RQ-4 Global hawk

The Global Hawk UAV system comprises the RQ-4 air vehicle, which is outfitted with various equipment such as sensor packages and communication systems; and a ground element consisting of a Launch and Recovery Element (LRE), and a Mission Control Element (MCE) with ground communications equipment.[53] Each RQ-4 air vehicle is powered by an Allison Rolls-Royce AE3007H turbofan engine with 7,050 lbf (31.4 kN) thrust, and carries a payload of 2,000 pounds (910 kilograms). The fuselage comprises an aluminum, semi-monocoque construction with V-tail; the wings are made of composite materials.

There have been several iterations of the Global Hawk with different features and capabilities. The first version to be used operationally was the RQ-4A Block 10, which performed imagery intelligence (IMINT) with a 2,000 lb (910 kg) payload of a synthetic aperture radar (SAR) with electro-optical (EO) and infrared (IR) sensors; seven A-model Block 10s were delivered and all were retired by 2011. The RQ-4B Block 20 was the first of the B-model Global Hawks, which has a greater 3,000 lb (1,400 kg) payload and employs upgraded SAR and EO/IR sensors; four Block 20s were converted into communications relays with the Battlefield Airborne Communications Node (BACN) payload. The RQ-4B Block 30 is capable of multi-intelligence (multi-INT) collecting with SAR and EO/IR sensors along with the Airborne Signals Intelligence Payload (ASIP), a wide-spectrum signals intelligence (SIGINT) sensor. The RQ-4B Block 40 is equipped with the multi-platform radar technology insertion program (MP-RTIP) active electronically scanned array (AESA) radar, which provides SAR and moving target indication (MTI) data for wide-area surveillance of stationary and moving targets.

Since the RQ-4 is capable of conducting sorties lasting up to 30 hours long, scheduled maintenance has to be performed sooner than on other aircraft with less endurance. However, since it flies at higher altitudes than normal aircraft, it experiences less wear during flight