The General Dynamics MQ-9 Reaper is an evolution of the older Predator drone (it's also called the Predator B). While it is sometimes said the MQ-9 ER (Extended Range) variant achieves 40+ hours in endurance, this is somewhat deceptive. Endurance hinges on a range of factors, including payload, the altitude at which it is operated, and other mission-specific considerations. The MQ-9 ER can achieve over 40 hours of endurance, but only in an ideal environment with minimal weapons, the most economical cruise, minimal maneuvering, and optimized altitude and throttle. In realistic combat patrol conditions, the endurance will likely collapse to...