diff --git a/extern/osgQt/GraphicsWindowQt b/extern/osgQt/GraphicsWindowQt
index 3be1da0515..1e34fc9db6 100644
--- a/extern/osgQt/GraphicsWindowQt
+++ b/extern/osgQt/GraphicsWindowQt
@@ -37,16 +37,6 @@ namespace osgQt
 // forward declarations
 class GraphicsWindowQt;
 
-/** The function sets the viewer that will be used after entering
- *  the Qt main loop (QCoreApplication::exec()).
- *
- *  The function also initializes internal structures required for proper
- *  scene rendering.
- *
- *  The method must be called from main thread. */
-void setViewer( osgViewer::ViewerBase *viewer );
-
-
 class GLWidget : public QGLWidget
 {
     typedef QGLWidget inherited;
diff --git a/extern/osgQt/GraphicsWindowQt.cpp b/extern/osgQt/GraphicsWindowQt.cpp
index 17150bed4b..9e5f6e55ea 100644
--- a/extern/osgQt/GraphicsWindowQt.cpp
+++ b/extern/osgQt/GraphicsWindowQt.cpp
@@ -26,28 +26,6 @@
 
 using namespace osgQt;
 
-/// The object responsible for the scene re-rendering.
-class HeartBeat : public QObject {
-public:
-    int _timerId;
-    osg::Timer _lastFrameStartTime;
-    osg::observer_ptr< osgViewer::ViewerBase > _viewer;
-
-    virtual ~HeartBeat();
-
-    void init( osgViewer::ViewerBase *viewer );
-    void stopTimer();
-    void timerEvent( QTimerEvent *event );
-
-    static HeartBeat* instance();
-private:
-    HeartBeat();
-
-    static QPointer<HeartBeat> heartBeat;
-};
-
-QPointer<HeartBeat> HeartBeat::heartBeat;
-
 #if (QT_VERSION < QT_VERSION_CHECK(5, 2, 0))
     #define GETDEVICEPIXELRATIO() 1.0
 #else
@@ -637,104 +615,3 @@ private:
     QtWindowingSystem& operator=( const QtWindowingSystem& );
 };
 
-
-void osgQt::setViewer( osgViewer::ViewerBase *viewer )
-{
-    HeartBeat::instance()->init( viewer );
-}
-
-
-/// Constructor. Must be called from main thread.
-HeartBeat::HeartBeat() : _timerId( 0 )
-{
-}
-
-
-/// Destructor. Must be called from main thread.
-HeartBeat::~HeartBeat()
-{
-    stopTimer();
-}
-
-HeartBeat* HeartBeat::instance()
-{
-    if (!heartBeat)
-    {
-        heartBeat = new HeartBeat();
-    }
-    return heartBeat;
-}
-
-void HeartBeat::stopTimer()
-{
-    if ( _timerId != 0 )
-    {
-        killTimer( _timerId );
-        _timerId = 0;
-    }
-}
-
-
-/// Initializes the loop for viewer. Must be called from main thread.
-void HeartBeat::init( osgViewer::ViewerBase *viewer )
-{
-    if( _viewer == viewer )
-        return;
-
-    stopTimer();
-
-    _viewer = viewer;
-
-    if( viewer )
-    {
-        _timerId = startTimer( 0 );
-        _lastFrameStartTime.setStartTick( 0 );
-    }
-}
-
-
-void HeartBeat::timerEvent( QTimerEvent * /*event*/ )
-{
-    osg::ref_ptr< osgViewer::ViewerBase > viewer;
-    if( !_viewer.lock( viewer ) )
-    {
-        // viewer has been deleted -> stop timer
-        stopTimer();
-        return;
-    }
-
-    // limit the frame rate
-    if( viewer->getRunMaxFrameRate() > 0.0)
-    {
-        double dt = _lastFrameStartTime.time_s();
-        double minFrameTime = 1.0 / viewer->getRunMaxFrameRate();
-        if (dt < minFrameTime)
-            OpenThreads::Thread::microSleep(static_cast<unsigned int>(1000000.0*(minFrameTime-dt)));
-    }
-    else
-    {
-        // avoid excessive CPU loading when no frame is required in ON_DEMAND mode
-        if( viewer->getRunFrameScheme() == osgViewer::ViewerBase::ON_DEMAND )
-        {
-            double dt = _lastFrameStartTime.time_s();
-            if (dt < 0.01)
-                OpenThreads::Thread::microSleep(static_cast<unsigned int>(1000000.0*(0.01-dt)));
-        }
-
-        // record start frame time
-        _lastFrameStartTime.setStartTick();
-
-        // make frame
-        if( viewer->getRunFrameScheme() == osgViewer::ViewerBase::ON_DEMAND )
-        {
-            if( viewer->checkNeedToDoFrame() )
-            {
-                viewer->frame();
-            }
-        }
-        else
-        {
-            viewer->frame();
-        }
-    }
-}