diff --git a/core/src/net/sf/openrocket/aerodynamics/barrowman/TubeCalc.java b/core/src/net/sf/openrocket/aerodynamics/barrowman/TubeCalc.java
index 60117d808..5a0f96283 100644
--- a/core/src/net/sf/openrocket/aerodynamics/barrowman/TubeCalc.java
+++ b/core/src/net/sf/openrocket/aerodynamics/barrowman/TubeCalc.java
@@ -6,8 +6,17 @@ import net.sf.openrocket.rocketcomponent.RocketComponent;
 import net.sf.openrocket.rocketcomponent.Tube;
 import net.sf.openrocket.util.MathUtil;
 
-public abstract class TubeCalc extends RocketComponentCalc {
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public abstract class TubeCalc extends RocketComponentCalc {
+	
+	private final static Logger log = LoggerFactory.getLogger(TubeFinSetCalc.class);
+
+	// air density (standard conditions)
+	private final double rho = 1.225; // kg/m^3
+	
 	private final double diameter;
 	private final double length;
 	protected double refArea;
@@ -25,18 +34,37 @@ public abstract class TubeCalc extends RocketComponentCalc {
 	@Override
 	public double calculatePressureCD(FlightConditions conditions,
 			double stagnationCD, double baseCD, WarningSet warnings) {
+		// These calculations come from a mix of theoretical and empirical
+		// results, and are marked with (t) for theoretical and (e) for empirical.
+		// The theoretical results should not be modified; the empirical can be adjusted
+		// to better simulate real rockets.
 
-		// calculation of pressure drop through pipe from "Atlas Copco Air Compendium", 1975,
-		// quoted as equation 14 in Carello, Ivanov, and Mazza, "Pressure drop in pipe
+		// Temperature
+		final double T = conditions.getAtmosphericConditions().getTemperature();
+		
+		// Sutherland Equation for viscosity of air (e)
+		final double mu = 1.458e-6 * Math.pow(T, 3/2) / (T + 110.4); //
+
+		// Volume flow rate (t)
+		final double Q = conditions.getVelocity() * refArea;
+		
+		// Reynolds number (note Reynolds number for the interior of a pipe is based on diameter,
+		// not length (t)
+		final double Re = (4 * rho * Q) / (Math.PI * diameter * mu);
+		
+		// quoted as equation 12 in Carello, Ivanov, and Mazza, "Pressure drop in pipe
 		// lines for compressed air: comparison between experimental and theoretical analysis",
 		// Transactions on Engineering Sciences vol 18, ISSN 1743-35331998, 1998.
 
-		// Volume flow rate
-		final double Q = conditions.getVelocity() * refArea;
-
-		// pressure drop
-		final double deltap = 1.6 * Math.pow(Q, 1.85) * length /
-			(Math.pow(diameter, 5) * conditions.getAtmosphericConditions().getPressure());
+		// friction coefficient (for tube interior) (e)
+		final double lambda = 0.3164 * Math.pow(Re, -0.25);
+		
+		// pressure drop (e)
+		// 101.325 is standard pressure
+		// Power in equation is 5 in original source.  That was experimentally derived; I'm adjusting
+		// it to match the data I've got from two rockets.
+		final double deltap = (lambda * 8 * length * rho * MathUtil.pow2(Q) * T * 101.325) /
+			(MathUtil.pow2(Math.PI) * Math.pow(diameter, 4.8) * 273 * conditions.getAtmosphericConditions().getPressure());
 
 		// convert to CD and return
 		return deltap * refArea / conditions.getRefArea();