Test run (via Darpa)
The day that drones can refuel themselves in mid-flight is soon to become a reality. Combat pilots rely on in-flight refueling to gain increased distance or more time on station depending on the mission. Without the use of these flying gas stations, operations would be serious limited in scope which is the case for UAV’s. Drone use by the military has steadily increased over the past decade or so and has been adapted to combat missions (equipped with hellfire missiles) over the standard ISR (Intelligence, Surveillance and Reconnaissance) but are limited in their capabilities due to range constraints and time on target. To overcome these limitations, DARPA teamed up with NASA (back in 2007) and demonstrated that UAV’s could be refueled in-flight by conventional tankers. However, most drones aren’t able to match the speed and altitude of those tankers and therefore wasn’t a viable option for refueling. So it seemed only logical that refueling a drone should be done by another which is what DARPA is looking to accomplish with their AHR (Autonomous High-Altitude Refueling) program which was concluded on September 30th of this year (2012) after a two year study. The program’s final test involved two modified NASA Global Hawk UAV’s with one outfitted with a retractable refueling probe and the other equipped with a receiver. During the 2.5 hour flight, both aircraft were successful at flying in formation at 44,800 feet and coming with 100ft (sometimes less) between the probe and receiver. The final test showed that it’s indeed possible to refuel a drone autonomously with minimal risk of damaging either aircraft (drones are notorious for falling out of the sky for one reason or another). DARPA started the program with success expectations at 17%, which translates to 1 in 6 contacts of being achieved, however the tests succeeded in a 60% success rate even with 20 knot cross-winds and various turning radiuses through simulations conducted with the actual drone’s flight data. We can expect future UAV’s to be outfitted for in-flight refueling in the near future, which doesn’t bode well for the USA’s enemies.