Fuselage layout enhancement and modification by xjjiang · Pull Request #1205 · OpenMDAO/Aviary

xjjiang · 2026-06-26T16:43:28Z

Summary

For FLOPS based geometry, business seats are added to transporter aircraft. For GASP based geometry, business class seats are added to BWB aircraft. In both cases, users can set:

different seat widths for first class, business class, and economy class.
different seat pitches for first class, business class, and economy class.

For FLOPS based models, there will be differences of fuselage layout if business class seats are included for transporter aircraft because FLOPS does not consider business seats in its layout algorithm. This message is added to the top of output .csv file.

GASP based geometry does not have a detailed layout for transporter aircraft. We do not add this feature in this PR.

Related Issues

Resolves Add Business Class seat information to DetailedCabinLayout component #912

Backwards incompatibilities

None

New Dependencies

None

…ECONOMY

…ECONOMY. Fixed a bug DetailedCabinLayout. Added business class to DetailedCabinLayout

…IDTH_BUSINESS

…ECONOMY. added Aircraft.Fuselage.SEAT_WIDTH_BUSINESS and Aircraft.Fuselage.SEAT_WIDTH_FIRST. removed LEAPS1.

…ge.SEAT_WIDTH_FIRST

…ansporters

…fect fuselage layout

…t is used for transporter aircraft using FLOPS based geometry.

…fuselage_layout

cmbenne3 · 2026-07-08T14:15:40Z

+        else:
+            if design_type == AircraftTypes.BLENDED_WING_BODY:
+                if verbosity >= Verbosity.BRIEF:
+                    raise UserWarning('Aircraft.Fuselage.SEAT_WIDTH_ECONOMY is not set.')


Does it default? If so we should let the user know what value it defaulted to.

GASP does not have a default value. This will throw an error message. Maybe, we can take the FLOPS default (20 inches)? @cmbenne3

cmbenne3 · 2026-07-08T15:05:21Z

                num_seat_abreast_economy = 8
-            if num_seat_abreast_first > 0 and num_seat_abreast_first <= 0:
+                if verbosity > Verbosity.BRIEF:
+                    print('Set Aircraft.CrewPayload.Design.NUM_SEATS_ABREAST_ECONOMY = 8')


Very small comment - Perhaps remove hardcoded value of '8' in the print() and format with f'{num_seat_abreast_economy'} like the print statements below for consistency.

cmbenne3 · 2026-07-08T15:33:05Z


        self.aviary_options = AviaryValues()

-        self.aviary_options.set_val(Aircraft.CrewPayload.Design.NUM_SEATS_ABREAST_ECONOMY, 18)


Why don't we need this value anymore? Does it default to 18 if we don't set it?

cmbenne3 · 2026-07-08T15:36:51Z

@@ -44,7 +44,7 @@ def compute(self, inputs, outputs):
        options = self.options
        verbosity = options[Settings.VERBOSITY]
        seats_abreast = options[Aircraft.CrewPayload.Design.NUM_SEATS_ABREAST_ECONOMY]


I know it's not a change you've made in this PR, so perhaps out of scope here, but I think NUM_SEATS_ABREAST variables should be under Aircraft.Fuselage. not under Aircraft.CrewPayload.Design

cmbenne3 · 2026-07-08T15:38:13Z

+                print('Warning: No business class passengers or cabins are included.')
+        if (pax_FC + pax_BC) > pax:
            raise ValueError(
                'Number of first class passengers must not exceed the total number of passengers.'


Suggested change

'Number of first class passengers must not exceed the total number of passengers.'

f'Number of first {pax_FC} and business {pax_BC} class passengers must not exceed the total number of passengers {pax}.'

Not sure if you can include an f string value inserts in a ValueError message, but if so it might be helpful!

Yep you can do that!

cmbenne3 · 2026-07-08T15:54:54Z

        ]
+
        # The 200 was derived from B757 - the largest single aisle western desig.
        if num_economy_class_pax > 200:


This comment is outside the scope of the PR, and probably one for @jkirk5 - should these if/else blocks that set the values of inputs/options be moved out of the fuselage calculation component and into preprocessors? That would clean up the component, and set the 'defaults' for sensible values elsewhere in the code...?

jkirk5

Some additional comments, full review WIP

jkirk5 · 2026-07-10T21:40:25Z

+            if design_type == AircraftTypes.BLENDED_WING_BODY:
+                if verbosity >= Verbosity.BRIEF:
+                    raise UserWarning('Aircraft.Fuselage.SEAT_WIDTH_ECONOMY is not set.')


As far as I can tell there isn't a reason to raise an error if this variable is missing, I don't think we need these lines

jkirk5 · 2026-07-10T21:41:48Z

+                if verbosity >= Verbosity.BRIEF:
+                    aviary_options.set_val(Aircraft.Fuselage.SEAT_WIDTH_FIRST, 28.0, 'inch')


You are only setting this default if verbosity is set to a certain level?! Maybe the verbosity line got included by accident, remove it

jkirk5 · 2026-07-10T21:43:40Z

+        if mass_method == LegacyCode.FLOPS:
+            if design_type == AircraftTypes.TRANSPORT:
+                aviary_options.set_val(Aircraft.Fuselage.SEAT_WIDTH_FIRST, 25.0, 'inch')
+        else:


The way this code is set up is there are only defaults for FLOPS transport and GASP BWB being set here? If so, add an elif mass_method is LegacyCode.GASP: instead of just an else so it still works if more mass methods are added.

jkirk5 · 2026-07-10T21:52:17Z

+                print('Warning: No business class passengers or cabins are included.')
+        if (pax_FC + pax_BC) > pax:
            raise ValueError(
                'Number of first class passengers must not exceed the total number of passengers.'


Yep you can do that!

jkirk5 · 2026-07-10T22:04:41Z

+    def test_detailed_layout(self):
+        """Test DetailedCabinLayout component."""
+        case_name = 'LargeSingleAisle1FLOPS'
+        flops_inputs = get_flops_inputs(case_name)
+        flops_inputs.set_val(Aircraft.Fuselage.SIMPLE_LAYOUT, False)
+        flops_inputs.set_val(Settings.VERBOSITY, 0)
+
+        # do not override these variables which are outputs from DetailedCabinLayout
+        flops_inputs.delete(Aircraft.Fuselage.LENGTH)
+        flops_inputs.delete(Aircraft.Fuselage.PASSENGER_COMPARTMENT_LENGTH)
+        flops_inputs.delete(Aircraft.Fuselage.MAX_WIDTH)
+        flops_inputs.delete(Aircraft.Fuselage.MAX_HEIGHT)
+
+        engines = [build_engine_deck(flops_inputs)]
+        preprocess_options(flops_inputs, engine_models=engines)
+        # get geom subsystem only
+        default_premission_subsystems = [get_default_premission_subsystems('FLOPS', engines)[1]]
+
+        prob = self.prob
+
+        prob.model.add_subsystem(
+            'pre_mission',
+            CorePreMission(
+                aviary_options=flops_inputs,
+                subsystems=default_premission_subsystems,
+                subsystem_options={},
+            ),
+            promotes_inputs=['*'],
+            promotes_outputs=['*'],
+        )
+
+        setup_model_options(prob, flops_inputs)
+        prob.setup(check=False, force_alloc_complex=True)
+        set_aviary_initial_values(prob, flops_inputs)
+        prob.run_model()
+
+        expected_values = {
+            # geometry subsystem, DetailedCabinLayout component
+            Aircraft.Fuselage.LENGTH: 148.37731944,
+            Aircraft.Fuselage.PASSENGER_COMPARTMENT_LENGTH: 108.37731944,
+            Aircraft.Fuselage.MAX_WIDTH: 12.19,
+            Aircraft.Fuselage.MAX_HEIGHT: 13.09,
+        }
+
+        tol = 1e-5
+        for var_name, expected in expected_values.items():
+            with self.subTest(var=var_name):
+                assert_near_equal(prob[var_name], expected, tol)
+


This test is completely redundant with the tests in flops_based test_fuselage.py! We don't need it here too
React

xjjiang and others added 14 commits June 26, 2026 12:31

renamed Aircraft.Fuselage.SEAT_WIDTH to Aircraft.Fuselage.SEAT_WIDTH_…

363a42e

…ECONOMY

renamed Aircraft.Fuselage.SEAT_WIDTH to Aircraft.Fuselage.SEAT_WIDTH_…

a00038e

…ECONOMY. Fixed a bug DetailedCabinLayout. Added business class to DetailedCabinLayout

added Aircraft.Fuselage.SEAT_WIDTH_FIRST and Aircraft.Fuselage.SEAT_W…

1ba5541

…IDTH_BUSINESS

minor update

17997a0

try again

bb2fb13

try again 2

df38d4a

minor update

9f24c4c

minor mix

d9c7d5d

fixed wrong order

2c47b5e

update sizing_results_for_test.json

9476478

Merge branch 'main' into fuselage_layout

769eb24

update DetailedCabinLayout

6f972aa

Merge branch 'OpenMDAO:main' into fuselage_layout

df14090

added a unit test with business class

303a3a8

xjjiang force-pushed the fuselage_layout branch from a94c60a to 303a3a8 Compare June 30, 2026 21:43

xjjiang added 12 commits June 30, 2026 18:09

renamed Aircraft.Fuselage.SEAT_WIDTH to Aircraft.Fuselage.SEAT_WIDTH_…

01d6ebf

…ECONOMY. added Aircraft.Fuselage.SEAT_WIDTH_BUSINESS and Aircraft.Fuselage.SEAT_WIDTH_FIRST. removed LEAPS1.

put LEAPS1 tag back

cd4295a

preprocessed Aircraft.Fuselage.SEAT_WIDTH_ECONOMY and Aircraft.Fusela…

5e7fd7f

…ge.SEAT_WIDTH_FIRST

added business class to GASP based fuselage layout

1deece1

removed one tag of LEAPS1

1b2c2b7

removed one LEAPS1.

3206ad0

removed another LEAPS1

0b3355b

removed the last LEAPS1

c6a9c87

put LEAPS1 back

c30fa28

added and fine tune business class layout.

8b10ad2

update doc for GASP based BWB

f53ed86

blended_wing_body_GASP.ipynb

1de0fde

xjjiang marked this pull request as ready for review July 1, 2026 19:00

xjjiang changed the title ~~[Draft] Fuselage layout enhancement and modification~~ Fuselage layout enhancement and modification Jul 1, 2026

minor update

f608b9c

xjjiang marked this pull request as draft July 1, 2026 23:13

xjjiang changed the title ~~Fuselage layout enhancement and modification~~ [Draft] Fuselage layout enhancement and modification Jul 1, 2026

xjjiang and others added 9 commits July 1, 2026 20:32

added a warning message when business class seats are included for tr…

ec1f18d

…ansporters

Merge branch 'OpenMDAO:main' into fuselage_layout

eb1df71

Merge branch 'OpenMDAO:main' into fuselage_layout

8691551

Merge branch 'OpenMDAO:main' into fuselage_layout

ed479e1

added a m=warning message when business class is included that may af…

c165efa

…fect fuselage layout

work in progress: adding a unit test for the case when detailed layou…

2942a08

…t is used for transporter aircraft using FLOPS based geometry.

Merge branch 'OpenMDAO:main' into fuselage_layout

3803d7d

XMerge branch 'fuselage_layout' of github.com:xjjiang/om-Aviary into …

bacf737

…fuselage_layout

added a unit test for detailed layout in FLOPS based geometry

1544895

xjjiang changed the title ~~[Draft] Fuselage layout enhancement and modification~~ Fuselage layout enhancement and modification Jul 7, 2026

xjjiang marked this pull request as ready for review July 7, 2026 17:25

xjjiang and others added 3 commits July 7, 2026 13:33

minor update

8686233

minor update to test_flops_based_premission.py

33c4c26

Merge branch 'OpenMDAO:main' into fuselage_layout

170eede

cmbenne3 reviewed Jul 8, 2026

View reviewed changes

xjjiang mentioned this pull request Jul 10, 2026

Convert Options to Inputs #598

Open

jkirk5 reviewed Jul 10, 2026

View reviewed changes


		self.aviary_options = AviaryValues()

		self.aviary_options.set_val(Aircraft.CrewPayload.Design.NUM_SEATS_ABREAST_ECONOMY, 18)

	'Number of first class passengers must not exceed the total number of passengers.'
	f'Number of first {pax_FC} and business {pax_BC} class passengers must not exceed the total number of passengers {pax}.'

		if verbosity >= Verbosity.BRIEF:
		aviary_options.set_val(Aircraft.Fuselage.SEAT_WIDTH_FIRST, 28.0, 'inch')

Uh oh!

Conversation

xjjiang commented Jun 26, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary

Related Issues

Backwards incompatibilities

New Dependencies

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

jkirk5 left a comment

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

jkirk5 Jul 10, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

xjjiang commented Jun 26, 2026 •

edited

Loading

jkirk5 Jul 10, 2026 •

edited

Loading