diff --git a/rocket_twin/drivers/fueling_rocket.py b/rocket_twin/drivers/fueling_rocket.py
index 4477684..31a7384 100644
--- a/rocket_twin/drivers/fueling_rocket.py
+++ b/rocket_twin/drivers/fueling_rocket.py
@@ -35,6 +35,7 @@ def __init__(self, name: str, w_out, dt, owner: Optional["System"] = None, **kwa
         init = {
             "rocket.dyn.switch": False,
             "rocket.tank.w_out_temp": 0.0,
+            "pipe.is_open" : True,
             "g_tank.w_in": 0.0,
             "g_tank.w_out_temp": w_out,
         }
diff --git a/rocket_twin/drivers/vertical_flying_rocket.py b/rocket_twin/drivers/vertical_flying_rocket.py
index 9976904..dee72f2 100644
--- a/rocket_twin/drivers/vertical_flying_rocket.py
+++ b/rocket_twin/drivers/vertical_flying_rocket.py
@@ -35,7 +35,7 @@ def __init__(self, name: str, w_out, dt, owner: Optional["System"] = None, **kwa
         init = {
             "rocket.dyn.switch": True,
             "g_tank.w_in": 0.0,
-            "g_tank.w_out_temp": 0.0,
+            "pipe.is_open": False,
             "rocket.tank.w_out_temp": w_out,
         }