diff --git a/libraries/SITL/SIM_Aircraft.h b/libraries/SITL/SIM_Aircraft.h
index 5a1339bb3d..d22f550a6c 100644
--- a/libraries/SITL/SIM_Aircraft.h
+++ b/libraries/SITL/SIM_Aircraft.h
@@ -72,6 +72,9 @@ public:
     /* fill a sitl_fdm structure from the simulator state */
     void fill_fdm(struct sitl_fdm &fdm) const;
 
+    // get frame rate of model in Hz
+    float get_rate_hz(void) const { return rate_hz; }       
+    
 protected:
     Location home;
     Location location;
diff --git a/libraries/SITL/SITL.cpp b/libraries/SITL/SITL.cpp
index ee20ca2771..b38ed9a5e1 100644
--- a/libraries/SITL/SITL.cpp
+++ b/libraries/SITL/SITL.cpp
@@ -23,6 +23,7 @@
 #include <AP_Common/AP_Common.h>
 #include <AP_HAL/AP_HAL.h>
 #include <GCS_MAVLink/GCS_MAVLink.h>
+#include <DataFlash/DataFlash.h>
 
 extern const AP_HAL::HAL& hal;
 
@@ -104,7 +105,7 @@ void SITL::simstate_send(mavlink_channel_t chan)
 }
 
 /* report SITL state to DataFlash */
-void SITL::Log_Write_SIMSTATE(DataFlash_Class &DataFlash)
+void SITL::Log_Write_SIMSTATE(DataFlash_Class *DataFlash)
 {
     float yaw;
 
@@ -124,7 +125,7 @@ void SITL::Log_Write_SIMSTATE(DataFlash_Class &DataFlash)
         lat     : (int32_t)(state.latitude*1.0e7),
         lng     : (int32_t)(state.longitude*1.0e7)
     };
-    DataFlash.WriteBlock(&pkt, sizeof(pkt));
+    DataFlash->WriteBlock(&pkt, sizeof(pkt));
 }
 
 /*
diff --git a/libraries/SITL/SITL.h b/libraries/SITL/SITL.h
index 85e0925176..4cf492740f 100644
--- a/libraries/SITL/SITL.h
+++ b/libraries/SITL/SITL.h
@@ -2,9 +2,10 @@
 
 #pragma once
 
-#include <DataFlash/DataFlash.h>
 #include <GCS_MAVLink/GCS_MAVLink.h>
 
+class DataFlash_Class;
+
 namespace SITL {
 
 struct PACKED sitl_fdm {
@@ -26,7 +27,6 @@ struct PACKED sitl_fdm {
 // number of rc output channels
 #define SITL_NUM_CHANNELS 14
 
-
 class SITL {
 public:
 
@@ -49,6 +49,12 @@ public:
 
     struct sitl_fdm state;
 
+    // loop update rate in Hz
+    uint16_t update_rate_hz;
+
+    // true when motors are active
+    bool motors_on;
+
     static const struct AP_Param::GroupInfo var_info[];
 
     // noise levels for simulated sensors
@@ -105,7 +111,7 @@ public:
 
     void simstate_send(mavlink_channel_t chan);
 
-    void Log_Write_SIMSTATE(DataFlash_Class &dataflash);
+    void Log_Write_SIMSTATE(DataFlash_Class *dataflash);
 
     // convert a set of roll rates from earth frame to body frame
     static void convert_body_frame(double rollDeg, double pitchDeg,