Set gears that go off map to gmDestroy instead of collision, disable morewind for no-gravity gears, restrict application of wind to gears that are already moving and not colliding.

#include <QtGui/QApplication>
#include "mainwindow.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    return a.exec();
}