This Australian brand has developed engines for UAVs, of small displacement and running on HFE, heavy fuel such as Jet-A1, Jet-A4, Jet-A5 etc.

-It uses preheaters for fuel so that it can be ignited by normal spark plugs.

“Orbital engine for UAV”

-This is "Orbital Corp. Ltd."

-The name given to this Orbital engine is "Redback". It is a two-cylinder boxer.

-The "Flex D-1" for Aerosonde UAV. Works with spark plugs and diesel fuel. JP-5 kerosene for naval operations and JP-8, kerosene for land operations.

From Appendix 12: It is Orbital Heavy Fuel Engines. The engine designed is multi-fuel for UAV.

"HFE cylinder section"

"Rear section of the UAV Scan Eagle"