def cp_max_calc(Ma):
    """
    Calculates the maximum pressure coefficient for modified Newtonian flow
    
    Inputs:
        Ma: Free stream mach number
    Outputs:
        CpMax: Maximum pressure coefficient 
    """
    k = 1.4
    
    PO2_pinf = (((k+1)**2 * Ma**2)/(4*k*Ma**2 - 2*(k-1)))**(k/(1-k)) * \
               ((1-k+2*k*Ma**2)/(k+1))
               
    CpMax = (2/(k*Ma**2))*(PO2_pinf-1)
    
    return CpMax