diff --git a/Makefile b/Makefile
index da30e7fd1..cb91bfaf5 100644
--- a/Makefile
+++ b/Makefile
@@ -270,12 +270,12 @@ pipxtreme_%: uavobjects_flight
 sim_posix: sim_posix_elf
 
 sim_posix_%: uavobjects_flight
-	mkdir -p $(BUILD_DIR)/simulation
-	$(MAKE) OUTDIR="$(BUILD_DIR)/simulation" -C $(ROOT_DIR)/flight/OpenPilot --file=$(ROOT_DIR)/flight/OpenPilot/Makefile.posix $*
+	mkdir -p $(BUILD_DIR)/flight/sitl_posix
+	$(MAKE) -C $(ROOT_DIR)/flight/OpenPilot --file=$(ROOT_DIR)/flight/OpenPilot/Makefile.posix $*
 
 .PHONY: sim_win32
 sim_win32: sim_win32_exe
 
 sim_win32_%: uavobjects_flight
-	mkdir -p $(BUILD_DIR)/simulation
-	$(MAKE) OUTDIR="$(BUILD_DIR)/simulation" -C $(ROOT_DIR)/flight/OpenPilot --file=$(ROOT_DIR)/flight/OpenPilot/Makefile.win32 $*
+	mkdir -p $(BUILD_DIR)/flight/sitl_win32
+	$(MAKE) -C $(ROOT_DIR)/flight/OpenPilot --file=$(ROOT_DIR)/flight/OpenPilot/Makefile.win32 $*
diff --git a/flight/OpenPilot/Makefile.posix b/flight/OpenPilot/Makefile.posix
index 8c21cd895..397853ac7 100644
--- a/flight/OpenPilot/Makefile.posix
+++ b/flight/OpenPilot/Makefile.posix
@@ -77,7 +77,7 @@ BOOT_MODEL    = $(MODEL)_NB
 endif
 
 # Directory for output files (lst, obj, dep, elf, sym, map, hex, bin etc.)
-OUTDIR = Build.posix
+OUTDIR = ../../build/flight/sitl_posix
 
 # Target file name (without extension).
 TARGET = OpenPilot
diff --git a/flight/OpenPilot/Makefile.win32 b/flight/OpenPilot/Makefile.win32
index c018bd92f..101be1bba 100644
--- a/flight/OpenPilot/Makefile.win32
+++ b/flight/OpenPilot/Makefile.win32
@@ -76,7 +76,7 @@ MODEL    = HD_NB
 endif
 
 # Directory for output files (lst, obj, dep, elf, sym, map, hex, bin etc.)
-OUTDIR = Build.win32
+OUTDIR = ../../build/flight/sitl_win32
 
 # Target file name (without extension).
 TARGET = OpenPilot
@@ -117,6 +117,15 @@ FLIGHTPLANS = $(OPMODULEDIR)/FlightPlan/flightplans
 MODNAMES = $(notdir ${MODULES})   
 
 ifndef TESTAPP
+
+## PyMite files
+SRC += $(OUTDIR)/pmlib_img.c
+SRC += $(OUTDIR)/pmlib_nat.c
+SRC += $(OUTDIR)/pmlibusr_img.c
+SRC += $(OUTDIR)/pmlibusr_nat.c
+SRC += $(wildcard ${PYMITEVM}/*.c)
+SRC += $(wildcard ${PYMITEPLAT}/*.c)
+
 ## MODULES
 SRC += ${foreach MOD, ${MODULES}, ${wildcard ${OPMODULEDIR}/${MOD}/*.c}}
 SRC += ${OUTDIR}/InitMods.c
@@ -203,15 +212,6 @@ SRC += $(RTOSSRCDIR)/tasks.c
 SRC += $(RTOSSRCDIR)/portable/GCC/Win32/port.c
 SRC += $(RTOSSRCDIR)/portable/MemMang/heap_3.c
 
-## PyMite files
-SRC += $(wildcard ${PYMITEVM}/*.c)
-SRC += $(wildcard ${PYMITEPLAT}/*.c)
-SRC += $(OUTDIR)/pmlib_img.c
-SRC += $(OUTDIR)/pmlib_nat.c
-SRC += $(OUTDIR)/pmlibusr_img.c
-SRC += $(OUTDIR)/pmlibusr_nat.c
-
-
 
 # List C source files here which must be compiled in ARM-Mode (no -mthumb).
 # use file-extension c for "c-only"-files