# What's the thrust coefficient for a convergent nozzle?

As you know, the Ideal Thrust Coefficient of convergent-divergent nozzle is calculated using this equation:

But what about a convegent nozzle? Is there any equation to calculate the Ideal Thrust Coefficient for a convergent nozzle?

I don't know how this equation was derived, but when I studied jet engines a factor in $$C_f$$ expression was from a empirical basis, so maybe you cannot use only your math skills to get there.
Respect your question, I think the equation can be used directly considering that $$A_e=A^*$$ if the nozzle is choked ($$M_e=1$$) and using the proper expression for $$p_e$$.