This is my smallest model up to now (2010). The rotordiameter is 6 cm, the
weight 130 mg. It flies only 15 seconds in my livingroom, but in an 8 metre high
hall it climbs to the ceiling and the duration is much longer.
The model is
based on Thedo André's Simpelcopter
and the extremely small matchbox models
on the site "Twin Pushers and Other Free Flight Oddities".
This is not a model to build if you don't know how to get extremely thin
rubber....