A U.S. startup developing a single-person hybrid-electric multicopter is looking at potential military applications as a logistic or soldier transport.
ElectraFly has signed a memorandum of understanding to fly its aircraft at the Deseret unmanned aircraft system (UAS) test site in Utah in early 2019.
Founder John Manning says ElectraFly was formed to tackle the range and payload limitations of multirotor air vehicles. The startup’s goal is to develop a hybrid-electric personal flying vehicle, but the initial application is expected to be in unmanned package delivery, he says.
Compared with a conventional quadrotor, the design has some key differences. To overcome the low energy density of batteries, which limits the payload and range of multicopters, the vehicle has a turbine engine that tilts down to produce thrust in vertical flight and back for forward flight.
In a 75-lb. aircraft, the turbojet produces 50 lb. of thrust near the center of gravity. This reduces the lift required from the rotors for vertical takeoff to 30 lb., Manning says. In the initial aircraft, the electric system is independent from the turbine, but the turbine could be used to generate electricity.
A multicopter drone hovers with its rotors in the same horizontal plane, and tilts nose-down to fly forward. This results in reduced lift and increased drag, Manning says. The ElectraFlyer hovers nose high, and flies forward with the rotors horizontal, which reduces drag, the turbine providing thrust.
The ElectraFlyer also features pitchable wings on the four arms carrying the rotors. These wings pivot aerodynamically to produce lift in forward flight—more efficiently than the rotors—but pitch up into the rotor downwash in the hover to minimize the downforce, avoiding the penalty of fixed wings.
So far self-funded, ElectraFlyer has conducted tethered hover flights and teamed with Deseret UAS to conduct forward flights over an FAA-sanctioned test area, Manning says. The vehicle is sized to carry a single person in a motorcycle-style riding position, with two joysticks for control.
The vehicle is basic: the turbine is mounted under the seat and the rotors are just above the rider’s head height when seated. There is no cabin or cargo area, at least initially. “We built something with a minimum feature set because we need to do the best with what we have,” he says.
ElectraFlyer is looking at the ultralight or experimental category as a route to commercialization, but is also talking to the military about logistics, soldier or casualty transport. “We want to show this is something an everyday soldier can use, with no skill required,” Manning says.