Electric Sky to Test Long-Distance Power Transmission for UAVs
Schematic of a typical laser power beaming technique. (Image: LaserMotive)
DARPA persists in funding research into extending the power range and mission endurance of UAVs.
Electric Sky is building a Whisper Beam transmitter to power UAV swarms wirelessly in flight, using Small Business Innovation Research funds from DARPA.
The Seattle-based SME will build and test a laboratory bench demonstrator at short distances. These experiments will supply data needed to upgrade the self-focusing beam with higher power for longer distances, and then adapt the transmitter to follow UAVs across the sky.
Wireless power tends to use lasers or microwaves, which start strong but weaken as they travel. In contrast, Whisper Beam technology starts weak and gathers strength the closer it gets to the receiver.
DARPA has been exploring wireless power transmission with UAV platforms for some time: in mid-2018, for instance, it selected the solar electric-powered Silent Falcon small UAS for its Stand-off Ubiquitous Power/Energy Replenishment – Power Beaming Demonstration (SUPER PBD).
The main aim of the project was to enable remote electric refuelling in small aircraft via high-intensity laser power beaming.
Whisper Beam technology self-focuses radio waves at the receiver, enabling the UAV to draw kilowatts of power in all weather. For military UAVs on combat operations, this could increase the mission operation time in contested and remote areas.
Whisper-Beam inventor Jeff Greason said: ‘It’s a myth that long-distance power transmission is impossible, it’s just never been economical. This new method reduces the cost of the ground transmitter and the size of the vehicle’s onboard receiver.’
Greason added: ‘Any type of electric aircraft can draw power while in flight – battery-electric, hydrogen fuel cell, and hybrid. Whisper Beam technology is particularly helpful in the power-hungry phases of takeoff and climb, enabling vehicle designers to meet other requirements to extend range, enhance flight safety, reduce peak loads on batteries, and shorten ground turnaround times.’