In September 2015 the U.S. Air Force received its first MQ-9 Reaper ER UAV. This occurred a year after the air force ordered 38 of them. Reaper ER is an upgrade of the original MQ-9 design that allows longer endurance (up to 35 hours) by carrying two fuel tanks (one under each wing) that use a new fuel management system that ensures fuel is taken from the main fuel tank and the two external tanks in such a way that the aircraft does not become unbalanced. The new version also has the engine modified so that it can generate more power on takeoff, enabling the MQ-9 to achieve heavier takeoff weight. The ER version is also getting 20 percent longer wings. Since the wings already carry fuel, this helps increase fuel and endurance to about 42 hours. The air force asked for the Reaper ER to be developed and delivered quickly which in this case was done. That was unusual in the military procurement world. Older MQ-9s can be upgraded to ER partially (by equipping a MQ-9 with the two fuel tanks and fuel management software) or completely (by installing the larger wings and new engine).
The original MQ-9 Reaper looked like the earlier 1.2 ton MQ-1 Predator but was larger. The 4.7 ton MQ-9 is an 11.6 meters (36 foot) long aircraft with a 21.3 meters (66 foot) wingspan. It has six hard points and can carry 682 kg (1,500 pounds) of weapons. These include Hellfire missiles (up to eight), two Sidewinder or two AMRAAM air-to-air missiles, two Maverick missiles, or two 227 kg (500 pound) smart bombs (laser or GPS guided). Max speed is 400 kilometers an hour, and max endurance was originally 15 hours. The Reaper is considered a combat aircraft, to replace F-16s or A-10s in many situations. Most of the nearly 150 Reapers built so far have been for the U.S. Air Force and since introduced in 2007 these Reapers have flown over two million hours.