 The research led to mesicopter rotor designs where the rotor looked much more like the blades of an ordinary room fan than the rotor of a conventional helicopter.Propeller designs did not achieve desired efficiency and the Mesicopter was never able to lift the weight of its own energy source.The DARPA MAV effort ended in 2000 and the results of the effort were somewhat negative, demonstrating that a 15 centimeter UAV was simply too small to be useful or even workable, at least over the short run.