diff --git a/swing/src/net/sf/openrocket/gui/main/BasicFrame.java b/swing/src/net/sf/openrocket/gui/main/BasicFrame.java
index 2987ded5a..842b8919c 100644
--- a/swing/src/net/sf/openrocket/gui/main/BasicFrame.java
+++ b/swing/src/net/sf/openrocket/gui/main/BasicFrame.java
@@ -1369,7 +1369,7 @@ public class BasicFrame extends JFrame {
 
 		((SwingPreferences) Application.getPreferences()).setDefaultDirectory(chooser.getCurrentDirectory());
 
-		file = FileHelper.forceExtension(file, "ork");
+		file = FileHelper.forceExtension(file, "rkt");
 		if (FileHelper.confirmWrite(file, this) ) {
 			return saveAsRocksim(file);
 		}