PartInfoItem objects are now pooled.
PartInfoItem objects are now pooled.

--- a/Documents/CHANGES.txt
+++ b/Documents/CHANGES.txt
@@ -1,3 +1,7 @@
+1.0.16.3, 27-04-2015
+    Fixed issue with the toolbar icons not being created.
+    Removed superfluous 'm/s' on the mach slider in the build engineer.
+
 1.0.16.2, 27-04-2015
     Changed the atmospheric slider on the build engineer to default to 0km when changing bodies.
 

--- a/KerbalEngineer/Editor/BuildAdvanced.cs
+++ b/KerbalEngineer/Editor/BuildAdvanced.cs
@@ -65,6 +65,7 @@
         private GUIStyle titleStyle;
         private bool visible = true;
         private GUIStyle windowStyle;
+        private float maxMach;
 
         #endregion
 
@@ -139,7 +140,7 @@
             }
             catch (Exception ex)
             {
-                Logger.Exception(ex);
+                Logger.Exception(ex, "BuildAdvanced.Awake()");
             }
         }
 
@@ -165,7 +166,7 @@
             }
             catch (Exception ex)
             {
-                Logger.Exception(ex);
+                Logger.Exception(ex, "BuildAdvanced.OnDestroy()");
             }
         }
 
@@ -215,7 +216,7 @@
             }
             catch (Exception ex)
             {
-                Logger.Exception(ex);
+                Logger.Exception(ex, "BuildAdvanced.OnGUI()");
             }
         }
 
@@ -228,7 +229,7 @@
             }
             catch (Exception ex)
             {
-                Logger.Exception(ex);
+                Logger.Exception(ex, "BuildAdvanced.Start()");
             }
         }
 
@@ -270,7 +271,7 @@
             }
             catch (Exception ex)
             {
-                Logger.Exception(ex, "BuildAdvanced->Update");
+                Logger.Exception(ex, "BuildAdvanced.Update()");
             }
         }
 
@@ -294,23 +295,30 @@
         /// </summary>
         private void DrawAtmosphericDetails()
         {
-            GUILayout.BeginHorizontal();
-            GUILayout.BeginVertical();
-            GUILayout.Label("Altitude: " + (Altitude * 0.001f).ToString("F1") + "km", this.settingAtmoStyle, GUILayout.Width(125.0f * GuiDisplaySize.Offset));
-            GUI.skin = HighLogic.Skin;
-            Altitude = GUILayout.HorizontalSlider(Altitude, 0.0f, (float)(CelestialBodies.SelectedBody.CelestialBody.atmosphereDepth));
-            GUI.skin = null;
-            GUILayout.EndVertical();
-
-            GUILayout.Space(5.0f);
-
-            GUILayout.BeginVertical();
-            GUILayout.Label("Mach: " + this.atmosphericMach.ToString("F1") + "m/s", this.settingAtmoStyle, GUILayout.Width(125.0f * GuiDisplaySize.Offset));
-            GUI.skin = HighLogic.Skin;
-            atmosphericMach = GUILayout.HorizontalSlider(Mathf.Clamp(atmosphericMach, 0.0f, SimManager.LastStage.maxMach), 0.0f, SimManager.LastStage.maxMach);
-            GUI.skin = null;
-            GUILayout.EndVertical();
-            GUILayout.EndHorizontal();
+            try
+            {
+                GUILayout.BeginHorizontal();
+                GUILayout.BeginVertical();
+                GUILayout.Label("Altitude: " + (Altitude * 0.001f).ToString("F1") + "km", this.settingAtmoStyle, GUILayout.Width(125.0f * GuiDisplaySize.Offset));
+                GUI.skin = HighLogic.Skin;
+                Altitude = GUILayout.HorizontalSlider(Altitude, 0.0f, (float)(CelestialBodies.SelectedBody.CelestialBody.atmosphereDepth));
+                GUI.skin = null;
+                GUILayout.EndVertical();
+
+                GUILayout.Space(5.0f);
+
+                GUILayout.BeginVertical();
+                GUILayout.Label("Mach: " + this.atmosphericMach.ToString("F1"), this.settingAtmoStyle, GUILayout.Width(125.0f * GuiDisplaySize.Offset));
+                GUI.skin = HighLogic.Skin;
+                atmosphericMach = GUILayout.HorizontalSlider(Mathf.Clamp(atmosphericMach, 0.0f, maxMach), 0.0f, maxMach);
+                GUI.skin = null;
+                GUILayout.EndVertical();
+                GUILayout.EndHorizontal();
+            }
+            catch (Exception ex)
+            {
+                Logger.Exception(ex, "BuildAdvanced.DrawAtmosphericDetails()");
+            }
         }
 
         private void DrawBodiesList()
@@ -590,7 +598,11 @@
 
         private void GetStageInfo()
         {
-            this.stages = SimManager.Stages;
+            stages = SimManager.Stages;
+            if (stages != null && stages.Length > 0)
+            {
+                maxMach = stages[stages.Length - 1].maxMach;
+            }
         }
 
         /// <summary>
@@ -703,7 +715,7 @@
             }
             catch (Exception ex)
             {
-                Logger.Exception(ex, "BuildAdvanced->Load");
+                Logger.Exception(ex, "BuildAdvanced.Load()");
             }
         }
 
@@ -798,7 +810,7 @@
             }
             catch (Exception ex)
             {
-                Logger.Exception(ex);
+                Logger.Exception(ex, "BuildAdvanced.Window()");
             }
         }
 

--- a/KerbalEngineer/Editor/BuildOverlayPartInfo.cs
+++ b/KerbalEngineer/Editor/BuildOverlayPartInfo.cs
@@ -128,6 +128,8 @@
                         return;
                     }
 
+                    PartInfoItem.ReleaseAll();
+
                     this.SetCostInfo();
                     this.SetMassItems();
                     this.SetResourceItems();
@@ -186,16 +188,16 @@
             }
 
             var alternator = this.selectedPart.GetModule<ModuleAlternator>();
-            this.infoItems.Add(new PartInfoItem("Alternator"));
+            this.infoItems.Add(PartInfoItem.Create("Alternator"));
             foreach (var resource in alternator.outputResources)
             {
-                this.infoItems.Add(new PartInfoItem("\t" + resource.name, resource.rate.ToRate()));
+                this.infoItems.Add(PartInfoItem.Create("\t" + resource.name, resource.rate.ToRate()));
             }
         }
 
         private void SetCostInfo()
         {
-            this.infoItems.Add(new PartInfoItem("Cost", Units.ConcatF(this.selectedPart.GetCostDry(), this.selectedPart.GetCostWet())));
+            this.infoItems.Add(PartInfoItem.Create("Cost", Units.ConcatF(this.selectedPart.GetCostDry(), this.selectedPart.GetCostWet())));
         }
 
         private void SetDecouplerInfo()
@@ -206,10 +208,10 @@
             }
 
             var decoupler = this.selectedPart.GetProtoModuleDecoupler();
-            this.infoItems.Add(new PartInfoItem("Ejection Force", decoupler.EjectionForce.ToForce()));
+            this.infoItems.Add(PartInfoItem.Create("Ejection Force", decoupler.EjectionForce.ToForce()));
             if (decoupler.IsOmniDecoupler)
             {
-                this.infoItems.Add(new PartInfoItem("Omni-directional"));
+                this.infoItems.Add(PartInfoItem.Create("Omni-directional"));
             }
         }
 
@@ -221,15 +223,15 @@
             }
 
             var engine = this.selectedPart.GetProtoModuleEngine();
-            this.infoItems.Add(new PartInfoItem("Thrust", Units.ToForce(engine.MinimumThrust, engine.MaximumThrust)));
-            this.infoItems.Add(new PartInfoItem("Isp", Units.ConcatF(engine.GetSpecificImpulse(1.0f), engine.GetSpecificImpulse(0.0f)) + "s"));
+            this.infoItems.Add(PartInfoItem.Create("Thrust", Units.ToForce(engine.MinimumThrust, engine.MaximumThrust)));
+            this.infoItems.Add(PartInfoItem.Create("Isp", Units.ConcatF(engine.GetSpecificImpulse(1.0f), engine.GetSpecificImpulse(0.0f)) + "s"));
             if (engine.Propellants.Count > 0)
             {
-                this.infoItems.Add(new PartInfoItem("Propellants"));
+                this.infoItems.Add(PartInfoItem.Create("Propellants"));
                 var totalRatio = engine.Propellants.Sum(p => p.ratio);
                 foreach (var propellant in engine.Propellants)
                 {
-                    this.infoItems.Add(new PartInfoItem("\t" + propellant.name, (propellant.ratio / totalRatio).ToPercent()));
+                    this.infoItems.Add(PartInfoItem.Create("\t" + propellant.name, (propellant.ratio / totalRatio).ToPercent()));
                 }
             }
         }
@@ -244,23 +246,23 @@
             var generator = this.selectedPart.GetModule<ModuleGenerator>();
             if (generator.inputList.Count > 0)
             {
-                this.infoItems.Add(new PartInfoItem("Generator Input"));
+                this.infoItems.Add(PartInfoItem.Create("Generator Input"));
                 foreach (var resource in generator.inputList)
                 {
-                    this.infoItems.Add(new PartInfoItem("\t" + resource.name, resource.rate.ToRate()));
+                    this.infoItems.Add(PartInfoItem.Create("\t" + resource.name, resource.rate.ToRate()));
                 }
             }
             if (generator.outputList.Count > 0)
             {
-                this.infoItems.Add(new PartInfoItem("Generator Output"));
+                this.infoItems.Add(PartInfoItem.Create("Generator Output"));
                 foreach (var resource in generator.outputList)
                 {
-                    this.infoItems.Add(new PartInfoItem("\t" + resource.name, resource.rate.ToRate()));
+                    this.infoItems.Add(PartInfoItem.Create("\t" + resource.name, resource.rate.ToRate()));
                 }
             }
             if (generator.isAlwaysActive)
             {
-                this.infoItems.Add(new PartInfoItem("Generator is Always Active"));
+                this.infoItems.Add(PartInfoItem.Create("Generator is Always Active"));
             }
         }
 
@@ -272,14 +274,14 @@
             }
 
             var gimbal = this.selectedPart.GetModule<ModuleGimbal>();
-            this.infoItems.Add(new PartInfoItem("Thrust Vectoring", gimbal.gimbalRange.ToString("F2")));
+            this.infoItems.Add(PartInfoItem.Create("Thrust Vectoring", gimbal.gimbalRange.ToString("F2")));
         }
 
         private void SetMassItems()
         {
             if (this.selectedPart.physicalSignificance == Part.PhysicalSignificance.FULL)
             {
-                this.infoItems.Add(new PartInfoItem("Mass", Units.ToMass(this.selectedPart.GetDryMass(), this.selectedPart.GetWetMass())));
+                this.infoItems.Add(PartInfoItem.Create("Mass", Units.ToMass(this.selectedPart.GetDryMass(), this.selectedPart.GetWetMass())));
             }
         }
 
@@ -291,9 +293,9 @@
             }
 
             var parachute = this.selectedPart.GetModule<ModuleParachute>();
-            this.infoItems.Add(new PartInfoItem("Deployed Drag", Units.ConcatF(parachute.semiDeployedDrag, parachute.fullyDeployedDrag)));
-            this.infoItems.Add(new PartInfoItem("Deployment Altitude", parachute.deployAltitude.ToDistance()));
-            this.infoItems.Add(new PartInfoItem("Deployment Pressure", parachute.minAirPressureToOpen.ToString("F2")));
+            this.infoItems.Add(PartInfoItem.Create("Deployed Drag", Units.ConcatF(parachute.semiDeployedDrag, parachute.fullyDeployedDrag)));
+            this.infoItems.Add(PartInfoItem.Create("Deployment Altitude", parachute.deployAltitude.ToDistance()));
+            this.infoItems.Add(PartInfoItem.Create("Deployment Pressure", parachute.minAirPressureToOpen.ToString("F2")));
         }
 
         private void SetRcsInfo()
@@ -304,8 +306,8 @@
             }
 
             var rcs = this.selectedPart.GetModule<ModuleRCS>();
-            this.infoItems.Add(new PartInfoItem("Thruster Power", rcs.thrusterPower.ToForce()));
-            this.infoItems.Add(new PartInfoItem("Specific Impulse", Units.ConcatF(rcs.atmosphereCurve.Evaluate(1.0f), rcs.atmosphereCurve.Evaluate(0.0f)) + "s"));
+            this.infoItems.Add(PartInfoItem.Create("Thruster Power", rcs.thrusterPower.ToForce()));
+            this.infoItems.Add(PartInfoItem.Create("Specific Impulse", Units.ConcatF(rcs.atmosphereCurve.Evaluate(1.0f), rcs.atmosphereCurve.Evaluate(0.0f)) + "s"));
         }
 
         private void SetReactionWheelInfo()
@@ -316,13 +318,13 @@
             }
 
             var reactionWheel = this.selectedPart.GetModule<ModuleReactionWheel>();
-            this.infoItems.Add(new PartInfoItem("Reaction Wheel Torque"));
-            this.infoItems.Add(new PartInfoItem("\tPitch", reactionWheel.PitchTorque.ToTorque()));
-            this.infoItems.Add(new PartInfoItem("\tRoll", reactionWheel.RollTorque.ToTorque()));
-            this.infoItems.Add(new PartInfoItem("\tYaw", reactionWheel.YawTorque.ToTorque()));
+            this.infoItems.Add(PartInfoItem.Create("Reaction Wheel Torque"));
+            this.infoItems.Add(PartInfoItem.Create("\tPitch", reactionWheel.PitchTorque.ToTorque()));
+            this.infoItems.Add(PartInfoItem.Create("\tRoll", reactionWheel.RollTorque.ToTorque()));
+            this.infoItems.Add(PartInfoItem.Create("\tYaw", reactionWheel.YawTorque.ToTorque()));
             foreach (var resource in reactionWheel.inputResources)
             {
-                this.infoItems.Add(new PartInfoItem("\t" + resource.name, resource.rate.ToRate()));
+                this.infoItems.Add(PartInfoItem.Create("\t" + resource.name, resource.rate.ToRate()));
             }
         }
 
@@ -330,12 +332,12 @@
         {
             if (this.selectedPart.Resources.list.Any(r => !r.hideFlow))
             {
-                this.infoItems.Add(new PartInfoItem("Resources"));
+                this.infoItems.Add(PartInfoItem.Create("Resources"));
                 foreach (var resource in this.selectedPart.Resources.list.Where(r => !r.hideFlow))
                 {
                     this.infoItems.Add(resource.GetDensity() > 0
-                        ? new PartInfoItem("\t" + resource.info.name, "(" + resource.GetMass().ToMass() + ") " + resource.amount.ToString("F1"))
-                        : new PartInfoItem("\t" + resource.info.name, resource.amount.ToString("F1")));
+                        ? PartInfoItem.Create("\t" + resource.info.name, "(" + resource.GetMass().ToMass() + ") " + resource.amount.ToString("F1"))
+                        : PartInfoItem.Create("\t" + resource.info.name, resource.amount.ToString("F1")));
                 }
             }
         }
@@ -344,7 +346,7 @@
         {
             if (this.selectedPart.HasModule<ModuleSAS>())
             {
-                this.infoItems.Add(new PartInfoItem("SAS Equiped"));
+                this.infoItems.Add(PartInfoItem.Create("SAS Equiped"));
             }
         }
 
@@ -352,7 +354,7 @@
         {
             if (this.selectedPart.HasModule<ModuleScienceContainer>())
             {
-                this.infoItems.Add(new PartInfoItem("Science Container"));
+                this.infoItems.Add(PartInfoItem.Create("Science Container"));
             }
         }
 
@@ -364,11 +366,11 @@
             }
 
             var experiment = this.selectedPart.GetModule<ModuleScienceExperiment>();
-            this.infoItems.Add(new PartInfoItem("Science Experiment", experiment.experimentActionName));
-            this.infoItems.Add(new PartInfoItem("\tTransmit Efficiency", experiment.xmitDataScalar.ToPercent()));
+            this.infoItems.Add(PartInfoItem.Create("Science Experiment", experiment.experimentActionName));
+            this.infoItems.Add(PartInfoItem.Create("\tTransmit Efficiency", experiment.xmitDataScalar.ToPercent()));
             if (!experiment.rerunnable)
             {
-                this.infoItems.Add(new PartInfoItem("\tSingle Usage"));
+                this.infoItems.Add(PartInfoItem.Create("\tSingle Usage"));
             }
         }
 
@@ -376,7 +378,7 @@
         {
             if (this.selectedPart.HasModule<ModuleAnimateGeneric>(m => m.isOneShot))
             {
-                this.infoItems.Add(new PartInfoItem("Single Activation"));
+                this.infoItems.Add(PartInfoItem.Create("Single Activation"));
             }
         }
 
@@ -388,14 +390,14 @@
             }
 
             var solarPanel = this.selectedPart.GetModule<ModuleDeployableSolarPanel>();
-            this.infoItems.Add(new PartInfoItem("Charge Rate", solarPanel.chargeRate.ToRate()));
+            this.infoItems.Add(PartInfoItem.Create("Charge Rate", solarPanel.chargeRate.ToRate()));
             if (solarPanel.isBreakable)
             {
-                this.infoItems.Add(new PartInfoItem("Breakable"));
+                this.infoItems.Add(PartInfoItem.Create("Breakable"));
             }
             if (solarPanel.sunTracking)
             {
-                this.infoItems.Add(new PartInfoItem("Sun Tracking"));
+                this.infoItems.Add(PartInfoItem.Create("Sun Tracking"));
             }
         }
 
@@ -407,9 +409,9 @@
             }
 
             var transmitter = this.selectedPart.GetModule<ModuleDataTransmitter>();
-            this.infoItems.Add(new PartInfoItem("Packet Size", transmitter.packetSize.ToString("F2") + " Mits"));
-            this.infoItems.Add(new PartInfoItem("Bandwidth", (transmitter.packetInterval * transmitter.packetSize).ToString("F2") + "Mits/sec"));
-            this.infoItems.Add(new PartInfoItem(transmitter.requiredResource, transmitter.packetResourceCost.ToString("F2") + "/Packet"));
+            this.infoItems.Add(PartInfoItem.Create("Packet Size", transmitter.packetSize.ToString("F2") + " Mits"));
+            this.infoItems.Add(PartInfoItem.Create("Bandwidth", (transmitter.packetInterval * transmitter.packetSize).ToString("F2") + "Mits/sec"));
+            this.infoItems.Add(PartInfoItem.Create(transmitter.requiredResource, transmitter.packetResourceCost.ToString("F2") + "/Packet"));
         }
 
         private void Window(int windowId)

--- a/KerbalEngineer/Editor/BuildOverlayVessel.cs
+++ b/KerbalEngineer/Editor/BuildOverlayVessel.cs
@@ -200,11 +200,12 @@
 
             if (this.lastStage != null)
             {
+                PartInfoItem.ReleaseAll();
                 this.infoItems.Clear();
-                this.infoItems.Add(new PartInfoItem("Delta-V", this.lastStage.deltaV.ToString("N0") + " / " + this.lastStage.totalDeltaV.ToString("N0") + "m/s"));
-                this.infoItems.Add(new PartInfoItem("Mass", Units.ToMass(this.lastStage.mass, this.lastStage.totalMass)));
-                this.infoItems.Add(new PartInfoItem("TWR", this.lastStage.thrustToWeight.ToString("F2") + " (" + this.lastStage.maxThrustToWeight.ToString("F2") + ")"));
-                this.infoItems.Add(new PartInfoItem("Parts", this.lastStage.partCount + " / " + this.lastStage.totalPartCount));
+                this.infoItems.Add(PartInfoItem.Create("Delta-V", this.lastStage.deltaV.ToString("N0") + " / " + this.lastStage.totalDeltaV.ToString("N0") + "m/s"));
+                this.infoItems.Add(PartInfoItem.Create("Mass", Units.ToMass(this.lastStage.mass, this.lastStage.totalMass)));
+                this.infoItems.Add(PartInfoItem.Create("TWR", this.lastStage.thrustToWeight.ToString("F2") + " (" + this.lastStage.maxThrustToWeight.ToString("F2") + ")"));
+                this.infoItems.Add(PartInfoItem.Create("Parts", this.lastStage.partCount + " / " + this.lastStage.totalPartCount));
             }
         }
 

--- a/KerbalEngineer/Editor/PartInfoItem.cs
+++ b/KerbalEngineer/Editor/PartInfoItem.cs
@@ -19,29 +19,38 @@
 
 namespace KerbalEngineer.Editor
 {
-    public class PartInfoItem
+    using VesselSimulator;
+
+    public class PartInfoItem : Pool<PartInfoItem>
     {
-        #region Constructors
-
-        public PartInfoItem(string name)
-        {
-            this.Name = name;
-        }
-
-        public PartInfoItem(string name, string value)
-        {
-            this.Name = name;
-            this.Value = value;
-        }
-
-        #endregion
-
-        #region Properties
-
         public string Name { get; set; }
 
         public string Value { get; set; }
 
-        #endregion
+        public static PartInfoItem Create(string name)
+        {
+            return GetPoolObject().Initialise(name);
+        }
+
+        public static PartInfoItem Create(string name, string value)
+        {
+            return GetPoolObject().Initialise(name, value);
+        }
+
+        public PartInfoItem Initialise(string name)
+        {
+            Name = name;
+            Value = string.Empty;
+
+            return this;
+        }
+
+        public PartInfoItem Initialise(string name, string value)
+        {
+            Name = name;
+            Value = value;
+
+            return this;
+        }
     }
 }

--- a/KerbalEngineer/EngineerGlobals.cs
+++ b/KerbalEngineer/EngineerGlobals.cs
@@ -33,7 +33,7 @@
         /// <summary>
         ///     Current version of the Kerbal Engineer assembly.
         /// </summary>
-        public const string AssemblyVersion = "1.0.16.2";
+        public const string AssemblyVersion = "1.0.16.3";
 
         #endregion
 

--- a/KerbalEngineer/Extensions/PartExtensions.cs
+++ b/KerbalEngineer/Extensions/PartExtensions.cs
@@ -17,21 +17,17 @@
 //     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 // 
 
-#region Using Directives
-
-using System;
-using System.Collections.Generic;
-using System.Linq;
-
-#endregion
-
 namespace KerbalEngineer.Extensions
 {
+    using System;
+    using System.Collections.Generic;
     using CompoundParts;
 
     public static class PartExtensions
     {
-        #region Methods: public
+        private static Part cachePart;
+        private static PartModule cachePartModule;
+        private static PartResource cachePartResource;
 
         /// <summary>
         ///     Gets whether the part contains a specific resource.
@@ -46,7 +42,14 @@
         /// </summary>
         public static bool ContainsResources(this Part part)
         {
-            return part.Resources.list.Count(p => p.amount > 0d) > 0;
+            for (int i = 0; i < part.Resources.list.Count; ++i)
+            {
+                if (part.Resources.list[i].amount > 0.0)
+                {
+                    return true;
+                }
+            }
+            return false;
         }
 
         /// <summary>
@@ -54,13 +57,16 @@
         /// </summary>
         public static bool EngineHasFuel(this Part part)
         {
-            if (part.HasModule<ModuleEngines>())
-            {
-                return part.GetModuleEngines().getFlameoutState;
-            }
-            if (part.HasModule<MultiModeEngine>())
-            {
-                return part.GetModuleMultiModeEngine().getFlameoutState;
+            cachePartModule = GetModule<ModuleEngines>(part);
+            if (cachePartModule != null)
+            {
+                return (cachePartModule as ModuleEngines).getFlameoutState;
+            }
+
+            cachePartModule = GetModuleMultiModeEngine(part);
+            if (cachePartModule != null)
+            {
+                return (cachePartModule as ModuleEnginesFX).getFlameoutState;
             }
 
             return false;
@@ -103,20 +109,19 @@
         /// </summary>
         public static double GetMaxThrust(this Part part)
         {
-            if (part.HasModule<ModuleEngines>())
-            {
-                return part.GetModuleEngines().maxThrust;
-            }
-            if (part.HasModule<MultiModeEngine>())
-            {
-                return part.GetModuleMultiModeEngine().maxThrust;
-            }
-            if (part.HasModule<ModuleEnginesFX>())
-            {
-                return part.GetModuleEnginesFx().maxThrust;
-            }
-
-            return 0d;
+            cachePartModule = GetModule<ModuleEngines>(part);
+            if (cachePartModule != null)
+            {
+                return (cachePartModule as ModuleEngines).maxThrust;
+            }
+
+            cachePartModule = GetModuleMultiModeEngine(part) ?? GetModule<ModuleEnginesFX>(part);
+            if (cachePartModule != null)
+            {
+                return (cachePartModule as ModuleEnginesFX).maxThrust;
+            }
+
+            return 0.0;
         }
 
         /// <summary>
@@ -124,7 +129,16 @@
         /// </summary>
         public static T GetModule<T>(this Part part) where T : PartModule
         {
-            return part.Modules.OfType<T>().FirstOrDefault();
+            PartModule partModule;
+            for (int i = 0; i < part.Modules.Count; ++i)
+            {
+                partModule = part.Modules[i];
+                if (partModule is T)
+                {
+                    return partModule as T;
+                }
+            }
+            return null;
         }
 
         /// <summary>
@@ -132,7 +146,7 @@
         /// </summary>
         public static T GetModule<T>(this Part part, string className) where T : PartModule
         {
-            return (T)Convert.ChangeType(part.Modules[className], typeof(T));
+            return part.Modules[className] as T;
         }
 
         /// <summary>
@@ -140,7 +154,7 @@
         /// </summary>
         public static T GetModule<T>(this Part part, int classId) where T : PartModule
         {
-            return (T)Convert.ChangeType(part.Modules[classId], typeof(T));
+            return part.Modules[classId] as T;
         }
 
         /// <summary>
@@ -148,7 +162,7 @@
         /// </summary>
         public static ModuleAlternator GetModuleAlternator(this Part part)
         {
-            return part.GetModule<ModuleAlternator>();
+            return GetModule<ModuleAlternator>(part);
         }
 
         /// <summary>
@@ -156,7 +170,7 @@
         /// </summary>
         public static ModuleDeployableSolarPanel GetModuleDeployableSolarPanel(this Part part)
         {
-            return part.GetModule<ModuleDeployableSolarPanel>();
+            return GetModule<ModuleDeployableSolarPanel>(part);
         }
 
         /// <summary>
@@ -164,12 +178,12 @@
         /// </summary>
         public static ModuleEngines GetModuleEngines(this Part part)
         {
-            return part.GetModule<ModuleEngines>();
+            return GetModule<ModuleEngines>(part);
         }
 
         public static ModuleEnginesFX GetModuleEnginesFx(this Part part)
         {
-            return part.GetModule<ModuleEnginesFX>();
+            return GetModule<ModuleEnginesFX>(part);
         }
 
         /// <summary>
@@ -177,7 +191,7 @@
         /// </summary>
         public static ModuleGenerator GetModuleGenerator(this Part part)
         {
-            return part.GetModule<ModuleGenerator>();
+            return GetModule<ModuleGenerator>(part);
         }
 
         /// <summary>
@@ -185,7 +199,7 @@
         /// </summary>
         public static ModuleGimbal GetModuleGimbal(this Part part)
         {
-            return part.GetModule<ModuleGimbal>();
+            return GetModule<ModuleGimbal>(part);
         }
 
         /// <summary>
@@ -193,8 +207,17 @@
         /// </summary>
         public static ModuleEnginesFX GetModuleMultiModeEngine(this Part part)
         {
-            var mode = part.GetModule<MultiModeEngine>().mode;
-            return part.Modules.OfType<ModuleEnginesFX>().FirstOrDefault(engine => engine.engineID == mode);
+            ModuleEnginesFX moduleEngineFx;
+            string mode = GetModule<MultiModeEngine>(part).mode;
+            for (int i = 0; i < part.Modules.Count; ++i)
+            {
+                moduleEngineFx = part.Modules[i] as ModuleEnginesFX;
+                if (moduleEngineFx != null && moduleEngineFx.engineID == mode)
+                {
+                    return moduleEngineFx;
+                }
+            }
+            return null;
         }
 
         /// <summary>
@@ -202,12 +225,12 @@
         /// </summary>
         public static ModuleParachute GetModuleParachute(this Part part)
         {
-            return part.GetModule<ModuleParachute>();
+            return GetModule<ModuleParachute>(part);
         }
 
         public static ModuleRCS GetModuleRcs(this Part part)
         {
-            return part.GetModule<ModuleRCS>();
+            return GetModule<ModuleRCS>(part);
         }
 
         /// <summary>
@@ -215,19 +238,30 @@
         /// </summary>
         public static List<T> GetModules<T>(this Part part) where T : PartModule
         {
-            return part.Modules.OfType<T>().ToList();
+            List<T> list = new List<T>();
+            for (int i = 0; i < part.Modules.Count; ++i)
+            {
+                T module = part.Modules[i] as T;
+                if (module != null)
+                {
+                    list.Add(module);
+                }
+            }
+            return list;
         }
 
         public static ProtoModuleDecoupler GetProtoModuleDecoupler(this Part part)
         {
-            if (HasModule<ModuleDecouple>(part))
-            {
-                return new ProtoModuleDecoupler(GetModule<ModuleDecouple>(part));
-            }
-            if (HasModule<ModuleAnchoredDecoupler>(part))
-            {
-                return new ProtoModuleDecoupler(GetModule<ModuleAnchoredDecoupler>(part));
-            }
+            cachePartModule = GetModule<ModuleDecouple>(part);
+            if (cachePartModule == null)
+            {
+                cachePartModule = GetModule<ModuleAnchoredDecoupler>(part);
+            }
+            if (cachePartModule != null)
+            {
+                return new ProtoModuleDecoupler(cachePartModule);
+            }
+
             return null;
         }
 
@@ -236,18 +270,18 @@
         /// </summary>
         public static ProtoModuleEngine GetProtoModuleEngine(this Part part)
         {
-            if (HasModule<ModuleEngines>(part))
-            {
-                return new ProtoModuleEngine(GetModule<ModuleEngines>(part));
-            }
-            if (HasModule<MultiModeEngine>(part))
-            {
-                return new ProtoModuleEngine(GetModuleMultiModeEngine(part));
-            }
-            if (HasModule<ModuleEnginesFX>(part))
-            {
-                return new ProtoModuleEngine(GetModule<ModuleEnginesFX>(part));
-            }
+            cachePartModule = GetModule<ModuleEngines>(part);
+            if (cachePartModule != null)
+            {
+                return new ProtoModuleEngine(cachePartModule);
+            }
+
+            cachePartModule = GetModuleMultiModeEngine(part) ?? GetModule<ModuleEnginesFX>(part);
+            if (cachePartModule != null)
+            {
+                return new ProtoModuleEngine(cachePartModule);
+            }
+
             return null;
         }
 
@@ -256,7 +290,13 @@
         /// </summary>
         public static double GetResourceCost(this Part part)
         {
-            return part.Resources.list.Sum(r => r.amount * r.info.unitCost);
+            double cost = 0.0;
+            for (int i = 0; i < part.Resources.list.Count; ++i)
+            {
+                cachePartResource = part.Resources.list[i];
+                cost = cost + (cachePartResource.amount * cachePartResource.info.unitCost);
+            }
+            return cost;
         }
 
         /// <summary>
@@ -264,7 +304,13 @@
         /// </summary>
         public static double GetResourceCostInverted(this Part part)
         {
-            return part.Resources.list.Sum(r => (r.maxAmount - r.amount) * r.info.unitCost);
+            double cost = 0.0;
+            for (int i = 0; i < part.Resources.list.Count; ++i)
+            {
+                cachePartResource = part.Resources.list[i];
+                cost = cost + ((cachePartResource.maxAmount - cachePartResource.amount) * cachePartResource.info.unitCost);
+            }
+            return cost;
         }
 
         /// <summary>
@@ -272,7 +318,13 @@
         /// </summary>
         public static double GetResourceCostMax(this Part part)
         {
-            return part.Resources.list.Sum(r => r.maxAmount * r.info.unitCost);
+            double cost = 0.0;
+            for (int i = 0; i < part.Resources.list.Count; ++i)
+            {
+                cachePartResource = part.Resources.list[i];
+                cost = cost + (cachePartResource.maxAmount * cachePartResource.info.unitCost);
+            }
+            return cost;
         }
 
         /// <summary>
@@ -280,20 +332,19 @@
         /// </summary>
         public static double GetSpecificImpulse(this Part part, float atmosphere)
         {
-            if (part.HasModule<ModuleEngines>())
-            {
-                return part.GetModuleEngines().atmosphereCurve.Evaluate(atmosphere);
-            }
-            if (part.HasModule<MultiModeEngine>())
-            {
-                return part.GetModuleMultiModeEngine().atmosphereCurve.Evaluate(atmosphere);
-            }
-            if (part.HasModule<ModuleEnginesFX>())
-            {
-                return part.GetModuleEnginesFx().atmosphereCurve.Evaluate(atmosphere);
-            }
-
-            return 0d;
+            cachePartModule = GetModule<ModuleEngines>(part);
+            if (cachePartModule != null)
+            {
+                return (cachePartModule as ModuleEngines).atmosphereCurve.Evaluate(atmosphere);
+            }
+
+            cachePartModule = GetModuleMultiModeEngine(part) ?? GetModule<ModuleEnginesFX>(part);
+            if (cachePartModule != null)
+            {
+                return (cachePartModule as ModuleEnginesFX).atmosphereCurve.Evaluate(atmosphere);
+            }
+
+            return 0.0;
         }
 
         /// <summary>
@@ -309,7 +360,14 @@
         /// </summary>
         public static bool HasModule<T>(this Part part) where T : PartModule
         {
-            return part.Modules.OfType<T>().Any();
+            for (int i = 0; i < part.Modules.Count; ++i)
+            {
+                if (part.Modules[i] is T)
+                {
+                    return true;
+                }
+            }
+            return false;
         }
 
         /// <summary>
@@ -317,7 +375,15 @@
         /// </summary>
         public static bool HasModule<T>(this Part part, Func<T, bool> predicate) where T : PartModule
         {
-            return part.Modules.OfType<T>().Any(predicate);
+            for (int i = 0; i < part.Modules.Count; ++i)
+            {
+                cachePartModule = part.Modules[i] as T;
+                if (cachePartModule != null && predicate(cachePartModule as T))
+                {
+                    return true;
+                }
+            }
+            return false;
         }
 
         /// <summary>
@@ -341,7 +407,8 @@
         /// </summary>
         public static bool HasOneShotAnimation(this Part part)
         {
-            return part.HasModule<ModuleAnimateGeneric>() && part.GetModule<ModuleAnimateGeneric>().isOneShot;
+            cachePartModule = GetModule<ModuleAnimateGeneric>(part);
+            return cachePartModule != null && (cachePartModule as ModuleAnimateGeneric).isOneShot;
         }
 
         /// <summary>
@@ -349,7 +416,7 @@
         /// </summary>
         public static bool IsCommandModule(this Part part)
         {
-            return part.HasModule<ModuleCommand>();
+            return HasModule<ModuleCommand>(part);
         }
 
         /// <summary>
@@ -357,7 +424,7 @@
         /// </summary>
         public static bool IsDecoupledInStage(this Part part, int stage)
         {
-            if ((part.IsDecoupler() || part.IsLaunchClamp()) && part.inverseStage == stage)
+            if ((IsDecoupler(part) || IsLaunchClamp(part)) && part.inverseStage == stage)
             {
                 return true;
             }
@@ -365,7 +432,7 @@
             {
                 return false;
             }
-            return part.parent.IsDecoupledInStage(stage);
+            return IsDecoupledInStage(part.parent, stage);
         }
 
         /// <summary>
@@ -373,7 +440,7 @@
         /// </summary>
         public static bool IsDecoupler(this Part part)
         {
-            return part.HasModule<ModuleDecouple>() || part.HasModule<ModuleAnchoredDecoupler>();
+            return HasModule<ModuleDecouple>(part) || HasModule<ModuleAnchoredDecoupler>(part);
         }
 
         /// <summary>
@@ -381,7 +448,7 @@
         /// </summary>
         public static bool IsEngine(this Part part)
         {
-            return part.HasModule<ModuleEngines>() || part.HasModule<ModuleEnginesFX>();
+            return HasModule<ModuleEngines>(part) || HasModule<ModuleEnginesFX>(part);
         }
 
         /// <summary>
@@ -389,7 +456,7 @@
         /// </summary>
         public static bool IsFuelLine(this Part part)
         {
-            return (HasModule<CModuleFuelLine>(part));
+            return HasModule<CModuleFuelLine>(part);
         }
 
         /// <summary>
@@ -397,7 +464,7 @@
         /// </summary>
         public static bool IsGenerator(this Part part)
         {
-            return part.HasModule<ModuleGenerator>();
+            return HasModule<ModuleGenerator>(part);
         }
 
         /// <summary>
@@ -405,7 +472,7 @@
         /// </summary>
         public static bool IsLaunchClamp(this Part part)
         {
-            return part.HasModule<LaunchClamp>();
+            return HasModule<LaunchClamp>(part);
         }
 
         /// <summary>
@@ -413,7 +480,7 @@
         /// </summary>
         public static bool IsParachute(this Part part)
         {
-            return part.HasModule<ModuleParachute>();
+            return HasModule<ModuleParachute>(part);
         }
 
         /// <summary>
@@ -421,14 +488,15 @@
         /// </summary>
         public static bool IsPrimary(this Part part, List<Part> partsList, PartModule module)
         {
-            foreach (var vesselPart in partsList)
-            {
-                if (!vesselPart.HasModule(module.ClassID))
+            for (int i = 0; i < partsList.Count; ++i)
+            {
+                cachePart = partsList[i];
+
+                if (HasModule(cachePart, module.ClassID) == false)
                 {
                     continue;
                 }
-
-                if (vesselPart == part)
+                if (cachePart == part)
                 {
                     return true;
                 }
@@ -440,7 +508,7 @@
 
         public static bool IsRcsModule(this Part part)
         {
-            return part.HasModule<ModuleRCS>();
+            return HasModule<ModuleRCS>(part);
         }
 
         /// <summary>
@@ -448,7 +516,7 @@
         /// </summary>
         public static bool IsSepratron(this Part part)
         {
-            return (part.IsSolidRocket() && part.ActivatesEvenIfDisconnected && part.IsDecoupledInStage(part.inverseStage));
+            return IsSolidRocket(part) && part.ActivatesEvenIfDisconnected && IsDecoupledInStage(part, part.inverseStage);
         }
 
         /// <summary>
@@ -456,7 +524,7 @@
         /// </summary>
         public static bool IsSolarPanel(this Part part)
         {
-            return part.HasModule<ModuleDeployableSolarPanel>();
+            return HasModule<ModuleDeployableSolarPanel>(part);
         }
 
         /// <summary>
@@ -464,160 +532,106 @@
         /// </summary>
         public static bool IsSolidRocket(this Part part)
         {
-            return (part.HasModule<ModuleEngines>() && part.GetModuleEngines().throttleLocked) || (part.HasModule<ModuleEnginesFX>() && part.GetModuleEnginesFx().throttleLocked);
-        }
-
-        #endregion
-
-        #region Nested Type: ProtoModuleDecoupler
+            return (HasModule<ModuleEngines>(part) && GetModuleEngines(part).throttleLocked) || (HasModule<ModuleEnginesFX>(part) && GetModuleEnginesFx(part).throttleLocked);
+        }
 
         public class ProtoModuleDecoupler
         {
-            #region Fields
-
             private readonly PartModule module;
 
-            #endregion
-
-            #region Constructors
-
             public ProtoModuleDecoupler(PartModule module)
             {
                 this.module = module;
 
                 if (this.module is ModuleDecouple)
                 {
-                    this.SetModuleDecouple();
+                    SetModuleDecouple();
                 }
                 else if (this.module is ModuleAnchoredDecoupler)
                 {
-                    this.SetModuleAnchoredDecoupler();
-                }
-            }
-
-            #endregion
-
-            #region Properties
+                    SetModuleAnchoredDecoupler();
+                }
+            }
 
             public double EjectionForce { get; private set; }
             public bool IsOmniDecoupler { get; private set; }
 
-            #endregion
-
-            #region Methods: private
-
             private void SetModuleAnchoredDecoupler()
             {
-                var decoupler = this.module as ModuleAnchoredDecoupler;
+                ModuleAnchoredDecoupler decoupler = module as ModuleAnchoredDecoupler;
                 if (decoupler == null)
                 {
                     return;
                 }
 
-                this.EjectionForce = decoupler.ejectionForce;
+                EjectionForce = decoupler.ejectionForce;
             }
 
             private void SetModuleDecouple()
             {
-                var decoupler = this.module as ModuleDecouple;
+                ModuleDecouple decoupler = module as ModuleDecouple;
                 if (decoupler == null)
                 {
                     return;
                 }
 
-                this.EjectionForce = decoupler.ejectionForce;
-                this.IsOmniDecoupler = decoupler.isOmniDecoupler;
-            }
-
-            #endregion
-        }
-
-        #endregion
-
-        #region Nested Type: ProtoModuleEngine
+                EjectionForce = decoupler.ejectionForce;
+                IsOmniDecoupler = decoupler.isOmniDecoupler;
+            }
+        }
 
         public class ProtoModuleEngine
         {
-            #region Fields
-
             private readonly PartModule module;
 
-            #endregion
-
-            #region Constructors
-
             public ProtoModuleEngine(PartModule module)
             {
                 this.module = module;
 
                 if (module is ModuleEngines)
                 {
-                    this.SetModuleEngines();
-                }
-                else if (module is ModuleEnginesFX)
-                {
-                    this.SetModuleEnginesFx();
-                }
-            }
-
-            #endregion
-
-            #region Properties
+                    SetModuleEngines();
+                }
+            }
 
             public double MaximumThrust { get; private set; }
             public double MinimumThrust { get; private set; }
             public List<Propellant> Propellants { get; private set; }
 
-            #endregion
-
-            #region Methods: public
-
             public float GetSpecificImpulse(float atmosphere)
             {
-                if (this.module is ModuleEngines)
-                {
-                    return (this.module as ModuleEngines).atmosphereCurve.Evaluate(atmosphere);
-                }
-                if (this.module is ModuleEnginesFX)
-                {
-                    return (this.module as ModuleEnginesFX).atmosphereCurve.Evaluate(atmosphere);
+                if (module is ModuleEngines)
+                {
+                    return (module as ModuleEngines).atmosphereCurve.Evaluate(atmosphere);
                 }
                 return 0.0f;
             }
 
-            #endregion
-
-            #region Methods: private
-
             private void SetModuleEngines()
             {
-                var engine = this.module as ModuleEngines;
+                ModuleEngines engine = module as ModuleEngines;
                 if (engine == null)
                 {
                     return;
                 }
 
-                this.MaximumThrust = engine.maxThrust * (engine.thrustPercentage * 0.01);
-                this.MinimumThrust = engine.minThrust;
-                this.Propellants = engine.propellants;
+                MaximumThrust = engine.maxThrust * (engine.thrustPercentage * 0.01);
+                MinimumThrust = engine.minThrust;
+                Propellants = engine.propellants;
             }
 
             private void SetModuleEnginesFx()
             {
-                var engine = this.module as ModuleEnginesFX;
+                ModuleEnginesFX engine = module as ModuleEnginesFX;
                 if (engine == null)
                 {
                     return;
                 }
 
-                this.MaximumThrust = engine.maxThrust * (engine.thrustPercentage * 0.01);
-                this.MinimumThrust = engine.minThrust;
-                this.Propellants = engine.propellants;
-            }
-
-            #endregion
-        }
-
-        #endregion
+                MaximumThrust = engine.maxThrust * (engine.thrustPercentage * 0.01);
+                MinimumThrust = engine.minThrust;
+                Propellants = engine.propellants;
+            }
+        }
     }
 }

--- a/KerbalEngineer/Helpers/Averager.cs
+++ b/KerbalEngineer/Helpers/Averager.cs
@@ -38,6 +38,12 @@
                 return Vector3d.zero;
             }
         }
+
+        public void Reset()
+        {
+            sum = Vector3d.zero;
+            count = 0;
+        }
     }
 
     public class WeightedVectorAverager
@@ -61,6 +67,12 @@
         public double GetTotalWeight() {
             return totalweight;
         }
+
+        public void Reset()
+        {
+            sum = Vector3d.zero;
+            totalweight = 0.0;
+        }
     }
 }
 

--- a/KerbalEngineer/Helpers/ForceAccumulator.cs
+++ b/KerbalEngineer/Helpers/ForceAccumulator.cs
@@ -99,5 +99,12 @@
         {
             return GetMinTorqueForceApplicationPoint(avgApplicationPoint.Get());
         }
+
+	    public void Reset()
+	    {
+	        totalForce = Vector3d.zero;
+	        totalZeroOriginTorque = Vector3d.zero;
+            avgApplicationPoint.Reset();
+	    }
 	}
 }

--- /dev/null
+++ b/KerbalEngineer/Helpers/Pool.cs
@@ -1,1 +1,53 @@
+namespace KerbalEngineer.VesselSimulator
+{
+    using System.Collections.Generic;
 
+    public class Pool<T> where T : new()
+    {
+        private static List<T> available = new List<T>();
+        private static List<T> inUse = new List<T>();
+
+        public static int PoolCount
+        {
+            get
+            {
+                return available.Count + inUse.Count;
+            }
+        }
+
+        public static T GetPoolObject()
+        {
+            T obj;
+            if (available.Count > 0)
+            {
+                obj = available[0];
+                available.RemoveAt(0);
+            }
+            else
+            {
+                obj = new T();
+            }
+
+            inUse.Add(obj);
+            return obj;
+        }
+
+        public static void Release(T obj)
+        {
+            if (inUse.Contains(obj))
+            {
+                inUse.Remove(obj);
+                available.Add(obj);
+            }
+        }
+
+        public static void ReleaseAll()
+        {
+            for (int i = 0; i < inUse.Count; ++i)
+            {
+                available.Add(inUse[i]);
+            }
+            inUse.Clear();
+        }
+    }
+}

--- a/KerbalEngineer/KerbalEngineer.csproj
+++ b/KerbalEngineer/KerbalEngineer.csproj
@@ -199,6 +199,7 @@
     <Compile Include="UIControls\WindowObject.cs" />
     <Compile Include="VesselSimulator\AttachNodeSim.cs" />
     <Compile Include="VesselSimulator\EngineSim.cs" />
+    <Compile Include="Helpers\Pool.cs" />
     <Compile Include="VesselSimulator\PartSim.cs" />
     <Compile Include="VesselSimulator\ResourceContainer.cs" />
     <Compile Include="VesselSimulator\SimManager.cs" />

--- a/KerbalEngineer/VesselSimulator/AttachNodeSim.cs
+++ b/KerbalEngineer/VesselSimulator/AttachNodeSim.cs
@@ -19,42 +19,44 @@
 
 #region Using Directives
 
-using System;
-using System.Text;
-
 #endregion
 
 namespace KerbalEngineer.VesselSimulator
 {
-    internal class AttachNodeSim
+    using System;
+    using System.Text;
+
+    internal class AttachNodeSim : Pool<AttachNodeSim>
     {
         public PartSim attachedPartSim;
         public String id;
         public AttachNode.NodeType nodeType;
 
-        public AttachNodeSim(PartSim partSim, String newId, AttachNode.NodeType newNodeType)
-        {
-            this.attachedPartSim = partSim;
-            this.nodeType = newNodeType;
-            this.id = newId;
-        }
-
         public void DumpToBuffer(StringBuilder buffer)
         {
-            if (this.attachedPartSim == null)
+            if (attachedPartSim == null)
             {
                 buffer.Append("<staged>:<n>");
             }
             else
             {
-                buffer.Append(this.attachedPartSim.name);
+                buffer.Append(attachedPartSim.name);
                 buffer.Append(":");
-                buffer.Append(this.attachedPartSim.partId);
+                buffer.Append(attachedPartSim.partId);
             }
             buffer.Append("#");
-            buffer.Append(this.nodeType);
+            buffer.Append(nodeType);
             buffer.Append(":");
-            buffer.Append(this.id);
+            buffer.Append(id);
+        }
+
+        public AttachNodeSim Initialise(PartSim partSim, String newId, AttachNode.NodeType newNodeType)
+        {
+            attachedPartSim = partSim;
+            nodeType = newNodeType;
+            id = newId;
+
+            return this;
         }
     }
 }

--- a/KerbalEngineer/VesselSimulator/EngineSim.cs
+++ b/KerbalEngineer/VesselSimulator/EngineSim.cs
@@ -26,10 +26,10 @@
     using Helpers;
     using UnityEngine;
 
-    public class EngineSim
+    public class EngineSim : Pool<EngineSim>
     {
-        public double actualThrust = 0;
-        public List<AppliedForce> appliedForces;
+        public double actualThrust = 0.0;
+        public List<AppliedForce> appliedForces = new List<AppliedForce>();
         public bool isActive = false;
         public double isp = 0;
         public PartSim partSim;
@@ -41,7 +41,7 @@
         public Vector3 thrustVec;
         private readonly ResourceContainer resourceConsumptions = new ResourceContainer();
 
-        public EngineSim(PartSim theEngine,
+        public EngineSim Initialise(PartSim theEngine,
             double atmosphere,
             float machNumber,
             float maxFuelFlow,
@@ -61,9 +61,14 @@
         {
             StringBuilder buffer = null;
 
+            isp = 0.0;
+            maxMach = 0.0f;
+            actualThrust = 0.0;
             partSim = theEngine;
             isActive = active;
             thrustVec = vecThrust;
+            resourceConsumptions.Reset();
+            appliedForces.Clear();
 
             double flowRate = 0.0;
             if (partSim.hasVessel)
@@ -97,51 +102,28 @@
                 flowRate = GetFlowRate(thrust, isp);
             }
 
-            if (SimManager.logOutput)
-            {
-                buffer = new StringBuilder(1024);
-                buffer.AppendFormat("flowRate = {0:g6}\n", flowRate);
-            }
-
-            float flowMass = 0f;
-            foreach (Propellant propellant in propellants)
-            {
+            float flowMass = 0.0f;
+
+            for (int i = 0; i < propellants.Count; ++i)
+            {
+                Propellant propellant = propellants[i];
                 flowMass += propellant.ratio * ResourceContainer.GetResourceDensity(propellant.id);
-            }
-
-            if (SimManager.logOutput)
-            {
-                buffer.AppendFormat("flowMass = {0:g6}\n", flowMass);
-            }
-
-            foreach (Propellant propellant in propellants)
-            {
-                if (propellant.name == "ElectricCharge" || propellant.name == "IntakeAir")
-                {
-                    continue;
-                }
 
                 double consumptionRate = propellant.ratio * flowRate / flowMass;
-                if (SimManager.logOutput)
-                {
-                    buffer.AppendFormat("Add consumption({0}, {1}:{2:d}) = {3:g6}\n", ResourceContainer.GetResourceName(propellant.id), theEngine.name, theEngine.partId, consumptionRate);
-                }
                 resourceConsumptions.Add(propellant.id, consumptionRate);
             }
 
-            if (SimManager.logOutput)
-            {
-                MonoBehaviour.print(buffer);
-            }
-
-            appliedForces = new List<AppliedForce>();
             double thrustPerThrustTransform = thrust / thrustTransforms.Count;
-            foreach (Transform thrustTransform in thrustTransforms)
-            {
+            for (int i = 0; i < thrustTransforms.Count; ++i)
+            {
+                Transform thrustTransform = thrustTransforms[i];
+
                 Vector3d direction = thrustTransform.forward.normalized;
                 Vector3d position = thrustTransform.position;
                 appliedForces.Add(new AppliedForce(direction * thrustPerThrustTransform, position));
             }
+
+            return this;
         }
 
         public ResourceContainer ResourceConsumptions
@@ -213,8 +195,9 @@
             // A dictionary to hold a set of parts for each resource
             Dictionary<int, HashSet<PartSim>> sourcePartSets = new Dictionary<int, HashSet<PartSim>>();
 
-            foreach (int type in resourceConsumptions.Types)
-            {
+            for (int i = 0; i < resourceConsumptions.Types.Count; ++i)
+            {
+                int type = resourceConsumptions.Types[i];
                 HashSet<PartSim> sourcePartSet = null;
                 switch (ResourceContainer.GetResourceFlowMode(type))
                 {
@@ -228,8 +211,10 @@
                         break;
 
                     case ResourceFlowMode.ALL_VESSEL:
-                        foreach (PartSim aPartSim in allParts)
-                        {
+                        for (int j = 0; j < allParts.Count; ++j)
+                        {
+                            PartSim aPartSim = allParts[j];
+
                             if (aPartSim.resources[type] > SimManager.RESOURCE_MIN && aPartSim.resourceFlowStates[type] != 0)
                             {
                                 if (sourcePartSet == null)
@@ -246,9 +231,10 @@
                         Dictionary<int, HashSet<PartSim>> stagePartSets = new Dictionary<int, HashSet<PartSim>>();
                         int maxStage = -1;
 
-                        //Logger.Log(type);
-                        foreach (PartSim aPartSim in allParts)
-                        {
+                        for (int j = 0; j < allParts.Count; ++j)
+                        {
+                            PartSim aPartSim = allParts[j];
+
                             if (aPartSim.resources[type] <= SimManager.RESOURCE_MIN || aPartSim.resourceFlowStates[type] == 0)
                             {
                                 continue;
@@ -268,10 +254,10 @@
                             sourcePartSet.Add(aPartSim);
                         }
 
-                        for (int i = 0; i <= maxStage; i++)
+                        for (int j = 0; j <= maxStage; j++)
                         {
                             HashSet<PartSim> stagePartSet;
-                            if (stagePartSets.TryGetValue(i, out stagePartSet) && stagePartSet.Count > 0)
+                            if (stagePartSets.TryGetValue(j, out stagePartSet) && stagePartSet.Count > 0)
                             {
                                 sourcePartSet = stagePartSet;
                             }
@@ -315,8 +301,10 @@
             }
 
             // If we don't have sources for all the needed resources then return false without setting up any drains
-            foreach (int type in resourceConsumptions.Types)
-            {
+            for(int i = 0; i < resourceConsumptions.Types.Count; ++i)
+            {
+                int type = resourceConsumptions.Types[i];
+
                 if (!sourcePartSets.ContainsKey(type))
                 {
                     if (SimManager.logOutput)
@@ -330,8 +318,10 @@
             }
 
             // Now we set the drains on the members of the sets and update the draining parts set
-            foreach (int type in resourceConsumptions.Types)
-            {
+            for (int i = 0; i < resourceConsumptions.Types.Count; ++i)
+            {
+                int type = resourceConsumptions.Types[i];
+
                 HashSet<PartSim> sourcePartSet = sourcePartSets[type];
                 // Loop through the members of the set 
                 double amount = resourceConsumptions[type] / sourcePartSet.Count;

--- a/KerbalEngineer/VesselSimulator/PartSim.cs
+++ b/KerbalEngineer/VesselSimulator/PartSim.cs
@@ -34,11 +34,11 @@
 {
     using CompoundParts;
 
-    public class PartSim
+    public class PartSim : Pool<PartSim>
     {
         private readonly List<AttachNodeSim> attachNodes = new List<AttachNodeSim>();
         public Vector3d centerOfMass;
-        public double baseMass = 0d;
+        public double baseMass;
         public double cost;
         public int decoupledInStage;
         public bool fuelCrossFeed;
@@ -71,8 +71,47 @@
         public String vesselName;
         public VesselType vesselType;
 
-        public PartSim(Part thePart, int id, double atmosphere, LogMsg log)
-        {
+        private static void Reset(PartSim partSim)
+        {
+            partSim.attachNodes.Clear();
+            partSim.fuelTargets.Clear();
+            partSim.resourceDrains.Reset();
+            partSim.resourceFlowStates.Reset();
+            partSim.resources.Reset();
+            partSim.baseMass = 0.0;
+            partSim.startMass = 0.0;
+            partSim.centerOfMass = Vector3d.zero;
+            partSim.cost = 0.0;
+            partSim.decoupledInStage = 0;
+            partSim.fuelCrossFeed = false;
+            partSim.hasModuleEngines = false;
+            partSim.hasModuleEnginesFX = false;
+            partSim.hasMultiModeEngine = false;
+            partSim.hasVessel = false;
+            partSim.initialVesselName = null;
+            partSim.inverseStage = 0;
+            partSim.isDecoupler = false;
+            partSim.isEngine = false;
+            partSim.isFuelLine = false;
+            partSim.isFuelTank = false;
+            partSim.isLanded = false;
+            partSim.isNoPhysics = false;
+            partSim.isSepratron = false;
+            partSim.localCorrectThrust = false;
+            partSim.name = null;
+            partSim.noCrossFeedNodeKey = null;
+            partSim.parent = null;
+            partSim.parentAttach = AttachModes.SRF_ATTACH;
+            partSim.part = null;
+            partSim.partId = 0;
+            partSim.vesselName = null;
+            partSim.vesselType = VesselType.Base;
+        }
+
+        public PartSim Initialise(Part thePart, int id, double atmosphere, LogMsg log)
+        {
+            Reset(this);
+
             this.part = thePart;
             this.centerOfMass = thePart.transform.TransformPoint(thePart.CoMOffset);
             this.partId = id;
@@ -97,13 +136,11 @@
             this.cost = this.part.GetCostWet();
 
             // Work out if the part should have no physical significance
-            this.isNoPhysics = this.part.HasModule<LaunchClamp>() ||
-                               this.part.physicalSignificance == Part.PhysicalSignificance.NONE ||
-                               this.part.PhysicsSignificance == 1;
-
-            if (!this.isNoPhysics)
-            {
-                this.baseMass = this.part.mass;
+            this.isNoPhysics = this.part.HasModule<LaunchClamp>();
+
+            if (isNoPhysics == false)
+            {
+                baseMass = part.mass;
             }
 
             if (SimManager.logOutput)
@@ -111,8 +148,10 @@
                 MonoBehaviour.print((this.isNoPhysics ? "Ignoring" : "Using") + " part.mass of " + this.part.mass);
             }
 
-            foreach (PartResource resource in this.part.Resources)
-            {
+            for (int i = 0; i < part.Resources.Count; ++i)
+            {
+                PartResource resource = part.Resources[i];
+
                 // Make sure it isn't NaN as this messes up the part mass and hence most of the values
                 // This can happen if a resource capacity is 0 and tweakable
                 if (!Double.IsNaN(resource.amount))
@@ -152,6 +191,8 @@
             {
                 MonoBehaviour.print("Created " + this.name + ". Decoupled in stage " + this.decoupledInStage);
             }
+
+            return this;
         }
 
         public ResourceContainer Resources
@@ -185,8 +226,12 @@
                 // The mode of the engine is the engineID of the ModuleEnginesFX that is active
                 string mode = this.part.GetModule<MultiModeEngine>().mode;
 
-                foreach (ModuleEnginesFX engine in this.part.GetModules<ModuleEnginesFX>())
-                {
+                List<ModuleEnginesFX> engines = part.GetModules<ModuleEnginesFX>();
+
+                for (int i = 0; i < engines.Count; ++i)
+                {
+                    ModuleEnginesFX engine = engines[i];
+
                     if (engine.engineID == mode)
                     {
                         if (log != null)
@@ -196,7 +241,7 @@
 
                         Vector3 thrustvec = this.CalculateThrustVector(vectoredThrust ? engine.thrustTransforms : null, log);
 
-                        EngineSim engineSim = new EngineSim(this,
+                        EngineSim engineSim = EngineSim.GetPoolObject().Initialise(this,
                             atmosphere,
                             (float)mach,
                             engine.maxFuelFlow,
@@ -221,8 +266,10 @@
             {
                 if (this.hasModuleEngines)
                 {
-                    foreach (ModuleEngines engine in this.part.GetModules<ModuleEngines>())
-                    {
+                    List<ModuleEngines> engines = part.GetModules<ModuleEngines>();
+                    for (int i = 0; i < engines.Count; ++i)
+                    {
+                        ModuleEngines engine = engines[i];
                         if (log != null)
                         {
                             log.buf.AppendLine("Module: " + engine.moduleName);
@@ -230,7 +277,7 @@
 
                         Vector3 thrustvec = this.CalculateThrustVector(vectoredThrust ? engine.thrustTransforms : null, log);
 
-                        EngineSim engineSim = new EngineSim(this,
+                        EngineSim engineSim = EngineSim.GetPoolObject().Initialise(this,
                             atmosphere,
                             (float)mach,
                             engine.maxFuelFlow,
@@ -266,8 +313,10 @@
             }
 
             Vector3 thrustvec = Vector3.zero;
-            foreach (Transform trans in thrustTransforms)
-            {
+            for (int i = 0; i < thrustTransforms.Count; ++i)
+            {
+                Transform trans = thrustTransforms[i];
+
                 if (log != null)
                 {
                     log.buf.AppendFormat("Transform = ({0:g6}, {1:g6}, {2:g6})   length = {3:g6}\n", trans.forward.x, trans.forward.y, trans.forward.z, trans.forward.magnitude);
@@ -320,9 +369,12 @@
                 log.buf.AppendLine("SetupAttachNodes for " + this.name + ":" + this.partId + "");
             }
 
-            this.attachNodes.Clear();
-            foreach (AttachNode attachNode in this.part.attachNodes)
-            {
+            attachNodes.Clear();
+
+            for (int i = 0; i < part.attachNodes.Count; ++i)
+            {
+                AttachNode attachNode = part.attachNodes[i];
+
                 if (log != null)
                 {
                     log.buf.AppendLine("AttachNode " + attachNode.id + " = " + (attachNode.attachedPart != null ? attachNode.attachedPart.partInfo.name : "null"));
@@ -338,7 +390,7 @@
                             log.buf.AppendLine("Adding attached node " + attachedSim.name + ":" + attachedSim.partId + "");
                         }
 
-                        this.attachNodes.Add(new AttachNodeSim(attachedSim, attachNode.id, attachNode.nodeType));
+                        attachNodes.Add(AttachNodeSim.GetPoolObject().Initialise(attachedSim, attachNode.id, attachNode.nodeType));
                     }
                     else
                     {
@@ -350,8 +402,10 @@
                 }
             }
 
-            foreach (Part p in this.part.fuelLookupTargets)
-            {
+            for (int i = 0; i < part.fuelLookupTargets.Count; ++i)
+            {
+                Part p = part.fuelLookupTargets[i];
+
                 if (p != null)
                 {
                     PartSim targetSim;
@@ -469,9 +523,10 @@
             // Rule 2: Part performs scan on start of every fuel pipe ending in it. This scan is done in order in which pipes were installed.
             // Then it makes an union of fuel tank sets each pipe scan returned. If the resulting list is not empty, it is returned as result.
             //MonoBehaviour.print("foreach fuel line");
-
-            foreach (PartSim partSim in this.fuelTargets)
-            {
+            for (int i = 0; i < fuelTargets.Count; ++i)
+            {
+                PartSim partSim = fuelTargets[i];
+
                 if (visited.Contains(partSim))
                 {
                     //if (log != null)
@@ -511,8 +566,10 @@
             if (this.fuelCrossFeed)
             {
                 //MonoBehaviour.print("foreach attach node");
-                foreach (AttachNodeSim attachSim in this.attachNodes)
-                {
+                for (int i = 0; i < attachNodes.Count; ++i)
+                {
+                    AttachNodeSim attachSim = attachNodes[i];
+
                     if (attachSim.attachedPartSim != null)
                     {
                         if (attachSim.nodeType == AttachNode.NodeType.Stack)
@@ -608,8 +665,10 @@
         public void RemoveAttachedParts(HashSet<PartSim> partSims)
         {
             // Loop through the attached parts
-            foreach (AttachNodeSim attachSim in this.attachNodes)
-            {
+            for (int i = 0; i < attachNodes.Count; ++i)
+            {
+                AttachNodeSim attachSim = attachNodes[i];
+
                 // If the part is in the set then "remove" it by clearing the PartSim reference
                 if (partSims.Contains(attachSim.attachedPartSim))
                 {
@@ -621,8 +680,10 @@
         public void DrainResources(double time)
         {
             //MonoBehaviour.print("DrainResources(" + name + ":" + partId + ", " + time + ")");
-            foreach (int type in this.resourceDrains.Types)
-            {
+            for (int i = 0; i < resourceDrains.Types.Count; ++i)
+            {
+                int type = resourceDrains.Types[i];
+
                 //MonoBehaviour.print("draining " + (time * resourceDrains[type]) + " " + ResourceContainer.GetResourceName(type));
                 this.resources.Add(type, -time * this.resourceDrains[type]);
                 //MonoBehaviour.print(ResourceContainer.GetResourceName(type) + " left = " + resources[type]);
@@ -634,8 +695,10 @@
             //MonoBehaviour.print("TimeToDrainResource(" + name + ":" + partId + ")");
             double time = double.MaxValue;
 
-            foreach (int type in this.resourceDrains.Types)
-            {
+            for (int i = 0; i < resourceDrains.Types.Count; ++i)
+            {
+                int type = resourceDrains.Types[i];
+
                 if (this.resourceDrains[type] > 0)
                 {
                     time = Math.Min(time, this.resources[type] / this.resourceDrains[type]);
@@ -686,9 +749,9 @@
         {
             double mass = this.baseMass;
 
-            foreach (int type in this.resources.Types)
-            {
-                mass += this.resources.GetResourceMass(type);
+            for (int i = 0; i < resources.Types.Count; ++i)
+            {
+                mass += this.resources.GetResourceMass(resources.Types[i]);
             }
 
             return mass;

--- a/KerbalEngineer/VesselSimulator/ResourceContainer.cs
+++ b/KerbalEngineer/VesselSimulator/ResourceContainer.cs
@@ -134,7 +134,7 @@
 
         public void Reset()
         {
-            this.resources = new Hashtable();
+            this.resources.Clear();
         }
 
         public void Debug()

--- a/KerbalEngineer/VesselSimulator/SimManager.cs
+++ b/KerbalEngineer/VesselSimulator/SimManager.cs
@@ -61,6 +61,9 @@
         private static bool hasInstalledKIDS;
         private static MethodInfo KIDS_Utils_GetIspMultiplier;
         private static bool bKIDSThrustISP = false;
+        private static List<Part> parts = new List<Part>(); 
+
+        private static Simulation simulation = new Simulation();
         #endregion
 
         #region Delegates
@@ -284,6 +287,7 @@
             try
             {
                 Stages = (simObject as Simulation).RunSimulation();
+
                 if (Stages != null && Stages.Length > 0)
                 {
                     if (logOutput)
@@ -298,8 +302,7 @@
             }
             catch (Exception e)
             {
-                MonoBehaviour.print("Exception in RunSimulation: " + e);
-                Logger.Exception(e);
+                Logger.Exception(e, "SimManager.RunSimulation()");
                 Stages = null;
                 LastStage = null;
                 failMessage = e.ToString();
@@ -351,7 +354,6 @@
                     timer.Start();
                 }
 
-                List<Part> parts;
                 if (HighLogic.LoadedSceneIsEditor)
                 {
                     parts = EditorLogic.fetch.ship.parts;
@@ -362,13 +364,11 @@
                     Atmosphere = FlightGlobals.ActiveVessel.staticPressurekPa * PhysicsGlobals.KpaToAtmospheres;
                 }
 
-                // Create the Simulation object in this thread
-                var sim = new Simulation();
-
                 // This call doesn't ever fail at the moment but we'll check and return a sensible error for display
-                if (sim.PrepareSimulation(parts, Gravity, Atmosphere, Mach, dumpTree, vectoredThrust))
-                {
-                    ThreadPool.QueueUserWorkItem(RunSimulation, sim);
+                if (simulation.PrepareSimulation(parts, Gravity, Atmosphere, Mach, dumpTree, vectoredThrust))
+                {
+                    ThreadPool.QueueUserWorkItem(RunSimulation, simulation);
+                    //RunSimulation(simulation);
                 }
                 else
                 {
@@ -382,8 +382,7 @@
             }
             catch (Exception e)
             {
-                MonoBehaviour.print("Exception in StartSimulation: " + e);
-                Logger.Exception(e);
+                Logger.Exception(e, "SimManager.StartSimulation()");
                 failMessage = e.ToString();
                 lock (locker)
                 {

--- a/KerbalEngineer/VesselSimulator/Simulation.cs
+++ b/KerbalEngineer/VesselSimulator/Simulation.cs
@@ -32,27 +32,30 @@
 {
     using CompoundParts;
     using Extensions;
+    using Helpers;
 
     public class Simulation
     {
-        private const double STD_GRAVITY = 9.82;
         private const double SECONDS_PER_DAY = 86400;
         private readonly Stopwatch _timer = new Stopwatch();
-        private List<EngineSim> activeEngines;
-        private List<EngineSim> allEngines;
-        private List<PartSim> allFuelLines;
-        private List<PartSim> allParts;
+        private List<EngineSim> activeEngines = new List<EngineSim>();
+        private List<EngineSim> allEngines = new List<EngineSim>();
+        private List<PartSim> allFuelLines = new List<PartSim>();
+        private List<PartSim> allParts = new List<PartSim>();
+        private Dictionary<Part, PartSim> partSimLookup = new Dictionary<Part, PartSim>();
         private double atmosphere;
         private int currentStage;
         private double currentisp;
         private bool doingCurrent;
-        private List<PartSim> dontStageParts;
-        private HashSet<PartSim> drainingParts;
-        private HashSet<int> drainingResources;
+        private List<PartSim> dontStageParts = new List<PartSim>();
+        List<List<PartSim>> dontStagePartsLists = new List<List<PartSim>>();
+        private HashSet<PartSim> drainingParts = new HashSet<PartSim>();
+        private HashSet<int> drainingResources = new HashSet<int>();
+        private HashSet<PartSim> decoupledParts = new HashSet<PartSim>();
         private double gravity;
 
         private int lastStage;
-        private List<Part> partList;
+        private List<Part> partList = new List<Part>();
         private double simpleTotalThrust;
         private double stageStartMass;
         private Vector3d stageStartCom;
@@ -63,7 +66,7 @@
         private double totalStageFlowRate;
         private double totalStageIspFlowRate;
         private double totalStageThrust;
-        private ForceAccumulator totalStageThrustForce;
+        private ForceAccumulator totalStageThrustForce = new ForceAccumulator();
         private Vector3 vecActualThrust;
         private Vector3 vecStageDeltaV;
         private Vector3 vecThrust;
@@ -71,6 +74,7 @@
         private float maxMach;
         public String vesselName;
         public VesselType vesselType;
+        private WeightedVectorAverager vectorAverager = new WeightedVectorAverager();
 
         public Simulation()
         {
@@ -86,9 +90,8 @@
             {
                 double mass = 0d;
 
-                foreach (PartSim partSim in this.allParts)
-                {
-                    mass += partSim.GetMass();
+                for (int i = 0; i < allParts.Count; ++i) { 
+                    mass += allParts[i].GetMass();
                 }
 
                 return mass;
@@ -99,14 +102,15 @@
         {
             get
             {
-                WeightedVectorAverager averager = new WeightedVectorAverager();
-
-                foreach (PartSim partSim in this.allParts)
-                {
-                    averager.Add(partSim.centerOfMass, partSim.GetMass());
-                }
-
-                return averager.Get();
+                vectorAverager.Reset();
+
+                for (int i = 0; i < allParts.Count; ++i)
+                {
+                    PartSim partSim = allParts[i];
+                    vectorAverager.Add(partSim.centerOfMass, partSim.GetMass());
+                }
+
+                return vectorAverager.Get();
             }
         }
 
@@ -133,16 +137,20 @@
             this.lastStage = Staging.lastStage;
             //MonoBehaviour.print("lastStage = " + lastStage);
 
-            // Create the lists for our simulation parts
-            this.allParts = new List<PartSim>();
-            this.allFuelLines = new List<PartSim>();
-            this.drainingParts = new HashSet<PartSim>();
-            this.allEngines = new List<EngineSim>();
-            this.activeEngines = new List<EngineSim>();
-            this.drainingResources = new HashSet<int>();
+            // Clear the lists for our simulation parts
+            allParts.Clear();
+            allFuelLines.Clear();
+            drainingParts.Clear();
+            allEngines.Clear();
+            activeEngines.Clear();
+            drainingResources.Clear();
+
+            PartSim.ReleaseAll();
+            EngineSim.ReleaseAll();
+            AttachNodeSim.ReleaseAll();
 
             // A dictionary for fast lookup of Part->PartSim during the preparation phase
-            Dictionary<Part, PartSim> partSimLookup = new Dictionary<Part, PartSim>();
+            partSimLookup.Clear();
 
             if (this.partList.Count > 0 && this.partList[0].vessel != null)
             {
@@ -152,8 +160,10 @@
 
             // First we create a PartSim for each Part (giving each a unique id)
             int partId = 1;
-            foreach (Part part in this.partList)
-            {
+            for (int i = 0; i < partList.Count; ++i)
+            {
+                Part part = partList[i];
+
                 // If the part is already in the lookup dictionary then log it and skip to the next part
                 if (partSimLookup.ContainsKey(part))
                 {
@@ -165,7 +175,7 @@
                 }
 
                 // Create the PartSim
-                PartSim partSim = new PartSim(part, partId, this.atmosphere, log);
+                PartSim partSim = PartSim.GetPoolObject().Initialise(part, partId, this.atmosphere, log);
 
                 // Add it to the Part lookup dictionary and the necessary lists
                 partSimLookup.Add(part, partSim);
@@ -199,8 +209,10 @@
             // Then, in the VAB/SPH, we add the parent of each fuel line to the fuelTargets list of their targets
             if (HighLogic.LoadedSceneIsEditor)
             {
-                foreach (PartSim partSim in this.allFuelLines)
-                {
+                for (int i = 0; i < allFuelLines.Count; ++i)
+                {
+                    PartSim partSim = allFuelLines[i];
+
                     CModuleFuelLine fuelLine = partSim.part.GetModule<CModuleFuelLine>();
                     if (fuelLine.target != null)
                     {
@@ -233,8 +245,10 @@
             }
 
             //MonoBehaviour.print("SetupAttachNodes and count stages");
-            foreach (PartSim partSim in this.allParts)
-            {
+            for (int i = 0; i < allParts.Count; ++i)
+            {
+                PartSim partSim = allParts[i];
+
                 partSim.SetupAttachNodes(partSimLookup, log);
                 if (partSim.decoupledInStage >= this.lastStage)
                 {
@@ -244,9 +258,9 @@
 
             // And finally release the Part references from all the PartSims
             //MonoBehaviour.print("ReleaseParts");
-            foreach (PartSim partSim in this.allParts)
-            {
-                partSim.ReleasePart();
+            for (int i = 0; i < allParts.Count; ++i)
+            { 
+                allParts[i].ReleasePart();
             }
 
             // And dereference the core's part list
@@ -291,8 +305,10 @@
             // currently active engines then generate an extra stage
             // Loop through all the engines
             bool anyActive = false;
-            foreach (EngineSim engine in this.allEngines)
-            {
+            for (int i = 0; i < allEngines.Count; ++i)
+            {
+                EngineSim engine = allEngines[i];
+
                 if (log != null)
                 {
                     log.buf.AppendLine("Testing engine mod of " + engine.partSim.name + ":" + engine.partSim.partId);
@@ -347,7 +363,7 @@
             }
 
             // Create a list of lists of PartSims that prevent decoupling
-            List<List<PartSim>> dontStagePartsLists = this.BuildDontStageLists(log);
+            BuildDontStageLists(log);
 
             if (log != null)
             {
@@ -420,8 +436,10 @@
 
                 // Calculate the cost and mass of this stage and add all engines and tanks that are decoupled
                 // in the next stage to the dontStageParts list
-                foreach (PartSim partSim in this.allParts)
-                {
+                for (int i = 0; i < allParts.Count; ++i)
+                {
+                    PartSim partSim = allParts[i];
+
                     if (partSim.decoupledInStage == this.currentStage - 1)
                     {
                         stage.cost += partSim.cost;
@@ -499,7 +517,7 @@
                     // If we have drained anything and the masses make sense then add this step's deltaV to the stage total
                     if (resourceDrainTime > 0d && this.stepStartMass > this.stepEndMass && this.stepStartMass > 0d && this.stepEndMass > 0d)
                     {
-                        this.vecStageDeltaV += this.vecThrust * (float)((this.currentisp * STD_GRAVITY * Math.Log(this.stepStartMass / this.stepEndMass)) / this.simpleTotalThrust);
+                        this.vecStageDeltaV += this.vecThrust * (float)((this.currentisp * Units.GRAVITY * Math.Log(this.stepStartMass / this.stepEndMass)) / this.simpleTotalThrust);
                     }
 
                     // Update the active engines and resource drains for the next step
@@ -543,7 +561,7 @@
                 // Note: If the mass doesn't change then this is a divide by zero
                 if (this.stageStartMass != this.stepStartMass)
                 {
-                    stage.isp = stage.deltaV / (STD_GRAVITY * Math.Log(this.stageStartMass / this.stepStartMass));
+                    stage.isp = stage.deltaV / (Units.GRAVITY * Math.Log(this.stageStartMass / this.stepStartMass));
                 }
                 else
                 {
@@ -617,20 +635,30 @@
             return stages;
         }
 
-        private List<List<PartSim>> BuildDontStageLists(LogMsg log)
+        private void BuildDontStageLists(LogMsg log)
         {
             if (log != null)
             {
                 log.buf.AppendLine("Creating list with capacity of " + (this.currentStage + 1));
             }
-            List<List<PartSim>> lists = new List<List<PartSim>>();
+
+            dontStagePartsLists.Clear();
             for (int i = 0; i <= this.currentStage; i++)
             {
-                lists.Add(new List<PartSim>());
-            }
-
-            foreach (PartSim partSim in this.allParts)
-            {
+                if (i < dontStagePartsLists.Count)
+                {
+                    dontStagePartsLists[i].Clear();
+                }
+                else
+                {
+                    dontStagePartsLists.Add(new List<PartSim>());
+                }
+            }
+
+            for (int i = 0; i < allParts.Count; ++i)
+            {
+                PartSim partSim = allParts[i];
+
                 if (partSim.isEngine || !partSim.Resources.Empty)
                 {
                     if (log != null)
@@ -647,28 +675,28 @@
                     }
                     else
                     {
-                        lists[partSim.decoupledInStage + 1].Add(partSim);
+                        dontStagePartsLists[partSim.decoupledInStage + 1].Add(partSim);
                     }
                 }
             }
 
             for (int i = 1; i <= this.lastStage; i++)
             {
-                if (lists[i].Count == 0)
-                {
-                    lists[i] = lists[i - 1];
-                }
-            }
-
-            return lists;
+                if (dontStagePartsLists[i].Count == 0)
+                {
+                    dontStagePartsLists[i] = dontStagePartsLists[i - 1];
+                }
+            }
         }
 
         // This function simply rebuilds the active engines by testing the isActive flag of all the engines
         private void UpdateActiveEngines()
         {
             this.activeEngines.Clear();
-            foreach (EngineSim engine in this.allEngines)
-            {
+            for (int i = 0; i < allEngines.Count; ++i)
+            {
+                EngineSim engine = allEngines[i];
+
                 if (engine.isActive)
                 {
                     this.activeEngines.Add(engine);
@@ -686,12 +714,14 @@
             this.totalStageActualThrust = 0d;
             this.totalStageFlowRate = 0d;
             this.totalStageIspFlowRate = 0d;
-            this.totalStageThrustForce = new ForceAccumulator();
+            this.totalStageThrustForce.Reset();
 
             // Loop through all the active engines totalling the thrust, actual thrust and mass flow rates
             // The thrust is totalled as vectors
-            foreach (EngineSim engine in this.activeEngines)
-            {
+            for (int i = 0; i < activeEngines.Count; ++i)
+            {
+                EngineSim engine = activeEngines[i];
+
                 this.simpleTotalThrust += engine.thrust;
                 this.vecThrust += ((float)engine.thrust * engine.thrustVec);
                 this.vecActualThrust += ((float)engine.actualThrust * engine.thrustVec);
@@ -699,8 +729,9 @@
                 this.totalStageFlowRate += engine.ResourceConsumptions.Mass;
                 this.totalStageIspFlowRate += engine.ResourceConsumptions.Mass * engine.isp;
 
-                foreach (AppliedForce f in engine.appliedForces) {
-                    this.totalStageThrustForce.AddForce(f);
+                for (int j = 0; j < engine.appliedForces.Count; ++j)
+                {
+                    this.totalStageThrustForce.AddForce(engine.appliedForces[j]);
                 }
             }
 
@@ -740,15 +771,17 @@
             this.drainingParts.Clear();
 
             // Loop through all the active engine modules
-            foreach (EngineSim engine in this.activeEngines)
-            {
+            for (int i = 0; i < activeEngines.Count; ++i)
+            {
+                EngineSim engine = activeEngines[i];
+
                 // Set the resource drains for this engine
                 if (engine.SetResourceDrains(this.allParts, this.allFuelLines, this.drainingParts))
                 {
                     // If it is active then add the consumed resource types to the set
-                    foreach (int type in engine.ResourceConsumptions.Types)
-                    {
-                        this.drainingResources.Add(type);
+                    for (int j = 0; j < engine.ResourceConsumptions.Types.Count; ++j)
+                    { 
+                        drainingResources.Add(engine.ResourceConsumptions.Types[j]);
                     }
                 }
             }
@@ -782,8 +815,10 @@
 
             if (this.activeEngines.Count > 0)
             {
-                foreach (PartSim partSim in this.dontStageParts)
-                {
+                for (int i = 0; i < dontStageParts.Count; ++i)
+                {
+                    PartSim partSim = dontStageParts[i];
+
                     if (SimManager.logOutput)
                     {
                         partSim.DumpPartToBuffer(buffer, "Testing: ");
@@ -802,8 +837,10 @@
 
                     if (partSim.isEngine)
                     {
-                        foreach (EngineSim engine in this.activeEngines)
-                        {
+                        for (int j = 0; j < activeEngines.Count; ++j)
+                        {
+                            EngineSim engine = activeEngines[j];
+
                             if (engine.partSim == partSim)
                             {
                                 if (SimManager.logOutput)
@@ -841,9 +878,11 @@
         private void ActivateStage()
         {
             // Build a set of all the parts that will be decoupled
-            HashSet<PartSim> decoupledParts = new HashSet<PartSim>();
-            foreach (PartSim partSim in this.allParts)
-            {
+            decoupledParts.Clear();
+            for (int i = 0; i < allParts.Count; ++i)
+            {
+                PartSim partSim = allParts[i];
+
                 if (partSim.decoupledInStage >= this.currentStage)
                 {
                     decoupledParts.Add(partSim);
@@ -873,15 +912,15 @@
             }
 
             // Loop through all the (remaining) parts
-            foreach (PartSim partSim in this.allParts)
-            {
+            for (int i = 0; i < allParts.Count; ++i) { 
                 // Ask the part to remove all the parts that are decoupled
-                partSim.RemoveAttachedParts(decoupledParts);
+                allParts[i].RemoveAttachedParts(decoupledParts);
             }
 
             // Now we loop through all the engines and activate those that are ignited in this stage
-            foreach (EngineSim engine in this.allEngines)
-            {
+            for (int i = 0; i < allEngines.Count; ++i)
+            {
+                EngineSim engine = allEngines[i];
                 if (engine.partSim.inverseStage == this.currentStage)
                 {
                     engine.isActive = true;

 Binary files a/Output/KerbalEngineer/KerbalEngineer.dll and b/Output/KerbalEngineer/KerbalEngineer.dll differ
--- a/Output/KerbalEngineer/KerbalEngineer.version
+++ b/Output/KerbalEngineer/KerbalEngineer.version
@@ -6,7 +6,7 @@
 		"MAJOR":1,
 		"MINOR":0,
 		"PATCH":16,
-		"BUILD":2
+		"BUILD":3
 	},
 	"KSP_VERSION":
 	{