diff --git a/aviary/utils/preprocessors.py b/aviary/utils/preprocessors.py
index deec2fb94..54f22bcee 100644
--- a/aviary/utils/preprocessors.py
+++ b/aviary/utils/preprocessors.py
@@ -397,6 +397,21 @@ def preprocess_propulsion(aviary_options: AviaryValues, engine_models: list = No
     aviary_options.set_val(Aircraft.Engine.NUM_WING_ENGINES, num_wing_engines_all)
     aviary_options.set_val(Aircraft.Engine.NUM_FUSELAGE_ENGINES, num_fuse_engines_all)
 
+    # Update nacelle-related variables in aero to be sized to the number of
+    # engine types.
+    if num_engine_type > 1:
+
+        keys = [
+            Aircraft.Nacelle.LAMINAR_FLOW_LOWER,
+            Aircraft.Nacelle.LAMINAR_FLOW_UPPER
+        ]
+
+        for var in keys:
+            try:
+                aviary_options.get_val(var)
+            except KeyError:
+                aviary_options.set_val(var, np.zeros(num_engine_type))
+
     if Mission.Summary.FUEL_FLOW_SCALER not in aviary_options:
         aviary_options.set_val(Mission.Summary.FUEL_FLOW_SCALER, 1.0)
 
diff --git a/aviary/validation_cases/benchmark_tests/test_bench_multiengine.py b/aviary/validation_cases/benchmark_tests/test_bench_multiengine.py
index 05093fc0b..4be6268fb 100644
--- a/aviary/validation_cases/benchmark_tests/test_bench_multiengine.py
+++ b/aviary/validation_cases/benchmark_tests/test_bench_multiengine.py
@@ -124,8 +124,8 @@ def test_multiengine_static(self):
         alloc_cruise = prob.get_val('traj.cruise.parameter_vals:throttle_allocations')
         alloc_descent = prob.get_val('traj.descent.parameter_vals:throttle_allocations')
 
-        assert_near_equal(alloc_climb[0], 0.5, tolerance=1e-2)
-        assert_near_equal(alloc_cruise[0], 0.64, tolerance=1e-2)
+        assert_near_equal(alloc_climb[0], 0.51, tolerance=1e-2)
+        assert_near_equal(alloc_cruise[0], 0.747, tolerance=1e-2)
         assert_near_equal(alloc_descent[0], 0.999, tolerance=1e-2)
 
     @require_pyoptsparse(optimizer="SNOPT")
@@ -166,7 +166,7 @@ def test_multiengine_dynamic(self):
         alloc_descent = prob.get_val('traj.descent.controls:throttle_allocations')
 
         # Cruise is pretty constant, check exact value.
-        assert_near_equal(alloc_cruise[0], 0.646, tolerance=1e-2)
+        assert_near_equal(alloc_cruise[0], 0.75, tolerance=1e-2)
 
         # Check general trend: favors engine 1.
         self.assertGreater(alloc_climb[2], 0.55)