VIDEO: Unmanned Vertical Takeoff and Landing aircraft takes flight 12/19/2013 - 00:00 The AirMule, an unmanned VTOL (Vertical Takeoff and Landing) aircraft developed by Tactical Robotics Ltd., a subsidiary of Urban Aeronautics, Ltd., has successfully completed a major milestone in preparation for full mission demonstrations scheduled for next year. The aircraft has completed several fully automatic test flights in which it carried out take-offs, flights to and from a specified location and landing back at its point of origination.The 1-ton vehicle is unique from all existing vertical take-off and landing aircraft in that it has no exposed rotors. This allows the aircraft to fly in air space that is off limits for any other aircraft.During these tests height above ground is maintained by two laser altimeters (to be augmented soon by a radar altimeter for dusty conditions). Accurate position is maintained through data fusion of GPS signals, INS data and optical reference to markers on the ground.Acoustic signature (Sound Pressure Level in dBA) has been recorded as a function of distance from the aircraft to a calibrated microphone and has been found to be significantly lower than an equivalent helicopter.Additional flight testing is planned for next year with a second prototype, now in construction, planned to join the flight test program in the second half of 2014.