Orbital UAV, a developer of integrated heavy fuel engine systems for military and commercial unmanned aircraft, explains that combustion efficiency begins with highly controlled fuel atomization, delivered by the FlexDI™ air assisted direct injection system.
The system produces fuel droplets measuring approximately 8 microns, whereas conventional injection methods typically generate droplets around 120 microns. The substantially smaller droplet size promotes more complete and rapid combustion. As a result, thermal efficiency is increased and specific fuel consumption can be reduced by up to 40 percent during cruise conditions.
FlexDI™ is designed to maintain consistent operation across a wide range of environmental conditions. Automatic compensation for altitude and temperature supports stable performance from sea level up to 20,000 feet. The system enables dependable cold starts at temperatures as low as minus 30 degrees Celsius. It is compatible with heavy fuels including JP-5, JP-8, and Jet A or Jet A-1, and also supports gasoline operation.
Electronic oil metering, combined with closed loop ECU control, regulates mixture formation and lubrication under varying load demands. This control architecture ensures accurate fuel delivery and lubrication management throughout the operating envelope.
Brake specific fuel consumption performance allows Unmanned Aerial Vehicle (UAV) operators to lower fuel mass, increase available payload capacity, and extend operational range. These attributes are particularly important for endurance focused missions where efficiency directly affects mission duration and capability.
FlexDI™ has completed three times FAR 33.49 150 hour endurance testing and has achieved qualification to MIL-STD-810H. This verification demonstrates the system’s capability to provide reliable power output in demanding operational environments.
