diff --git a/libraries/AC_AttitudeControl/AC_CommandModel.cpp b/libraries/AC_AttitudeControl/AC_CommandModel.cpp
index fd96adf048..103a2b447b 100644
--- a/libraries/AC_AttitudeControl/AC_CommandModel.cpp
+++ b/libraries/AC_AttitudeControl/AC_CommandModel.cpp
@@ -38,3 +38,12 @@ const AP_Param::GroupInfo AC_CommandModel::var_info[] = {
     AP_GROUPEND
 };
 
+// Constructor
+AC_CommandModel::AC_CommandModel(float initial_rate, float initial_expo, float initial_tc)
+{
+    AP_Param::setup_object_defaults(this, var_info);
+    rate = initial_rate;
+    expo = initial_expo;
+    rate_tc = initial_tc;
+}
+
diff --git a/libraries/AC_AttitudeControl/AC_CommandModel.h b/libraries/AC_AttitudeControl/AC_CommandModel.h
index 747be50c34..83e6e17e03 100644
--- a/libraries/AC_AttitudeControl/AC_CommandModel.h
+++ b/libraries/AC_AttitudeControl/AC_CommandModel.h
@@ -11,10 +11,7 @@
 
 class AC_CommandModel {
 public:
-    AC_CommandModel(void)
-        {
-            AP_Param::setup_object_defaults(this, var_info);
-        }
+    AC_CommandModel(float initial_rate, float initial_expo, float initial_tc);
 
     // Accessors for parameters
     float get_rate_tc() { return rate_tc; }