diff --git a/src/airfoil_data/polargenerator.py b/src/airfoil_data/polargenerator.py
index 5e83e57cac86bdd7b703857956c2dc95be815ce8..dc9dff8a0c98cdb4036f49baf0249f3960d854d8 100755
--- a/src/airfoil_data/polargenerator.py
+++ b/src/airfoil_data/polargenerator.py
@@ -93,7 +93,7 @@ def cleanup(airfoil):
     for file in os.listdir(cwd):
         if file.startswith("Coordinates_"):
             safe_rename(file, airfoil + ".dat")
-        elif file.startswith("Polar_"):
+        elif file.startswith("Polar_") and not (file.endswith(".txt")):
             safe_rename(file, file + ".txt")