The Predator B (AKA the MQ-9 Reaper) is a pretty impressive bit of machinery. The unmanned military drone has an official range of 1,151 mi (1,852 km, 1,000 nautical miles), and a flight endurance when fully loaded of 14 hours, but for the US Air Force that isn't good enough. At this year’s Farnborough Airshow, General Atomics Aeronautical Systems, Inc, the builder of the Predator B, announced the second successful endurance flight of its Predator B Extended Range (ER) Remote Piloted Aircraft (RPA), which flew from June 17 to June 18 as part of a program to improve the Predator’s endurance and capabilities.

"This flight was a significant milestone for Predator B ER in that it closes out its Phase 1 flight test period," said Frank W. Pace, president, Aircraft Systems for General Atomics. "The entire RPA system was successfully tested from start to finish, including flying a real-world representative mission with significant loiter time, and then returning to base."

The Predator B ER is an advanced version of the Predator B. It was introduced in April 2012 and first flew last February, extending the Predator B’s unloaded flight endurance from 27 hours to up to 35 hours. It manages this by means of an external fuel tank on each wing, heavier landing gear to take the increased payload, and a new fuel management system that keeps the fuel sources in the aircraft all thermally balanced.

In addition, there’s an Alcohol Water Injection (AWI) system that briefly injects a mist of water and alcohol into the engine air intakes, which momentarily cools the fuel/air mixture, resulting in greater air density in the intake and a burst of power. According to General Atomics, this allows the Preadtor B ER to work from shorter runways and take off from higher altitude airfields or in hotter weather, carry heavier payloads, and increases performance and fuel efficiency.

General Atomics says that more tests of the Predator B ER are scheduled for next year and that 38 of the aircraft are contracted to be built for the US Air Force. One goal of the ER program is to fit the Predator B with 79-ft (24-m) wings that will replace the current 66-ft (20-m) ones, to create a reconnaissance version capable of flying for 42 hours. The first versions of this configuration are scheduled to be built in the next couple of months, with the first flights next year.

The Predator B is one of the mainstay drones of the US Air Force and is also flown by the air forces of the United Kingdom, France, Italy, and the Netherlands. It’s already been upgraded a number of times. In 2012, it received an improved electrical power system, more secure communications, autoland capabilities, streamlined payload integration, and greater Gross Takeoff Weight (GTOW) to handle heavier payloads, and last year it was used to flight test a new prototype Sense and Avoid (SAA) system.