Читать книгу Introduction to UAV Systems - Mohammad H. Sadraey - Страница 41

The Global Hawk unmanned aerial system consists of the aircraft, payloads, data links, ground stations, and logistics support package. Global Hawk is the largest active current UAV with successful flights, and with a high altitude and long endurance (HALE). A Global Hawk (Figure 1.4) is equipped with a single AE 3007H turbofan engine – mounted on top of the rear fuselage – supplied by Rolls‐Royce. The engine is mounted on the top surface of the rear fuselage section with the engine exhaust between the V tail.

The wing and tail are made of graphite composite materials. The wing has structural hard points for external stores. The aluminum fuselage contains pressurized payload and avionics compartments. The V‐configuration of the tail provides a reduced radar and infrared signature. Some mass and geometry features as well as the flight performance of Global Hawk are provided in Table 1.1.

Figure 1.4 Global Hawk

(Source: Bobbi Zapka / Wikimedia Commons / Public Domain)

Table 1.1 RQ‐4B Global Hawk data and performance

No.	Parameter	Value (unit)
1	Wingspan	39.9 m
2	Length	14.5 m
3	Maximum takeoff mass	14,628 kg
4	External payload weight	3,000 lb
5	Internal payload weight	750 lb
6	Turbofan engine thrust	34 kN
7	Maximum speed	340 knots
8	Range	22,779 km
9	Endurance	32+ hours
10	Service ceiling	60,000 ft

The prime navigation and control system consists of two systems, the Inertial Navigation System and the Global Positioning System (INS/GPS). The aircraft is flown by entering specific way points into the mission plan. The GCS consists of two elements, the Launch and Recovery Element (LRE) and the Mission Control Element (MCE). The LRE is located at the air vehicle base. It launches and recovers the air vehicle and verifies the health and status of the various onboard systems. The MCE is employed to conduct the entire flight from after takeoff until before landing.

Many changes have been applied in the design of Northrop Grumman RQ‐4B Global Hawk as compared with RQ‐4A. For instance, the RQ‐4B Global Hawk has a 50% payload increase, larger wingspan (130.9 ft) and longer fuselage (47.6 ft), and a new generator to provide 150% more electrical output. Although RQ‐4B carries more fuel than RQ‐4A, it has a slightly shorter range and endurance, due to a heavier maximum takeoff weight.