diff --git a/CMakeLists.txt b/CMakeLists.txt
index 16281c215..50d2c1034 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -161,9 +161,9 @@ endif()
 option(SIMGEAR_SHARED    "Set to ON when SimGear was built as a shared library" OFF)
 option(LOGGING           "Set to ON to build FlightGear with logging support (default)" ON)
 option(JSBSIM_TERRAIN    "Set to ON to build FlightGear with JSBSim terrain handling code" ON)
-option(SP_FDMS           "Set to ON to build FlightGear with special-purpose FDMs" OFF)
-option(ENABLE_UIUC_MODEL "Set to ON to build FlightGear with UIUCModel FDM" OFF)
-option(ENABLE_LARCSIM    "Set to ON to build FlightGear with LaRCsim FDM" OFF)
+option(SP_FDMS           "Set to ON to build FlightGear with special-purpose FDMs" ON)
+option(ENABLE_UIUC_MODEL "Set to ON to build FlightGear with UIUCModel FDM" ON)
+option(ENABLE_LARCSIM    "Set to ON to build FlightGear with LaRCsim FDM" ON)
 option(ENABLE_YASIM      "Set to ON to build FlightGear with YASIM FDM (default)" ON)
 option(ENABLE_JSBSIM     "Set to ON to build FlightGear with JSBSim FDM (default)" ON)
 option(EVENT_INPUT       "Set to ON to build FlightGear with event-based Input support" ${EVENT_INPUT_DEFAULT})