diff --git a/core/src/net/sf/openrocket/aerodynamics/barrowman/SymmetricComponentCalc.java b/core/src/net/sf/openrocket/aerodynamics/barrowman/SymmetricComponentCalc.java
index 8d2634959..b5965b2ee 100644
--- a/core/src/net/sf/openrocket/aerodynamics/barrowman/SymmetricComponentCalc.java
+++ b/core/src/net/sf/openrocket/aerodynamics/barrowman/SymmetricComponentCalc.java
@@ -18,7 +18,8 @@ import net.sf.openrocket.util.MathUtil;
 import net.sf.openrocket.util.PolyInterpolator;
 import net.sf.openrocket.util.Transformation;
 
-
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * Calculates the aerodynamic properties of a <code>SymmetricComponent</code>.
@@ -32,6 +33,8 @@ import net.sf.openrocket.util.Transformation;
  */
 public class SymmetricComponentCalc extends RocketComponentCalc {
 	
+	private final static Logger log = LoggerFactory.getLogger(SymmetricComponentCalc.class);
+	
 	public static final double BODY_LIFT_K = 1.1;
 	
 	private final double length;
@@ -375,7 +378,16 @@ public class SymmetricComponentCalc extends RocketComponentCalc {
 				interpolator.addPoint(m, stag * Math.pow(int1.getValue(m) / stag, log4));
 			}
 		}
-		
+
+		// dump transonic/supersonic knots, in a format easily imported into python
+		String vel = "vel = [ ";
+		String cd = "cd = [ ";
+		for (double m : interpolator.getXPoints()) {
+			vel = vel + m + ", ";
+			cd = cd + interpolator.getValue(m) + ", ";
+		}
+		log.debug(vel + "]");
+		log.debug(cd + "]");
 
 		/*
 		 * Now the transonic/supersonic region is ok.  We still need to interpolate
@@ -391,6 +403,9 @@ public class SymmetricComponentCalc extends RocketComponentCalc {
 		
 		double cdMach0 = 0.8 * pow2(sinphi);
 		double minDeriv = (interpolator.getValue(min + 0.01) - minValue) / 0.01;
+
+		log.debug("cdMach0 = " + cdMach0);
+		log.debug("minDeriv = " + minDeriv);
 		
 		// These should not occur, but might cause havoc for the interpolation
 		if ((cdMach0 >= minValue - 0.01) || (minDeriv <= 0.01)) {
diff --git a/swing/resources/datafiles/presets/system.ser b/swing/resources/datafiles/presets/system.ser
index 33648114c..28a7bbe93 100644
Binary files a/swing/resources/datafiles/presets/system.ser and b/swing/resources/datafiles/presets/system.ser differ