@@ -37,6 +37,8 @@ If everything is set up correctly, your first `design_mission` should land a few
Due to many dependencies between the [sizing tools](../../sizing/index.md), performance data and component parameters are quite off within the first iteration. This can lead to an unstable aircraft configuration that will fail the `design_mission` (e.g. wrongly sized engines can't climb to the initial cruise altitude). To avoid this, the [low-fidelity 3D Standard Mission](methods.md/#lowfi)(`design_mission::breguet`) is triggered if no previous mission calculation can be found. Unlike the ordinary mission calculation, this sub-version of the `design_mission` finishes after a rough estimation of the fuel consumption. Once this method is finished, the `masses_cg_inertia/maximum_takeoff_mass/mass_properties/mass` node is updated and this block is written into the [Aircraft Exchange File](#acxml):
### XML output {#first_iterations_xml}
```xml
<missiondescription="Mission data"tool_level="0">
<design_missiondescription="Data of design mission">
...
...
@@ -117,6 +119,7 @@ Due to many dependencies between the [sizing tools](../../sizing/index.md), perf
After the initial loop, we expect a robuster behavior which we can use to calculate the flight segments with an increased resolution. To achieve this, every segment is split into little time and way increments (only a few seconds/meters per increment) aiming for the trajectory points that were written into the `mission file`. In each increment, all relevant parameters are saved into a `mission profile`. After the calculation is done, said `mission profile` is exported as a [CSV file](#csv_file) into the `mission_data` directory. Within the [Aircraft Exchange File](#acxml) the `masses_cg_inertia/maximum_takeoff_mass/mass_properties/mass` node is updated when calculating a `design_mission`; for a `study_mission` it's the `mission/study_mission/takeoff_mass` node. Having a higher resolution also increases the amount of data in the `mission` block:
### XML output {#further_iterations_xml}
```xml
<missiondescription="Mission data"tool_level="0">
...
...
@@ -309,6 +312,46 @@ After the initial loop, we expect a robuster behavior which we can use to calcul
</cruise_step>
</cruise_steps>
</cruise>
<takeoff_performance_parametersdescription="Performance parameters for takeoff steps from 0 ft to screen height (35 ft).">
<lift_off_speeddescription="Speed at lift-off">
<value>65</value>
<unit>m/s</unit>
<lower_boundary>0</lower_boundary>
<upper_boundary>350</upper_boundary>
</lift_off_speed>
<takeoff_stall_speeddescription="Stall speed until screen height (35 ft)">
<value>55</value>
<unit>m/s</unit>
<lower_boundary>0</lower_boundary>
<upper_boundary>350</upper_boundary>
</takeoff_stall_speed>
<lift_off_coefficientdescription="Lift coefficient at lift-off">
<value>2.0</value>
<unit>1</unit>
<lower_boundary>0</lower_boundary>
<upper_boundary>100</upper_boundary>
</lift_off_coefficient>
<lift_off_angle_of_attackdescription="Angle of attack at lift-off">
<value>0.15</value>
<unit>rad</unit>
<lower_boundary>0</lower_boundary>
<upper_boundary>1.57</upper_boundary>
</lift_off_angle_of_attack>
<takeoff_climb_angledescription="Climb angle towards screen height (35 ft)">
<value>0.15</value>
<unit>rad</unit>
<lower_boundary>0</lower_boundary>
<upper_boundary>1.57</upper_boundary>
</takeoff_climb_angle>
</takeoff_performance_parameters>
<landing_performance_parametersdescription="Performance parameters for landing steps from 50 ft to touchdown.">
<maximum_landing_angle_of_attackdescription="Maximum angle of attack while landing (between 50 ft and touchdown)">
<value>0.15</value>
<unit>rad</unit>
<lower_boundary>0</lower_boundary>
<upper_boundary>1.57</upper_boundary>
</maximum_landing_angle_of_attack>
</landing_performance_parameters>
</design_mission>
</mission>
```
...
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@@ -450,6 +493,7 @@ Program Settings
│ ├── Fidelity Level
│ ├── Mission Type
│ ├── Center Of Gravity Method
├── Interpolate Polars
├── Rate Of Climb Switch
└── Precision
├── Acceleration Increment
...
...
@@ -473,7 +517,7 @@ In the `program_specific` node, you can specify if the specific air range (SAR)
In `general` you can decide how the needed fuel is estimated and you can tell **mission_analysis** in which way it shall behave in different flight segments.
The `mode` node lets you choose the methods that are applied. Using the keyword `low`/`mid` you will trigger the low-fidelity/mid-fidelity version of the [Standard Mission](methods.md) method. It also has three sub-methods to differentiate between `design_mission`, `study_mission` and `requirements_mission` which can be selected in the `mission_type` node. Please mind that the low-fidelity method only accepts the `design_mission`. The `rate_of_climb_switch` will only affect the [Climb to Ceiling](mission_steps.md/#climb_to_ceiling_subparagraph) step of the `requirements_mission`. With this option, **mission_analysis** calculates the optimum rate of climb towards service ceiling.
The `mode` node lets you choose the methods that are applied. Using the keyword `low`/`mid` you will trigger the low-fidelity/mid-fidelity version of the [Standard Mission](methods.md) method. It also has three sub-methods to differentiate between `design_mission`, `study_mission` and `requirements_mission` which can be selected in the `mission_type` node. Please mind that the low-fidelity method only accepts the `design_mission`. After the first iteration, the [Weight and Balance tool](../weight_and_balance_analysis/index.md) delivers vectors containing center of gravity positions in addition to the aircraft mass (center of gravity shift due to defueling). To take that into account, you can activate `interpolate_polars`. For kerosene based propulsion, the effects are rather small, but once H2 is involved you should consider using it. Furthermore, the `rate_of_climb_switch` will only affect the [Climb to Ceiling](mission_steps.md/#climb_to_ceiling_subparagraph) step of the `requirements_mission`. With this option, **mission_analysis** calculates the optimum rate of climb towards service ceiling.
Finally, in `precision` you can set the parameters which will define the before mentioned increments of your mission profile.
