diff --git a/.bumpversion.cfg b/.bumpversion.cfg
index a3a4c1790..e7775a430 100644
--- a/.bumpversion.cfg
+++ b/.bumpversion.cfg
@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 0.9.4-dev
+current_version = 0.9.7-dev
 commit = False
 tag = False
 parse = (?P<major>\d+)\.(?P<minor>\d+)\.(?P<patch>\d+)(\-(?P<release>[a-z]+))?
diff --git a/.github/ISSUE_TEMPLATE/bug_report.yml b/.github/ISSUE_TEMPLATE/bug_report.yml
index cd237761c..ef04da1be 100644
--- a/.github/ISSUE_TEMPLATE/bug_report.yml
+++ b/.github/ISSUE_TEMPLATE/bug_report.yml
@@ -21,7 +21,7 @@ body:
     attributes:
       label: Aviary Version
       description: What version of Aviary is being used.
-      placeholder: "0.9.4-dev"
+      placeholder: "0.9.7-dev"
     validations:
       required: true
   - type: textarea
diff --git a/CITATION.cff b/CITATION.cff
index c44eee143..4a174317b 100644
--- a/CITATION.cff
+++ b/CITATION.cff
@@ -27,4 +27,4 @@ identifiers:
 repository-code: 'https://github.com/OpenMDAO/Aviary'
 repository: 'https://github.com/OpenMDAO/Aviary_Community'
 license: Apache-2.0
-version: 0.9.3
+version: 0.9.7
diff --git a/aviary/__init__.py b/aviary/__init__.py
index 50533e307..b336982d3 100644
--- a/aviary/__init__.py
+++ b/aviary/__init__.py
@@ -1 +1 @@
-__version__ = "0.9.6"
+__version__ = "0.9.7-dev"
diff --git a/aviary/subsystems/geometry/flops_based/canard.py b/aviary/subsystems/geometry/flops_based/canard.py
index b9ca8d92a..0542dc5fa 100644
--- a/aviary/subsystems/geometry/flops_based/canard.py
+++ b/aviary/subsystems/geometry/flops_based/canard.py
@@ -18,11 +18,11 @@ def initialize(self):
             desc='collection of Aircraft/Mission specific options')
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Canard.AREA, 0.0)
-        add_aviary_input(self, Aircraft.Canard.THICKNESS_TO_CHORD, 0.0)
-        add_aviary_input(self, Aircraft.Canard.WETTED_AREA_SCALER, 1.0)
+        add_aviary_input(self, Aircraft.Canard.AREA)
+        add_aviary_input(self, Aircraft.Canard.THICKNESS_TO_CHORD)
+        add_aviary_input(self, Aircraft.Canard.WETTED_AREA_SCALER)
 
-        add_aviary_output(self, Aircraft.Canard.WETTED_AREA, 0.0)
+        add_aviary_output(self, Aircraft.Canard.WETTED_AREA)
 
     def setup_partials(self):
         self.declare_partials(
diff --git a/aviary/subsystems/geometry/flops_based/characteristic_lengths.py b/aviary/subsystems/geometry/flops_based/characteristic_lengths.py
index ef9ce92dc..14396c9d8 100644
--- a/aviary/subsystems/geometry/flops_based/characteristic_lengths.py
+++ b/aviary/subsystems/geometry/flops_based/characteristic_lengths.py
@@ -21,66 +21,60 @@ def setup(self):
 
         self.add_input(Names.CROOT, 0.0, units='unitless')
 
-        add_aviary_input(self, Aircraft.Canard.AREA, 0.0)
-        add_aviary_input(self, Aircraft.Canard.ASPECT_RATIO, 0.0)
+        add_aviary_input(self, Aircraft.Canard.AREA)
+        add_aviary_input(self, Aircraft.Canard.ASPECT_RATIO)
         # add_aviary_input(self, Aircraft.Canard.LAMINAR_FLOW_LOWER, 0.0)
         # add_aviary_input(self, Aircraft.Canard.LAMINAR_FLOW_UPPER, 0.0)
-        add_aviary_input(self, Aircraft.Canard.THICKNESS_TO_CHORD, 0.0)
+        add_aviary_input(self, Aircraft.Canard.THICKNESS_TO_CHORD)
 
-        add_aviary_input(self, Aircraft.Fuselage.AVG_DIAMETER, 0.0)
+        add_aviary_input(self, Aircraft.Fuselage.AVG_DIAMETER)
         # add_aviary_input(self, Aircraft.Fuselage.LAMINAR_FLOW_LOWER, 0.0)
         # add_aviary_input(self, Aircraft.Fuselage.LAMINAR_FLOW_UPPER, 0.0)
-        add_aviary_input(self, Aircraft.Fuselage.LENGTH, 0.0)
+        add_aviary_input(self, Aircraft.Fuselage.LENGTH)
 
-        add_aviary_input(self, Aircraft.HorizontalTail.AREA, 0.0)
-        add_aviary_input(self, Aircraft.HorizontalTail.ASPECT_RATIO, 4.75)
+        add_aviary_input(self, Aircraft.HorizontalTail.AREA)
+        add_aviary_input(self, Aircraft.HorizontalTail.ASPECT_RATIO)
         # add_aviary_input(self, Aircraft.HorizontalTail.LAMINAR_FLOW_LOWER, 0.0)
         # add_aviary_input(self, Aircraft.HorizontalTail.LAMINAR_FLOW_UPPER, 0.0)
-        add_aviary_input(self, Aircraft.HorizontalTail.THICKNESS_TO_CHORD, 0.0)
+        add_aviary_input(self, Aircraft.HorizontalTail.THICKNESS_TO_CHORD)
 
-        add_aviary_input(self, Aircraft.Nacelle.AVG_DIAMETER, np.zeros(num_engine_type))
-        add_aviary_input(self, Aircraft.Nacelle.AVG_LENGTH, np.zeros(num_engine_type))
+        add_aviary_input(self, Aircraft.Nacelle.AVG_DIAMETER, shape=num_engine_type)
+        add_aviary_input(self, Aircraft.Nacelle.AVG_LENGTH, shape=num_engine_type)
         # add_aviary_input(self, Aircraft.Nacelle.LAMINAR_FLOW_LOWER, 0.0)
         # add_aviary_input(self, Aircraft.Nacelle.LAMINAR_FLOW_UPPER, 0.0)
 
-        add_aviary_input(self, Aircraft.VerticalTail.AREA, 0.0)
-        add_aviary_input(self, Aircraft.VerticalTail.ASPECT_RATIO, 0.0)
+        add_aviary_input(self, Aircraft.VerticalTail.AREA)
+        add_aviary_input(self, Aircraft.VerticalTail.ASPECT_RATIO)
         # add_aviary_input(self, Aircraft.VerticalTail.LAMINAR_FLOW_LOWER, 0.0)
         # add_aviary_input(self, Aircraft.VerticalTail.LAMINAR_FLOW_UPPER, 0.0)
-        add_aviary_input(self, Aircraft.VerticalTail.THICKNESS_TO_CHORD, 0.0)
+        add_aviary_input(self, Aircraft.VerticalTail.THICKNESS_TO_CHORD)
 
-        add_aviary_input(self, Aircraft.Wing.AREA, 0.0)
-        add_aviary_input(self, Aircraft.Wing.ASPECT_RATIO, 0.0)
-        add_aviary_input(self, Aircraft.Wing.GLOVE_AND_BAT, 0.0)
-        add_aviary_input(self, Aircraft.Wing.TAPER_RATIO, 0.0)
-        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD, 0.0)
+        add_aviary_input(self, Aircraft.Wing.AREA)
+        add_aviary_input(self, Aircraft.Wing.ASPECT_RATIO)
+        add_aviary_input(self, Aircraft.Wing.GLOVE_AND_BAT)
+        add_aviary_input(self, Aircraft.Wing.TAPER_RATIO)
+        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD)
         # add_aviary_input(self, Aircraft.Wing.LAMINAR_FLOW_LOWER, 0.0)
         # add_aviary_input(self, Aircraft.Wing.LAMINAR_FLOW_UPPER, 0.0)
 
-        add_aviary_output(self, Aircraft.Canard.CHARACTERISTIC_LENGTH, 0.0)
-        add_aviary_output(self, Aircraft.Canard.FINENESS, 0.0)
+        add_aviary_output(self, Aircraft.Canard.CHARACTERISTIC_LENGTH)
+        add_aviary_output(self, Aircraft.Canard.FINENESS)
 
-        add_aviary_output(self, Aircraft.Fuselage.CHARACTERISTIC_LENGTH, 0.0)
-        add_aviary_output(self, Aircraft.Fuselage.FINENESS, 0.0)
+        add_aviary_output(self, Aircraft.Fuselage.CHARACTERISTIC_LENGTH)
+        add_aviary_output(self, Aircraft.Fuselage.FINENESS)
 
-        add_aviary_output(
-            self, Aircraft.HorizontalTail.CHARACTERISTIC_LENGTH, 0.0
-        )
-
-        add_aviary_output(self, Aircraft.HorizontalTail.FINENESS, 0.0)
+        add_aviary_output(self, Aircraft.HorizontalTail.CHARACTERISTIC_LENGTH)
+        add_aviary_output(self, Aircraft.HorizontalTail.FINENESS)
 
         add_aviary_output(self, Aircraft.Nacelle.CHARACTERISTIC_LENGTH,
-                          np.zeros(num_engine_type))
-        add_aviary_output(self, Aircraft.Nacelle.FINENESS, np.zeros(num_engine_type))
-
-        add_aviary_output(
-            self, Aircraft.VerticalTail.CHARACTERISTIC_LENGTH, 0.0
-        )
+                          shape=num_engine_type)
+        add_aviary_output(self, Aircraft.Nacelle.FINENESS, shape=num_engine_type)
 
-        add_aviary_output(self, Aircraft.VerticalTail.FINENESS, 0.0)
+        add_aviary_output(self, Aircraft.VerticalTail.CHARACTERISTIC_LENGTH)
+        add_aviary_output(self, Aircraft.VerticalTail.FINENESS)
 
-        add_aviary_output(self, Aircraft.Wing.CHARACTERISTIC_LENGTH, 0.0)
-        add_aviary_output(self, Aircraft.Wing.FINENESS, 0.0)
+        add_aviary_output(self, Aircraft.Wing.CHARACTERISTIC_LENGTH)
+        add_aviary_output(self, Aircraft.Wing.FINENESS)
 
     def setup_partials(self):
         self._setup_partials_wing()
diff --git a/aviary/subsystems/geometry/flops_based/fuselage.py b/aviary/subsystems/geometry/flops_based/fuselage.py
index 2b73da704..ca87a6266 100644
--- a/aviary/subsystems/geometry/flops_based/fuselage.py
+++ b/aviary/subsystems/geometry/flops_based/fuselage.py
@@ -16,12 +16,12 @@ class FuselagePrelim(om.ExplicitComponent):
     """
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Fuselage.LENGTH, val=0.0)
-        add_aviary_input(self, Aircraft.Fuselage.MAX_HEIGHT, val=0.0)
-        add_aviary_input(self, Aircraft.Fuselage.MAX_WIDTH, val=0.0)
+        add_aviary_input(self, Aircraft.Fuselage.LENGTH)
+        add_aviary_input(self, Aircraft.Fuselage.MAX_HEIGHT)
+        add_aviary_input(self, Aircraft.Fuselage.MAX_WIDTH)
 
-        add_aviary_output(self, Aircraft.Fuselage.AVG_DIAMETER, val=0.0)
-        add_aviary_output(self, Aircraft.Fuselage.PLANFORM_AREA, val=0.0)
+        add_aviary_output(self, Aircraft.Fuselage.AVG_DIAMETER)
+        add_aviary_output(self, Aircraft.Fuselage.PLANFORM_AREA)
 
     def setup_partials(self):
         self.declare_partials(of=[Aircraft.Fuselage.AVG_DIAMETER],
diff --git a/aviary/subsystems/geometry/flops_based/nacelle.py b/aviary/subsystems/geometry/flops_based/nacelle.py
index c8c9adf97..4b2c5fab7 100644
--- a/aviary/subsystems/geometry/flops_based/nacelle.py
+++ b/aviary/subsystems/geometry/flops_based/nacelle.py
@@ -18,16 +18,13 @@ def initialize(self):
 
     def setup(self):
         num_engine_type = len(self.options[Aircraft.Engine.NUM_ENGINES])
-        add_aviary_input(self, Aircraft.Nacelle.AVG_DIAMETER,
-                         val=np.zeros(num_engine_type))
-        add_aviary_input(self, Aircraft.Nacelle.AVG_LENGTH,
-                         val=np.zeros(num_engine_type))
+        add_aviary_input(self, Aircraft.Nacelle.AVG_DIAMETER, shape=num_engine_type)
+        add_aviary_input(self, Aircraft.Nacelle.AVG_LENGTH, shape=num_engine_type)
         add_aviary_input(self, Aircraft.Nacelle.WETTED_AREA_SCALER,
-                         val=np.zeros(num_engine_type))
+                         shape=num_engine_type)
 
-        add_aviary_output(self, Aircraft.Nacelle.TOTAL_WETTED_AREA, 0.0)
-        add_aviary_output(self, Aircraft.Nacelle.WETTED_AREA,
-                          val=np.zeros(num_engine_type))
+        add_aviary_output(self, Aircraft.Nacelle.TOTAL_WETTED_AREA)
+        add_aviary_output(self, Aircraft.Nacelle.WETTED_AREA, shape=num_engine_type)
 
     def setup_partials(self):
         # derivatives w.r.t vectorized engine inputs have known sparsity pattern
diff --git a/aviary/subsystems/geometry/flops_based/prep_geom.py b/aviary/subsystems/geometry/flops_based/prep_geom.py
index 37cf27e1b..49ac2ed27 100644
--- a/aviary/subsystems/geometry/flops_based/prep_geom.py
+++ b/aviary/subsystems/geometry/flops_based/prep_geom.py
@@ -116,27 +116,25 @@ def initialize(self):
         add_aviary_option(self, Aircraft.Wing.SPAN_EFFICIENCY_REDUCTION)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Fuselage.AVG_DIAMETER, 0.0)
-        add_aviary_input(self, Aircraft.Fuselage.MAX_WIDTH, 0.0)
-
-        add_aviary_input(self, Aircraft.HorizontalTail.AREA, 0.0)
-        add_aviary_input(self, Aircraft.HorizontalTail.ASPECT_RATIO,
-                         4.75, units="unitless")
-        add_aviary_input(self, Aircraft.HorizontalTail.TAPER_RATIO,
-                         0.352, units="unitless")
-        add_aviary_input(self, Aircraft.HorizontalTail.THICKNESS_TO_CHORD, 0.0)
-
-        add_aviary_input(self, Aircraft.VerticalTail.AREA, 0.0)
-        add_aviary_input(self, Aircraft.VerticalTail.ASPECT_RATIO, 0.0)
-        add_aviary_input(self, Aircraft.VerticalTail.TAPER_RATIO, 0.0)
-        add_aviary_input(self, Aircraft.VerticalTail.THICKNESS_TO_CHORD, 0.0)
-
-        add_aviary_input(self, Aircraft.Wing.AREA, 0.0)
-        add_aviary_input(self, Aircraft.Wing.GLOVE_AND_BAT, 0.0)
+        add_aviary_input(self, Aircraft.Fuselage.AVG_DIAMETER)
+        add_aviary_input(self, Aircraft.Fuselage.MAX_WIDTH)
+
+        add_aviary_input(self, Aircraft.HorizontalTail.AREA)
+        add_aviary_input(self, Aircraft.HorizontalTail.ASPECT_RATIO)
+        add_aviary_input(self, Aircraft.HorizontalTail.TAPER_RATIO)
+        add_aviary_input(self, Aircraft.HorizontalTail.THICKNESS_TO_CHORD)
+
+        add_aviary_input(self, Aircraft.VerticalTail.AREA)
+        add_aviary_input(self, Aircraft.VerticalTail.ASPECT_RATIO)
+        add_aviary_input(self, Aircraft.VerticalTail.TAPER_RATIO)
+        add_aviary_input(self, Aircraft.VerticalTail.THICKNESS_TO_CHORD)
+
+        add_aviary_input(self, Aircraft.Wing.AREA)
+        add_aviary_input(self, Aircraft.Wing.GLOVE_AND_BAT)
         # NOTE: FLOPS/aviary1 calculate span locally
-        add_aviary_input(self, Aircraft.Wing.SPAN, 0.0)
-        add_aviary_input(self, Aircraft.Wing.TAPER_RATIO, 0.0)
-        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD, 0.0)
+        add_aviary_input(self, Aircraft.Wing.SPAN)
+        add_aviary_input(self, Aircraft.Wing.TAPER_RATIO)
+        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD)
 
         self.add_output(Names.CROOT, 1.0, units='unitless')
         self.add_output(Names.CROOTB, 1.0, units='unitless')
@@ -492,10 +490,10 @@ def setup(self):
         self.add_input(Names.XDX, 0.0, units='unitless')
         self.add_input(Names.XMULT, 0.0, units='unitless')
 
-        add_aviary_input(self, Aircraft.Wing.AREA, 0.0)
-        add_aviary_input(self, Aircraft.Wing.WETTED_AREA_SCALER, 1.0)
+        add_aviary_input(self, Aircraft.Wing.AREA)
+        add_aviary_input(self, Aircraft.Wing.WETTED_AREA_SCALER)
 
-        add_aviary_output(self, Aircraft.Wing.WETTED_AREA, 0.0)
+        add_aviary_output(self, Aircraft.Wing.WETTED_AREA)
 
     def setup_partials(self):
         self.declare_partials(
@@ -567,19 +565,17 @@ def setup(self):
         self.add_input(Names.XMULTH, 0.0, units='unitless')
         self.add_input(Names.XMULTV, 0.0, units='unitless')
 
-        add_aviary_input(self, Aircraft.HorizontalTail.AREA, 0.0)
+        add_aviary_input(self, Aircraft.HorizontalTail.AREA)
 
-        add_aviary_input(
-            self, Aircraft.HorizontalTail.VERTICAL_TAIL_FRACTION, 0.0
-        )
+        add_aviary_input(self, Aircraft.HorizontalTail.VERTICAL_TAIL_FRACTION)
 
-        add_aviary_input(self, Aircraft.HorizontalTail.WETTED_AREA_SCALER, 1.0)
+        add_aviary_input(self, Aircraft.HorizontalTail.WETTED_AREA_SCALER)
 
-        add_aviary_input(self, Aircraft.VerticalTail.AREA, 0.0)
-        add_aviary_input(self, Aircraft.VerticalTail.WETTED_AREA_SCALER, 1.0)
+        add_aviary_input(self, Aircraft.VerticalTail.AREA)
+        add_aviary_input(self, Aircraft.VerticalTail.WETTED_AREA_SCALER)
 
-        add_aviary_output(self, Aircraft.HorizontalTail.WETTED_AREA, 0.0)
-        add_aviary_output(self, Aircraft.VerticalTail.WETTED_AREA, 0.0)
+        add_aviary_output(self, Aircraft.HorizontalTail.WETTED_AREA)
+        add_aviary_output(self, Aircraft.VerticalTail.WETTED_AREA)
 
     def setup_partials(self):
         self.declare_partials(
@@ -727,27 +723,24 @@ def setup(self):
         self.add_input(Names.CROTVT, 0.0, units='unitless')
         self.add_input(Names.CRTHTB, 0.0, units='unitless')
 
-        add_aviary_input(self, Aircraft.Fuselage.AVG_DIAMETER, 0.0)
-        add_aviary_input(self, Aircraft.Fuselage.LENGTH, 0.0)
-        add_aviary_input(self, Aircraft.Fuselage.WETTED_AREA_SCALER, 1.0)
-
-        add_aviary_input(self, Aircraft.HorizontalTail.THICKNESS_TO_CHORD, 0.0)
+        add_aviary_input(self, Aircraft.Fuselage.AVG_DIAMETER)
+        add_aviary_input(self, Aircraft.Fuselage.LENGTH)
+        add_aviary_input(self, Aircraft.Fuselage.WETTED_AREA_SCALER)
 
-        add_aviary_input(
-            self, Aircraft.HorizontalTail.VERTICAL_TAIL_FRACTION, 0.0
-        )
+        add_aviary_input(self, Aircraft.HorizontalTail.THICKNESS_TO_CHORD)
+        add_aviary_input(self, Aircraft.HorizontalTail.VERTICAL_TAIL_FRACTION)
 
-        add_aviary_input(self, Aircraft.VerticalTail.THICKNESS_TO_CHORD, 0.0)
+        add_aviary_input(self, Aircraft.VerticalTail.THICKNESS_TO_CHORD)
 
-        add_aviary_input(self, Aircraft.Wing.AREA, 0.0)
-        add_aviary_input(self, Aircraft.Wing.ASPECT_RATIO, 0.0)
-        add_aviary_input(self, Aircraft.Wing.GLOVE_AND_BAT, 0.0)
-        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD, 0.0)
+        add_aviary_input(self, Aircraft.Wing.AREA)
+        add_aviary_input(self, Aircraft.Wing.ASPECT_RATIO)
+        add_aviary_input(self, Aircraft.Wing.GLOVE_AND_BAT)
+        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD)
 
-        add_aviary_output(self, Aircraft.Fuselage.CROSS_SECTION, 0.0)
-        add_aviary_output(self, Aircraft.Fuselage.DIAMETER_TO_WING_SPAN, 0.0)
-        add_aviary_output(self, Aircraft.Fuselage.LENGTH_TO_DIAMETER, 0.0)
-        add_aviary_output(self, Aircraft.Fuselage.WETTED_AREA, 0.0)
+        add_aviary_output(self, Aircraft.Fuselage.CROSS_SECTION)
+        add_aviary_output(self, Aircraft.Fuselage.DIAMETER_TO_WING_SPAN)
+        add_aviary_output(self, Aircraft.Fuselage.LENGTH_TO_DIAMETER)
+        add_aviary_output(self, Aircraft.Fuselage.WETTED_AREA)
 
     def setup_partials(self):
         self.declare_partials(
diff --git a/aviary/subsystems/geometry/flops_based/wetted_area_total.py b/aviary/subsystems/geometry/flops_based/wetted_area_total.py
index 63b2a4fab..f787fb4a6 100644
--- a/aviary/subsystems/geometry/flops_based/wetted_area_total.py
+++ b/aviary/subsystems/geometry/flops_based/wetted_area_total.py
@@ -11,14 +11,14 @@ class TotalWettedArea(om.ExplicitComponent):
     """
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Canard.WETTED_AREA, 0.0)
-        add_aviary_input(self, Aircraft.Fuselage.WETTED_AREA, 0.0)
-        add_aviary_input(self, Aircraft.HorizontalTail.WETTED_AREA, 0.0)
-        add_aviary_input(self, Aircraft.Nacelle.TOTAL_WETTED_AREA, 0.0)
-        add_aviary_input(self, Aircraft.VerticalTail.WETTED_AREA, 0.0)
-        add_aviary_input(self, Aircraft.Wing.WETTED_AREA, 0.0)
+        add_aviary_input(self, Aircraft.Canard.WETTED_AREA)
+        add_aviary_input(self, Aircraft.Fuselage.WETTED_AREA)
+        add_aviary_input(self, Aircraft.HorizontalTail.WETTED_AREA)
+        add_aviary_input(self, Aircraft.Nacelle.TOTAL_WETTED_AREA)
+        add_aviary_input(self, Aircraft.VerticalTail.WETTED_AREA)
+        add_aviary_input(self, Aircraft.Wing.WETTED_AREA)
 
-        add_aviary_output(self, Aircraft.Design.TOTAL_WETTED_AREA, 0.0)
+        add_aviary_output(self, Aircraft.Design.TOTAL_WETTED_AREA)
 
     def setup_partials(self):
         self.declare_partials('*', '*', val=1.0)
diff --git a/aviary/subsystems/geometry/flops_based/wing.py b/aviary/subsystems/geometry/flops_based/wing.py
index f6c7c09e2..4f945ff49 100644
--- a/aviary/subsystems/geometry/flops_based/wing.py
+++ b/aviary/subsystems/geometry/flops_based/wing.py
@@ -14,11 +14,11 @@ class WingPrelim(om.ExplicitComponent):
     """
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Wing.AREA, val=0.0)
-        add_aviary_input(self, Aircraft.Wing.GLOVE_AND_BAT, val=0.0)
-        add_aviary_input(self, Aircraft.Wing.SPAN, val=0.0)
+        add_aviary_input(self, Aircraft.Wing.AREA)
+        add_aviary_input(self, Aircraft.Wing.GLOVE_AND_BAT)
+        add_aviary_input(self, Aircraft.Wing.SPAN)
 
-        add_aviary_output(self, Aircraft.Wing.ASPECT_RATIO, val=0.0)
+        add_aviary_output(self, Aircraft.Wing.ASPECT_RATIO)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
diff --git a/aviary/subsystems/geometry/gasp_based/electric.py b/aviary/subsystems/geometry/gasp_based/electric.py
index 07d423edd..ac58a4a0b 100644
--- a/aviary/subsystems/geometry/gasp_based/electric.py
+++ b/aviary/subsystems/geometry/gasp_based/electric.py
@@ -17,13 +17,11 @@ def setup(self):
         total_num_wing_engines = self.options[Aircraft.Propulsion.TOTAL_NUM_WING_ENGINES]
 
         add_aviary_input(self, Aircraft.Engine.WING_LOCATIONS,
-                         val=np.full(int(total_num_wing_engines/2), 0.35))
+                         shape=int(total_num_wing_engines/2))
+        add_aviary_input(self, Aircraft.Wing.SPAN)
+        add_aviary_input(self, Aircraft.Fuselage.AVG_DIAMETER)
 
-        add_aviary_input(self, Aircraft.Wing.SPAN, val=128)
-
-        add_aviary_input(self, Aircraft.Fuselage.AVG_DIAMETER, val=10)
-
-        add_aviary_output(self, Aircraft.Electrical.HYBRID_CABLE_LENGTH, val=0)
+        add_aviary_output(self, Aircraft.Electrical.HYBRID_CABLE_LENGTH)
 
         self.declare_partials(
             Aircraft.Electrical.HYBRID_CABLE_LENGTH,
diff --git a/aviary/subsystems/geometry/gasp_based/empennage.py b/aviary/subsystems/geometry/gasp_based/empennage.py
index 5cdb6aa03..c1446c86b 100644
--- a/aviary/subsystems/geometry/gasp_based/empennage.py
+++ b/aviary/subsystems/geometry/gasp_based/empennage.py
@@ -33,23 +33,19 @@ def setup(self):
         else:
             self.k = [0.43, 0.38, 0.85]
 
-        add_aviary_input(self, Aircraft.HorizontalTail.VERTICAL_TAIL_FRACTION, val=0)
+        add_aviary_input(self, Aircraft.HorizontalTail.VERTICAL_TAIL_FRACTION)
 
-        add_aviary_input(self, Aircraft.Fuselage.LENGTH, val=129.4)
+        add_aviary_input(self, Aircraft.Fuselage.LENGTH)
 
         self.add_input("cab_w", 13.1, units="ft", desc="SWF: Cabin width")
 
-        add_aviary_input(self, Aircraft.Wing.AREA, val=1370)
+        add_aviary_input(self, Aircraft.Wing.AREA)
 
-        self.add_input(
-            "wing_ref",
-            12.615,
-            units="ft",
-            desc=(
-                "CBARW | B: Wing reference parameter. Wing chord for a "
-                "horizontal tail. Wing span for a vertical tail."
-            ),
-        )
+        self.add_input("wing_ref", 12.615, units="ft",
+                       desc=(
+                           "CBARW | B: Wing reference parameter. Wing chord for a "
+                           "horizontal tail. Wing span for a vertical tail.")
+                       )
 
         self.add_output(
             "vol_coef", units="unitless", desc="VBARH | VBARV: Tail volume coefficient")
@@ -90,37 +86,28 @@ class TailSize(om.ExplicitComponent):
 
     def setup(self):
         # defaults here for Large Single Aisle 1 horizontal tail
-        self.add_input(
-            "vol_coef", 1.189, units="unitless",
-            desc="VBARH | VBARV: Horizontal tail volume coefficient"
-        )
-
-        add_aviary_input(self, Aircraft.Wing.AREA, val=1370)
-
-        self.add_input(
-            "r_arm",
-            0.2307,
-            units="unitless",
-            desc=(
-                "COELTH | BOELTV: For a horizontal tail, the ratio of "
-                "wing chord to tail moment arm. For a vertical tail, the "
-                "ratio of wing span to vertical tail moment arm."
-            ),
-        )
-        self.add_input(
-            "wing_ref",
-            12.615,
-            units="ft",
-            desc=(
-                "CBARW | B: Reference wing parameter for tail moment arm. "
-                "For a horizontal tail, the mean wing chord. For a "
-                "vertical tail, the wing span."
-            ),
-        )
-        self.add_input(
-            "ar", 4.75, units="unitless", desc="ARHT | ARVT: Tail aspect ratio.")
-        self.add_input(
-            "tr", 0.352, units="unitless", desc="SLMH | SLMV: Tail taper ratio.")
+        self.add_input("vol_coef", 1.189, units="unitless",
+                       desc="VBARH | VBARV: Horizontal tail volume coefficient"
+                       )
+
+        add_aviary_input(self, Aircraft.Wing.AREA)
+
+        self.add_input("r_arm", 0.2307, units="unitless",
+                       desc=(
+                           "COELTH | BOELTV: For a horizontal tail, the ratio of "
+                           "wing chord to tail moment arm. For a vertical tail, the "
+                           "ratio of wing span to vertical tail moment arm.")
+                       )
+        self.add_input("wing_ref", 12.615, units="ft",
+                       desc=(
+                           "CBARW | B: Reference wing parameter for tail moment arm. "
+                           "For a horizontal tail, the mean wing chord. For a "
+                           "vertical tail, the wing span.")
+                       )
+        self.add_input("ar", 0.0, units="unitless",
+                       desc="ARHT | ARVT: Tail aspect ratio.")
+        self.add_input("tr", 0.0, units="unitless",
+                       desc="SLMH | SLMV: Tail taper ratio.")
 
         self.add_output("area", units="ft**2", desc="SHT | SVT: Tail area")
         self.add_output("span", units="ft", desc="BHT | BVT: Tail span")
@@ -307,11 +294,6 @@ def setup(self):
             promotes_outputs=higher_level_outputs_vtail + rename_outputs_vtail,
         )
 
-        self.set_input_defaults(Aircraft.Wing.AVERAGE_CHORD, 12.615, units="ft")
-        self.set_input_defaults(Aircraft.Wing.SPAN, 117.8054, units="ft")
-
-        # override horizontal tail defaults
-        self.set_input_defaults(Aircraft.VerticalTail.VOLUME_COEFFICIENT, 0.145)
-        self.set_input_defaults(Aircraft.VerticalTail.MOMENT_RATIO, 2.362)
-        self.set_input_defaults(Aircraft.VerticalTail.ASPECT_RATIO, 1.67)
-        self.set_input_defaults(Aircraft.VerticalTail.TAPER_RATIO, 0.801)
+        # override vertical tail defaults
+        self.set_input_defaults(Aircraft.VerticalTail.ASPECT_RATIO, 0.0)
+        self.set_input_defaults(Aircraft.VerticalTail.TAPER_RATIO, 0.0)
diff --git a/aviary/subsystems/geometry/gasp_based/engine.py b/aviary/subsystems/geometry/gasp_based/engine.py
index 545427ac7..2c9657ca0 100644
--- a/aviary/subsystems/geometry/gasp_based/engine.py
+++ b/aviary/subsystems/geometry/gasp_based/engine.py
@@ -18,18 +18,18 @@ def setup(self):
         num_engine_type = len(self.options[Aircraft.Engine.NUM_ENGINES])
 
         add_aviary_input(self, Aircraft.Engine.REFERENCE_DIAMETER,
-                         np.full(num_engine_type, 5.8))
-        add_aviary_input(self, Aircraft.Engine.SCALE_FACTOR, np.ones(num_engine_type))
+                         shape=num_engine_type)
+        add_aviary_input(self, Aircraft.Engine.SCALE_FACTOR, shape=num_engine_type)
         add_aviary_input(self, Aircraft.Nacelle.CORE_DIAMETER_RATIO,
-                         np.full(num_engine_type, 1.25))
-        add_aviary_input(self, Aircraft.Nacelle.FINENESS, np.full(num_engine_type, 2))
+                         shape=num_engine_type)
+        add_aviary_input(self, Aircraft.Nacelle.FINENESS, shape=num_engine_type)
 
         add_aviary_output(self, Aircraft.Nacelle.AVG_DIAMETER,
-                          val=np.zeros(num_engine_type))
+                          shape=num_engine_type)
         add_aviary_output(self, Aircraft.Nacelle.AVG_LENGTH,
-                          val=np.zeros(num_engine_type))
+                          shape=num_engine_type)
         add_aviary_output(self, Aircraft.Nacelle.SURFACE_AREA,
-                          val=np.zeros(num_engine_type))
+                          shape=num_engine_type)
 
     def setup_partials(self):
         # derivatives w.r.t vectorized engine inputs have known sparsity pattern
diff --git a/aviary/subsystems/geometry/gasp_based/fuselage.py b/aviary/subsystems/geometry/gasp_based/fuselage.py
index f525118f1..ce1b1e241 100644
--- a/aviary/subsystems/geometry/gasp_based/fuselage.py
+++ b/aviary/subsystems/geometry/gasp_based/fuselage.py
@@ -34,10 +34,10 @@ def initialize(self):
 
     def setup(self):
 
-        add_aviary_input(self, Aircraft.Fuselage.DELTA_DIAMETER, val=4.5)
-        add_aviary_input(self, Aircraft.Fuselage.PILOT_COMPARTMENT_LENGTH, val=9.5)
+        add_aviary_input(self, Aircraft.Fuselage.DELTA_DIAMETER)
+        add_aviary_input(self, Aircraft.Fuselage.PILOT_COMPARTMENT_LENGTH)
 
-        add_aviary_output(self, Aircraft.Fuselage.AVG_DIAMETER, val=0, units='inch')
+        add_aviary_output(self, Aircraft.Fuselage.AVG_DIAMETER, units='inch')
         self.add_output("cabin_height", val=0, units="ft", desc="HC: height of cabin")
         self.add_output("cabin_len", val=0, units="ft", desc="LC: length of cabin")
         self.add_output("nose_height", val=0, units="ft", desc="HN: height of nose")
@@ -112,19 +112,17 @@ class FuselageSize(om.ExplicitComponent):
     """
 
     def setup(self):
-
-        add_aviary_input(self, Aircraft.Fuselage.NOSE_FINENESS, val=1)
+        add_aviary_input(self, Aircraft.Fuselage.NOSE_FINENESS)
         self.add_input("nose_height", val=0, units="ft", desc="HN: height of nose")
-        add_aviary_input(self, Aircraft.Fuselage.PILOT_COMPARTMENT_LENGTH, val=9.5)
+        add_aviary_input(self, Aircraft.Fuselage.PILOT_COMPARTMENT_LENGTH)
         self.add_input("cabin_len", val=0, units="ft", desc="LC: length of cabin")
-        add_aviary_input(self, Aircraft.Fuselage.TAIL_FINENESS, val=3)
+        add_aviary_input(self, Aircraft.Fuselage.TAIL_FINENESS)
         self.add_input("cabin_height", val=0, units="ft", desc="HC: height of cabin")
-        add_aviary_input(self, Aircraft.Fuselage.WETTED_AREA_SCALER,
-                         val=1, units="unitless")
+        add_aviary_input(self, Aircraft.Fuselage.WETTED_AREA_SCALER)
 
-        add_aviary_output(self, Aircraft.Fuselage.LENGTH, val=0)
-        add_aviary_output(self, Aircraft.Fuselage.WETTED_AREA, val=0)
-        add_aviary_output(self, Aircraft.TailBoom.LENGTH, val=0)
+        add_aviary_output(self, Aircraft.Fuselage.LENGTH)
+        add_aviary_output(self, Aircraft.Fuselage.WETTED_AREA)
+        add_aviary_output(self, Aircraft.TailBoom.LENGTH)
 
         self.declare_partials(
             Aircraft.Fuselage.LENGTH,
@@ -267,6 +265,3 @@ def setup(self):
             promotes_inputs=connected_input_outputs + ["aircraft:*"],
             promotes_outputs=["aircraft:*"],
         )
-
-        self.set_input_defaults(
-            Aircraft.Fuselage.PILOT_COMPARTMENT_LENGTH, val=9.5, units="ft")
diff --git a/aviary/subsystems/geometry/gasp_based/non_dimensional_conversion.py b/aviary/subsystems/geometry/gasp_based/non_dimensional_conversion.py
index c8da2494b..bdb03ae32 100644
--- a/aviary/subsystems/geometry/gasp_based/non_dimensional_conversion.py
+++ b/aviary/subsystems/geometry/gasp_based/non_dimensional_conversion.py
@@ -14,16 +14,16 @@ def initialize(self):
         add_aviary_option(self, Aircraft.Wing.HAS_STRUT)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Wing.SPAN, val=0)
+        add_aviary_input(self, Aircraft.Wing.SPAN)
 
         if self.options[Aircraft.Strut.DIMENSIONAL_LOCATION_SPECIFIED]:
-            add_aviary_input(self, Aircraft.Strut.ATTACHMENT_LOCATION, val=0)
+            add_aviary_input(self, Aircraft.Strut.ATTACHMENT_LOCATION)
             add_aviary_output(
-                self, Aircraft.Strut.ATTACHMENT_LOCATION_DIMENSIONLESS, val=0)
+                self, Aircraft.Strut.ATTACHMENT_LOCATION_DIMENSIONLESS)
         else:
             add_aviary_input(
-                self, Aircraft.Strut.ATTACHMENT_LOCATION_DIMENSIONLESS, val=0)
-            add_aviary_output(self, Aircraft.Strut.ATTACHMENT_LOCATION, val=0)
+                self, Aircraft.Strut.ATTACHMENT_LOCATION_DIMENSIONLESS)
+            add_aviary_output(self, Aircraft.Strut.ATTACHMENT_LOCATION)
 
     def setup_partials(self):
 
@@ -70,14 +70,14 @@ def initialize(self):
         add_aviary_option(self, Aircraft.Wing.FOLD_DIMENSIONAL_LOCATION_SPECIFIED)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Wing.SPAN, val=0)
+        add_aviary_input(self, Aircraft.Wing.SPAN)
 
         if self.options[Aircraft.Wing.FOLD_DIMENSIONAL_LOCATION_SPECIFIED]:
-            add_aviary_input(self, Aircraft.Wing.FOLDED_SPAN, val=25)
-            add_aviary_output(self, Aircraft.Wing.FOLDED_SPAN_DIMENSIONLESS, val=0)
+            add_aviary_input(self, Aircraft.Wing.FOLDED_SPAN)
+            add_aviary_output(self, Aircraft.Wing.FOLDED_SPAN_DIMENSIONLESS)
         else:
-            add_aviary_input(self, Aircraft.Wing.FOLDED_SPAN_DIMENSIONLESS, val=0)
-            add_aviary_output(self, Aircraft.Wing.FOLDED_SPAN, val=0)
+            add_aviary_input(self, Aircraft.Wing.FOLDED_SPAN_DIMENSIONLESS)
+            add_aviary_output(self, Aircraft.Wing.FOLDED_SPAN)
 
     def setup_partials(self):
 
diff --git a/aviary/subsystems/geometry/gasp_based/strut.py b/aviary/subsystems/geometry/gasp_based/strut.py
index 2c3fd83f0..8e80f290f 100644
--- a/aviary/subsystems/geometry/gasp_based/strut.py
+++ b/aviary/subsystems/geometry/gasp_based/strut.py
@@ -13,20 +13,17 @@ class StrutGeom(om.ExplicitComponent):
     """
 
     def setup(self):
-
-        add_aviary_input(self, Aircraft.Wing.AREA, val=150)
-        add_aviary_input(self, Aircraft.Strut.AREA_RATIO, val=.2)
-
-        add_aviary_input(self, Aircraft.Strut.ATTACHMENT_LOCATION, val=0, units="ft")
-
-        add_aviary_input(self, Aircraft.Fuselage.AVG_DIAMETER, val=10.0)
+        add_aviary_input(self, Aircraft.Wing.AREA)
+        add_aviary_input(self, Aircraft.Strut.AREA_RATIO)
+        add_aviary_input(self, Aircraft.Strut.ATTACHMENT_LOCATION)
+        add_aviary_input(self, Aircraft.Fuselage.AVG_DIAMETER)
 
         self.add_output(
             "strut_y", val=30, units="ft", desc="YSTRUT: attachment location of strut"
         )
-        add_aviary_output(self, Aircraft.Strut.LENGTH, val=1.0)
-        add_aviary_output(self, Aircraft.Strut.AREA, val=30)
-        add_aviary_output(self, Aircraft.Strut.CHORD, val=1.0)
+        add_aviary_output(self, Aircraft.Strut.LENGTH)
+        add_aviary_output(self, Aircraft.Strut.AREA)
+        add_aviary_output(self, Aircraft.Strut.CHORD)
 
     def setup_partials(self):
 
diff --git a/aviary/subsystems/geometry/gasp_based/test/test_empennage.py b/aviary/subsystems/geometry/gasp_based/test/test_empennage.py
index aa77dbeab..6cb29add1 100644
--- a/aviary/subsystems/geometry/gasp_based/test/test_empennage.py
+++ b/aviary/subsystems/geometry/gasp_based/test/test_empennage.py
@@ -49,9 +49,6 @@ def setUp(self):
             Aircraft.HorizontalTail.VERTICAL_TAIL_FRACTION, val=0, units="unitless"
         )
         self.prob.model.set_input_defaults("vvc.cab_w", val=13.1, units="ft")
-        self.prob.model.set_input_defaults(
-            Aircraft.Wing.AREA, val=1370.3, units="ft**2"
-        )
         self.prob.model.set_input_defaults("vvc.wing_ref", 117.8054, units="ft")
         self.prob.setup(check=False, force_alloc_complex=True)
 
@@ -75,7 +72,6 @@ class TestTailComp(
     def setUp(self):
         self.prob = om.Problem()
         self.prob.model.add_subsystem("tail", TailSize(), promotes=["*"])
-        self.prob.setup(check=False, force_alloc_complex=True)
 
         # values for horizontal tail
         self.prob.model.set_input_defaults("vol_coef", val=1.189, units="unitless")
@@ -86,6 +82,7 @@ def setUp(self):
         self.prob.model.set_input_defaults("wing_ref", val=12.615, units="ft")
         self.prob.model.set_input_defaults("ar", val=4.75, units="unitless")
         self.prob.model.set_input_defaults("tr", val=0.352, units="unitless")
+        self.prob.setup(check=False, force_alloc_complex=True)
 
     def test_large_sinle_aisle_1_htail(self):
         self.prob.run_model()
@@ -101,7 +98,6 @@ def test_large_sinle_aisle_1_htail(self):
     def test_large_sinle_aisle_1_vtail(self):
         # override horizontal tail defaults for vertical tail
         self.prob.set_val("vol_coef", 0.145, units="unitless")
-        self.prob.set_val(Aircraft.Wing.AREA, 1370.3, units="ft**2")
         self.prob.set_val("r_arm", 2.362, units="unitless")
         self.prob.set_val("wing_ref", 117.8, units="ft")
         self.prob.set_val("ar", 1.67, units="unitless")
diff --git a/aviary/subsystems/geometry/gasp_based/test/test_size_group.py b/aviary/subsystems/geometry/gasp_based/test/test_size_group.py
index 90ad3170a..4c2849d73 100644
--- a/aviary/subsystems/geometry/gasp_based/test/test_size_group.py
+++ b/aviary/subsystems/geometry/gasp_based/test/test_size_group.py
@@ -242,6 +242,9 @@ def setUp(self):
         self.prob.model.set_input_defaults(
             Aircraft.HorizontalTail.MOMENT_RATIO, val=0.2307, units="unitless"
         )
+        self.prob.model.set_input_defaults(
+            Aircraft.HorizontalTail.TAPER_RATIO, val=0.352, units="unitless"
+        )
         self.prob.model.set_input_defaults(
             Aircraft.VerticalTail.MOMENT_RATIO, 2.362, units="unitless")
         self.prob.model.set_input_defaults(
diff --git a/aviary/subsystems/geometry/gasp_based/test/test_wing.py b/aviary/subsystems/geometry/gasp_based/test/test_wing.py
index 5cb91f101..dd2f74811 100644
--- a/aviary/subsystems/geometry/gasp_based/test/test_wing.py
+++ b/aviary/subsystems/geometry/gasp_based/test/test_wing.py
@@ -59,6 +59,15 @@ def tearDown(self):
     def test_case1(self):
         self.prob = om.Problem()
         self.prob.model.add_subsystem("size", WingSize(), promotes=["*"])
+        self.prob.model.set_input_defaults(
+            Mission.Design.GROSS_MASS, 175400, units="lbm"
+        )
+        self.prob.model.set_input_defaults(
+            Aircraft.Wing.LOADING, 128, units="lbf/ft**2"
+        )
+        self.prob.model.set_input_defaults(
+            Aircraft.Wing.ASPECT_RATIO, 10.13, units="unitless"
+        )
         self.prob.setup(check=False, force_alloc_complex=True)
 
         partial_data = self.prob.check_partials(out_stream=None, method="cs")
@@ -580,6 +589,32 @@ def setUp(self):
         self.prob.model.set_input_defaults(
             Aircraft.Strut.ATTACHMENT_LOCATION, val=0, units="ft"
         )
+        self.prob.model.set_input_defaults(
+            Aircraft.Strut.AREA_RATIO, val=.2, units='unitless'
+        )
+        self.prob.model.set_input_defaults(
+            Aircraft.Fuselage.AVG_DIAMETER, val=10.0, units='ft'
+        )
+        self.prob.model.set_input_defaults(
+            Mission.Design.GROSS_MASS, val=152000.0, units='lbm'
+        )
+        self.prob.model.set_input_defaults(
+            Aircraft.Wing.LOADING, 128, units="lbf/ft**2"
+        )
+        self.prob.model.set_input_defaults(
+            Aircraft.Fuel.WING_FUEL_FRACTION, val=.6, units='unitless'
+        )
+
+        self.prob.model.set_input_defaults(
+            Aircraft.Wing.ASPECT_RATIO, val=10.13, units="unitless")
+        self.prob.model.set_input_defaults(
+            Aircraft.Wing.TAPER_RATIO, val=0.33, units="unitless")
+        self.prob.model.set_input_defaults(
+            Aircraft.Wing.THICKNESS_TO_CHORD_ROOT, val=0.11, units="unitless"
+        )
+        self.prob.model.set_input_defaults(
+            Aircraft.Wing.THICKNESS_TO_CHORD_TIP, val=0.1, units="unitless"
+        )
 
         setup_model_options(self.prob, options)
 
diff --git a/aviary/subsystems/geometry/gasp_based/wing.py b/aviary/subsystems/geometry/gasp_based/wing.py
index 85ce6cf1b..bd7e759ad 100644
--- a/aviary/subsystems/geometry/gasp_based/wing.py
+++ b/aviary/subsystems/geometry/gasp_based/wing.py
@@ -17,12 +17,12 @@ class WingSize(om.ExplicitComponent):
 
     def setup(self):
 
-        add_aviary_input(self, Mission.Design.GROSS_MASS, val=152000)
-        add_aviary_input(self, Aircraft.Wing.LOADING, val=128)
-        add_aviary_input(self, Aircraft.Wing.ASPECT_RATIO, val=10.13)
+        add_aviary_input(self, Mission.Design.GROSS_MASS)
+        add_aviary_input(self, Aircraft.Wing.LOADING)
+        add_aviary_input(self, Aircraft.Wing.ASPECT_RATIO)
 
-        add_aviary_output(self, Aircraft.Wing.AREA, val=0)
-        add_aviary_output(self, Aircraft.Wing.SPAN, val=0)
+        add_aviary_output(self, Aircraft.Wing.AREA)
+        add_aviary_output(self, Aircraft.Wing.SPAN)
 
         self.declare_partials(
             Aircraft.Wing.AREA, [Mission.Design.GROSS_MASS, Aircraft.Wing.LOADING]
@@ -83,19 +83,19 @@ def initialize(self):
 
     def setup(self):
 
-        add_aviary_input(self, Aircraft.Wing.AREA, val=2)
-        add_aviary_input(self, Aircraft.Wing.SPAN, val=2)
-        add_aviary_input(self, Aircraft.Wing.ASPECT_RATIO, val=10.13)
-        add_aviary_input(self, Aircraft.Wing.TAPER_RATIO, val=0.33)
-        add_aviary_input(self, Aircraft.Wing.SWEEP, val=25)
-        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD_ROOT, val=0.11)
-        add_aviary_input(self, Aircraft.Fuselage.AVG_DIAMETER, val=10)
-        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD_TIP, val=0.1)
+        add_aviary_input(self, Aircraft.Wing.AREA)
+        add_aviary_input(self, Aircraft.Wing.SPAN)
+        add_aviary_input(self, Aircraft.Wing.ASPECT_RATIO)
+        add_aviary_input(self, Aircraft.Wing.TAPER_RATIO)
+        add_aviary_input(self, Aircraft.Wing.SWEEP)
+        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD_ROOT)
+        add_aviary_input(self, Aircraft.Fuselage.AVG_DIAMETER)
+        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD_TIP)
 
         if not self.options[Aircraft.Wing.HAS_FOLD]:
 
-            add_aviary_input(self, Aircraft.Fuel.WING_FUEL_FRACTION, val=0.6)
-            add_aviary_output(self, Aircraft.Fuel.WING_VOLUME_GEOMETRIC_MAX, val=0)
+            add_aviary_input(self, Aircraft.Fuel.WING_FUEL_FRACTION)
+            add_aviary_output(self, Aircraft.Fuel.WING_VOLUME_GEOMETRIC_MAX)
 
             self.declare_partials(
                 Aircraft.Fuel.WING_VOLUME_GEOMETRIC_MAX,
@@ -111,12 +111,11 @@ def setup(self):
                 ],
             )
 
-        add_aviary_output(self, Aircraft.Wing.CENTER_CHORD, val=0)
-        add_aviary_output(self, Aircraft.Wing.AVERAGE_CHORD, val=0)
-        add_aviary_output(self, Aircraft.Wing.ROOT_CHORD, val=0)
-        add_aviary_output(self, Aircraft.Wing.THICKNESS_TO_CHORD_UNWEIGHTED, val=0)
-        add_aviary_output(self, Aircraft.Wing.LEADING_EDGE_SWEEP,
-                          val=0.4763948, units="rad")
+        add_aviary_output(self, Aircraft.Wing.CENTER_CHORD)
+        add_aviary_output(self, Aircraft.Wing.AVERAGE_CHORD)
+        add_aviary_output(self, Aircraft.Wing.ROOT_CHORD)
+        add_aviary_output(self, Aircraft.Wing.THICKNESS_TO_CHORD_UNWEIGHTED)
+        add_aviary_output(self, Aircraft.Wing.LEADING_EDGE_SWEEP)
 
         self.declare_partials(
             Aircraft.Wing.CENTER_CHORD,
@@ -517,12 +516,8 @@ def initialize(self):
     def setup(self):
 
         if not self.options[Aircraft.Wing.CHOOSE_FOLD_LOCATION]:
-            self.add_input(
-                "strut_y",
-                val=25,
-                units="ft",
-                desc="YSTRUT: attachment location of strut",
-            )
+            self.add_input("strut_y", val=25, units="ft",
+                           desc="YSTRUT: attachment location of strut")
 
             self.declare_partials("nonfolded_taper_ratio", "strut_y")
             self.declare_partials(Aircraft.Wing.FOLDING_AREA, "strut_y")
@@ -540,44 +535,32 @@ def setup(self):
             self.declare_partials(Aircraft.Fuel.WING_VOLUME_GEOMETRIC_MAX,
                                   Aircraft.Wing.FOLDED_SPAN)
 
-            add_aviary_input(self, Aircraft.Wing.FOLDED_SPAN, val=25, units='ft')
+            add_aviary_input(self, Aircraft.Wing.FOLDED_SPAN)
 
-        add_aviary_input(self, Aircraft.Wing.AREA, val=200)
-        add_aviary_input(self, Aircraft.Wing.SPAN, val=118)
-        add_aviary_input(self, Aircraft.Wing.TAPER_RATIO, val=0.33)
-        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD_ROOT, val=0.11)
-        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD_TIP, val=0.1)
-        add_aviary_input(self, Aircraft.Fuel.WING_FUEL_FRACTION, val=0.6)
+        add_aviary_input(self, Aircraft.Wing.AREA)
+        add_aviary_input(self, Aircraft.Wing.SPAN)
+        add_aviary_input(self, Aircraft.Wing.TAPER_RATIO)
+        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD_ROOT)
+        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD_TIP)
+        add_aviary_input(self, Aircraft.Fuel.WING_FUEL_FRACTION)
 
-        self.add_output(
-            "nonfolded_taper_ratio",
-            val=0.1,
-            units="unitless",
-            desc="SLM_NF: taper ratio between wing root and fold location",
-        )
+        self.add_output("nonfolded_taper_ratio", val=0.1, units="unitless",
+                        desc="SLM_NF: taper ratio between wing root and fold location",
+                        )
 
-        add_aviary_output(self, Aircraft.Wing.FOLDING_AREA, val=50)
+        add_aviary_output(self, Aircraft.Wing.FOLDING_AREA)
 
-        self.add_output(
-            "nonfolded_wing_area",
-            val=150,
-            units="ft**2",
-            desc="SW_NF: wing area of part of wings that does not fold",
-        )
-        self.add_output(
-            "tc_ratio_mean_folded",
-            val=0.12,
-            units="unitless",
-            desc="TCM: mean value of thickess to chord ratio between root and fold",
-        )
-        self.add_output(
-            "nonfolded_AR",
-            val=10,
-            units="unitless",
-            desc="AR_NF: aspect ratio of non-folding part of wing",
-        )
+        self.add_output("nonfolded_wing_area", val=150, units="ft**2",
+                        desc="SW_NF: wing area of part of wings that does not fold",
+                        )
+        self.add_output("tc_ratio_mean_folded", val=0.12, units="unitless",
+                        desc="TCM: mean value of thickess to chord ratio between root and fold",
+                        )
+        self.add_output("nonfolded_AR", val=10, units="unitless",
+                        desc="AR_NF: aspect ratio of non-folding part of wing",
+                        )
 
-        add_aviary_output(self, Aircraft.Fuel.WING_VOLUME_GEOMETRIC_MAX, val=0)
+        add_aviary_output(self, Aircraft.Fuel.WING_VOLUME_GEOMETRIC_MAX)
 
         self.declare_partials(
             "nonfolded_taper_ratio",
@@ -1008,12 +991,3 @@ def setup(self):
                 check_fold_location_definition(choose_fold_location, has_strut)
                 self.promotes("strut", outputs=["strut_y"])
                 self.promotes("fold", inputs=["strut_y"])
-
-        self.set_input_defaults(Aircraft.Wing.ASPECT_RATIO, val=10.13, units="unitless")
-        self.set_input_defaults(Aircraft.Wing.TAPER_RATIO, val=0.33, units="unitless")
-        self.set_input_defaults(
-            Aircraft.Wing.THICKNESS_TO_CHORD_ROOT, val=0.11, units="unitless"
-        )
-        self.set_input_defaults(
-            Aircraft.Wing.THICKNESS_TO_CHORD_TIP, val=0.1, units="unitless"
-        )
diff --git a/aviary/subsystems/mass/flops_based/air_conditioning.py b/aviary/subsystems/mass/flops_based/air_conditioning.py
index 4e2db1cfe..be41e8fc4 100644
--- a/aviary/subsystems/mass/flops_based/air_conditioning.py
+++ b/aviary/subsystems/mass/flops_based/air_conditioning.py
@@ -19,15 +19,12 @@ def initialize(self):
         add_aviary_option(self, Mission.Constraints.MAX_MACH)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.AirConditioning.MASS_SCALER, val=1.0)
+        add_aviary_input(self, Aircraft.AirConditioning.MASS_SCALER)
+        add_aviary_input(self, Aircraft.Avionics.MASS)
+        add_aviary_input(self, Aircraft.Fuselage.MAX_HEIGHT)
+        add_aviary_input(self, Aircraft.Fuselage.PLANFORM_AREA)
 
-        add_aviary_input(self, Aircraft.Avionics.MASS, val=0.0)
-
-        add_aviary_input(self, Aircraft.Fuselage.MAX_HEIGHT, val=0.0)
-
-        add_aviary_input(self, Aircraft.Fuselage.PLANFORM_AREA, val=0.0)
-
-        add_aviary_output(self, Aircraft.AirConditioning.MASS, val=0.0)
+        add_aviary_output(self, Aircraft.AirConditioning.MASS)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
@@ -83,9 +80,9 @@ def initialize(self):
         add_aviary_option(self, Aircraft.CrewPayload.Design.NUM_PASSENGERS)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.AirConditioning.MASS_SCALER, val=1.0)
+        add_aviary_input(self, Aircraft.AirConditioning.MASS_SCALER)
 
-        add_aviary_output(self, Aircraft.AirConditioning.MASS, val=0.0)
+        add_aviary_output(self, Aircraft.AirConditioning.MASS)
 
     def setup_partials(self):
         self.declare_partials(of=Aircraft.AirConditioning.MASS, wrt='*')
diff --git a/aviary/subsystems/mass/flops_based/anti_icing.py b/aviary/subsystems/mass/flops_based/anti_icing.py
index 9d7a485da..038b8e36b 100644
--- a/aviary/subsystems/mass/flops_based/anti_icing.py
+++ b/aviary/subsystems/mass/flops_based/anti_icing.py
@@ -23,18 +23,13 @@ def initialize(self):
     def setup(self):
         num_engine_type = len(self.options[Aircraft.Engine.NUM_ENGINES])
 
-        add_aviary_input(self, Aircraft.AntiIcing.MASS_SCALER, val=1.0)
+        add_aviary_input(self, Aircraft.AntiIcing.MASS_SCALER)
+        add_aviary_input(self, Aircraft.Fuselage.MAX_WIDTH)
+        add_aviary_input(self, Aircraft.Nacelle.AVG_DIAMETER, shape=num_engine_type)
+        add_aviary_input(self, Aircraft.Wing.SPAN)
+        add_aviary_input(self, Aircraft.Wing.SWEEP)
 
-        add_aviary_input(self, Aircraft.Fuselage.MAX_WIDTH, val=0.0)
-
-        add_aviary_input(self, Aircraft.Nacelle.AVG_DIAMETER,
-                         val=np.zeros(num_engine_type))
-
-        add_aviary_input(self, Aircraft.Wing.SPAN, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.SWEEP, val=0.0)
-
-        add_aviary_output(self, Aircraft.AntiIcing.MASS, val=0.0)
+        add_aviary_output(self, Aircraft.AntiIcing.MASS)
 
     def setup_partials(self):
         self.declare_partials("*", "*")
diff --git a/aviary/subsystems/mass/flops_based/apu.py b/aviary/subsystems/mass/flops_based/apu.py
index d71b2ac38..6a36e2f46 100644
--- a/aviary/subsystems/mass/flops_based/apu.py
+++ b/aviary/subsystems/mass/flops_based/apu.py
@@ -15,11 +15,10 @@ def initialize(self):
         add_aviary_option(self, Aircraft.CrewPayload.Design.NUM_PASSENGERS)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.APU.MASS_SCALER, val=1.0)
+        add_aviary_input(self, Aircraft.APU.MASS_SCALER)
+        add_aviary_input(self, Aircraft.Fuselage.PLANFORM_AREA)
 
-        add_aviary_input(self, Aircraft.Fuselage.PLANFORM_AREA, val=0.0)
-
-        add_aviary_output(self, Aircraft.APU.MASS, val=0.0)
+        add_aviary_output(self, Aircraft.APU.MASS)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
diff --git a/aviary/subsystems/mass/flops_based/avionics.py b/aviary/subsystems/mass/flops_based/avionics.py
index 1f7e75f7d..e681baf7d 100644
--- a/aviary/subsystems/mass/flops_based/avionics.py
+++ b/aviary/subsystems/mass/flops_based/avionics.py
@@ -16,13 +16,11 @@ def initialize(self):
         add_aviary_option(self, Aircraft.CrewPayload.NUM_FLIGHT_CREW)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Avionics.MASS_SCALER, val=1.0)
+        add_aviary_input(self, Aircraft.Avionics.MASS_SCALER)
+        add_aviary_input(self, Aircraft.Fuselage.PLANFORM_AREA)
+        add_aviary_input(self, Mission.Design.RANGE)
 
-        add_aviary_input(self, Aircraft.Fuselage.PLANFORM_AREA, val=0.0)
-
-        add_aviary_input(self, Mission.Design.RANGE, val=0.0)
-
-        add_aviary_output(self, Aircraft.Avionics.MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Avionics.MASS)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
diff --git a/aviary/subsystems/mass/flops_based/canard.py b/aviary/subsystems/mass/flops_based/canard.py
index e40b374d3..980e2960b 100644
--- a/aviary/subsystems/mass/flops_based/canard.py
+++ b/aviary/subsystems/mass/flops_based/canard.py
@@ -12,12 +12,12 @@ class CanardMass(om.ExplicitComponent):
     '''
 
     def setup(self):
-        add_aviary_input(self, Mission.Design.GROSS_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Canard.AREA, val=0.0)
-        add_aviary_input(self, Aircraft.Canard.TAPER_RATIO, val=00)
-        add_aviary_input(self, Aircraft.Canard.MASS_SCALER, val=1.0)
+        add_aviary_input(self, Mission.Design.GROSS_MASS)
+        add_aviary_input(self, Aircraft.Canard.AREA)
+        add_aviary_input(self, Aircraft.Canard.TAPER_RATIO)
+        add_aviary_input(self, Aircraft.Canard.MASS_SCALER)
 
-        add_aviary_output(self, Aircraft.Canard.MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Canard.MASS)
 
     def setup_partials(self):
         self.declare_partials("*", "*")
diff --git a/aviary/subsystems/mass/flops_based/cargo.py b/aviary/subsystems/mass/flops_based/cargo.py
index dd388e067..ef5311d80 100644
--- a/aviary/subsystems/mass/flops_based/cargo.py
+++ b/aviary/subsystems/mass/flops_based/cargo.py
@@ -22,15 +22,13 @@ def initialize(self):
         add_aviary_option(self, Aircraft.CrewPayload.NUM_PASSENGERS)
 
     def setup(self):
-        add_aviary_output(self, Aircraft.CrewPayload.PASSENGER_MASS, 0.)
-        add_aviary_output(self, Aircraft.CrewPayload.BAGGAGE_MASS, 0.)
-        add_aviary_output(self, Aircraft.CrewPayload.PASSENGER_PAYLOAD_MASS, 0.)
-
-        add_aviary_input(self, Aircraft.CrewPayload.WING_CARGO, 0.)
-        add_aviary_input(self, Aircraft.CrewPayload.MISC_CARGO, 0.)
-
-        add_aviary_output(self, Aircraft.CrewPayload.CARGO_MASS, 0.)
-        add_aviary_output(self, Aircraft.CrewPayload.TOTAL_PAYLOAD_MASS, 0.)
+        add_aviary_input(self, Aircraft.CrewPayload.WING_CARGO)
+        add_aviary_input(self, Aircraft.CrewPayload.MISC_CARGO)
+        add_aviary_output(self, Aircraft.CrewPayload.PASSENGER_MASS)
+        add_aviary_output(self, Aircraft.CrewPayload.BAGGAGE_MASS)
+        add_aviary_output(self, Aircraft.CrewPayload.PASSENGER_PAYLOAD_MASS)
+        add_aviary_output(self, Aircraft.CrewPayload.CARGO_MASS)
+        add_aviary_output(self, Aircraft.CrewPayload.TOTAL_PAYLOAD_MASS)
 
     def setup_partials(self):
 
diff --git a/aviary/subsystems/mass/flops_based/cargo_containers.py b/aviary/subsystems/mass/flops_based/cargo_containers.py
index 18460dcaf..8f0b11d11 100644
--- a/aviary/subsystems/mass/flops_based/cargo_containers.py
+++ b/aviary/subsystems/mass/flops_based/cargo_containers.py
@@ -14,14 +14,11 @@ class TransportCargoContainersMass(om.ExplicitComponent):
     '''
 
     def setup(self):
-        add_aviary_input(
-            self, Aircraft.CrewPayload.CARGO_CONTAINER_MASS_SCALER, val=1.0)
+        add_aviary_input(self, Aircraft.CrewPayload.CARGO_CONTAINER_MASS_SCALER)
+        add_aviary_input(self, Aircraft.CrewPayload.CARGO_MASS)
+        add_aviary_input(self, Aircraft.CrewPayload.BAGGAGE_MASS)
 
-        add_aviary_input(self, Aircraft.CrewPayload.CARGO_MASS, val=0.0)
-
-        add_aviary_input(self, Aircraft.CrewPayload.BAGGAGE_MASS, val=0.0)
-
-        add_aviary_output(self, Aircraft.CrewPayload.CARGO_CONTAINER_MASS, val=0.0)
+        add_aviary_output(self, Aircraft.CrewPayload.CARGO_CONTAINER_MASS)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
diff --git a/aviary/subsystems/mass/flops_based/crew.py b/aviary/subsystems/mass/flops_based/crew.py
index 924840101..1afd6e217 100644
--- a/aviary/subsystems/mass/flops_based/crew.py
+++ b/aviary/subsystems/mass/flops_based/crew.py
@@ -18,10 +18,9 @@ def initialize(self):
         add_aviary_option(self, Aircraft.CrewPayload.NUM_GALLEY_CREW)
 
     def setup(self):
-        add_aviary_input(
-            self, Aircraft.CrewPayload.NON_FLIGHT_CREW_MASS_SCALER, 1.)
+        add_aviary_input(self, Aircraft.CrewPayload.NON_FLIGHT_CREW_MASS_SCALER)
 
-        add_aviary_output(self, Aircraft.CrewPayload.NON_FLIGHT_CREW_MASS, 0)
+        add_aviary_output(self, Aircraft.CrewPayload.NON_FLIGHT_CREW_MASS)
 
     def setup_partials(self):
         self.declare_partials(
@@ -75,10 +74,9 @@ def initialize(self):
         add_aviary_option(self, Aircraft.LandingGear.CARRIER_BASED)
 
     def setup(self):
-        add_aviary_input(
-            self, Aircraft.CrewPayload.FLIGHT_CREW_MASS_SCALER, 1.)
+        add_aviary_input(self, Aircraft.CrewPayload.FLIGHT_CREW_MASS_SCALER)
 
-        add_aviary_output(self, Aircraft.CrewPayload.FLIGHT_CREW_MASS, 0.)
+        add_aviary_output(self, Aircraft.CrewPayload.FLIGHT_CREW_MASS)
 
     def setup_partials(self):
         self.declare_partials(
diff --git a/aviary/subsystems/mass/flops_based/electrical.py b/aviary/subsystems/mass/flops_based/electrical.py
index 7ba6ee967..6dfc06288 100644
--- a/aviary/subsystems/mass/flops_based/electrical.py
+++ b/aviary/subsystems/mass/flops_based/electrical.py
@@ -20,11 +20,11 @@ def initialize(self):
         add_aviary_option(self, Aircraft.Propulsion.TOTAL_NUM_ENGINES)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Fuselage.LENGTH, 0.0)
-        add_aviary_input(self, Aircraft.Fuselage.MAX_WIDTH, 0.0)
-        add_aviary_input(self, Aircraft.Electrical.MASS_SCALER, 1.0)
+        add_aviary_input(self, Aircraft.Fuselage.LENGTH)
+        add_aviary_input(self, Aircraft.Fuselage.MAX_WIDTH)
+        add_aviary_input(self, Aircraft.Electrical.MASS_SCALER)
 
-        add_aviary_output(self, Aircraft.Electrical.MASS, 1.0)
+        add_aviary_output(self, Aircraft.Electrical.MASS)
 
     def setup_partials(self):
         self.declare_partials(of='*', wrt='*')
@@ -81,9 +81,9 @@ def initialize(self):
         add_aviary_option(self, Aircraft.CrewPayload.Design.NUM_PASSENGERS)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Electrical.MASS_SCALER, 1.0)
+        add_aviary_input(self, Aircraft.Electrical.MASS_SCALER)
 
-        add_aviary_output(self, Aircraft.Electrical.MASS, 1.0)
+        add_aviary_output(self, Aircraft.Electrical.MASS)
 
     def setup_partials(self):
         self.declare_partials(of='*', wrt='*')
diff --git a/aviary/subsystems/mass/flops_based/empty_margin.py b/aviary/subsystems/mass/flops_based/empty_margin.py
index 43fca2b20..5b2ce8b2c 100644
--- a/aviary/subsystems/mass/flops_based/empty_margin.py
+++ b/aviary/subsystems/mass/flops_based/empty_margin.py
@@ -10,15 +10,12 @@ class EmptyMassMargin(om.ExplicitComponent):
     """
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Propulsion.MASS, val=0.)
+        add_aviary_input(self, Aircraft.Propulsion.MASS)
+        add_aviary_input(self, Aircraft.Design.STRUCTURE_MASS)
+        add_aviary_input(self, Aircraft.Design.SYSTEMS_EQUIP_MASS)
+        add_aviary_input(self, Aircraft.Design.EMPTY_MASS_MARGIN_SCALER)
 
-        add_aviary_input(self, Aircraft.Design.STRUCTURE_MASS, val=0.)
-
-        add_aviary_input(self, Aircraft.Design.SYSTEMS_EQUIP_MASS, val=0.)
-
-        add_aviary_input(self, Aircraft.Design.EMPTY_MASS_MARGIN_SCALER, val=0.0)
-
-        add_aviary_output(self, Aircraft.Design.EMPTY_MASS_MARGIN, val=0.0)
+        add_aviary_output(self, Aircraft.Design.EMPTY_MASS_MARGIN)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
diff --git a/aviary/subsystems/mass/flops_based/engine.py b/aviary/subsystems/mass/flops_based/engine.py
index 93740cccb..169ff1179 100644
--- a/aviary/subsystems/mass/flops_based/engine.py
+++ b/aviary/subsystems/mass/flops_based/engine.py
@@ -24,16 +24,12 @@ def initialize(self):
     def setup(self):
         num_engine_type = len(self.options[Aircraft.Engine.NUM_ENGINES])
 
-        add_aviary_input(self, Aircraft.Engine.SCALED_SLS_THRUST,
-                         val=np.zeros(num_engine_type))
+        add_aviary_input(self, Aircraft.Engine.SCALED_SLS_THRUST, shape=num_engine_type)
+        add_aviary_input(self, Aircraft.Engine.MASS_SCALER, shape=num_engine_type)
 
-        add_aviary_input(self, Aircraft.Engine.MASS_SCALER,
-                         val=np.zeros(num_engine_type))
-
-        add_aviary_output(self, Aircraft.Engine.MASS, val=np.zeros(num_engine_type))
-        add_aviary_output(self, Aircraft.Engine.ADDITIONAL_MASS,
-                          val=np.zeros(num_engine_type))
-        add_aviary_output(self, Aircraft.Propulsion.TOTAL_ENGINE_MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Engine.MASS, shape=num_engine_type)
+        add_aviary_output(self, Aircraft.Engine.ADDITIONAL_MASS, shape=num_engine_type)
+        add_aviary_output(self, Aircraft.Propulsion.TOTAL_ENGINE_MASS)
 
     def compute(self, inputs, outputs):
         options = self.options
diff --git a/aviary/subsystems/mass/flops_based/engine_controls.py b/aviary/subsystems/mass/flops_based/engine_controls.py
index 17058a821..d8a121fd3 100644
--- a/aviary/subsystems/mass/flops_based/engine_controls.py
+++ b/aviary/subsystems/mass/flops_based/engine_controls.py
@@ -27,11 +27,9 @@ def initialize(self):
         add_aviary_option(self, Aircraft.Propulsion.TOTAL_NUM_ENGINES)
 
     def setup(self):
-        add_aviary_input(
-            self, Aircraft.Propulsion.TOTAL_SCALED_SLS_THRUST, val=0.0, units='lbf')
+        add_aviary_input(self, Aircraft.Propulsion.TOTAL_SCALED_SLS_THRUST)
 
-        add_aviary_output(
-            self, Aircraft.Propulsion.TOTAL_ENGINE_CONTROLS_MASS, val=0.0, units='lbm')
+        add_aviary_output(self, Aircraft.Propulsion.TOTAL_ENGINE_CONTROLS_MASS)
 
     def setup_partials(self):
         self.declare_partials(Aircraft.Propulsion.TOTAL_ENGINE_CONTROLS_MASS,
diff --git a/aviary/subsystems/mass/flops_based/engine_oil.py b/aviary/subsystems/mass/flops_based/engine_oil.py
index 14fc7f429..8ad1e5ea2 100644
--- a/aviary/subsystems/mass/flops_based/engine_oil.py
+++ b/aviary/subsystems/mass/flops_based/engine_oil.py
@@ -24,11 +24,10 @@ def initialize(self):
         add_aviary_option(self, Aircraft.Propulsion.TOTAL_NUM_ENGINES)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Propulsion.ENGINE_OIL_MASS_SCALER, val=1.0)
+        add_aviary_input(self, Aircraft.Propulsion.ENGINE_OIL_MASS_SCALER)
+        add_aviary_input(self, Aircraft.Propulsion.TOTAL_SCALED_SLS_THRUST)
 
-        add_aviary_input(self, Aircraft.Propulsion.TOTAL_SCALED_SLS_THRUST, val=0.0)
-
-        add_aviary_output(self, Aircraft.Propulsion.TOTAL_ENGINE_OIL_MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Propulsion.TOTAL_ENGINE_OIL_MASS)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
@@ -70,9 +69,9 @@ def initialize(self):
         add_aviary_option(self, Aircraft.CrewPayload.Design.NUM_PASSENGERS)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Propulsion.ENGINE_OIL_MASS_SCALER, val=1.0)
+        add_aviary_input(self, Aircraft.Propulsion.ENGINE_OIL_MASS_SCALER)
 
-        add_aviary_output(self, Aircraft.Propulsion.TOTAL_ENGINE_OIL_MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Propulsion.TOTAL_ENGINE_OIL_MASS)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
diff --git a/aviary/subsystems/mass/flops_based/engine_pod.py b/aviary/subsystems/mass/flops_based/engine_pod.py
index c1c262481..c53be1554 100644
--- a/aviary/subsystems/mass/flops_based/engine_pod.py
+++ b/aviary/subsystems/mass/flops_based/engine_pod.py
@@ -22,21 +22,20 @@ def initialize(self):
     def setup(self):
         num_engine_type = len(self.options[Aircraft.Engine.NUM_ENGINES])
 
-        add_aviary_input(self, Aircraft.Electrical.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Fuel.FUEL_SYSTEM_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Hydraulics.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Instruments.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Nacelle.MASS, val=np.zeros(num_engine_type))
-        add_aviary_input(self, Aircraft.Propulsion.TOTAL_ENGINE_CONTROLS_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Engine.MASS, val=np.zeros(num_engine_type))
-        add_aviary_input(self, Aircraft.Propulsion.TOTAL_STARTER_MASS, val=0.0)
+        add_aviary_input(self, Aircraft.Electrical.MASS)
+        add_aviary_input(self, Aircraft.Fuel.FUEL_SYSTEM_MASS)
+        add_aviary_input(self, Aircraft.Hydraulics.MASS)
+        add_aviary_input(self, Aircraft.Instruments.MASS)
+        add_aviary_input(self, Aircraft.Nacelle.MASS, shape=num_engine_type)
+        add_aviary_input(self, Aircraft.Propulsion.TOTAL_ENGINE_CONTROLS_MASS)
+        add_aviary_input(self, Aircraft.Engine.MASS, shape=num_engine_type)
+        add_aviary_input(self, Aircraft.Propulsion.TOTAL_STARTER_MASS)
         add_aviary_input(self, Aircraft.Engine.THRUST_REVERSERS_MASS,
-                         val=np.zeros(num_engine_type))
-        add_aviary_input(self, Aircraft.Engine.SCALED_SLS_THRUST,
-                         val=np.zeros(num_engine_type))
-        add_aviary_input(self, Aircraft.Propulsion.TOTAL_SCALED_SLS_THRUST, val=0.0)
+                         shape=num_engine_type)
+        add_aviary_input(self, Aircraft.Engine.SCALED_SLS_THRUST, shape=num_engine_type)
+        add_aviary_input(self, Aircraft.Propulsion.TOTAL_SCALED_SLS_THRUST)
 
-        add_aviary_output(self, Aircraft.Engine.POD_MASS, val=np.zeros(num_engine_type))
+        add_aviary_output(self, Aircraft.Engine.POD_MASS, shape=num_engine_type)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
diff --git a/aviary/subsystems/mass/flops_based/fin.py b/aviary/subsystems/mass/flops_based/fin.py
index b4e9f79ab..280a943dc 100644
--- a/aviary/subsystems/mass/flops_based/fin.py
+++ b/aviary/subsystems/mass/flops_based/fin.py
@@ -15,12 +15,12 @@ def initialize(self):
         add_aviary_option(self, Aircraft.Fins.NUM_FINS)
 
     def setup(self):
-        add_aviary_input(self, Mission.Design.GROSS_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Fins.AREA, val=0.0)
-        add_aviary_input(self, Aircraft.Fins.TAPER_RATIO, val=0.0)
-        add_aviary_input(self, Aircraft.Fins.MASS_SCALER, val=1.0)
+        add_aviary_input(self, Mission.Design.GROSS_MASS)
+        add_aviary_input(self, Aircraft.Fins.AREA)
+        add_aviary_input(self, Aircraft.Fins.TAPER_RATIO)
+        add_aviary_input(self, Aircraft.Fins.MASS_SCALER)
 
-        add_aviary_output(self, Aircraft.Fins.MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Fins.MASS)
 
     def setup_partials(self):
         self.declare_partials("*", "*")
diff --git a/aviary/subsystems/mass/flops_based/fuel_capacity.py b/aviary/subsystems/mass/flops_based/fuel_capacity.py
index d1d2009b6..76e83dbef 100644
--- a/aviary/subsystems/mass/flops_based/fuel_capacity.py
+++ b/aviary/subsystems/mass/flops_based/fuel_capacity.py
@@ -38,9 +38,9 @@ class FuselageFuelCapacity(om.ExplicitComponent):
     """
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Fuel.TOTAL_CAPACITY, 0.0),
-        add_aviary_input(self, Aircraft.Fuel.WING_FUEL_CAPACITY, 0.0),
-        add_aviary_output(self, Aircraft.Fuel.FUSELAGE_FUEL_CAPACITY, 0.0),
+        add_aviary_input(self, Aircraft.Fuel.TOTAL_CAPACITY),
+        add_aviary_input(self, Aircraft.Fuel.WING_FUEL_CAPACITY),
+        add_aviary_output(self, Aircraft.Fuel.FUSELAGE_FUEL_CAPACITY),
 
     def setup_partials(self):
         self.declare_partials(
@@ -62,10 +62,10 @@ class AuxFuelCapacity(om.ExplicitComponent):
     """
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Fuel.TOTAL_CAPACITY, 0.0),
-        add_aviary_input(self, Aircraft.Fuel.WING_FUEL_CAPACITY, 0.0),
-        add_aviary_input(self, Aircraft.Fuel.FUSELAGE_FUEL_CAPACITY, 0.0),
-        add_aviary_output(self, Aircraft.Fuel.AUXILIARY_FUEL_CAPACITY, 0.0),
+        add_aviary_input(self, Aircraft.Fuel.TOTAL_CAPACITY),
+        add_aviary_input(self, Aircraft.Fuel.WING_FUEL_CAPACITY),
+        add_aviary_input(self, Aircraft.Fuel.FUSELAGE_FUEL_CAPACITY),
+        add_aviary_output(self, Aircraft.Fuel.AUXILIARY_FUEL_CAPACITY),
 
     def setup_partials(self):
         self.declare_partials(
@@ -91,10 +91,10 @@ class TotalFuelCapacity(om.ExplicitComponent):
     """
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Fuel.WING_FUEL_CAPACITY, 0.0),
-        add_aviary_input(self, Aircraft.Fuel.FUSELAGE_FUEL_CAPACITY, 0.0),
-        add_aviary_input(self, Aircraft.Fuel.AUXILIARY_FUEL_CAPACITY, 0.0),
-        add_aviary_output(self, Aircraft.Fuel.TOTAL_CAPACITY, 0.0),
+        add_aviary_input(self, Aircraft.Fuel.WING_FUEL_CAPACITY),
+        add_aviary_input(self, Aircraft.Fuel.FUSELAGE_FUEL_CAPACITY),
+        add_aviary_input(self, Aircraft.Fuel.AUXILIARY_FUEL_CAPACITY),
+        add_aviary_output(self, Aircraft.Fuel.TOTAL_CAPACITY),
 
     def setup_partials(self):
         self.declare_partials(
@@ -120,20 +120,18 @@ class WingFuelCapacity(om.ExplicitComponent):
     """
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Fuel.DENSITY_RATIO, 1.0)
-        add_aviary_input(self, Aircraft.Fuel.WING_REF_CAPACITY, 0.0)
-        add_aviary_input(self, Aircraft.Fuel.WING_REF_CAPACITY_AREA, 0.0)
-        add_aviary_input(self, Aircraft.Fuel.WING_REF_CAPACITY_TERM_A, 0.0)
-        add_aviary_input(self, Aircraft.Fuel.WING_REF_CAPACITY_TERM_B, 0.0)
-
-        add_aviary_input(self, Aircraft.Fuel.CAPACITY_FACTOR, 23.0)
-
-        add_aviary_input(self, Aircraft.Wing.AREA, 0.0)
-        add_aviary_input(self, Aircraft.Wing.SPAN, 0.0)
-        add_aviary_input(self, Aircraft.Wing.TAPER_RATIO, 0.0)
-        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD, 0.0)
-
-        add_aviary_output(self, Aircraft.Fuel.WING_FUEL_CAPACITY, 0.0)
+        add_aviary_input(self, Aircraft.Fuel.DENSITY_RATIO)
+        add_aviary_input(self, Aircraft.Fuel.WING_REF_CAPACITY)
+        add_aviary_input(self, Aircraft.Fuel.WING_REF_CAPACITY_AREA)
+        add_aviary_input(self, Aircraft.Fuel.WING_REF_CAPACITY_TERM_A)
+        add_aviary_input(self, Aircraft.Fuel.WING_REF_CAPACITY_TERM_B)
+        add_aviary_input(self, Aircraft.Fuel.CAPACITY_FACTOR)
+        add_aviary_input(self, Aircraft.Wing.AREA)
+        add_aviary_input(self, Aircraft.Wing.SPAN)
+        add_aviary_input(self, Aircraft.Wing.TAPER_RATIO)
+        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD)
+
+        add_aviary_output(self, Aircraft.Fuel.WING_FUEL_CAPACITY)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
diff --git a/aviary/subsystems/mass/flops_based/fuel_system.py b/aviary/subsystems/mass/flops_based/fuel_system.py
index 78dfe92bc..61162104e 100644
--- a/aviary/subsystems/mass/flops_based/fuel_system.py
+++ b/aviary/subsystems/mass/flops_based/fuel_system.py
@@ -19,11 +19,10 @@ def initialize(self):
         add_aviary_option(self, Mission.Constraints.MAX_MACH)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Fuel.FUEL_SYSTEM_MASS_SCALER, val=1.0)
+        add_aviary_input(self, Aircraft.Fuel.FUEL_SYSTEM_MASS_SCALER)
+        add_aviary_input(self, Aircraft.Fuel.TOTAL_CAPACITY)
 
-        add_aviary_input(self, Aircraft.Fuel.TOTAL_CAPACITY, 0.0)
-
-        add_aviary_output(self, Aircraft.Fuel.FUEL_SYSTEM_MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Fuel.FUEL_SYSTEM_MASS)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
@@ -65,11 +64,10 @@ def initialize(self):
         add_aviary_option(self, Aircraft.Fuel.NUM_TANKS)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Fuel.TOTAL_CAPACITY, val=0.0)
-
-        add_aviary_input(self, Aircraft.Fuel.FUEL_SYSTEM_MASS_SCALER, val=1.0)
+        add_aviary_input(self, Aircraft.Fuel.TOTAL_CAPACITY)
+        add_aviary_input(self, Aircraft.Fuel.FUEL_SYSTEM_MASS_SCALER)
 
-        add_aviary_output(self, Aircraft.Fuel.FUEL_SYSTEM_MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Fuel.FUEL_SYSTEM_MASS)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
diff --git a/aviary/subsystems/mass/flops_based/furnishings.py b/aviary/subsystems/mass/flops_based/furnishings.py
index edba25346..4c931fc68 100644
--- a/aviary/subsystems/mass/flops_based/furnishings.py
+++ b/aviary/subsystems/mass/flops_based/furnishings.py
@@ -20,15 +20,12 @@ def initialize(self):
         add_aviary_option(self, Aircraft.Fuselage.NUM_FUSELAGES)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Furnishings.MASS_SCALER, val=1.0)
+        add_aviary_input(self, Aircraft.Furnishings.MASS_SCALER)
+        add_aviary_input(self, Aircraft.Fuselage.PASSENGER_COMPARTMENT_LENGTH)
+        add_aviary_input(self, Aircraft.Fuselage.MAX_WIDTH)
+        add_aviary_input(self, Aircraft.Fuselage.MAX_HEIGHT)
 
-        add_aviary_input(self, Aircraft.Fuselage.PASSENGER_COMPARTMENT_LENGTH, val=0.0)
-
-        add_aviary_input(self, Aircraft.Fuselage.MAX_WIDTH, val=0.0)
-
-        add_aviary_input(self, Aircraft.Fuselage.MAX_HEIGHT, val=0.0)
-
-        add_aviary_output(self, Aircraft.Furnishings.MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Furnishings.MASS)
 
     def setup_partials(self):
         self.declare_partials(of=Aircraft.Furnishings.MASS, wrt='*')
@@ -103,19 +100,15 @@ def initialize(self):
         add_aviary_option(self, Aircraft.Fuselage.MILITARY_CARGO_FLOOR)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Furnishings.MASS_SCALER, val=1.0)
+        add_aviary_input(self, Aircraft.Furnishings.MASS_SCALER)
+        add_aviary_input(self, Aircraft.BWB.CABIN_AREA)
 
-        add_aviary_input(self, Aircraft.BWB.CABIN_AREA, val=100.0)
+        add_aviary_input(self, Aircraft.Fuselage.MAX_WIDTH)
 
-        add_aviary_input(self, Aircraft.Fuselage.MAX_WIDTH, val=30.0)
+        add_aviary_input(self, Aircraft.Fuselage.MAX_HEIGHT)
+        add_aviary_input(self, Aircraft.BWB.PASSENGER_LEADING_EDGE_SWEEP)
 
-        add_aviary_input(self, Aircraft.Fuselage.MAX_HEIGHT, val=15.0)
-
-        add_aviary_input(
-            self, Aircraft.BWB.PASSENGER_LEADING_EDGE_SWEEP, val=45.0
-        )
-
-        add_aviary_output(self, Aircraft.Furnishings.MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Furnishings.MASS)
 
     def setup_partials(self):
         self.declare_partials(of=Aircraft.Furnishings.MASS, wrt='*')
@@ -239,9 +232,9 @@ def initialize(self):
         add_aviary_option(self, Aircraft.CrewPayload.Design.NUM_PASSENGERS)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Furnishings.MASS_SCALER, val=1.0)
+        add_aviary_input(self, Aircraft.Furnishings.MASS_SCALER)
 
-        add_aviary_output(self, Aircraft.Furnishings.MASS_BASE, val=0.0)
+        add_aviary_output(self, Aircraft.Furnishings.MASS_BASE)
 
     def setup_partials(self):
         self.declare_partials(of=Aircraft.Furnishings.MASS_BASE, wrt='*')
@@ -272,15 +265,12 @@ class AltFurnishingsGroupMass(om.ExplicitComponent):
     '''
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Furnishings.MASS_BASE, val=0.0)
-
-        add_aviary_input(self, Aircraft.Design.STRUCTURE_MASS, val=0.0)
-
-        add_aviary_input(self, Aircraft.Propulsion.MASS, val=0.0)
-
-        add_aviary_input(self, Aircraft.Design.SYSTEMS_EQUIP_MASS_BASE, val=0.0)
+        add_aviary_input(self, Aircraft.Furnishings.MASS_BASE)
+        add_aviary_input(self, Aircraft.Design.STRUCTURE_MASS)
+        add_aviary_input(self, Aircraft.Propulsion.MASS)
+        add_aviary_input(self, Aircraft.Design.SYSTEMS_EQUIP_MASS_BASE)
 
-        add_aviary_output(self, Aircraft.Furnishings.MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Furnishings.MASS)
 
     def setup_partials(self):
         self.declare_partials(
diff --git a/aviary/subsystems/mass/flops_based/fuselage.py b/aviary/subsystems/mass/flops_based/fuselage.py
index dc0ad71ec..00a757fb6 100644
--- a/aviary/subsystems/mass/flops_based/fuselage.py
+++ b/aviary/subsystems/mass/flops_based/fuselage.py
@@ -20,13 +20,11 @@ def initialize(self):
         add_aviary_option(self, Aircraft.Propulsion.TOTAL_NUM_FUSELAGE_ENGINES)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Fuselage.LENGTH, val=0.0)
+        add_aviary_input(self, Aircraft.Fuselage.LENGTH)
+        add_aviary_input(self, Aircraft.Fuselage.MASS_SCALER)
+        add_aviary_input(self, Aircraft.Fuselage.AVG_DIAMETER)
 
-        add_aviary_input(self, Aircraft.Fuselage.MASS_SCALER, val=1.0)
-
-        add_aviary_input(self, Aircraft.Fuselage.AVG_DIAMETER, val=0.0)
-
-        add_aviary_output(self, Aircraft.Fuselage.MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Fuselage.MASS)
 
     def setup_partials(self):
         self.declare_partials(Aircraft.Fuselage.MASS, "*")
@@ -81,15 +79,12 @@ class AltFuselageMass(om.ExplicitComponent):
     """
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Fuselage.MASS_SCALER, 1.0)
-
-        add_aviary_input(self, Aircraft.Fuselage.WETTED_AREA, 0.0)
-
-        add_aviary_input(self, Aircraft.Fuselage.MAX_HEIGHT, 0.0)
-
-        add_aviary_input(self, Aircraft.Fuselage.MAX_WIDTH, 0.0)
+        add_aviary_input(self, Aircraft.Fuselage.MASS_SCALER)
+        add_aviary_input(self, Aircraft.Fuselage.WETTED_AREA)
+        add_aviary_input(self, Aircraft.Fuselage.MAX_HEIGHT)
+        add_aviary_input(self, Aircraft.Fuselage.MAX_WIDTH)
 
-        add_aviary_output(self, Aircraft.Fuselage.MASS, 1.0)
+        add_aviary_output(self, Aircraft.Fuselage.MASS)
 
     def setup_partials(self):
         self.declare_partials(of='*', wrt='*')
diff --git a/aviary/subsystems/mass/flops_based/horizontal_tail.py b/aviary/subsystems/mass/flops_based/horizontal_tail.py
index a647ebd8f..91f7125db 100644
--- a/aviary/subsystems/mass/flops_based/horizontal_tail.py
+++ b/aviary/subsystems/mass/flops_based/horizontal_tail.py
@@ -12,15 +12,12 @@ class HorizontalTailMass(om.ExplicitComponent):
     '''
 
     def setup(self):
-        add_aviary_input(self, Aircraft.HorizontalTail.AREA, val=0.0)
+        add_aviary_input(self, Aircraft.HorizontalTail.AREA)
+        add_aviary_input(self, Aircraft.HorizontalTail.TAPER_RATIO)
+        add_aviary_input(self, Mission.Design.GROSS_MASS)
+        add_aviary_input(self, Aircraft.HorizontalTail.MASS_SCALER)
 
-        add_aviary_input(self, Aircraft.HorizontalTail.TAPER_RATIO, val=0.352)
-
-        add_aviary_input(self, Mission.Design.GROSS_MASS, val=0.0)
-
-        add_aviary_input(self, Aircraft.HorizontalTail.MASS_SCALER, val=1.0)
-
-        add_aviary_output(self, Aircraft.HorizontalTail.MASS, val=0.0)
+        add_aviary_output(self, Aircraft.HorizontalTail.MASS)
 
     def setup_partials(self):
         self.declare_partials("*", "*")
@@ -65,11 +62,10 @@ class AltHorizontalTailMass(om.ExplicitComponent):
     '''
 
     def setup(self):
-        add_aviary_input(self, Aircraft.HorizontalTail.AREA, val=0.0)
-
-        add_aviary_input(self, Aircraft.HorizontalTail.MASS_SCALER, val=1.0)
+        add_aviary_input(self, Aircraft.HorizontalTail.AREA)
+        add_aviary_input(self, Aircraft.HorizontalTail.MASS_SCALER)
 
-        add_aviary_output(self, Aircraft.HorizontalTail.MASS, val=0.0)
+        add_aviary_output(self, Aircraft.HorizontalTail.MASS)
 
     def setup_partials(self):
         self.declare_partials("*", "*")
diff --git a/aviary/subsystems/mass/flops_based/hydraulics.py b/aviary/subsystems/mass/flops_based/hydraulics.py
index e2f5ca58c..74aee4af8 100644
--- a/aviary/subsystems/mass/flops_based/hydraulics.py
+++ b/aviary/subsystems/mass/flops_based/hydraulics.py
@@ -27,17 +27,13 @@ def initialize(self):
         add_aviary_option(self, Mission.Constraints.MAX_MACH)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Fuselage.PLANFORM_AREA, val=0.0)
+        add_aviary_input(self, Aircraft.Fuselage.PLANFORM_AREA)
+        add_aviary_input(self, Aircraft.Hydraulics.SYSTEM_PRESSURE)
+        add_aviary_input(self, Aircraft.Hydraulics.MASS_SCALER)
+        add_aviary_input(self, Aircraft.Wing.AREA)
+        add_aviary_input(self, Aircraft.Wing.VAR_SWEEP_MASS_PENALTY)
 
-        add_aviary_input(self, Aircraft.Hydraulics.SYSTEM_PRESSURE, val=0.0)
-
-        add_aviary_input(self, Aircraft.Hydraulics.MASS_SCALER, val=1.0)
-
-        add_aviary_input(self, Aircraft.Wing.AREA, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.VAR_SWEEP_MASS_PENALTY, val=0.0)
-
-        add_aviary_output(self, Aircraft.Hydraulics.MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Hydraulics.MASS)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
@@ -105,17 +101,13 @@ class AltHydraulicsGroupMass(om.ExplicitComponent):
     '''
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Wing.AREA, val=0.0)
-
-        add_aviary_input(self, Aircraft.HorizontalTail.WETTED_AREA, val=0.0)
-
-        add_aviary_input(self, Aircraft.HorizontalTail.THICKNESS_TO_CHORD, val=0.0)
-
-        add_aviary_input(self, Aircraft.VerticalTail.AREA, val=0.0)
-
-        add_aviary_input(self, Aircraft.Hydraulics.MASS_SCALER, val=1.0)
+        add_aviary_input(self, Aircraft.Wing.AREA)
+        add_aviary_input(self, Aircraft.HorizontalTail.WETTED_AREA)
+        add_aviary_input(self, Aircraft.HorizontalTail.THICKNESS_TO_CHORD)
+        add_aviary_input(self, Aircraft.VerticalTail.AREA)
+        add_aviary_input(self, Aircraft.Hydraulics.MASS_SCALER)
 
-        add_aviary_output(self, Aircraft.Hydraulics.MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Hydraulics.MASS)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
diff --git a/aviary/subsystems/mass/flops_based/instruments.py b/aviary/subsystems/mass/flops_based/instruments.py
index 04bcda862..1b7ca0bd9 100644
--- a/aviary/subsystems/mass/flops_based/instruments.py
+++ b/aviary/subsystems/mass/flops_based/instruments.py
@@ -23,8 +23,8 @@ def initialize(self):
         add_aviary_option(self, Mission.Constraints.MAX_MACH)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Fuselage.PLANFORM_AREA, 0.0)
-        add_aviary_input(self, Aircraft.Instruments.MASS_SCALER, 1.0)
+        add_aviary_input(self, Aircraft.Fuselage.PLANFORM_AREA)
+        add_aviary_input(self, Aircraft.Instruments.MASS_SCALER)
 
         add_aviary_output(self, Aircraft.Instruments.MASS, 0.0)
 
diff --git a/aviary/subsystems/mass/flops_based/landing_gear.py b/aviary/subsystems/mass/flops_based/landing_gear.py
index 97f03615f..2bcda12cc 100644
--- a/aviary/subsystems/mass/flops_based/landing_gear.py
+++ b/aviary/subsystems/mass/flops_based/landing_gear.py
@@ -19,19 +19,14 @@ class LandingGearMass(om.ExplicitComponent):
     # equations
 
     def setup(self):
-        add_aviary_input(self, Aircraft.LandingGear.MAIN_GEAR_OLEO_LENGTH, val=0.0)
+        add_aviary_input(self, Aircraft.LandingGear.MAIN_GEAR_OLEO_LENGTH)
+        add_aviary_input(self, Aircraft.LandingGear.MAIN_GEAR_MASS_SCALER)
+        add_aviary_input(self, Aircraft.LandingGear.NOSE_GEAR_OLEO_LENGTH)
+        add_aviary_input(self, Aircraft.LandingGear.NOSE_GEAR_MASS_SCALER)
+        add_aviary_input(self, Aircraft.Design.TOUCHDOWN_MASS)
 
-        add_aviary_input(self, Aircraft.LandingGear.MAIN_GEAR_MASS_SCALER, val=1.0)
-
-        add_aviary_input(self, Aircraft.LandingGear.NOSE_GEAR_OLEO_LENGTH, val=0.0)
-
-        add_aviary_input(self, Aircraft.LandingGear.NOSE_GEAR_MASS_SCALER, val=1.0)
-
-        add_aviary_input(self, Aircraft.Design.TOUCHDOWN_MASS, val=0.0)
-
-        add_aviary_output(self, Aircraft.LandingGear.MAIN_GEAR_MASS, val=0.0)
-
-        add_aviary_output(self, Aircraft.LandingGear.NOSE_GEAR_MASS, val=0.0)
+        add_aviary_output(self, Aircraft.LandingGear.MAIN_GEAR_MASS)
+        add_aviary_output(self, Aircraft.LandingGear.NOSE_GEAR_MASS)
 
         # TODO landing weight is not a landing_gear component level variable
         # self.add_input('aircraft:landing_gear:weights:landing_weight', val=0.0, desc='design landing weight', units='lbf')
@@ -131,19 +126,14 @@ class AltLandingGearMass(om.ExplicitComponent):
     '''
 
     def setup(self):
-        add_aviary_input(self, Aircraft.LandingGear.MAIN_GEAR_OLEO_LENGTH, val=0.0)
-
-        add_aviary_input(self, Aircraft.LandingGear.MAIN_GEAR_MASS_SCALER, val=1.0)
-
-        add_aviary_input(self, Aircraft.LandingGear.NOSE_GEAR_OLEO_LENGTH, val=0.0)
-
-        add_aviary_input(self, Aircraft.LandingGear.NOSE_GEAR_MASS_SCALER, val=1.0)
-
-        add_aviary_input(self, Mission.Design.GROSS_MASS, val=0.0)
-
-        add_aviary_output(self, Aircraft.LandingGear.MAIN_GEAR_MASS, val=0.0)
+        add_aviary_input(self, Aircraft.LandingGear.MAIN_GEAR_OLEO_LENGTH)
+        add_aviary_input(self, Aircraft.LandingGear.MAIN_GEAR_MASS_SCALER)
+        add_aviary_input(self, Aircraft.LandingGear.NOSE_GEAR_OLEO_LENGTH)
+        add_aviary_input(self, Aircraft.LandingGear.NOSE_GEAR_MASS_SCALER)
+        add_aviary_input(self, Mission.Design.GROSS_MASS)
 
-        add_aviary_output(self, Aircraft.LandingGear.NOSE_GEAR_MASS, val=0.0)
+        add_aviary_output(self, Aircraft.LandingGear.MAIN_GEAR_MASS)
+        add_aviary_output(self, Aircraft.LandingGear.NOSE_GEAR_MASS)
 
     def setup_partials(self):
         self.declare_partials(Aircraft.LandingGear.MAIN_GEAR_MASS, [
@@ -245,8 +235,8 @@ class NoseGearLength(om.ExplicitComponent):
     """
 
     def setup(self):
-        add_aviary_input(self, Aircraft.LandingGear.MAIN_GEAR_OLEO_LENGTH, val=0.0)
-        add_aviary_output(self, Aircraft.LandingGear.NOSE_GEAR_OLEO_LENGTH, val=0.0)
+        add_aviary_input(self, Aircraft.LandingGear.MAIN_GEAR_OLEO_LENGTH)
+        add_aviary_output(self, Aircraft.LandingGear.NOSE_GEAR_OLEO_LENGTH)
 
     def setup_partials(self):
         self.declare_partials(Aircraft.LandingGear.NOSE_GEAR_OLEO_LENGTH,
@@ -271,20 +261,20 @@ def setup(self):
         num_engine_type = len(self.options[Aircraft.Engine.NUM_ENGINES])
         num_wing_engines = self.options[Aircraft.Engine.NUM_WING_ENGINES]
 
-        add_aviary_input(self, Aircraft.Fuselage.LENGTH, val=0.0)
-        add_aviary_input(self, Aircraft.Fuselage.MAX_WIDTH, val=0.0)
-        add_aviary_input(self, Aircraft.Nacelle.AVG_DIAMETER,
-                         val=np.zeros(num_engine_type))
+        add_aviary_input(self, Aircraft.Fuselage.LENGTH)
+        add_aviary_input(self, Aircraft.Fuselage.MAX_WIDTH)
+        add_aviary_input(self, Aircraft.Nacelle.AVG_DIAMETER, shape=num_engine_type)
         if any(num_wing_engines) > 0:
+            # XJ: shape=(num_engine_type, int(num_wing_engines[0]/2))
             add_aviary_input(self, Aircraft.Engine.WING_LOCATIONS, val=np.zeros(
                 (num_engine_type, int(num_wing_engines[0] / 2))))
         else:
             add_aviary_input(self, Aircraft.Engine.WING_LOCATIONS,
                              val=[[0.0]])
-        add_aviary_input(self, Aircraft.Wing.DIHEDRAL, val=0.0)
-        add_aviary_input(self, Aircraft.Wing.SPAN, val=0.0)
+        add_aviary_input(self, Aircraft.Wing.DIHEDRAL)
+        add_aviary_input(self, Aircraft.Wing.SPAN)
 
-        add_aviary_output(self, Aircraft.LandingGear.MAIN_GEAR_OLEO_LENGTH, val=0.0)
+        add_aviary_output(self, Aircraft.LandingGear.MAIN_GEAR_OLEO_LENGTH)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
diff --git a/aviary/subsystems/mass/flops_based/landing_mass.py b/aviary/subsystems/mass/flops_based/landing_mass.py
index b809b51dc..721ac1b73 100644
--- a/aviary/subsystems/mass/flops_based/landing_mass.py
+++ b/aviary/subsystems/mass/flops_based/landing_mass.py
@@ -11,11 +11,10 @@ class LandingTakeoffMassRatio(om.ExplicitComponent):
     '''
 
     def setup(self):
-        add_aviary_input(self, Mission.Summary.CRUISE_MACH, val=0.0)
+        add_aviary_input(self, Mission.Summary.CRUISE_MACH)
+        add_aviary_input(self, Mission.Design.RANGE)
 
-        add_aviary_input(self, Mission.Design.RANGE, val=0.0)
-
-        add_aviary_output(self, Aircraft.Design.LANDING_TO_TAKEOFF_MASS_RATIO, val=0.0)
+        add_aviary_output(self, Aircraft.Design.LANDING_TO_TAKEOFF_MASS_RATIO)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
@@ -53,11 +52,10 @@ class LandingMass(om.ExplicitComponent):
     '''
 
     def setup(self):
-        add_aviary_input(self, Mission.Design.GROSS_MASS, val=0.0)
-
-        add_aviary_input(self, Aircraft.Design.LANDING_TO_TAKEOFF_MASS_RATIO, val=0.0)
+        add_aviary_input(self, Mission.Design.GROSS_MASS)
+        add_aviary_input(self, Aircraft.Design.LANDING_TO_TAKEOFF_MASS_RATIO)
 
-        add_aviary_output(self, Aircraft.Design.TOUCHDOWN_MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Design.TOUCHDOWN_MASS)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
diff --git a/aviary/subsystems/mass/flops_based/mass_summation.py b/aviary/subsystems/mass/flops_based/mass_summation.py
index 2a3ae8103..30570ca34 100644
--- a/aviary/subsystems/mass/flops_based/mass_summation.py
+++ b/aviary/subsystems/mass/flops_based/mass_summation.py
@@ -80,18 +80,18 @@ def initialize(self):
     def setup(self):
         num_engine_type = len(self.options[Aircraft.Engine.NUM_ENGINES])
 
-        add_aviary_input(self, Aircraft.Canard.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Fins.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Fuselage.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.HorizontalTail.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.LandingGear.MAIN_GEAR_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.LandingGear.NOSE_GEAR_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Nacelle.MASS, val=np.zeros(num_engine_type))
-        add_aviary_input(self, Aircraft.Paint.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.VerticalTail.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Wing.MASS, val=0.0)
-
-        add_aviary_output(self, Aircraft.Design.STRUCTURE_MASS, val=0.0)
+        add_aviary_input(self, Aircraft.Canard.MASS)
+        add_aviary_input(self, Aircraft.Fins.MASS)
+        add_aviary_input(self, Aircraft.Fuselage.MASS)
+        add_aviary_input(self, Aircraft.HorizontalTail.MASS)
+        add_aviary_input(self, Aircraft.LandingGear.MAIN_GEAR_MASS)
+        add_aviary_input(self, Aircraft.LandingGear.NOSE_GEAR_MASS)
+        add_aviary_input(self, Aircraft.Nacelle.MASS, shape=num_engine_type)
+        add_aviary_input(self, Aircraft.Paint.MASS)
+        add_aviary_input(self, Aircraft.VerticalTail.MASS)
+        add_aviary_input(self, Aircraft.Wing.MASS)
+
+        add_aviary_output(self, Aircraft.Design.STRUCTURE_MASS)
 
     def setup_partials(self):
         num_engine_type = len(self.options[Aircraft.Engine.NUM_ENGINES])
@@ -120,13 +120,12 @@ def compute(self, inputs, outputs):
 class PropulsionMass(om.ExplicitComponent):
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Fuel.FUEL_SYSTEM_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Propulsion.TOTAL_MISC_MASS, val=0.0)
-        add_aviary_input(
-            self, Aircraft.Propulsion.TOTAL_THRUST_REVERSERS_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Propulsion.TOTAL_ENGINE_MASS, val=0.0)
+        add_aviary_input(self, Aircraft.Fuel.FUEL_SYSTEM_MASS)
+        add_aviary_input(self, Aircraft.Propulsion.TOTAL_MISC_MASS)
+        add_aviary_input(self, Aircraft.Propulsion.TOTAL_THRUST_REVERSERS_MASS)
+        add_aviary_input(self, Aircraft.Propulsion.TOTAL_ENGINE_MASS)
 
-        add_aviary_output(self, Aircraft.Propulsion.MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Propulsion.MASS)
 
     def setup_partials(self):
         prop_wrt = [
@@ -150,18 +149,18 @@ def compute(self, inputs, outputs):
 class SystemsEquipMass(om.ExplicitComponent):
 
     def setup(self):
-        add_aviary_input(self, Aircraft.AirConditioning.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.AntiIcing.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.APU.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Avionics.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Electrical.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Furnishings.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Hydraulics.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Instruments.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Wing.SURFACE_CONTROL_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Design.EXTERNAL_SUBSYSTEMS_MASS, val=0.0)
-
-        add_aviary_output(self, Aircraft.Design.SYSTEMS_EQUIP_MASS, val=0.0)
+        add_aviary_input(self, Aircraft.AirConditioning.MASS)
+        add_aviary_input(self, Aircraft.AntiIcing.MASS)
+        add_aviary_input(self, Aircraft.APU.MASS)
+        add_aviary_input(self, Aircraft.Avionics.MASS)
+        add_aviary_input(self, Aircraft.Electrical.MASS)
+        add_aviary_input(self, Aircraft.Furnishings.MASS)
+        add_aviary_input(self, Aircraft.Hydraulics.MASS)
+        add_aviary_input(self, Aircraft.Instruments.MASS)
+        add_aviary_input(self, Aircraft.Wing.SURFACE_CONTROL_MASS)
+        add_aviary_input(self, Aircraft.Design.EXTERNAL_SUBSYSTEMS_MASS)
+
+        add_aviary_output(self, Aircraft.Design.SYSTEMS_EQUIP_MASS)
 
     def setup_partials(self):
         self.declare_partials(Aircraft.Design.SYSTEMS_EQUIP_MASS, '*', val=1)
@@ -187,18 +186,18 @@ def compute(self, inputs, outputs):
 class AltSystemsEquipMassBase(om.ExplicitComponent):
 
     def setup(self):
-        add_aviary_input(self, Aircraft.AirConditioning.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.AntiIcing.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.APU.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Avionics.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Electrical.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Furnishings.MASS_BASE, val=0.0)
-        add_aviary_input(self, Aircraft.Hydraulics.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Instruments.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Wing.SURFACE_CONTROL_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Design.EXTERNAL_SUBSYSTEMS_MASS, val=0.0)
-
-        add_aviary_output(self, Aircraft.Design.SYSTEMS_EQUIP_MASS_BASE, val=0.0)
+        add_aviary_input(self, Aircraft.AirConditioning.MASS)
+        add_aviary_input(self, Aircraft.AntiIcing.MASS)
+        add_aviary_input(self, Aircraft.APU.MASS)
+        add_aviary_input(self, Aircraft.Avionics.MASS)
+        add_aviary_input(self, Aircraft.Electrical.MASS)
+        add_aviary_input(self, Aircraft.Furnishings.MASS_BASE)
+        add_aviary_input(self, Aircraft.Hydraulics.MASS)
+        add_aviary_input(self, Aircraft.Instruments.MASS)
+        add_aviary_input(self, Aircraft.Wing.SURFACE_CONTROL_MASS)
+        add_aviary_input(self, Aircraft.Design.EXTERNAL_SUBSYSTEMS_MASS)
+
+        add_aviary_output(self, Aircraft.Design.SYSTEMS_EQUIP_MASS_BASE)
 
     def setup_partials(self):
         self.declare_partials(Aircraft.Design.SYSTEMS_EQUIP_MASS_BASE, '*', val=1)
@@ -224,11 +223,11 @@ def compute(self, inputs, outputs):
 class AltSystemsEquipMass(om.ExplicitComponent):
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Design.SYSTEMS_EQUIP_MASS_BASE, val=0.0)
-        add_aviary_input(self, Aircraft.Design.STRUCTURE_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Propulsion.MASS, val=0.0)
+        add_aviary_input(self, Aircraft.Design.SYSTEMS_EQUIP_MASS_BASE)
+        add_aviary_input(self, Aircraft.Design.STRUCTURE_MASS)
+        add_aviary_input(self, Aircraft.Propulsion.MASS)
 
-        add_aviary_output(self, Aircraft.Design.SYSTEMS_EQUIP_MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Design.SYSTEMS_EQUIP_MASS)
 
     def setup_partials(self):
         self.declare_partials(
@@ -256,12 +255,12 @@ def compute(self, inputs, outputs):
 class EmptyMass(om.ExplicitComponent):
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Design.EMPTY_MASS_MARGIN, val=0.0)
-        add_aviary_input(self, Aircraft.Design.STRUCTURE_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Propulsion.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Design.SYSTEMS_EQUIP_MASS, val=0.0)
+        add_aviary_input(self, Aircraft.Design.EMPTY_MASS_MARGIN)
+        add_aviary_input(self, Aircraft.Design.STRUCTURE_MASS)
+        add_aviary_input(self, Aircraft.Propulsion.MASS)
+        add_aviary_input(self, Aircraft.Design.SYSTEMS_EQUIP_MASS)
 
-        add_aviary_output(self, Aircraft.Design.EMPTY_MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Design.EMPTY_MASS)
 
     def setup_partials(self):
         self.declare_partials(Aircraft.Design.EMPTY_MASS, '*', val=1)
@@ -279,12 +278,12 @@ def compute(self, inputs, outputs):
 class AltEmptyMass(om.ExplicitComponent):
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Design.EMPTY_MASS_MARGIN, val=0.0)
-        add_aviary_input(self, Aircraft.Design.STRUCTURE_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Propulsion.MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Design.SYSTEMS_EQUIP_MASS_BASE, val=0.0)
+        add_aviary_input(self, Aircraft.Design.EMPTY_MASS_MARGIN)
+        add_aviary_input(self, Aircraft.Design.STRUCTURE_MASS)
+        add_aviary_input(self, Aircraft.Propulsion.MASS)
+        add_aviary_input(self, Aircraft.Design.SYSTEMS_EQUIP_MASS_BASE)
 
-        add_aviary_output(self, Aircraft.Design.EMPTY_MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Design.EMPTY_MASS)
 
     def setup_partials(self):
         self.declare_partials(Aircraft.Design.EMPTY_MASS,
@@ -309,15 +308,15 @@ def compute(self, inputs, outputs):
 class OperatingMass(om.ExplicitComponent):
 
     def setup(self):
-        add_aviary_input(self, Aircraft.CrewPayload.CARGO_CONTAINER_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.CrewPayload.NON_FLIGHT_CREW_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.CrewPayload.FLIGHT_CREW_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.CrewPayload.PASSENGER_SERVICE_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Design.EMPTY_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Fuel.UNUSABLE_FUEL_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Propulsion.TOTAL_ENGINE_OIL_MASS, val=0.0)
+        add_aviary_input(self, Aircraft.CrewPayload.CARGO_CONTAINER_MASS)
+        add_aviary_input(self, Aircraft.CrewPayload.NON_FLIGHT_CREW_MASS)
+        add_aviary_input(self, Aircraft.CrewPayload.FLIGHT_CREW_MASS)
+        add_aviary_input(self, Aircraft.CrewPayload.PASSENGER_SERVICE_MASS)
+        add_aviary_input(self, Aircraft.Design.EMPTY_MASS)
+        add_aviary_input(self, Aircraft.Fuel.UNUSABLE_FUEL_MASS)
+        add_aviary_input(self, Aircraft.Propulsion.TOTAL_ENGINE_OIL_MASS)
 
-        add_aviary_output(self, Aircraft.Design.OPERATING_MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Design.OPERATING_MASS)
 
     def setup_partials(self):
         self.declare_partials(Aircraft.Design.OPERATING_MASS, '*', val=1)
@@ -339,12 +338,12 @@ def compute(self, inputs, outputs):
 class ZeroFuelMass(om.ExplicitComponent):
 
     def setup(self):
-        add_aviary_input(self, Aircraft.CrewPayload.PASSENGER_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.CrewPayload.BAGGAGE_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.CrewPayload.CARGO_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Design.OPERATING_MASS, val=0.0)
+        add_aviary_input(self, Aircraft.CrewPayload.PASSENGER_MASS)
+        add_aviary_input(self, Aircraft.CrewPayload.BAGGAGE_MASS)
+        add_aviary_input(self, Aircraft.CrewPayload.CARGO_MASS)
+        add_aviary_input(self, Aircraft.Design.OPERATING_MASS)
 
-        add_aviary_output(self, Aircraft.Design.ZERO_FUEL_MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Design.ZERO_FUEL_MASS)
 
     def setup_partials(self):
         self.declare_partials(Aircraft.Design.ZERO_FUEL_MASS, '*', val=1)
@@ -362,10 +361,10 @@ def compute(self, inputs, outputs):
 class FuelMass(om.ExplicitComponent):
 
     def setup(self):
-        add_aviary_input(self, Mission.Design.GROSS_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Design.ZERO_FUEL_MASS, val=0.0)
+        add_aviary_input(self, Mission.Design.GROSS_MASS)
+        add_aviary_input(self, Aircraft.Design.ZERO_FUEL_MASS)
 
-        add_aviary_output(self, Mission.Design.FUEL_MASS, val=0.0)
+        add_aviary_output(self, Mission.Design.FUEL_MASS)
 
     def setup_partials(self):
         self.declare_partials(Mission.Design.FUEL_MASS,
diff --git a/aviary/subsystems/mass/flops_based/misc_engine.py b/aviary/subsystems/mass/flops_based/misc_engine.py
index a77ca24c9..94b7bd11f 100644
--- a/aviary/subsystems/mass/flops_based/misc_engine.py
+++ b/aviary/subsystems/mass/flops_based/misc_engine.py
@@ -24,13 +24,12 @@ def initialize(self):
     def setup(self):
         num_engine_type = len(self.options[Aircraft.Engine.NUM_ENGINES])
 
-        add_aviary_input(
-            self, Aircraft.Engine.ADDITIONAL_MASS, val=np.zeros(num_engine_type))
-        add_aviary_input(self, Aircraft.Propulsion.MISC_MASS_SCALER, val=0.0)
-        add_aviary_input(self, Aircraft.Propulsion.TOTAL_ENGINE_CONTROLS_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Propulsion.TOTAL_STARTER_MASS, val=0.0)
+        add_aviary_input(self, Aircraft.Engine.ADDITIONAL_MASS, shape=num_engine_type)
+        add_aviary_input(self, Aircraft.Propulsion.MISC_MASS_SCALER)
+        add_aviary_input(self, Aircraft.Propulsion.TOTAL_ENGINE_CONTROLS_MASS)
+        add_aviary_input(self, Aircraft.Propulsion.TOTAL_STARTER_MASS)
 
-        add_aviary_output(self, Aircraft.Propulsion.TOTAL_MISC_MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Propulsion.TOTAL_MISC_MASS)
 
         self.declare_partials(
             of=Aircraft.Propulsion.TOTAL_MISC_MASS,
diff --git a/aviary/subsystems/mass/flops_based/nacelle.py b/aviary/subsystems/mass/flops_based/nacelle.py
index 7ec531053..7ed085d9a 100644
--- a/aviary/subsystems/mass/flops_based/nacelle.py
+++ b/aviary/subsystems/mass/flops_based/nacelle.py
@@ -25,19 +25,12 @@ def initialize(self):
     def setup(self):
         num_engine_type = len(self.options[Aircraft.Engine.NUM_ENGINES])
 
-        add_aviary_input(self, Aircraft.Nacelle.AVG_DIAMETER,
-                         val=np.zeros(num_engine_type))
+        add_aviary_input(self, Aircraft.Nacelle.AVG_DIAMETER, shape=num_engine_type)
+        add_aviary_input(self, Aircraft.Nacelle.AVG_LENGTH, shape=num_engine_type)
+        add_aviary_input(self, Aircraft.Nacelle.MASS_SCALER, shape=num_engine_type)
+        add_aviary_input(self, Aircraft.Engine.SCALED_SLS_THRUST, shape=num_engine_type)
 
-        add_aviary_input(self, Aircraft.Nacelle.AVG_LENGTH,
-                         val=np.zeros(num_engine_type))
-
-        add_aviary_input(self, Aircraft.Nacelle.MASS_SCALER,
-                         val=np.ones(num_engine_type))
-
-        add_aviary_input(self, Aircraft.Engine.SCALED_SLS_THRUST,
-                         val=np.zeros(num_engine_type))
-
-        add_aviary_output(self, Aircraft.Nacelle.MASS, val=np.zeros(num_engine_type))
+        add_aviary_output(self, Aircraft.Nacelle.MASS, shape=num_engine_type)
 
     def setup_partials(self):
         # derivatives w.r.t vectorized engine inputs have known sparsity pattern
diff --git a/aviary/subsystems/mass/flops_based/paint.py b/aviary/subsystems/mass/flops_based/paint.py
index 4781a13e6..6e866ae98 100644
--- a/aviary/subsystems/mass/flops_based/paint.py
+++ b/aviary/subsystems/mass/flops_based/paint.py
@@ -10,11 +10,10 @@ class PaintMass(om.ExplicitComponent):
     '''
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Design.TOTAL_WETTED_AREA, val=0.0)
+        add_aviary_input(self, Aircraft.Design.TOTAL_WETTED_AREA)
+        add_aviary_input(self, Aircraft.Paint.MASS_PER_UNIT_AREA)
 
-        add_aviary_input(self, Aircraft.Paint.MASS_PER_UNIT_AREA, val=0.0)
-
-        add_aviary_output(self, Aircraft.Paint.MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Paint.MASS)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
diff --git a/aviary/subsystems/mass/flops_based/passenger_service.py b/aviary/subsystems/mass/flops_based/passenger_service.py
index f333b4011..b7f23cfde 100644
--- a/aviary/subsystems/mass/flops_based/passenger_service.py
+++ b/aviary/subsystems/mass/flops_based/passenger_service.py
@@ -23,23 +23,10 @@ def initialize(self):
         add_aviary_option(self, Mission.Constraints.MAX_MACH)
 
     def setup(self):
-        add_aviary_input(
-            self,
-            Aircraft.CrewPayload.PASSENGER_SERVICE_MASS_SCALER,
-            val=1.,
-        )
+        add_aviary_input(self, Aircraft.CrewPayload.PASSENGER_SERVICE_MASS_SCALER)
+        add_aviary_input(self, Mission.Design.RANGE)
 
-        add_aviary_input(
-            self,
-            Mission.Design.RANGE,
-            val=0.0,
-        )
-
-        add_aviary_output(
-            self,
-            Aircraft.CrewPayload.PASSENGER_SERVICE_MASS,
-            val=0.0,
-        )
+        add_aviary_output(self, Aircraft.CrewPayload.PASSENGER_SERVICE_MASS)
 
     def setup_partials(self):
         self.declare_partials('*', '*')
diff --git a/aviary/subsystems/mass/flops_based/starter.py b/aviary/subsystems/mass/flops_based/starter.py
index 2bf04fb07..0a2bc5a04 100644
--- a/aviary/subsystems/mass/flops_based/starter.py
+++ b/aviary/subsystems/mass/flops_based/starter.py
@@ -24,10 +24,9 @@ def initialize(self):
     def setup(self):
         num_engine_type = len(self.options[Aircraft.Engine.NUM_ENGINES])
 
-        add_aviary_input(self, Aircraft.Nacelle.AVG_DIAMETER,
-                         val=np.zeros(num_engine_type))
+        add_aviary_input(self, Aircraft.Nacelle.AVG_DIAMETER, shape=num_engine_type)
 
-        add_aviary_output(self, Aircraft.Propulsion.TOTAL_STARTER_MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Propulsion.TOTAL_STARTER_MASS)
 
     def setup_partials(self):
         self.declare_partials("*", "*")
diff --git a/aviary/subsystems/mass/flops_based/surface_controls.py b/aviary/subsystems/mass/flops_based/surface_controls.py
index fb109e427..462e9c6e1 100644
--- a/aviary/subsystems/mass/flops_based/surface_controls.py
+++ b/aviary/subsystems/mass/flops_based/surface_controls.py
@@ -15,12 +15,12 @@ def initialize(self):
         add_aviary_option(self, Mission.Constraints.MAX_MACH)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Wing.SURFACE_CONTROL_MASS_SCALER, val=1.0)
-        add_aviary_input(self, Mission.Design.GROSS_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Wing.CONTROL_SURFACE_AREA_RATIO, val=0.0)
-        add_aviary_input(self, Aircraft.Wing.AREA, val=0.0)
+        add_aviary_input(self, Aircraft.Wing.SURFACE_CONTROL_MASS_SCALER)
+        add_aviary_input(self, Mission.Design.GROSS_MASS)
+        add_aviary_input(self, Aircraft.Wing.CONTROL_SURFACE_AREA_RATIO)
+        add_aviary_input(self, Aircraft.Wing.AREA)
 
-        add_aviary_output(self, Aircraft.Wing.SURFACE_CONTROL_MASS, val=10)
+        add_aviary_output(self, Aircraft.Wing.SURFACE_CONTROL_MASS)
         add_aviary_output(self, Aircraft.Wing.CONTROL_SURFACE_AREA, val=2)
 
         self.declare_partials(Aircraft.Wing.SURFACE_CONTROL_MASS, '*')
diff --git a/aviary/subsystems/mass/flops_based/test/test_furnishings.py b/aviary/subsystems/mass/flops_based/test/test_furnishings.py
index 7dab4cc72..cc0e10d18 100644
--- a/aviary/subsystems/mass/flops_based/test/test_furnishings.py
+++ b/aviary/subsystems/mass/flops_based/test/test_furnishings.py
@@ -151,6 +151,12 @@ def test_case(self):
             promotes_outputs=['*'],
             promotes_inputs=['*']
         )
+        prob.model.set_input_defaults(
+            Aircraft.BWB.CABIN_AREA, val=100., units="ft**2")
+        prob.model.set_input_defaults(
+            Aircraft.Fuselage.MAX_WIDTH, val=30., units="ft")
+        prob.model.set_input_defaults(
+            Aircraft.Fuselage.MAX_HEIGHT, val=15., units="ft")
         prob.setup(check=False, force_alloc_complex=True)
 
         partial_data = prob.check_partials(out_stream=None, method="cs")
diff --git a/aviary/subsystems/mass/flops_based/test/test_wing_common.py b/aviary/subsystems/mass/flops_based/test/test_wing_common.py
index 5652de62c..4ddd4103c 100644
--- a/aviary/subsystems/mass/flops_based/test/test_wing_common.py
+++ b/aviary/subsystems/mass/flops_based/test/test_wing_common.py
@@ -223,6 +223,7 @@ def test_case(self):
         prob.set_val(Aircraft.Wing.SHEAR_CONTROL_MASS, 4000, 'lbm')
         prob.set_val(Aircraft.Wing.SPAN, 100, 'ft')
         prob.set_val(Aircraft.Wing.SWEEP, 20, 'deg')
+        prob.set_val(Aircraft.Wing.ULTIMATE_LOAD_FACTOR, 3.75, 'unitless')
 
         partial_data = prob.check_partials(out_stream=None, method="cs")
         assert_check_partials(partial_data, atol=1e-12, rtol=1e-12)
diff --git a/aviary/subsystems/mass/flops_based/thrust_reverser.py b/aviary/subsystems/mass/flops_based/thrust_reverser.py
index 6821f182b..5193d6005 100644
--- a/aviary/subsystems/mass/flops_based/thrust_reverser.py
+++ b/aviary/subsystems/mass/flops_based/thrust_reverser.py
@@ -28,14 +28,14 @@ def setup(self):
         num_engine_type = len(self.options[Aircraft.Engine.NUM_ENGINES])
 
         add_aviary_input(
-            self, Aircraft.Engine.THRUST_REVERSERS_MASS_SCALER, val=np.zeros(num_engine_type))
+            self, Aircraft.Engine.THRUST_REVERSERS_MASS_SCALER, shape=num_engine_type)
         add_aviary_input(
-            self, Aircraft.Engine.SCALED_SLS_THRUST, val=np.zeros(num_engine_type))
+            self, Aircraft.Engine.SCALED_SLS_THRUST, shape=num_engine_type)
 
         add_aviary_output(
-            self, Aircraft.Engine.THRUST_REVERSERS_MASS, val=np.zeros(num_engine_type))
+            self, Aircraft.Engine.THRUST_REVERSERS_MASS, shape=num_engine_type)
         add_aviary_output(
-            self, Aircraft.Propulsion.TOTAL_THRUST_REVERSERS_MASS, val=0)
+            self, Aircraft.Propulsion.TOTAL_THRUST_REVERSERS_MASS)
 
     def setup_partials(self):
         # derivatives w.r.t vectorized engine inputs have known sparsity pattern
diff --git a/aviary/subsystems/mass/flops_based/unusable_fuel.py b/aviary/subsystems/mass/flops_based/unusable_fuel.py
index 8913549ee..9aa6c5406 100644
--- a/aviary/subsystems/mass/flops_based/unusable_fuel.py
+++ b/aviary/subsystems/mass/flops_based/unusable_fuel.py
@@ -25,19 +25,14 @@ def initialize(self):
 
     def setup(self):
         add_aviary_input(
-            self, Aircraft.Fuel.UNUSABLE_FUEL_MASS_SCALER, val=1.0)
-
-        add_aviary_input(self, Aircraft.Fuel.DENSITY_RATIO, 1.0)
-
-        add_aviary_input(self, Aircraft.Fuel.TOTAL_CAPACITY, 0.0)
-
-        add_aviary_input(self, Aircraft.Propulsion.TOTAL_SCALED_SLS_THRUST, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.AREA, val=0.0)
-
-        add_aviary_output(self, Aircraft.Fuel.TOTAL_VOLUME, val=0.0)
-
-        add_aviary_output(self, Aircraft.Fuel.UNUSABLE_FUEL_MASS, val=0.0)
+            self, Aircraft.Fuel.UNUSABLE_FUEL_MASS_SCALER)
+        add_aviary_input(self, Aircraft.Fuel.DENSITY_RATIO)
+        add_aviary_input(self, Aircraft.Fuel.TOTAL_CAPACITY)
+        add_aviary_input(self, Aircraft.Propulsion.TOTAL_SCALED_SLS_THRUST)
+        add_aviary_input(self, Aircraft.Wing.AREA)
+        add_aviary_output(self, Aircraft.Fuel.TOTAL_VOLUME)
+
+        add_aviary_output(self, Aircraft.Fuel.UNUSABLE_FUEL_MASS)
 
     def setup_partials(self):
 
diff --git a/aviary/subsystems/mass/flops_based/vertical_tail.py b/aviary/subsystems/mass/flops_based/vertical_tail.py
index 0f95fb3da..007218103 100644
--- a/aviary/subsystems/mass/flops_based/vertical_tail.py
+++ b/aviary/subsystems/mass/flops_based/vertical_tail.py
@@ -16,14 +16,11 @@ def initialize(self):
 
     def setup(self):
         add_aviary_input(self, Aircraft.VerticalTail.AREA, val=0.0)
-
         add_aviary_input(self, Aircraft.VerticalTail.TAPER_RATIO, val=0.0)
+        add_aviary_input(self, Aircraft.VerticalTail.MASS_SCALER)
+        add_aviary_input(self, Mission.Design.GROSS_MASS)
 
-        add_aviary_input(self, Aircraft.VerticalTail.MASS_SCALER, val=1.0)
-
-        add_aviary_input(self, Mission.Design.GROSS_MASS, val=0.0)
-
-        add_aviary_output(self, Aircraft.VerticalTail.MASS, val=0.0)
+        add_aviary_output(self, Aircraft.VerticalTail.MASS)
 
     def setup_partials(self):
         self.declare_partials("*", "*")
diff --git a/aviary/subsystems/mass/flops_based/wing_common.py b/aviary/subsystems/mass/flops_based/wing_common.py
index a932a4e49..b82b1c347 100644
--- a/aviary/subsystems/mass/flops_based/wing_common.py
+++ b/aviary/subsystems/mass/flops_based/wing_common.py
@@ -16,23 +16,23 @@ def initialize(self):
         add_aviary_option(self, Aircraft.Fuselage.NUM_FUSELAGES)
 
     def setup(self):
-        add_aviary_input(self, Mission.Design.GROSS_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Wing.AEROELASTIC_TAILORING_FACTOR, val=0.0)
-        add_aviary_input(self, Aircraft.Wing.BENDING_MATERIAL_FACTOR, val=0.0)
-        add_aviary_input(self, Aircraft.Wing.BENDING_MATERIAL_MASS_SCALER, val=1.0)
-        add_aviary_input(self, Aircraft.Wing.COMPOSITE_FRACTION, val=0.0)
-        add_aviary_input(self, Aircraft.Wing.ENG_POD_INERTIA_FACTOR, val=0.0)
-        add_aviary_input(self, Aircraft.Wing.LOAD_FRACTION, val=0.0)
-        add_aviary_input(self, Aircraft.Wing.MISC_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Wing.MISC_MASS_SCALER, val=1.0)
-        add_aviary_input(self, Aircraft.Wing.SHEAR_CONTROL_MASS, val=0.0)
-        add_aviary_input(self, Aircraft.Wing.SHEAR_CONTROL_MASS_SCALER, val=1.0)
-        add_aviary_input(self, Aircraft.Wing.SPAN, val=0.0)
-        add_aviary_input(self, Aircraft.Wing.SWEEP, val=0.0)
-        add_aviary_input(self, Aircraft.Wing.ULTIMATE_LOAD_FACTOR, val=3.75)
-        add_aviary_input(self, Aircraft.Wing.VAR_SWEEP_MASS_PENALTY, val=0.0)
-
-        add_aviary_output(self, Aircraft.Wing.BENDING_MATERIAL_MASS, val=0.0)
+        add_aviary_input(self, Mission.Design.GROSS_MASS)
+        add_aviary_input(self, Aircraft.Wing.AEROELASTIC_TAILORING_FACTOR)
+        add_aviary_input(self, Aircraft.Wing.BENDING_MATERIAL_FACTOR)
+        add_aviary_input(self, Aircraft.Wing.BENDING_MATERIAL_MASS_SCALER)
+        add_aviary_input(self, Aircraft.Wing.COMPOSITE_FRACTION)
+        add_aviary_input(self, Aircraft.Wing.ENG_POD_INERTIA_FACTOR)
+        add_aviary_input(self, Aircraft.Wing.LOAD_FRACTION)
+        add_aviary_input(self, Aircraft.Wing.MISC_MASS)
+        add_aviary_input(self, Aircraft.Wing.MISC_MASS_SCALER)
+        add_aviary_input(self, Aircraft.Wing.SHEAR_CONTROL_MASS)
+        add_aviary_input(self, Aircraft.Wing.SHEAR_CONTROL_MASS_SCALER)
+        add_aviary_input(self, Aircraft.Wing.SPAN)
+        add_aviary_input(self, Aircraft.Wing.SWEEP)
+        add_aviary_input(self, Aircraft.Wing.ULTIMATE_LOAD_FACTOR)
+        add_aviary_input(self, Aircraft.Wing.VAR_SWEEP_MASS_PENALTY)
+
+        add_aviary_output(self, Aircraft.Wing.BENDING_MATERIAL_MASS)
 
         self.A1 = 8.80
         self.A2 = 6.25
@@ -212,15 +212,12 @@ def initialize(self):
             desc='Aircfaft type: Tranpsport, HWB, or GA')
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Wing.COMPOSITE_FRACTION, val=0.0)
+        add_aviary_input(self, Aircraft.Wing.COMPOSITE_FRACTION)
+        add_aviary_input(self, Aircraft.Wing.CONTROL_SURFACE_AREA)
+        add_aviary_input(self, Mission.Design.GROSS_MASS)
+        add_aviary_input(self, Aircraft.Wing.SHEAR_CONTROL_MASS_SCALER)
 
-        add_aviary_input(self, Aircraft.Wing.CONTROL_SURFACE_AREA, val=0.0)
-
-        add_aviary_input(self, Mission.Design.GROSS_MASS, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.SHEAR_CONTROL_MASS_SCALER, val=1.0)
-
-        add_aviary_output(self, Aircraft.Wing.SHEAR_CONTROL_MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Wing.SHEAR_CONTROL_MASS)
 
         if (
             (self.options['aircraft_type'] == 'Transport')
@@ -289,13 +286,11 @@ def initialize(self):
             desc='Aircfaft type: Tranpsport, HWB, or GA')
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Wing.COMPOSITE_FRACTION, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.AREA, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.MISC_MASS_SCALER, val=1.0)
+        add_aviary_input(self, Aircraft.Wing.COMPOSITE_FRACTION)
+        add_aviary_input(self, Aircraft.Wing.AREA)
+        add_aviary_input(self, Aircraft.Wing.MISC_MASS_SCALER)
 
-        add_aviary_output(self, Aircraft.Wing.MISC_MASS, val=0.0)
+        add_aviary_output(self, Aircraft.Wing.MISC_MASS)
 
         if (
             (self.options['aircraft_type'] == 'Transport')
@@ -339,17 +334,13 @@ class WingTotalMass(om.ExplicitComponent):
     """
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Wing.BENDING_MATERIAL_MASS, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.SHEAR_CONTROL_MASS, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.MISC_MASS, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.BWB_AFTBODY_MASS, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.MASS_SCALER, val=1.0)
+        add_aviary_input(self, Aircraft.Wing.BENDING_MATERIAL_MASS)
+        add_aviary_input(self, Aircraft.Wing.SHEAR_CONTROL_MASS)
+        add_aviary_input(self, Aircraft.Wing.MISC_MASS)
+        add_aviary_input(self, Aircraft.Wing.BWB_AFTBODY_MASS)
+        add_aviary_input(self, Aircraft.Wing.MASS_SCALER)
 
-        add_aviary_output(self, Aircraft.Wing.MASS, val=0)
+        add_aviary_output(self, Aircraft.Wing.MASS)
 
     def setup_partials(self):
         self.declare_partials("*", "*")
diff --git a/aviary/subsystems/mass/flops_based/wing_detailed.py b/aviary/subsystems/mass/flops_based/wing_detailed.py
index f645f812a..00e468c42 100644
--- a/aviary/subsystems/mass/flops_based/wing_detailed.py
+++ b/aviary/subsystems/mass/flops_based/wing_detailed.py
@@ -33,52 +33,30 @@ def setup(self):
         # wing_location_default = np.empty(num_engine_type, object)
         # wing_location_default[:] = [np.array([0]*int(num)) for num in num_wing_engines/2]
 
-        add_aviary_input(
-            self,
-            Aircraft.Wing.LOAD_PATH_SWEEP_DIST,
-            val=np.zeros(num_input_stations - 1),
-        )
-
-        add_aviary_input(
-            self,
-            Aircraft.Wing.THICKNESS_TO_CHORD_DIST,
-            val=np.zeros(num_input_stations),
-        )
-
-        add_aviary_input(
-            self,
-            Aircraft.Wing.CHORD_PER_SEMISPAN_DIST,
-            val=np.zeros(num_input_stations),
-        )
-
-        add_aviary_input(self, Mission.Design.GROSS_MASS, val=0.0)
-
-        add_aviary_input(self, Aircraft.Engine.POD_MASS, val=np.zeros(num_engine_type))
-
-        add_aviary_input(self, Aircraft.Wing.ASPECT_RATIO, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.ASPECT_RATIO_REF, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.STRUT_BRACING_FACTOR, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.AEROELASTIC_TAILORING_FACTOR, val=0.0)
+        add_aviary_input(self, Aircraft.Wing.LOAD_PATH_SWEEP_DIST,
+                         shape=num_input_stations - 1)
+        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD_DIST,
+                         shape=num_input_stations)
+        add_aviary_input(self, Aircraft.Wing.CHORD_PER_SEMISPAN_DIST,
+                         shape=num_input_stations)
+        add_aviary_input(self, Mission.Design.GROSS_MASS)
+        add_aviary_input(self, Aircraft.Engine.POD_MASS, shape=num_engine_type)
+        add_aviary_input(self, Aircraft.Wing.ASPECT_RATIO)
+        add_aviary_input(self, Aircraft.Wing.ASPECT_RATIO_REF)
+        add_aviary_input(self, Aircraft.Wing.STRUT_BRACING_FACTOR)
+        add_aviary_input(self, Aircraft.Wing.AEROELASTIC_TAILORING_FACTOR)
 
         if total_num_wing_engines > 0:
-            add_aviary_input(
-                self,
-                Aircraft.Engine.WING_LOCATIONS,
-                val=np.zeros(int(total_num_wing_engines / 2)),
-            )
+            add_aviary_input(self, Aircraft.Engine.WING_LOCATIONS,
+                             shape=int(total_num_wing_engines/2))
         else:
-            add_aviary_input(self, Aircraft.Engine.WING_LOCATIONS, val=[[0.0]])
-
-        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD_REF, val=0.0)
+            add_aviary_input(self, Aircraft.Engine.WING_LOCATIONS)
 
-        add_aviary_output(self, Aircraft.Wing.BENDING_MATERIAL_FACTOR, val=0.0)
+        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD)
+        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD_REF)
 
-        add_aviary_output(self, Aircraft.Wing.ENG_POD_INERTIA_FACTOR, val=0.0)
+        add_aviary_output(self, Aircraft.Wing.BENDING_MATERIAL_FACTOR)
+        add_aviary_output(self, Aircraft.Wing.ENG_POD_INERTIA_FACTOR)
 
     def setup_partials(self):
         # TODO: Analytic derivs will be challenging, but possible.
diff --git a/aviary/subsystems/mass/flops_based/wing_simple.py b/aviary/subsystems/mass/flops_based/wing_simple.py
index 04808ebdb..05779757a 100644
--- a/aviary/subsystems/mass/flops_based/wing_simple.py
+++ b/aviary/subsystems/mass/flops_based/wing_simple.py
@@ -15,25 +15,17 @@ def initialize(self):
         add_aviary_option(self, Aircraft.Propulsion.TOTAL_NUM_WING_ENGINES)
 
     def setup(self):
-        add_aviary_input(self, Aircraft.Wing.AREA, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.SPAN, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.TAPER_RATIO, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.STRUT_BRACING_FACTOR, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.AEROELASTIC_TAILORING_FACTOR, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.ASPECT_RATIO, val=0.0)
-
-        add_aviary_input(self, Aircraft.Wing.SWEEP, val=0.0)
-
-        add_aviary_output(self, Aircraft.Wing.BENDING_MATERIAL_FACTOR, val=0.0)
-
-        add_aviary_output(self, Aircraft.Wing.ENG_POD_INERTIA_FACTOR, val=0.0)
+        add_aviary_input(self, Aircraft.Wing.AREA)
+        add_aviary_input(self, Aircraft.Wing.SPAN)
+        add_aviary_input(self, Aircraft.Wing.TAPER_RATIO)
+        add_aviary_input(self, Aircraft.Wing.THICKNESS_TO_CHORD)
+        add_aviary_input(self, Aircraft.Wing.STRUT_BRACING_FACTOR)
+        add_aviary_input(self, Aircraft.Wing.AEROELASTIC_TAILORING_FACTOR)
+        add_aviary_input(self, Aircraft.Wing.ASPECT_RATIO)
+        add_aviary_input(self, Aircraft.Wing.SWEEP)
+
+        add_aviary_output(self, Aircraft.Wing.BENDING_MATERIAL_FACTOR)
+        add_aviary_output(self, Aircraft.Wing.ENG_POD_INERTIA_FACTOR)
 
     def setup_partials(self):
         self.declare_partials(
diff --git a/aviary/subsystems/mass/gasp_based/design_load.py b/aviary/subsystems/mass/gasp_based/design_load.py
index dac622bc0..6cf418340 100644
--- a/aviary/subsystems/mass/gasp_based/design_load.py
+++ b/aviary/subsystems/mass/gasp_based/design_load.py
@@ -39,25 +39,16 @@ def setup(self):
 
             add_aviary_input(self, Aircraft.Wing.LOADING, val=128)
 
-        self.add_output(
-            "max_airspeed",
-            val=0,
-            units="kn",
-            desc="VM0: maximum operating equivalent airspeed",
-        )
-        self.add_output(
-            "vel_c",
-            val=0,
-            units="kn",
-            desc="VGC: Velocity used in Gust Load Factor calculation at cruise conditions.\
-                This is Minimum Design Cruise Speed for Part 23 aircraft and VM0 for Part 25 aircraft",
-        )
-        self.add_output(
-            "max_maneuver_factor",
-            val=0,
-            units="unitless",
-            desc="EMLF: maximum maneuver load factor, units are in g`s",
-        )
+        self.add_output("max_airspeed", val=0, units="kn",
+                        desc="VM0: maximum operating equivalent airspeed",
+                        )
+        self.add_output("vel_c", val=0, units="kn",
+                        desc="VGC: Velocity used in Gust Load Factor calculation at cruise conditions.\
+                        This is Minimum Design Cruise Speed for Part 23 aircraft and VM0 for Part 25 aircraft",
+                        )
+        self.add_output("max_maneuver_factor", val=0, units="unitless",
+                        desc="EMLF: maximum maneuver load factor, units are in g`s",
+                        )
         self.add_output("min_dive_vel", val=0, units="kn", desc="VDMIN: dive velocity")
 
         self.declare_partials("*", "*")
diff --git a/aviary/subsystems/mass/gasp_based/fixed.py b/aviary/subsystems/mass/gasp_based/fixed.py
index 8bf15c09d..9def994dc 100644
--- a/aviary/subsystems/mass/gasp_based/fixed.py
+++ b/aviary/subsystems/mass/gasp_based/fixed.py
@@ -959,7 +959,7 @@ def setup(self):
         add_aviary_input(self, Aircraft.Fuselage.LENGTH, val=200)
         add_aviary_input(self, Aircraft.HorizontalTail.SPAN, val=7)
         add_aviary_input(self, Aircraft.LandingGear.TAIL_HOOK_MASS_SCALER, val=1)
-        add_aviary_input(self, Aircraft.HorizontalTail.TAPER_RATIO, val=0.352)
+        add_aviary_input(self, Aircraft.HorizontalTail.TAPER_RATIO)
         add_aviary_input(self, Aircraft.VerticalTail.MASS_COEFFICIENT, val=0.289)
         add_aviary_input(self, Aircraft.Wing.SPAN, val=118)
         add_aviary_input(self, Aircraft.HorizontalTail.AREA, val=15)
diff --git a/aviary/subsystems/mass/gasp_based/fuel.py b/aviary/subsystems/mass/gasp_based/fuel.py
index 8a202aece..4092e3bb3 100644
--- a/aviary/subsystems/mass/gasp_based/fuel.py
+++ b/aviary/subsystems/mass/gasp_based/fuel.py
@@ -55,12 +55,12 @@ def setup(self):
         add_aviary_input(self, Mission.Design.FUEL_MASS, val=3000)
         add_aviary_input(self, Aircraft.Design.OPERATING_MASS, val=94417)
 
-        self.add_output(
-            Aircraft.Fuel.AUXILIARY_FUEL_CAPACITY,
-            val=0,
-            units="lbm",
-            desc="WFXTRA: extra amount of fuel that is required but does not fit in wings",
-        )
+        add_aviary_output(self, Aircraft.Fuel.AUXILIARY_FUEL_CAPACITY, val=0,
+                          desc="WFXTRA: extra amount of fuel that is required but does not fit in wings")
+        # self.add_output(
+        #     Aircraft.Fuel.AUXILIARY_FUEL_CAPACITY, val=0, units="lbm",
+        #     desc="WFXTRA: extra amount of fuel that is required but does not fit in wings",
+        # )
         self.add_output(
             "extra_fuel_volume",
             val=0,
diff --git a/aviary/variable_info/functions.py b/aviary/variable_info/functions.py
index 9961ae891..fa385de2a 100644
--- a/aviary/variable_info/functions.py
+++ b/aviary/variable_info/functions.py
@@ -59,13 +59,22 @@ def add_aviary_input(comp, varname, val=None, units=None, desc=None, shape_by_co
     else:
         input_desc = meta['desc']
     if val is None:
-        val = meta['default_value']
+        if shape is None:
+            val = meta['default_value']
+            if val is None:
+                val = 0.0
+        else:
+            val = meta['default_value']
+            if val is None:
+                val = np.zeros(shape)
+            else:
+                val = np.ones(shape) * val
     comp.add_input(varname, val=val, units=input_units,
                    desc=input_desc, shape_by_conn=shape_by_conn, shape=shape)
 
 
-def add_aviary_output(comp, varname, val, units=None, desc=None, shape_by_conn=False,
-                      meta_data=_MetaData):
+def add_aviary_output(comp, varname, val=None, units=None, desc=None, shape_by_conn=False,
+                      meta_data=_MetaData, shape=None):
     """
     This function provides a clean way to add variables from the
     variable hierarchy into components as Aviary outputs. It takes
@@ -91,6 +100,8 @@ def add_aviary_output(comp, varname, val, units=None, desc=None, shape_by_conn=F
     meta_data: dict
         (Optional) Aviary metadata dictionary. If unspecified, the built-in metadata will
         be used.
+    shape: tuple
+        (Optional) shape for this input.
     """
     meta = meta_data[varname]
     if units:
@@ -104,6 +115,17 @@ def add_aviary_output(comp, varname, val, units=None, desc=None, shape_by_conn=F
         output_desc = desc
     else:
         output_desc = meta['desc']
+    if val is None:
+        if shape is None:
+            val = meta['default_value']
+            if val is None:
+                val = 0.0
+        else:
+            val = meta['default_value']
+            if val is None:
+                val = np.zeros(shape)
+            else:
+                val = np.ones(shape) * val
     comp.add_output(varname, val=val, units=output_units,
                     desc=output_desc, shape_by_conn=shape_by_conn)
 
diff --git a/aviary/variable_info/variable_meta_data.py b/aviary/variable_info/variable_meta_data.py
index 22862daa9..ad23851d1 100644
--- a/aviary/variable_info/variable_meta_data.py
+++ b/aviary/variable_info/variable_meta_data.py
@@ -70,7 +70,7 @@
     },
     units='lbm',
     desc='air conditioning system mass',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -122,7 +122,7 @@
     },
     units='lbm',
     desc='mass of anti-icing system (auxiliary gear)',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -163,7 +163,7 @@
     },
     units='lbm',
     desc='mass of auxiliary power unit',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -204,7 +204,7 @@
     },
     units='lbm',
     desc='avionics mass',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -418,7 +418,7 @@
     },
     units='unitless',
     desc='canard theoretical aspect ratio',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -434,6 +434,7 @@
     },
     units='ft',
     desc='Reynolds characteristic length for the canard',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -449,6 +450,7 @@
     },
     units='unitless',
     desc='canard fineness ratio',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -493,7 +495,7 @@
     },
     units='lbm',
     desc='mass of canards',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -519,7 +521,7 @@
     },
     units='unitless',
     desc='canard theoretical taper ratio',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -553,7 +555,7 @@
     },
     units='ft**2',
     desc='canard wetted area',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -645,6 +647,7 @@
     },
     units='lbm',
     desc='mass of passenger baggage',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -677,7 +680,7 @@
     },
     units='lbm',
     desc='mass of cargo containers',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -708,6 +711,7 @@
     },
     units='lbm',
     desc='total mass of cargo',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -803,7 +807,7 @@
     },
     units='lbm',
     desc='total mass of the flight crew and their baggage',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -863,7 +867,7 @@
     },
     units='lbm',
     desc='total mass of the non-flight crew and their baggage',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -1010,6 +1014,7 @@
     },
     units='lbm',
     desc='TBD: total mass of all passengers without their baggage',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -1030,6 +1035,7 @@
     historical_name={"GASP": 'INGASP.WPL', "FLOPS": None, "LEAPS1": None},
     units='lbm',
     desc='mass of passenger payload, including passengers, passenger baggage',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -1048,7 +1054,7 @@
     },
     units='lbm',
     desc='mass of passenger service equipment',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -1242,7 +1248,7 @@
     },
     units='lbm',
     desc='empty mass margin',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -1270,6 +1276,7 @@
     meta_data=_MetaData,
     units='lbm',
     desc='total mass of all user-defined external subsystems',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -1350,7 +1357,7 @@
     },
     units='unitless',
     desc='ratio of maximum landing mass to maximum takeoff mass',
-    default_value=0.9,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -1418,6 +1425,7 @@
     desc='operating mass of the aircraft, or aircraft mass without mission fuel, or '
     'passengers. Includes crew, unusable fuel, oil, and operational items like '
     'cargo containers and passenger service mass.',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -1497,6 +1505,7 @@
     },
     units='lbm',
     desc='Total structural group mass',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -1547,6 +1556,7 @@
     },
     units='lbm',
     desc='Total systems & equipment group mass',
+    default_value=0.0,
 )
 
 # TODO intermediate calculated values with no uses by other systems may not belong in the
@@ -1560,6 +1570,7 @@
     historical_name={"GASP": None, "FLOPS": None, "LEAPS1": None},
     units='lbm',
     desc='Total systems & equipment group mass without additional 1% of ' 'empty mass',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -1584,6 +1595,7 @@
     },
     units='ft**2',
     desc='total aircraft wetted area',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -1605,7 +1617,7 @@
     },
     units='lbm',
     desc='design landing mass',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -1666,6 +1678,7 @@
     },
     units='lbm',
     desc='zero fuel mass',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -1707,6 +1720,7 @@
     historical_name={"GASP": 'INGASP.LCABLE', "FLOPS": None, "LEAPS1": None},
     units='ft',
     desc='length of cable for hybrid electric augmented system',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -1725,7 +1739,7 @@
     },
     units='lbm',
     desc='mass of the electrical system',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -1775,8 +1789,8 @@
     units='unitless',
     option=True,
     desc='fraction of (scaled) engine mass used to calculate additional propulsion '
-         'system mass added to engine control and starter mass, or used to '
-         'calculate engine installation mass',
+    'system mass added to engine control and starter mass, or used to '
+    'calculate engine installation mass',
     types=(float, int, np.ndarray),
     multivalue=True,
     default_value=0.0,
@@ -2069,7 +2083,7 @@
     types=(np.ndarray, int),
     multivalue=True,
     option=True,
-    default_value=[2]
+    default_value=[2],
 )
 
 add_meta_data(
@@ -2085,7 +2099,7 @@
     option=True,
     types=(np.ndarray, int),
     multivalue=True,
-    default_value=0
+    default_value=0,
 )
 
 add_meta_data(
@@ -2102,7 +2116,7 @@
     option=True,
     types=(np.ndarray, int),
     multivalue=True,
-    default_value=[0]
+    default_value=[0],
 )
 
 add_meta_data(
@@ -2507,7 +2521,7 @@
     option=True,
     types=(int, np.ndarray),
     multivalue=True,
-    default_value=0
+    default_value=0,
 )
 
 add_meta_data(
@@ -2587,7 +2601,7 @@
     },
     units='lbm',
     desc='mass of vertical fins',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -2628,7 +2642,7 @@
     },
     units='unitless',
     desc='vertical fin theoretical taper ratio',
-    default_value=None,
+    default_value=0.0,
 )
 
 #  ______                  _
@@ -2649,7 +2663,7 @@
     },
     units='lbm',
     desc='fuel capacity of the auxiliary tank',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -2670,7 +2684,7 @@
     },
     units='unitless',
     desc='fuel capacity factor',
-    default_value=23.0,
+    default_value=1.0,
 )
 
 add_meta_data(
@@ -2724,7 +2738,7 @@
     },
     units='lbm',
     desc='fuel system mass',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -2763,7 +2777,7 @@
     },
     units='lbm',
     desc='fuel capacity of the fuselage',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -2796,7 +2810,7 @@
     desc='Total fuel capacity of the aircraft including wing, fuselage and '
     'auxiliary tanks. Used in generating payload-range diagram (Default = '
     'wing_capacity + fuselage_capacity + aux_capacity)',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -2814,6 +2828,7 @@
     },
     units='galUS',  # need to check this
     desc='Total fuel volume',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -2832,7 +2847,7 @@
     },
     units='lbm',
     desc='unusable fuel mass',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -2868,7 +2883,7 @@
     },
     units='lbm',
     desc='fuel capacity of the auxiliary tank',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -2877,6 +2892,7 @@
     historical_name={"GASP": 'INGASP.SKWF', "FLOPS": None, "LEAPS1": None},
     units='unitless',
     desc='fraction of total theoretical wing volume used for wing fuel',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -2959,6 +2975,7 @@
     historical_name={"GASP": 'INGASP.FVOLW_GEOM', "FLOPS": None, "LEAPS1": None},
     units='ft**3',
     desc='wing tank fuel volume based on geometry',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -2997,7 +3014,7 @@
     },
     units='lbm',
     desc='Total furnishings system mass',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3006,6 +3023,7 @@
     historical_name={"GASP": None, "FLOPS": None, "LEAPS1": None},
     units='lbm',
     desc='Base furnishings system mass without additional 1% empty mass',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3054,6 +3072,7 @@
     },
     units='ft',
     desc='average fuselage diameter',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3069,6 +3088,7 @@
     },
     units='ft',
     desc='Reynolds characteristic length for the fuselage',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3089,7 +3109,7 @@
     historical_name={"GASP": 'INGASP.HCK', "FLOPS": None, "LEAPS1": None},
     units='ft',
     desc='mean fuselage cabin diameter minus mean fuselage nose diameter',
-    default_value=4.5,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3102,6 +3122,7 @@
     },
     units='unitless',
     desc='fuselage diameter to wing span ratio',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3117,6 +3138,7 @@
     },
     units='unitless',
     desc='fuselage fineness ratio',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3198,6 +3220,7 @@
     },
     units='unitless',
     desc='fuselage length to diameter ratio',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3216,7 +3239,7 @@
     },
     units='lbm',
     desc='mass of the fuselage structure',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3251,6 +3274,7 @@
     },
     units='ft',
     desc='maximum fuselage height',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3368,6 +3392,7 @@
     historical_name={"GASP": 'INGASP.ELPC', "FLOPS": None, "LEAPS1": None},
     units='ft',
     desc='length of the pilot compartment',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3380,6 +3405,7 @@
     },
     units='ft**2',
     desc='fuselage planform area',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3437,7 +3463,7 @@
     },
     units='ft**2',
     desc='fuselage wetted area',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3488,7 +3514,7 @@
     },
     units='unitless',
     desc='horizontal tail theoretical aspect ratio',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3512,6 +3538,7 @@
     },
     units='ft',
     desc='Reynolds characteristic length for the horizontal tail',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3527,6 +3554,7 @@
     },
     units='unitless',
     desc='horizontal tail fineness ratio',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3580,7 +3608,7 @@
     },
     units='lbm',
     desc='mass of horizontal tail',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3662,7 +3690,7 @@
     },
     units='unitless',
     desc='horizontal tail theoretical taper ratio',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3692,7 +3720,7 @@
     'tail is mounted. Defaults: 0.0 == for body mounted (default for '
     'transport with all engines on wing); 1.0 == for T tail '
     '(default for transport with multiple engines on fuselage)',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3720,7 +3748,7 @@
     },
     units='ft**2',
     desc='horizontal tail wetted area',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3780,7 +3808,7 @@
     },
     units='lbm',
     desc='mass of hydraulic system',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3807,7 +3835,7 @@
     },
     units='psi',
     desc='hydraulic system pressure',
-    default_value=3000.0,
+    default_value=0.0,
 )
 
 #
@@ -3835,7 +3863,7 @@
     },
     units='lbm',
     desc='instrument group mass',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -3936,6 +3964,7 @@
     },
     units='lbm',
     desc='mass of main landing gear',
+    default_value=0,
 )
 
 add_meta_data(
@@ -3997,7 +4026,7 @@
     },
     units='lbm',
     desc='mass of nose landing gear',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4075,6 +4104,7 @@
     },
     units='ft',
     desc='Average diameter of engine nacelles for each engine model',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4089,6 +4119,7 @@
     },
     units='ft',
     desc='Average length of nacelles for each engine model',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4104,6 +4135,7 @@
     },
     units='ft',
     desc='Reynolds characteristic length for nacelle for each engine model',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4137,6 +4169,7 @@
     },
     units='unitless',
     desc='nacelle fineness ratio',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4190,7 +4223,7 @@
     },
     units='lbm',
     desc='estimated mass of the nacelles for each engine model',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4234,6 +4267,7 @@
     },
     units='ft**2',
     desc='total nacelles wetted area',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4249,6 +4283,7 @@
     },
     units='ft**2',
     desc='wetted area of a single nacelle for each engine model',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4285,6 +4320,7 @@
     },
     units='lbm',
     desc='mass of paint for all wetted area',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4339,6 +4375,7 @@
     },
     units='lbm',
     desc='Total propulsion group mass',
+    default_value=0.0,
 )
 
 # TODO clash with per-engine scaling, need to resolve w/ heterogeneous engine
@@ -4363,6 +4400,7 @@
     historical_name={"GASP": None, "FLOPS": None, "LEAPS1": None},
     units='lbm',
     desc='total estimated mass of the engine controls for all engines on aircraft',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4371,6 +4409,7 @@
     historical_name={"GASP": 'INGASP.WEP', "FLOPS": None, "LEAPS1": None},
     units='lbm',
     desc='total mass of all engines on aircraft',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4389,7 +4428,7 @@
     },
     units='lbm',
     desc='engine oil mass',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4409,7 +4448,7 @@
     units='lbm',
     desc='sum of engine control, starter, and additional mass for all engines '
     'on aircraft',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4481,7 +4520,7 @@
     historical_name={"GASP": None, "FLOPS": None, "LEAPS1": None},
     units='lbm',
     desc='total mass of thrust reversers for all engines on aircraft',
-    default_value=None,
+    default_value=0.0,
 )
 
 #   _____   _                    _
@@ -4507,6 +4546,7 @@
     historical_name={"GASP": 'INGASP.SSTQSW', "FLOPS": None, "LEAPS1": None},
     units='unitless',
     desc='ratio of strut area to wing area',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4519,6 +4559,7 @@
     },
     units='ft',
     desc='attachment location of strut the full attachment-to-attachment span',
+    default_value=0.0,
 )
 
 # related to Aircraft.Strut.ATTACHMENT_LOCATION
@@ -4528,6 +4569,7 @@
     historical_name={"GASP": None, "FLOPS": None, "LEAPS1": None},
     units='unitless',
     desc='attachment location of strut as fraction of the half-span',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4536,6 +4578,7 @@
     historical_name={"GASP": 'INGASP.STRTCHD', "FLOPS": None, "LEAPS1": None},
     units='ft',
     desc='chord of the strut',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4653,7 +4696,7 @@
     },
     units='unitless',
     desc='vertical tail theoretical aspect ratio',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4677,6 +4720,7 @@
     },
     units='ft',
     desc='Reynolds characteristic length for the vertical tail',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4692,6 +4736,7 @@
     },
     units='unitless',
     desc='vertical tail fineness ratio',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4745,7 +4790,7 @@
     },
     units='lbm',
     desc='mass of vertical tail',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4842,7 +4887,7 @@
     },
     units='unitless',
     desc='vertical tail theoretical taper ratio',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -4885,7 +4930,7 @@
     },
     units='ft**2',
     desc='vertical tails wetted area',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5014,6 +5059,7 @@
     },
     units='unitless',
     desc='Reference aspect ratio, used for detailed wing mass estimation.',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5022,6 +5068,7 @@
     historical_name={"GASP": 'INGASP.CBARW', "FLOPS": None, "LEAPS1": None},
     units='ft',
     desc='mean aerodynamic chord of the wing',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5035,6 +5082,7 @@
     units='unitless',
     desc='Wing bending material factor with sweep adjustment. Used to compute '
     'Aircraft.Wing.BENDING_MATERIAL_MASS',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5049,7 +5097,7 @@
     },
     units='lbm',
     desc='wing mass breakdown term 1',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5077,7 +5125,7 @@
     },
     units='lbm',
     desc='wing mass breakdown term 4',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5099,6 +5147,7 @@
     historical_name={"GASP": 'INGASP.CRCLW', "FLOPS": None, "LEAPS1": None},
     units='ft',
     desc='wing chord at fuselage centerline',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5123,6 +5172,7 @@
     },
     units='ft',
     desc='Reynolds characteristic length for the wing',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5149,7 +5199,7 @@
     units='unitless',
     desc='chord lengths as fractions of semispan at station locations; '
     'overwrites station_chord_lengths',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5184,6 +5234,7 @@
     },
     units='ft**2',
     desc='area of wing control surfaces',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5198,7 +5249,7 @@
     units='unitless',
     desc='Defines the ratio of total moveable wing control surface areas '
     '(flaps, elevators, spoilers, etc.) to reference wing area.',
-    default_value=0.333,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5240,6 +5291,7 @@
     units='unitless',
     desc='Engine inertia relief factor for wingspan inboard of engine locations. Used '
     'to compute Aircraft.Wing.BENDING_MATERIAL_MASS',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5255,6 +5307,7 @@
     },
     units='unitless',
     desc='wing fineness ratio',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5356,7 +5409,7 @@
     historical_name={"GASP": 'INGASP.YWFOLD', "FLOPS": None, "LEAPS1": None},
     units='ft',
     desc='folded wingspan',
-    default_value=118,
+    default_value=0,
 )
 
 add_meta_data(
@@ -5515,6 +5568,7 @@
     historical_name={"GASP": 'INGASP.SWPLE', "FLOPS": None, "LEAPS1": None},
     units='rad',
     desc='sweep angle at leading edge of wing',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5556,7 +5610,7 @@
     desc='Define the sweep of load path at station locations. Typically '
     'parallel to rear spar tending toward max t/c of airfoil. The Ith value '
     'is used between wing stations I and I+1.',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5569,6 +5623,7 @@
     },
     units='lbf/ft**2',
     desc='wing loading',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5598,7 +5653,7 @@
     },
     units='lbm',
     desc='wing total mass',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5707,7 +5762,7 @@
     },
     units='lbm',
     desc='wing mass breakdown term 3',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5785,6 +5840,7 @@
     },
     units='ft',
     desc='wing chord length at wing root',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5799,7 +5855,7 @@
     },
     units='lbm',
     desc='wing mass breakdown term 2',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5926,7 +5982,7 @@
     },
     units='lbm',
     desc='mass of surface controls',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -5974,7 +6030,7 @@
     },
     units='deg',
     desc='quarter-chord sweep angle of the wing',
-    default_value=0.0,  # TODO required
+    default_value=0.0,  # TODO required.
 )
 
 add_meta_data(
@@ -5999,7 +6055,7 @@
     },
     units='unitless',
     desc='taper ratio of the wing',
-    default_value=0.0,  # TODO required
+    default_value=0.0,  # TODO required.
 )
 
 add_meta_data(
@@ -6038,7 +6094,7 @@
     },
     units='unitless',
     desc='the thickeness-chord ratios at station locations',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -6060,6 +6116,7 @@
     historical_name={"GASP": 'INGASP.TCR', "FLOPS": None, "LEAPS1": None},
     units='unitless',
     desc='thickness-to-chord ratio at the root of the wing',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -6068,6 +6125,7 @@
     historical_name={"GASP": 'INGASP.TCT', "FLOPS": None, "LEAPS1": None},
     units='unitless',
     desc='thickness-to-chord ratio at the tip of the wing',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -6076,6 +6134,7 @@
     historical_name={"GASP": 'INGASP.TC', "FLOPS": None, "LEAPS1": None},
     units='unitless',
     desc='wing thickness-chord ratio at the wing station of the mean aerodynamic chord',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -6123,7 +6182,7 @@
     },
     units='ft**2',
     desc='wing wetted area',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -6727,6 +6786,7 @@
     units='lbm',
     desc='fuel carried by the aircraft when it is on the ramp at the '
     'beginning of the design mission',
+    default_value=0.0,
 )
 
 add_meta_data(
@@ -6757,7 +6817,7 @@
     },
     units='lbm',
     desc='design gross mass of the aircraft',
-    default_value=None,
+    default_value=0.0,
 )
 
 add_meta_data(
diff --git a/setup.py b/setup.py
index 465292ffd..89835c49e 100644
--- a/setup.py
+++ b/setup.py
@@ -31,7 +31,7 @@
     version=__version__,
     packages=find_packages(),
     install_requires=[
-        "openmdao>=3.33.0",
+        "openmdao>=3.36.0",
         "dymos>=1.8.1",
         "hvplot",
         "importlib_resources",
@@ -68,7 +68,7 @@
             "models/small_single_aisle/*",
             "models/test_aircraft/*",
             "visualization/assets/*",
-            "visualization/assets/aviary_vars/*"
+            "visualization/assets/aviary_vars/*",
         ],
         f"{pkgname}.docs": [
             "*.py",
@@ -87,6 +87,6 @@
         ],
         'openmdao_report': [
             'aviary_reports=aviary.interface.reports:register_custom_reports',
-        ]
-    }
+        ],
+    },
 )