Flowcopter begins flight testing of the world’s first hydraulically powered unmanned aerial vehicle.

Edinburgh-based startup Flowcopter has created cargo unmanned aerial vehicles. They run on certified internal combustion engines. Displacement pumps put them into operation – they distribute and regulate the hydraulic flow to balance the drone in flight.

Multicopters can lift heavy loads and stay in the air longer if they use a high-density power source such as gasoline instead of low-density lithium batteries. But the recoil of gasoline engines is not fast enough to keep the multicopter in balance.

So the engineers decided to use electric motors and internal combustion engines together. At the same time, the gas engine provides a more or less constant torque, and the electric motors turn on when speed control is required.

The power of each hydraulic motor is approximately 96 kW (129 hp) and weighs only 5.5 kg. Combustion engine and digital displacement pump provide near instantaneous torque control, massive power and exceptional range

The weight of the pump and motor make up a significant portion of its design, but gasoline provides enough usable power that the benefits outweigh the drawbacks. The company notes that the design can work continuously for up to 6 hours and fly over a distance of up to 900 km.

The payload will be up to 150 kg for shorter missions.