My friend sent me a link today, and it is the Draganfly UAV. There are two types of UAV they have, and the helicopter one (X6) is really amazing. After viewing some of its videos, I can only say ``Wow...''
The X6 has different configuration from the R/C type which has four arms and blades. The three sets of counter-rotating blades of X6 should improve its aerodynamic performance, and also saves the energy from wasting on anti-torque.
Here are some videos of Draganflyer X6. Hope you enjoy with it.