diff --git a/src/net/sf/openrocket/file/rocksim/FinSetHandler.java b/src/net/sf/openrocket/file/rocksim/FinSetHandler.java
index 9b9239dc4..08c917775 100644
--- a/src/net/sf/openrocket/file/rocksim/FinSetHandler.java
+++ b/src/net/sf/openrocket/file/rocksim/FinSetHandler.java
@@ -277,7 +277,7 @@ class FinSetHandler extends ElementHandler {
         if (shapeCode == 0) {
             //Trapezoidal
             result = new TrapezoidFinSet();
-            ((TrapezoidFinSet) result).setFinShape(rootChord, tipChord, sweepDistance, midChordLen, thickness);
+            ((TrapezoidFinSet) result).setFinShape(rootChord, tipChord, sweepDistance, semiSpan, thickness);
         }
         else if (shapeCode == 1) {
             //Elliptical
diff --git a/test/net/sf/openrocket/file/rocksim/FinSetHandlerTest.java b/test/net/sf/openrocket/file/rocksim/FinSetHandlerTest.java
index 5b02142b5..1cc4792ed 100644
--- a/test/net/sf/openrocket/file/rocksim/FinSetHandlerTest.java
+++ b/test/net/sf/openrocket/file/rocksim/FinSetHandlerTest.java
@@ -104,6 +104,9 @@ public class FinSetHandlerTest extends TestCase {
         assertTrue(fins instanceof TrapezoidFinSet);
         assertEquals(4, fins.getFinCount());
 
+        assertEquals(0.012d, ((TrapezoidFinSet) fins).getHeight());
+        assertEquals(0.012d, fins.getSpan());
+        
         assertEquals(0.2d, fins.getThickness());
         assertEquals(0.4d, fins.getTabLength());
         assertEquals(0.5d, fins.getTabHeight());