I'm currently attempting to assign handling qualities to the A-4D, and I would like to know how to find the term:

$$n / \alpha = \overline{q} \times C_{L\alpha} / (W / S)$$

where $$C_{L\alpha}$$ is the lift-curve slope. I think I could solve for the lift-curve slope by using the value $$1/T_{\theta2}$$ or $$1/T_{P2}$$, the phugoid frequency, somehow, but I cannot find that equation.

I'm not given a chart of the change in lift-curve slope per Mach number.

• Who or what is A-4D? Is this homework? – bogl Oct 25 '18 at 7:31
• A-4D is the airplane assigned-- a military fighter pilot that could reach transonic speeds. It's a project I am doing for a class. I can find the lift-curve slope before before M=.6 using a certain equation I got from a NASA document, but the A-4D achieves up to M=.9, so the compressibility of the gas affects the lift-curve slope. A plot of lift-curve slope (lcs) for a plane shows that the lcs is constant until about M=.4, then you get an exponential growth as M approaches 1. I am either trying to find a plot of this for the A-4D or an equation for lcs that works until M=.9. – Albert Garcia Oct 25 '18 at 15:00
• I would prefer the equation that I asked for above because that equation was developed from empirical relations, so it is usually close to the actual lcs(lift-curve slope), but if you have a graph of Mach number vs lcs, that would work better since those are the actual, tested values. – Albert Garcia Oct 25 '18 at 15:06