Cai Hong-4 (CH-4) is a medium-altitude, long-endurance (MALE) unmanned aerial vehicle (UAV) system designed and built by China Academy of Aerospace Aerodynamics (CAAA, also known as the 11th Academy) of the China Aerospace Science & Technology Corporation (CASC) consortium.
The development of the CH-4 began in 2010 and the UAV first flew in September 2011. The UAV has been exported to Egypt, Saudi Arabia, and Iraq, and may have also been in operational service with the PLAAF since 2014 according to some Chinese media reports.
The largest in size in CAAA’s Cai Hong (“Rainbow”) UAV/UCAV family, the CH-4 is roughly similar in size to the General Atomics MQ-1 Predator. It is a multirole unmanned aerial system capable of intelligence, surveillance, target acquisition and reconnaissance (ISTAR), air interdiction (AI), and electronic warfare (EW) missions. In addition, it can also be used for border petrol, law enforcement, and counterterrorism purposes.
The CH-4 has an operational ceiling of 8,000 m (26,246 ft), a maximum range of 3,500 km (2,175 miles), and a maximum take-off weight of 1,330 kg. The UAV can carry up to 345 kg of weapon or mission payload, with 165 kg fuel. It can fly continuously for up to 38 hours, though this reduces to 14 hours when operating to maximum payload and fuel.
The CH-4 is 9 m in total length and 18 m in wingspan, with 80% of its airframe made of composite materials. The UAV has four underwing pylons (75 kg payload on outer pylons and 120 kg payload on inner pylons). The UAV can carry 4 to 6 AR-1 semi-active laser-guided missiles. The missile is 1.45 m in length, 0.18 m in diameter, and 45 kg in mass. It has an effective range of 2 to 8 km, and an accuracy of under 1.5 m CEP. It has a penetration depth of 1,000 mm when used against armoured targets and 1,200 mm against ground buildings.
Alternatively, the UAV can carry FT-9 guided bombs (50 kg, GPS/INS guidance) or conventional unguided bombs.
The UAV’s sensor payloads includes an electro-optic turret, which incorporates forward-looking infrared (FLIR), laser rangefinder, and laser designator functions. The turret has a maximum range of 15 km, and provides target designation for the AR-1 missile throughout its flight. The UAV also carries a Synthetic Aperture Radar (SAR), which has a maximum detection range of 30 km.
The CH-4 is able to deliver its weaponry from an altitude of 5,000 m (16,404 ft), and the AR-1 missile allows 20 degrees off-boresight launch, giving significantly increased flexibility and much reduced response time in operation.
The ground control segment of the system is integrated in a truck-carried workshop, with four operators (communications operator, pilot, weapon operator, and electro-optic reconnaissance operator).
The Iraqi Ministry of Defence (MoD) announced on 10 October 2015 that a UAV had carried out its first attack on an ISIS target in Al-Anbar province. It also released a video showing Defence Minister Khalid al-Obaidi inspecting one of the new UAVs at Kut Air Base. Although not directly confirmed by the MoD, the UAV was clearly identified as a CASC CH-4.
In December 2015, CASC confirmed that CAAA had completed CH-4 weapon delivery tests using guided/unguided bombs and sub-munitions. According to the report, a total of 7 flights were carried out in three days, delivering 14 munitions from 4,000 to 5,000 m altitudes. The guided bombs achieved an accuracy of 0.8 m, while unguided bombs also achieved an accuracy of 8 to 18 m.