The Predator B ER -- also known as the MQ-9 Reaper -- is a highly sophisticated unmanned military drone that recently completed its second successful endurance test flight.
The Predator B ER is an advanced version of the Predator B drone. Its flight endurance is 35 hours, eight hours more than that of the old Predator B. This improvement was made possible by the fitting of an external fuel tank on each wing, heavier landing gear to facilitate increased payloads as well as an advanced fuel management that helps thermally balance the aircraft's fuel sources.
The drone also features a special Alcohol Water Injection system that injects a mist of water and alcohol into the engine air intakes, allowing the craft to take off from shorter runways and carry heavier payloads.