World’s First Hydraulic Drone Promises Six-Hour Flight Times

Leveraging a new type of hydraulic pump, Flowcopter claims that it has created a large drone that is significantly lighter, more robust, lower in cost, and capable of greater range than any other in its segment on the market.

The Problems Facing Long-Range Drones

The Flowcopter drone doesn’t use batteries and electric motors like are found in basically every other drone on the market, but instead uses pumps and gas engines to deliver what it promises to be a range of hundreds of miles and flight times that can extend up to six hours, Gizmodo reports.

Most drones, even those used for long-distance or transport purposes, use either fully electric rotors or some kind of hybrid gas propeller and electric lift system. The benefit of electric motors is that they are a lot easier to control precisely as the ability to adjust the rotation speed of each rotor is extremely important in order to retain controlled flight. This isn’t a big deal for objects that just need to provide thrust in a single direction, Gizmodo explains, but is increasingly important for objects like drones with four, six, or eight propellers that need to be regularly adjusted to compensate for wind, direction, and gravity.


The downside, at least for now, is that electric motors rely on batteries that don’t have the power to last for very long on their own. While the goal is to eventually move to fully electric, current technological boundaries mean that relying on fossil fuels for long-range flights is still the reality. While some companies use fossil fuels like gasoline to power electric motors, Flowcopter is trying an entirely new strategy that leverages hydraulics.

The World’s First Hydraulic Drone

The drone uses hydraulic motors that are powered by a continuous flow of hydraulic fluid pushed through hoses to make the blades spin. The company is using a new type of hydraulic pump called the Digital Displacement Pump. It claims it is highly efficient, features high bandwidth control of four independent motors that allow it to adjust for altitude, is robust enough to handle harsh environments, and has a better power to weight ratio than the equivalent “best in class” electric motors.

The hydraulic pump is powered by a liquid fuel “light-aircraft certified engine” that Flowcopter says has 20 times the energy to weight ratio of the best battery technology that currently exists. That engine along with the Digital Displacement Pump can control the flow of hydraulic fluid with enough precision to provide stable lift while also dramatically improving flight times. Each hydraulic motor can provide 129 horsepower but weigh less than 12 pounds.

Flowcopter Diagram

12 pounds on four rotors plus the weight of the engine and the frame doesn’t make for a light aircraft, but Flowcopter says that it’s lighter than the equivalent lithium battery requirements and dramatically increases the range of the drone. Flowcopter says that its hydraulic drone can stay in the air without refueling for up to six hours and cross distances of up to 900 kilometers (about 560 miles) with a payload of up to 330 pounds.

The company says the drone isn’t always going to have its propellers spinning in those six hours and will somehow switch to a non-powered gliding flight mode like a traditional winged aircraft, but that likely would require a different design than the one shown in the few demonstrations videos on Flowcopter’s website.

Whatever the case, the drone’s main purpose would be short-range autonomous delivery, but there isn’t any reason why it also could not be used to survey large portions of land if it were equipped with a camera system, which could be very robust given the weight the drone is capable of carrying.