Boeing has patented a system for recharging drones in the air, overcoming a long-recognised roadblock in drone development. But there’s a catch: the system only works with airships and other buoyant UAVs, raising the possibility that they could become the dominant drone technology.

The recharging concept described in the patent involves connecting the drone to a power source on the ground, a vehicle or a building via a tether, which recharges the UAV while it floats in mid-air. Airships and other buoyant drones can float in this way without the need for power, allowing them to be recharged fully before continuing their journey.

The development could be highly significant, enabling drones to be used for long-distance work such as cargo deliveries or climate monitoring, and for all-day use such as filming and local food delivery.

If the technology is able to be developed for commercial use, it could mark a shift in drone use away from the wildly common quadcopter design, and towards what the patent describes as “electrically powered buoyant aircraft”.

The system works by feeding a ground-based power supply to the drone via a tether, which itself consists of “an electrical bus; a communication bus; and a fluid passage tube”. The drone would either come equipped with this and unreel it to a connection point on a tower, or fly up to a floating version and connect to it in the air, stopping it from needing to return to the ground to power up.

At the top of the tether is a ball that connects to a latch mechanism on the drone. This feeds power to the drone until it is fully charged, when the drone’s control mechanism automatically disconnects and continues its flight.

The patent offers a range of possibilities for the location and features of the tether, including fixing it to a buoyant balloon so it could float while bearing the weight of a lot of cable, thus enabling docking at a relatively high altitude.

Among the other suggestions is the proposal to connect it to a moving vehicle or a ship, allowing charging on-the-go or as part of a surveillance system.

It is unclear as to how much work Boeing has done to make this system a reality, but with powering drones being such a hot topic at present, it is likely that they are at least experimenting with the proposal.

Drones are poised to become a key technology in everything from surveillance to surveying and delivery to detection, but limited power supplies are a definite limiting factor.

If airship-style drones are able to resolve this problem first, they could well move from being a fringe technology to being the dominant version, particularly for certain applications such as long-term surveying and surveillance.

And given there have already been some efforts to bring back airships for cargo purposes, this technology could help to return us to a world where airships are a familiar and frequent sight.

Of course, attempts will no-doubt be made to make similar systems work for quadcopters and fixed wing designs, but if airship drones have a head start, they may establish themselves before their rivals can get going.

Featured image: StratoBus, an airship drone designed for stratospheric monitoring and telecommunications. Image courtesy of Thales.