diff --git a/core/resources/l10n/messages.properties b/core/resources/l10n/messages.properties
index 5951d39c5..106ceb46e 100644
--- a/core/resources/l10n/messages.properties
+++ b/core/resources/l10n/messages.properties
@@ -1632,7 +1632,7 @@ FlightDataType.TYPE_ROLL_RATE = Roll rate
 FlightDataType.TYPE_PITCH_RATE = Pitch rate
 FlightDataType.TYPE_YAW_RATE = Yaw rate
 FlightDataType.TYPE_MASS = Mass
-FlightDataType.TYPE_PROPELLANT_MASS = Propellant mass
+FlightDataType.TYPE_MOTOR_MASS = Motor mass
 FlightDataType.TYPE_LONGITUDINAL_INERTIA = Longitudinal moment of inertia
 FlightDataType.TYPE_ROTATIONAL_INERTIA = Rotational moment of inertia
 FlightDataType.TYPE_CP_LOCATION = CP location
diff --git a/core/resources/l10n/messages_es.properties b/core/resources/l10n/messages_es.properties
index 2e9bd3c35..15416c61d 100644
--- a/core/resources/l10n/messages_es.properties
+++ b/core/resources/l10n/messages_es.properties
@@ -314,7 +314,7 @@ FlightDataType.TYPE_POSITION_X                 = Posici\u00f3n contra el viento
 FlightDataType.TYPE_POSITION_XY                = Distancia lateral
 FlightDataType.TYPE_POSITION_Y                 = Posici\u00f3n a favor del viento
 FlightDataType.TYPE_PRESSURE_DRAG_COEFF        = Presi\u00f3n del Coeficiente de rozamiento
-FlightDataType.TYPE_PROPELLANT_MASS            = Masa del propulsor
+FlightDataType.TYPE_MOTOR_MASS                 = Masa del propulsor
 FlightDataType.TYPE_REFERENCE_AREA             = \u00c1rea de referencia
 FlightDataType.TYPE_REFERENCE_LENGTH           = Longitud de referencia 
 FlightDataType.TYPE_REYNOLDS_NUMBER            = N\u00famero de Reynolds
diff --git a/core/resources/l10n/messages_fr.properties b/core/resources/l10n/messages_fr.properties
index c5fd19271..181838f72 100644
--- a/core/resources/l10n/messages_fr.properties
+++ b/core/resources/l10n/messages_fr.properties
@@ -305,7 +305,7 @@ FlightDataType.TYPE_POSITION_X                 = Position contre le vent
 FlightDataType.TYPE_POSITION_XY                = Distance lat\u00E9rale
 FlightDataType.TYPE_POSITION_Y                 = Position parall\u00E8le au vent
 FlightDataType.TYPE_PRESSURE_DRAG_COEFF        = Coefficient de tra\u00EEn\u00E9e de pression
-FlightDataType.TYPE_PROPELLANT_MASS            = Masse du propergol
+FlightDataType.TYPE_MOTOR_MASS                 = Masse du propergol
 FlightDataType.TYPE_REFERENCE_AREA             = Surface de r\u00E9f\u00E9rence
 FlightDataType.TYPE_REFERENCE_LENGTH           = Longueur de r\u00E9f\u00E9rence
 FlightDataType.TYPE_REYNOLDS_NUMBER            = Nombre de Reynolds
diff --git a/core/resources/l10n/messages_ja.properties b/core/resources/l10n/messages_ja.properties
index 1b1133f77..09c788dc7 100644
--- a/core/resources/l10n/messages_ja.properties
+++ b/core/resources/l10n/messages_ja.properties
@@ -1385,7 +1385,7 @@ FlightDataType.TYPE_ROLL_RATE  = \u89D2\u901F\u5EA6\uFF08\u30ED\u30FC\u30EB\uFF0
 FlightDataType.TYPE_PITCH_RATE  = \u89D2\u901F\u5EA6\uFF08\u30D4\u30C3\u30C1\uFF09
 FlightDataType.TYPE_YAW_RATE  = \u89D2\u901F\u5EA6\uFF08\u30E8\u30FC\uFF09
 FlightDataType.TYPE_MASS  = \u8CEA\u91CF
-FlightDataType.TYPE_PROPELLANT_MASS  = \u8EF8\u65B9\u5411\u6163\u6027\u30E2\u30FC\u30E1\u30F3\u30C8
+FlightDataType.TYPE_MOTOR_MASS  = \u8EF8\u65B9\u5411\u6163\u6027\u30E2\u30FC\u30E1\u30F3\u30C8
 FlightDataType.TYPE_LONGITUDINAL_INERTIA  = \u9577\u624B\u65B9\u5411\u6163\u6027\u30E2\u30FC\u30E1\u30F3\u30C8
 FlightDataType.TYPE_ROTATIONAL_INERTIA  = \u30ED\u30FC\u30EB\u65B9\u5411\u6163\u6027\u30E2\u30FC\u30E1\u30F3\u30C8
 FlightDataType.TYPE_CP_LOCATION  = CP\u4F4D\u7F6E
diff --git a/core/resources/l10n/messages_pt.properties b/core/resources/l10n/messages_pt.properties
index 33b1c387a..fc1d3e0d4 100644
--- a/core/resources/l10n/messages_pt.properties
+++ b/core/resources/l10n/messages_pt.properties
@@ -294,7 +294,7 @@ FlightDataType.TYPE_POSITION_X                 = Posi\u00e7\u00e3o a favor do ve
 FlightDataType.TYPE_POSITION_XY                = Dist\u00e2ncia lateral
 FlightDataType.TYPE_POSITION_Y                 = Posi\u00e7\u00e3o paralela ao vento
 FlightDataType.TYPE_PRESSURE_DRAG_COEFF        = Coeficiente de arrasto de press\u00e3o
-FlightDataType.TYPE_PROPELLANT_MASS            = Massa do propelente
+FlightDataType.TYPE_MOTOR_MASS            = Massa do propelente
 FlightDataType.TYPE_REFERENCE_AREA             = \u00c1rea de refer\u00eancia
 FlightDataType.TYPE_REFERENCE_LENGTH           = Comprimento de refer\u00eancia
 FlightDataType.TYPE_REYNOLDS_NUMBER            = N\u00famero de Reynolds
diff --git a/core/resources/l10n/messages_ru.properties b/core/resources/l10n/messages_ru.properties
index 9ae7b5970..a60b361d5 100644
--- a/core/resources/l10n/messages_ru.properties
+++ b/core/resources/l10n/messages_ru.properties
@@ -1477,7 +1477,7 @@ FlightDataType.TYPE_ROLL_RATE = \u0423\u0433\u043b\u043e\u0432\u0430\u044f \u044
 FlightDataType.TYPE_PITCH_RATE = \u0423\u0433\u043b\u043e\u0432\u0430\u044f \u0441\u043a\u043e\u0440\u043e\u0441\u0442\u044c \u0442\u0430\u043d\u0433\u0430\u0436\u0430
 FlightDataType.TYPE_YAW_RATE = \u0423\u0433\u043b\u043e\u0432\u0430\u044f \u0441\u043a\u043e\u0440\u043e\u0441\u0442\u044c \u0440\u044b\u0441\u043a\u0430\u043d\u044c\u044f
 FlightDataType.TYPE_MASS = \u041c\u0430\u0441\u0441\u0430
-FlightDataType.TYPE_PROPELLANT_MASS = \u041c\u0430\u0441\u0441\u0430 \u0442\u043e\u043f\u043b\u0438\u0432\u0430
+FlightDataType.TYPE_MOTOR_MASS = \u041c\u0430\u0441\u0441\u0430 \u0442\u043e\u043f\u043b\u0438\u0432\u0430
 FlightDataType.TYPE_LONGITUDINAL_INERTIA = \u041f\u0440\u043e\u0434\u043e\u043b\u044c\u043d\u044b\u0439 \u043c\u043e\u043c\u0435\u043d\u0442 \u0438\u043d\u0435\u0440\u0446\u0438\u0438
 FlightDataType.TYPE_ROTATIONAL_INERTIA = \u041a\u0440\u0443\u0442\u044f\u0449\u0438\u0439 \u043c\u043e\u043c\u0435\u043d\u0442 \u0438\u043d\u0435\u0440\u0446\u0438\u0438
 FlightDataType.TYPE_CP_LOCATION = \u041f\u043e\u043b\u043e\u0436\u0435\u043d\u0438\u0435 \u0426\u0414
diff --git a/core/resources/l10n/messages_uk_UA.properties b/core/resources/l10n/messages_uk_UA.properties
index 05fbebbc7..ed4b301c9 100644
--- a/core/resources/l10n/messages_uk_UA.properties
+++ b/core/resources/l10n/messages_uk_UA.properties
@@ -1483,7 +1483,7 @@ FlightDataType.TYPE_ROLL_RATE = Roll rate
 FlightDataType.TYPE_PITCH_RATE = Pitch rate
 FlightDataType.TYPE_YAW_RATE = Yaw rate
 FlightDataType.TYPE_MASS = Mass
-FlightDataType.TYPE_PROPELLANT_MASS = Propellant mass
+FlightDataType.TYPE_MOTOR_MASS = Motor mass
 FlightDataType.TYPE_LONGITUDINAL_INERTIA = Longitudinal moment of inertia
 FlightDataType.TYPE_ROTATIONAL_INERTIA = Rotational moment of inertia
 FlightDataType.TYPE_CP_LOCATION = CP location
diff --git a/core/resources/l10n/messages_zh_CN.properties b/core/resources/l10n/messages_zh_CN.properties
index d6fba3c2c..26b7181a4 100644
--- a/core/resources/l10n/messages_zh_CN.properties
+++ b/core/resources/l10n/messages_zh_CN.properties
@@ -330,7 +330,7 @@ FlightDataType.TYPE_POSITION_X                 = \u8FCE\u98CE\u4F4D\u7F6E
 FlightDataType.TYPE_POSITION_XY                = \u6A2A\u5411\u8DE8\u8DDD
 FlightDataType.TYPE_POSITION_Y                 = \u5E73\u884C\u98CE\u4F4D\u7F6E
 FlightDataType.TYPE_PRESSURE_DRAG_COEFF        = \u538B\u5DEE\u963B\u529B\u7CFB\u6570
-FlightDataType.TYPE_PROPELLANT_MASS            = \u63A8\u8FDB\u5242\u8D28\u91CF
+FlightDataType.TYPE_MOTOR_MASS            = \u63A8\u8FDB\u5242\u8D28\u91CF
 FlightDataType.TYPE_REFERENCE_AREA             = \u53C2\u8003\u9762\u79EF
 FlightDataType.TYPE_REFERENCE_LENGTH           = \u53C2\u8003\u957F\u5EA6
 FlightDataType.TYPE_REYNOLDS_NUMBER            = \u96F7\u8BFA\u6570
diff --git a/core/src/net/sf/openrocket/masscalc/MassCalculation.java b/core/src/net/sf/openrocket/masscalc/MassCalculation.java
index 0a318e350..3f51f2ed5 100644
--- a/core/src/net/sf/openrocket/masscalc/MassCalculation.java
+++ b/core/src/net/sf/openrocket/masscalc/MassCalculation.java
@@ -390,15 +390,15 @@ public class MassCalculation {
 //		}
 
 		if (component.isMotorMount()) {
-			MassCalculation propellant = this.copy(component, parentTransform);
+			MassCalculation motor = this.copy(component, parentTransform);
 			
-			propellant.calculateMountData();
+			motor.calculateMountData();
 
-			this.merge( propellant );
+			this.merge( motor );
 
 //			// vvv DEBUG
-//			if( 0 < propellant.getMass() ) {
-//				System.err.println(String.format( "%s........++ propellantData: %s", prefix, propellant.toCMDebug()));
+//			if( 0 < motor.getMass() ) {
+//				System.err.println(String.format( "%s........++ motorData: %s", prefix, propellant.toCMDebug()));
 //			}
 
 		}
diff --git a/core/src/net/sf/openrocket/masscalc/MassCalculator.java b/core/src/net/sf/openrocket/masscalc/MassCalculator.java
index 6036f853a..72731740b 100644
--- a/core/src/net/sf/openrocket/masscalc/MassCalculator.java
+++ b/core/src/net/sf/openrocket/masscalc/MassCalculator.java
@@ -19,7 +19,7 @@ public class MassCalculator implements Monitorable {
 	 */
 	//	private HashMap< Integer, MassData> stageMassCache = new HashMap<Integer, MassData >();
 	//	private MassData rocketSpentMassCache;
-	//	private MassData propellantMassCache;
+	//	private MassData motorMassCache;
 
 	private int modId = 0;
 	
diff --git a/core/src/net/sf/openrocket/simulation/BasicLandingStepper.java b/core/src/net/sf/openrocket/simulation/BasicLandingStepper.java
index cf2cf6e04..75259962a 100644
--- a/core/src/net/sf/openrocket/simulation/BasicLandingStepper.java
+++ b/core/src/net/sf/openrocket/simulation/BasicLandingStepper.java
@@ -122,7 +122,7 @@ public class BasicLandingStepper extends AbstractSimulationStepper {
 		data.setValue(FlightDataType.TYPE_MACH_NUMBER, mach);
 		
 		data.setValue(FlightDataType.TYPE_MASS, mass);
-		data.setValue(FlightDataType.TYPE_PROPELLANT_MASS, 0.0); // Is this a reasonable assumption? Probably.
+		data.setValue(FlightDataType.TYPE_MOTOR_MASS, 0.0); // Is this a reasonable assumption? Probably.
 		
 		data.setValue(FlightDataType.TYPE_THRUST_FORCE, 0);
 		data.setValue(FlightDataType.TYPE_DRAG_FORCE, dragForce);
diff --git a/core/src/net/sf/openrocket/simulation/BasicTumbleStepper.java b/core/src/net/sf/openrocket/simulation/BasicTumbleStepper.java
index f1e3795dc..97a387976 100644
--- a/core/src/net/sf/openrocket/simulation/BasicTumbleStepper.java
+++ b/core/src/net/sf/openrocket/simulation/BasicTumbleStepper.java
@@ -121,7 +121,7 @@ public class BasicTumbleStepper extends AbstractSimulationStepper {
 		data.setValue(FlightDataType.TYPE_MACH_NUMBER, mach);
 		
 		data.setValue(FlightDataType.TYPE_MASS, mass);
-		data.setValue(FlightDataType.TYPE_PROPELLANT_MASS, 0.0); // Is this a reasonable assumption? Probably.
+		data.setValue(FlightDataType.TYPE_MOTOR_MASS, 0.0); // Is this a reasonable assumption? Probably.
 		
 		data.setValue(FlightDataType.TYPE_THRUST_FORCE, 0);
 		data.setValue(FlightDataType.TYPE_DRAG_FORCE, dragForce);
diff --git a/core/src/net/sf/openrocket/simulation/FlightDataType.java b/core/src/net/sf/openrocket/simulation/FlightDataType.java
index 615334913..55240861e 100644
--- a/core/src/net/sf/openrocket/simulation/FlightDataType.java
+++ b/core/src/net/sf/openrocket/simulation/FlightDataType.java
@@ -91,8 +91,8 @@ public class FlightDataType implements Comparable<FlightDataType> {
 	//// Stability information
 	//// Mass
 	public static final FlightDataType TYPE_MASS = newType(trans.get("FlightDataType.TYPE_MASS"), "m", UnitGroup.UNITS_MASS, 50);
-	//// Propellant mass
-	public static final FlightDataType TYPE_PROPELLANT_MASS = newType(trans.get("FlightDataType.TYPE_PROPELLANT_MASS"), "mp", UnitGroup.UNITS_MASS, 51);
+	//// Motor mass
+	public static final FlightDataType TYPE_MOTOR_MASS = newType(trans.get("FlightDataType.TYPE_MOTOR_MASS"), "mp", UnitGroup.UNITS_MASS, 51);
 	//// Longitudinal moment of inertia
 	public static final FlightDataType TYPE_LONGITUDINAL_INERTIA = newType(trans.get("FlightDataType.TYPE_LONGITUDINAL_INERTIA"), "Il", UnitGroup.UNITS_INERTIA, 52);
 	//// Rotational moment of inertia
@@ -209,7 +209,7 @@ public class FlightDataType implements Comparable<FlightDataType> {
 		TYPE_PITCH_RATE,
 		TYPE_YAW_RATE,
 		TYPE_MASS,
-		TYPE_PROPELLANT_MASS,
+		TYPE_MOTOR_MASS,
 		TYPE_LONGITUDINAL_INERTIA,
 		TYPE_ROTATIONAL_INERTIA,
 		TYPE_CP_LOCATION,
diff --git a/core/src/net/sf/openrocket/simulation/GroundStepper.java b/core/src/net/sf/openrocket/simulation/GroundStepper.java
index 55355b324..27c50014f 100644
--- a/core/src/net/sf/openrocket/simulation/GroundStepper.java
+++ b/core/src/net/sf/openrocket/simulation/GroundStepper.java
@@ -62,7 +62,7 @@ public class GroundStepper extends AbstractSimulationStepper {
 		data.setValue(FlightDataType.TYPE_MACH_NUMBER, 0.0);
 		
 		data.setValue(FlightDataType.TYPE_MASS, calculateStructureMass(status).getMass());
-		data.setValue(FlightDataType.TYPE_PROPELLANT_MASS, 0.0); // Is this a reasonable assumption? Probably.
+		data.setValue(FlightDataType.TYPE_MOTOR_MASS, 0.0); // Is this a reasonable assumption? Probably.
 		
 		data.setValue(FlightDataType.TYPE_THRUST_FORCE, 0.0);
 		data.setValue(FlightDataType.TYPE_DRAG_FORCE, 0.0);
diff --git a/core/src/net/sf/openrocket/simulation/RK4SimulationStepper.java b/core/src/net/sf/openrocket/simulation/RK4SimulationStepper.java
index 7625e113a..77a061662 100644
--- a/core/src/net/sf/openrocket/simulation/RK4SimulationStepper.java
+++ b/core/src/net/sf/openrocket/simulation/RK4SimulationStepper.java
@@ -613,9 +613,9 @@ public class RK4SimulationStepper extends AbstractSimulationStepper {
 		}
 
 		if( null != store.motorMass ){
-			data.setValue(FlightDataType.TYPE_PROPELLANT_MASS, store.motorMass.getMass());
-			//data.setValue(FlightDataType.TYPE_PROPELLANT_LONGITUDINAL_INERTIA, store.propellantMassData.getLongitudinalInertia());
-			//data.setValue(FlightDataType.TYPE_PROPELLANT_ROTATIONAL_INERTIA, store.propellantMassData.getRotationalInertia());
+			data.setValue(FlightDataType.TYPE_MOTOR_MASS, store.motorMass.getMass());
+			//data.setValue(FlightDataType.TYPE_MOTOR_LONGITUDINAL_INERTIA, store.motorMassData.getLongitudinalInertia());
+			//data.setValue(FlightDataType.TYPE_MOTOR_ROTATIONAL_INERTIA, store.motorMassData.getRotationalInertia());
 		}
 		if (store.rocketMass != null) {
 			// N.B.: These refer to total mass
diff --git a/core/src/net/sf/openrocket/simulation/listeners/example/DampingMoment.java b/core/src/net/sf/openrocket/simulation/listeners/example/DampingMoment.java
index cb8bc78c8..0665766e6 100644
--- a/core/src/net/sf/openrocket/simulation/listeners/example/DampingMoment.java
+++ b/core/src/net/sf/openrocket/simulation/listeners/example/DampingMoment.java
@@ -41,7 +41,7 @@ public class DampingMoment extends AbstractSimulationListener {
 		// dm/dt = (thrust - ma)/v
 		FlightDataBranch data = status.getFlightData();
 		
-		List<Double> mpAll = data.get(FlightDataType.TYPE_PROPELLANT_MASS);
+		List<Double> mpAll = data.get(FlightDataType.TYPE_MOTOR_MASS);
 		List<Double> time = data.get(FlightDataType.TYPE_TIME);
 		if (mpAll == null || time == null) {
 			return Double.NaN;
diff --git a/swing/src/net/sf/openrocket/gui/print/DesignReport.java b/swing/src/net/sf/openrocket/gui/print/DesignReport.java
index 84f9a854f..626b7a227 100644
--- a/swing/src/net/sf/openrocket/gui/print/DesignReport.java
+++ b/swing/src/net/sf/openrocket/gui/print/DesignReport.java
@@ -145,7 +145,7 @@ public class DesignReport {
 	private static final String MAX_THRUST = "Max Thrust";
 	private static final String TOTAL_IMPULSE = "Total Impulse";
 	private static final String THRUST_TO_WT = "Thrust to Wt";
-	private static final String PROPELLANT_WT = "Propellant Wt";
+	private static final String MOTOR_WT = "Motor Wt";
 	private static final String SIZE = "Size";
 	private static final String ALTITUDE = "Altitude";
 	private static final String FLIGHT_TIME = "Flight Time";
@@ -377,7 +377,7 @@ public class DesignReport {
 		motorTable.addCell(ITextHelper.createCell(MAX_THRUST, PdfPCell.BOTTOM, PrintUtilities.SMALL));
 		motorTable.addCell(ITextHelper.createCell(TOTAL_IMPULSE, PdfPCell.BOTTOM, PrintUtilities.SMALL));
 		motorTable.addCell(ITextHelper.createCell(THRUST_TO_WT, PdfPCell.BOTTOM, PrintUtilities.SMALL));
-		motorTable.addCell(ITextHelper.createCell(PROPELLANT_WT, PdfPCell.BOTTOM, PrintUtilities.SMALL));
+		motorTable.addCell(ITextHelper.createCell(MOTOR_WT, PdfPCell.BOTTOM, PrintUtilities.SMALL));
 		motorTable.addCell(ITextHelper.createCell(SIZE, PdfPCell.BOTTOM, PrintUtilities.SMALL));
 		
 		DecimalFormat ttwFormat = new DecimalFormat("0.00");