Note the one shown in the picture is a twin cylinder prototype. I believe the one in the contract is a single cylinder engine.
Orbital Corp wins $4.7m US Navy contract to supply drone aircraft engines by: Neil Dowling, motoring editor From: PerthNow June 20, 2012 11:06AM
Director of engineering Geoff Cathcart with an early prototype of the HFE "Redback" Small Unmanned Aerial System engine.
WA battler Orbital Corporation is flying high after winning a $4.7 million contract to supply a high-tech engine for a pilotless US Navy drone aircraft.
Orbital's tiny two-stroke engine - dubbed Redback - overcomes some limitations of existing drone engines, including the ability to run on military-specified heavy fuel.
In US military parlance, the Heavy Fuel Engine (HFE) designed and made by Orbital will run on kerosene-based fuel. Existing drones use standard petrol, but incur problems with high fuel use and volatility.