The Largest Security-Cleared Career Network for Defense and Intelligence Jobs - JOIN NOW


Wu Zhen 5 (WZ-5) / Chang Hong (CH-1)

The Wu Zhen 5 (WZ-5) UAV, also known as Chang Hong 1 (export name, = Long Rainbow, not to be confused with ChangKong-1) UAV is a reverse engineered US AQM-34N Ryan Firebee Model 147H. China's armed forces have operated the Chang Hong (CH-1) long-range, air-launched autonomous reconnaissance drone since the 1980s. China developed the CH-1 by reverse-engineering US Firebee reconnaissance drones recovered during the Vietnam War. Dozens of these AQM-34 drones were shot down over China in the late 1960s. An upgraded version of the system was displayed at the 2000 Zhuhai air show and is being offered for export. A PRC aviation periodical reported the CH-1 can carry either a daylight still, TV or infrared camera. It is likely not equipped with a data-link, which would allow remote control operation, nor is it capable of providing real-time payload feedback to the remote operator. China's armed forces also operate other UAVs, primarily for battlefield reconnaissance or electronic warfare.

Based on the needs of national defence and aeronautical R&D the government assigned a task in 1969 to the Beijing Institute of Aeronautics and Astronautics [BIAA] to develop a high altitude photographic reconnaissance pilotless aircraft. The BIAA is one of the universities and colleges which first carried out R&D in pilotless aircraft field. A pilotless aircraft section was established in 1963 and more than 50 technical people worked there: A systematic investigation and analysis to foreign technology of the pilotless aircraft began one year later and the development of a supersonic drone B-6 in 1965, which was terminated later because short of ramjet engine. But these activities prepared necessary technologies for later development of a high altitude reconnaissance pilotless aircraft WZ-5.

The design concept of the WZ-5 defined a pilotless aircraft which was capable to fly at high altitude and at high subsonic speed and to perform the mission of high altitude photographic reconnaissance in day time. Its visible light camera could swing left and right about its longitudinal axis so that it could take pictures from five windows. A small size and short life WP11 engine, an automatic control system and radio remote control and telemetering system were installed in the aircraft. No takeoff and landing device such as landing gear was installed so that it had to be carried by a carrier aircraft to a certain altitude and then to be released. It was guided to a predetermined recovering site and recovered by its own parachute after it had performed its mission.

In the development of the advanced high altitude photographic reconnaissance pilotless aircraft the BIAA was responsible to develop airframe, engine and ground radio control station and for final assembly, debugging and flight test. They rapidly gathered all technical staff inside the institute and set up a design team. Yang Weiming was appointed chief designer. More than 1,000 teachers, technical people, workers and students took part in the development. Two pilotless aircraft were built in 1972. In 1976 two more aircraft were built with all the domestic materials.

In addition to a lot of development ground tests a total of seven flight tests were carried out since first successful flight in 1972. The aerial photography was tested in second flight test in 1973 and its result was certified as good by photo reading. The predetermined objectives were realized in a high altitude and medium range development flight test carried out in 1975. The ground test for several engines was up to 100 hours. For test of ground control station four more flight tests over land and sea were carried out. In total one hundred and twenty flights were accumulated. The full size static test and resonance test to verify structure strength of the pilotless aircraft were carried out in October 1972 and these tests proved that they were in conformity with the design requirement. To the airborne equipment more than 10 environmental tests such as high and low temperature test, high altitude test, vibration test and impact test were also successively carried out according to the specification.

A good number of technical people tried their best to develop the advanced pilotless aircraft. The automatic control system was the most critical part of the aircraft and, therefore, a ground-based flight simulation test rig was specifically constructed by the BIAA and the Lanzhou Aero-instrument Factory. Several flight simulation tests of the aircraft were conducted in connection with the simulation test rig supported by a computer. The Doppler radar did not function normally at the outset. To solve the problem the Air Force flew its Trident and Tu-4 aircraft more than 80 hours over various surface features such as land, ocean, mountain, plain and desert and took various actual Doppler spectra to study the effect of frequency interference on the radar. After repeated tests and modifications the radar met the design requirement at last. In the development of the WP11 engine the machining of transonic axial compressor rotor was a challenging problem. At the outset it was built with precision cast steel and only one thirtieth of the products were up to standard. But the problem was solved by the technical people at last. For the design of radio control station there were not any similar stations or information which could be used as a reference. The technical people worked in a creative way and in the end a radio control system, which combined the capabilities of tracking, remote controlling and telemetering in one single system, was successfully developed. The ground control station could be used not only to track, remotely control and telemeter the pilotless aircraft, but also to display by instruments and digital display, and to record on paper tape and to mark automatically on a map the necessary flight information.

The certification test of the WZ-5 was completed in 1978. In the same year the BIAA formally set up a Pilotless Aircraft Design and Research Institute. The institute had sections of general layout, structure, engine, automatic control and radio, workshops of sub-assembly and final assembly and an environmental test laboratory. The type design was certificated by the government in 1980. It began to enter into service in 1981 and since then it has played important role in training and tactical reconnaissance.

The WZ-5 is mainly used for photographic reconnaissance but it can also be used as an air sampling aircraft and drone if the corresponding equipment were fitted. No doubt the successful development of the WZ-5 is a leap in the field of pilotless aircraft technology.

For the purpose of surveying small areas, the Northwest Polytechnic University developed a smaller remote controlled aircraft designated as the D4.


Join the mailing list

One Billion Americans: The Case for Thinking Bigger - by Matthew Yglesias

Page last modified: 06-07-2020 19:42:14 ZULU