diff --git a/Tools/autotest/sim_vehicle.sh b/Tools/autotest/sim_vehicle.sh
index 4ac1418f81..d01595561d 100755
--- a/Tools/autotest/sim_vehicle.sh
+++ b/Tools/autotest/sim_vehicle.sh
@@ -27,6 +27,7 @@ MODEL=""
 BREAKPOINT=""
 OVERRIDE_BUILD_TARGET=""
 DELAY_START=0
+DEFAULTS_PATH=""
 
 usage()
 {
@@ -232,42 +233,55 @@ EOF
 }
 
 
+autotest="../Tools/autotest"
+[ -d "$autotest" ] || {
+    # we are not running from one of the standard vehicle directories. Use 
+    # the location of the sim_vehicle.sh script to find the path
+    autotest=$(dirname $(readlink -e $0))
+}
+
 # modify build target based on copter frame type
 case $FRAME in
     +|quad)
 	BUILD_TARGET="sitl"
         MODEL="+"
+        DEFAULTS_PATH="$autotest/copter_params.parm"
 	;;
     X)
 	BUILD_TARGET="sitl"
         EXTRA_PARM="param set FRAME 1;"
         MODEL="X"
+        DEFAULTS_PATH="$autotest/copter_params.parm"
 	;;
     octa*)
 	BUILD_TARGET="sitl-octa"
         MODEL="$FRAME"
+        DEFAULTS_PATH="$autotest/copter_params.parm"
 	;;
     heli*)
 	BUILD_TARGET="sitl-heli"
         MODEL="$FRAME"
+        DEFAULTS_PATH="$autotest/Helicopter.parm"
 	;;
     heli-dual)
-  BUILD_TARGET="sitl-heli-dual"
+        BUILD_TARGET="sitl-heli-dual"
         EXTRA_SIM="$EXTRA_SIM --frame=heli-dual"
         MODEL="heli-dual"
-  ;;
+        ;;
     heli-compound)
-  BUILD_TARGET="sitl-heli-compound"
+        BUILD_TARGET="sitl-heli-compound"
         EXTRA_SIM="$EXTRA_SIM --frame=heli-compound"
         MODEL="heli-compound"
-  ;;
+        ;;
     IrisRos)
 	BUILD_TARGET="sitl"
+        DEFAULTS_PATH="$autotest/copter_params.parm"
 	;;
     Gazebo)
 	BUILD_TARGET="sitl"
         EXTRA_SIM="$EXTRA_SIM --frame=Gazebo"
         MODEL="$FRAME"
+        DEFAULTS_PATH="$autotest/copter_params.parm"
 	;;
     CRRCSim|last_letter*)
 	BUILD_TARGET="sitl"
@@ -277,14 +291,17 @@ case $FRAME in
 	BUILD_TARGET="sitl"
         MODEL="$FRAME"
         check_jsbsim_version
+        DEFAULTS_PATH="$autotest/ArduPlane.parm"
 	;;
     quadplane*)
 	BUILD_TARGET="sitl"
         MODEL="$FRAME"
+        DEFAULTS_PATH="$autotest/quadplane.parm"
 	;;
     *-heli)
 	BUILD_TARGET="sitl-heli"
         MODEL="$FRAME"
+        DEFAULTS_PATH="$autotest/Helicopter.parm"
 	;;
     *)
         MODEL="$FRAME"
@@ -299,12 +316,6 @@ if [ -n "$OVERRIDE_BUILD_TARGET" ]; then
     BUILD_TARGET="$OVERRIDE_BUILD_TARGET"
 fi
 
-autotest="../Tools/autotest"
-[ -d "$autotest" ] || {
-    # we are not running from one of the standard vehicle directories. Use 
-    # the location of the sim_vehicle.sh script to find the path
-    autotest=$(dirname $(readlink -e $0))
-}
 VEHICLEDIR="$autotest/../../$VEHICLE"
 [ -d "$VEHICLEDIR" ] || {
     VEHICLEDIR=$(dirname $(readlink -e $VEHICLEDIR))
@@ -400,6 +411,11 @@ if [ $USE_MAVLINK_GIMBAL == 1 ]; then
     cmd="$cmd --gimbal"
 fi
 
+if [ -n "$DEFAULTS_PATH" ]; then
+    echo "Using defaults from $DEFAULTS_PATH"
+    cmd="$cmd --defaults $DEFAULTS_PATH"
+fi
+
 if [ $START_HIL == 0 ]; then
 if [ $USE_VALGRIND == 1 ]; then
     echo "Using valgrind"