\text{geometric}}=8^{\circ}$$ and $$AR=9$$ it follows that $$\alpha_i=0.05~\text{rad}\approx 2.86^{\circ}$$.

It varies greatly in relation to the angle of attack, as low as $$1^{\circ}$$ in high-speed flight with low angle of attack and as high as $$3^{\circ}-4^{\circ}$$ at low-speed flight for a rectangular wing aircraft.