Military Drone Engines

Many military drones use engines in order to overcome the inherent limitations of batteries, particularly with regards to payload capacity, flight ranges and mission endurances.

While engines and fuel provide a greater power-to-weight ratio than batteries, they also require a greater carrying capacity. Military drones that utilize engines thus tend to be larger fixed-wing and multirotor platforms, as well as helicopter UAVs (unmanned aerial vehicles).

Diesel & Heavy-Fuel Military Engines

SP-275 TS CR 2-Stroke Engine for Military Target Drones

Diesel and heavy fuels are more common for military drones, unlike the civilian sector where many UAV engines run on gasoline. This is largely due to the desire of armed forces to simplify supply and logistics efforts as much as possible by utilizing a single fuel for all vehicles and equipment.

Propulsion Technology

Military drone engines may utilize a number of different propulsion technologies. Internal combustion engine types include piston-driven and rotary Wankel engines. While piston-driven engines are simpler and easier to maintain, Wankel rotary engines are quieter and produce fewer vibrations, giving them an advantage in applications such as ISR (intelligence, surveillance and reconnaissance) that utilize sensitive payloads and sensors.

DA70 70cc EFI UAV Engine for Military Applications by Innoflight Technology

Military UAVs may also utilize turbine engines, which ignite a mixture of air and fuel and use the resulting stream of gas to propel the aircraft. These engines deliver an excellent power-to-weight ratio, allowing drones to carry greater payloads, fly further, and stay in the air longer. They also provide greater responsiveness and maneuverability, as well as better performance at high altitudes. However, they are large and noisy, and their complex designs require them to undergo more complicated maintenance.

Ruggedization of Military Drone Engines

Due to the demanding conditions found in battlefield environments, military drones engines may have to be ruggedized against a wide range of environmental stressors. These include high and low temperatures, sand and dust, moisture and humidity, electromagnetic interference (EMI), salt spray, and ice. They may also require ballistic protection in order to withstand gunfire and shrapnel.