THE WHOLE IDEA behind drones is that they fly free. Unattached to the traffic-clogged, obstacle-riddled surface, they promise to change the way we move our stuff and even ourselves. So it’s strange to hear that one startup thinks the best way to fly drones is by tying them to the ground.
In that tether, CyPhy Works sees a different sort of liberty: freedom from short-lived batteries. The typical commercial drone can stay aloft for 20 to 30 minutes. “With the tether, we’re able to fly continuous operations for two weeks at a time without coming down,” says Laura Major, CTO of the Danvers, Massachusetts based startup. It only touched down after the fortnight because the ground power went out.
That kind of flight time may not matter when hauling burritos, but it can make drones significantly more useful for the military and first responders likely to use drones as “instant towers.” They want aircraft that can hover over a given spot, providing them a birds-eye view or relaying radio and cell signals. The longer they can stay airborne, the better. And as a bonus, that tether can double as a transmission line, moving data from the sky to the ground without relying on a wireless signal.
CyPhy designed its drone for long-term flight, with motors and circuitry that don’t burn out easily, and which are packaged to avoid overheating, which happens when components are crammed too closely together. A small battery on board can manage a safe landing if a sharp-billed goose slices the microfilament tether. It can also give the motors an extra boost of power if they need to resist a gust of wind. The drone, about four feet across with six spinning rotors, can fly at up to 400 feet, per FAA regulations. It can carry a camera that has a 30X optical zoom, good for vision for five to 10 miles, depending on conditions. Operators can swap that out for any payload up to six pounds, and the company has done tests of cell repeaters with Sprint.
One big potential application for persistent, tethered drone technology is getting communications up and running in areas hit by natural disasters like hurricanes. (The FCC slammed Verizon after Hurricane Michael in Florida in last month, saying it didn’t restore service fast enough.) It’s the same thing Alphabet’s Project Loon wants to do with balloons touring the stratosphere, and that Facebook unsuccessfully explored with massive winged drones.
Other companies, like Elistair and Hoverfly, offer small tethered drones-in-a-box solutions, for everything from filming sporting events to monitoring traffic. At the much larger end of the scale, Startup Karman Electric wants to use ground-based power lines to run people-filled flying taxis.
CyPhy’s system, Major says, can be set up in just 10 minutes and comes in two suitcase-sized ground units. One contains all the electronics and needs a power supply (you can plug it in, or hook it to a generator if you’re off the grid). The other is the spooler, the computer-controlled winch that reels the tether in and out. The idea is to keep it just taut enough that there’s no extra cable flapping around or weighing the drone down, but not so short that it actually tugs on the drone putting extra tension on the line.