While they’ve been around for years, drone technology is still relatively new to the general public, and isn’t close to being perfected. Drones aren’t unfamiliar to people working in the technology or engineering fields, and are revolutionizing how several functions in many different industries are performed – delivering goods, large-scale surveillance, and capturing cinematic overhead footage for movies, commercials, and other media platforms.
Being that these crafts are still in their developmental infancy, one of their design flaws is a drone’s airtime per charge. While current models available to the public typically don’t last more than 20 or 30 minutes per charge, researchers around the world are looking to prolong drone flight times indefinitely. In recent months, two potent methods have been successfully tested in order to achieve this goal that some hope will eventually eliminate the need for wired tethers and manually recharging drones out of the air: solar energy and a technology called wireless energy transfer.
Solar-powered drones have been tested on winged models instead of quadcopters. Companies like Facebook and Google are utilizing solar energy to power their drones, and made considerable progress. Almost one year after announcing it was developing an unmanned airplane to provide internet access to remote locations within a 60-mile diameter, Facebook’s Aquila completed its first test flight this past summer. Aquila is a 140-foot driverless aircraft powered by solar cells, whose inaugural flight lasted 96 minutes. While Aquila only reached a maximal altitude of 2,150 feet, Facebook hopes these planes can fly continuously for months at altitudes of 60,000-90,000 feet.
Google started its own solar-powered drone project (codenamed SkyBender) with similar aims of providing internet to people in remote locations. Conducting their research at an airfield in New Mexico, Google’s drone fleet is experimenting with millimeter-wave radio transmissions that in theory could transmit gigabits of data every second at a rate 40 times more than 4G LTE systems.
One comprehensive and underdeveloped method used in prolonging a drone’s airtime is the technological process called wireless energy transfer (WET). Unlike solar-powered drones, WET technology ultimately eliminates a drone’s need for a battery, which makes the aircraft lighter, requiring using less energy to use when they’re operated. Scientists at Imperial College London are developing a process where they’ve removed batteries from drones, alter the device’s electronics, and add a copper coil to its body that acts as a receiver. Using a transmitting platform comprised from a circuit board, power source, and its own copper coil, the device produces a magnetic field and an alternate electric current. The drone’s modified electronics then convert the electric current its receiver picks up from the transmitter, which thus powers the craft during flight.
This particular process isn’t new to science, and is a concept known as inductive coupling that’s been around since the days of Nicola Tesla. The tests ran by Imperial College were the first confirmed instances where inductive coupling has been used to power a flying vehicle. While these findings in WET technology are noteworthy, the process only works if the drone is within four inches of the transmitter, and won’t charge the craft if it moves any further. This innovative concept has inspired companies like Amazon to start new projects aimed at constructing a network of docking stations on cell towers and other tall structures that drones could use to recharge and exchange navigational information. Another company called Global Energy Transmissions also developed a power cord to wrap around buildings that could use WET to recharge passing drones equipped with wireless charging receivers.
