Petroleum / Gasoline UAV Engines

Petroleum, or gasoline, is a common fuel used for UAV (unmanned aerial vehicle) engines. It provides a greater energy density than batteries, allowing gasoline-powered drones to fly further and longer without needing to land, and also enables the transportation of heavier payloads. However, as the weight of an engine plus fuel is greater than most batteries, drones need to be above a certain size in order for gasoline to be a viable power source.

SP-55 FI TS ROS 1-Cylinder Gas Engine by Sky Power International

Advantages & Disadvantages of UAV Gas Engines

Gasoline has a lower flash point than heavy fuels such as jet fuel and kerosene, which are also used in some drone engines. This makes gasoline drone engines easier to start. However, this higher flash point means greater combustibility, making gasoline inherently more dangerous to use as well as store and transport, compared to both heavy fuels and batteries.

Gasoline also freezes at low temperatures, making it less suitable for drones flying in extremely cold climates or at high altitudes. Some UAV engines are multi-fuel and are capable of running on both gasoline and heavy fuels.

Carbureted Vs Fuel-Injected Petrol Engines for Drones

4-stroke gasoline engine for UAV by UAVOS

Drone petrol engines may be carbureted or fuel-injected.

• Carburetor engines vaporize fuel and mix it with air before it enters the engine, with the fuel-air ratio controlled by the throttle.
• Fuel injection engines vary the amount of fuel according to the measured airflow, and then vaporize and mix it with air before injecting it into the engine cylinders.

Fuel-injected gasoline engines are more efficient, whereas carburettor engines are easier to start and are simpler due to fewer parts.

Rotary & Wankel Gasoline Engines

Gasoline engines used for UAVs are most commonly two-stroke or four-stroke piston-driven internal combustion engines. However, rotary and Wankel designs for UAVs also exist. These engines use a rotor spinning within a housing to carry out the combustion cycle, and provide an excellent power-to-weight ratio as well as lower levels of heat, noise and vibration.