Actually they are quite stable, i,ve built a lynx with leds and rotors and that is about 3/4 the size, just need to think about where to run the wire and nowadays leds flash, so no little 555 circuit boards to fit as well, motors can be those used in mobile phone vibrators - tricky bit is removing the counterbalance weight without destroying the motor windings, even did a seahawk and then blew the motor - bah humbug