f027bdc024eb9e85eddf98907c11ef3216f70652,trunk/SUAVE/Methods/Performance/estimate_take_off_field_length.py,,estimate_take_off_field_length,#,34

Before Change

    // ==============================================
    // Determining vehicle maximum lift coefficient
    // ==============================================
    try:   // aircraft maximum lift informed by user
        maximum_lift_coefficient = vehicle.maximum_lift_coefficient
    except:
        
        // Condition to CLmax calculation: 90KTAS @ 10000ft, ISA
        conditions  = atmo.compute_values(10000. * Units.ft)
        conditions.freestream=Data()
        conditions.freestream.density   = conditions.density
        conditions.freestream.dynamic_viscosity = conditions.dynamic_viscosity
        conditions.freestream.velocity  = 90. * Units.knots
        try:
            // Using semi-empirical method for maximum lift coefficient calculation
            maximum_lift_coefficient, induced_drag_high_lift = compute_max_lift_coeff(vehicle,conditions)
            vehicle.maximum_lift_coefficient = maximum_lift_coefficient
        except:
            raise ValueError("Maximum lift coefficient calculation error. Please, check inputs")

    // ==============================================
    // Computing speeds (Vs, V2, 0.7*V2)
    // ==============================================
    stall_speed = (2 * weight * sea_level_gravity / (rho * reference_area * maximum_lift_coefficient)) ** 0.5
    V2_speed    = V2_VS_ratio * stall_speed
    speed_for_thrust  = 0.70 * V2_speed

After Change

        state.conditions.freestream.velocity          = np.array(np.atleast_1d(V2_speed))
        state.conditions.freestream.mach_number       = np.array(np.atleast_1d(V2_speed/ a))
        state.conditions.freestream.dynamic_viscosity = np.array(np.atleast_1d(mu))
        state.conditions.freestream.density          =  np.array(np.atleast_1d(rho))
        results = vehicle.propulsors["turbofan"].engine_out(state)
        thrust = results.thrust_force_vector[0][0]

        // Compute windmilling drag

Instances