Micro air vehicles (MAVs) are small, unmanned flying machines designed primarily to act as autonomous observers, and occasionally to carry small payloads. They come in many shapes, sizes, and designs, from tiny airplanes to gas-powered miniature helicopters.
CRG has developed its own MAV, called HALO™, a ten-inch diameter circular vehicle using a ducted fan system for lift and propulsion and rechargeable lithium polymer batteries for power. A ducted fan is a propulsion arrangement whereby a type of propeller system is mounted within a cylindrical shroud or duct. The duct reduces losses in thrust from the tip vortices of the fan, and varying the cross-section of the duct allows the designer to advantageously affect the velocity and pressure of the airflow according to Bernoulli's Principle. Ducted fan propulsion is used in aircraft, airboats and hovercraft. Ducted fans are favored for use in vertical take-off and landing (VTOL) aircraft for their higher thrust-to-weight ratio.
CRG's HALO (which stands for Hovering Autonomous Low-profile Observer) is intended to be a disruptive technology in the increasingly high-demand MAV industry. The HALO MAV is small, lightweight, and quiet compared with other MAVs with similar capabilities, making it ideal for covert operations and other applications where a low profile is desirable. It is also relatively inexpensive to produce, allowing for mass production and making individual units expendable.
MAVs are suitable for a wide variety of military and civil applications, including perimeter security, reconnaissance, search and rescue, and effects delivery. If manufactured inexpensively, their expendability makes them ideal for hazardous jobs, from reconnaissance in hot military zones to inspection of damaged power lines. Their small size makes them portable enough to fit in a backpack or to be deployed in large numbers from an aircraft.
Future goals in MAV development include replacing radio-controlled flight systems with fully autonomous autopilot systems, sophisticated controls such as voice and gesture recognition to allow an operator to "command" a vehicle in flight, structural batteries to increase the vehicle's payload and endurance and further reduce its weight, and scaled-up production to reduce unit cost and provide for large operations requiring hundreds or even thousands of units.
The video below shows a remote-controlled HALO MAV unit in action.
Micro air vehicles (MAVs) are small, unmanned flying machines designed primarily to act as autonomous observers, and occasionally to carry small payloads. They come in many shapes, sizes, and designs, from tiny airplanes to gas-powered miniature helicopters. 
