The Aergility ATLIS unmanned aerial vehicle, according to Founder and CEO Jim Vander Mey, is designed to take off and land vertically using electrically powered rotors. Once airborne, a gas-powered engine will provide all forward thrust to push the ATLIS at speeds around 100 mph.
An email reply from Jim states “the powerplant we have tentatively selected is the Hirth 3502/3 – about 70 hp max.”
For cruise, Aergility uses the term “Managed Autorotation.” Jim notes “it is the key to the ATLIS VTOL UAV with its high payload efficiency and long range. Basically the aircraft is a combination multicopter for VTOL and gyrocopter for cruise.”
To be honest, Jim does a much better job explaining “managed autorotation” than I could ever hope to summarize, so I’ll let his email carry the conversation…
“The ATLIS has a small (2kWhr) buffer battery, a gas propulsion engine and eight electric motors directly driving eight fixed pitch propeller/rotors (protors) — that’s all. No generators, wings, flight control surfaces and servos, etc. And it is a very unconventional gyrocopter where the flight controller manages the aircraft net electrical energy by controlling the RPMs of the eight fixed pitch protors to control aircraft pitch so that they generally dither about autorotation. Flight control is accomplished by driving more energy into some protors to increase RPM while regeneratively braking others to slow RPM. And for a short period of time of the initial flight portion, the flight controller adds a little extra aircraft pitch up and slightly more regenerative braking to replenish battery energy used during takeoff. So in effect, there is no net electrical energy consumed over the course of the flight, with the battery necessary only to buffer power for VTOL/flight control operations and provide for emergency multicopter operation in the case of propulsion engine failure. So power comes from the propulsion engine, including the extra power needed for additional protor ‘drag’ producing the regenerative braking. (Not defying the Second Law of Thermodynamics here!)”
The 800-pound gross weight autonomous UAV is designed to carry a 400-pound payload 200 miles. Construction of a full-scale ATLIS is planned to start summer of 2018 and take one year to complete, Jim reports.