Changkong 1 [CK-1] Drone Series
A drone is a kind of pilotless aircraft used as a target for air defence missiles, aeriel guns and anti-aircraft cannons. Drones used in China in 1950s mainly were the soviet built La-17. In 1968 the government formally assigned to the NAI a task of developing Changkong 1 medium-high altitude drone. In 1976 and 1977 the institute successfully developed Changkong 1 and Type 1015B radar parachute drone. The Pilotless Research Department was established in 1977 and it was expanded into a Pilotless Research Institute in 1979. In the institute there were four research sections, i.e. general configuration, stress analysis and systems, radio and electrical system and engine, as well as two workshops. In addition there were a research section of flight control system and a workshop of special equipment which were set in the Department of Automatic Control Engineering at NAI. After 1977 NAI completed the development of Changkong 1 nuclear test sampling aircraft, Changkong 1 low altitude drone and Changkong 1 high manoeuvarable drone. These drones have basically met the needs of target practice for domestic antiaircraft missiles and successfully fulfilled sampling task for nuclear tests.
Changkong 1 Medium-High Altitude Drone (CK-I)
The Changkong 1 medium-high altitude drone was developed on the technology base of the La-17 drone. The La-17 drone was brought into air by a carrier aircraft and then propelled by its own ramjet engine. Its performance was rather inferior and its operation was not convenient. Some modifications and innovations were incorporated into the design of the Changkong 1 drone. The WP6 engines which were going to be phased out were used to replace the ramjet engines; it took off from a ground running dolly rather than being delivered by carrier aircraft in air; a domestic autopilot was used; general layout was changed; structure strength and stiffness were improved; new fuel feeding system and control system were designed new flying trajectory was selected; aircraft electrical network was changed and a standby electrical system for power-off recovery was added; and a radio telemetering system was also added.
The Changkong 1 was a high subsonic drone with conventional aerodynamic configuration, rectangular wing, slender and circular cross section fuselage which consisted of streamlined parabolic revolutionary nose and tail and a cylindrical middle section. Underneath the fuselage was suspended an engine pod in which a WP6 engine was installed. A pod was carried at each wing tip. Both tailplane and vertical fin were rectangular surfaces. The drone automatically run and took off with the help of a takeoff dolly. It climbed at first under programable control system and then under radio remote control. Afterwards it could carry out either level flight or other manoeuvres. It could be guided to land by a remote control system after its mission had been performed. Generally the drone could come into target practice zone three times for every flight. If it had not been shot down in target practice, it could be guided to land and repaired for next use.
The development of the Changkong 1 medium-high altitude drone began in April 1968. A total of 9 prototype drones were flight-tested. The delivery began after its design certification in 1977. The target practice of the military Services showed its satisfactorily performance and conformity with the operational requirement.
Changkong 1 Nuclear Sampling Aircraft (CK-IA)
The government assigned a task to convert the Changkong 1 drone into a nuclear test sampling aircraft in March 1977. Sampling for a nuclear test is an important work for the development of nuclear weapons. Before the CKIA was developed the sampling for nuclear test was done by a manned aircraft. This was harmful to pilot. In addition because the cross-cloud-flight could only allowed at a later time, the sample taken would not be fresh enough and, therefore, the evaluation and analysis of the nuclear test would be adversely affected. The scientific people at NAI began the development of the CKIA with sense of serving the national defence and with sense of responsibility to pilot's health. Three sampling aircraft were constructed and a number of tests were carried out in a period of time as short as half a year. Prior to the mission flight a sampling simulation flight chased by a J-6 fighter was made. These tests and flight test showed that the development of the sampling aircraft was a success. On September 17, 1977 one sampling aircraft participated in the cross-cloud-flight sampling of 22nd nuclear test of our country. The aircraft was only 150 km away from center of explosion when the nuclear bomb exploded. It flew according to predefined course and crossed nuclear cloud twice with a door of the sampler opened. It landed in good condition at a designated site about ten minutes later with "fresh sample" in intact sampler.
The NAI supplied a number of sampling aircraft for nuclear test and these aircraft participated in four nuclear tests. Enough samples were obtained and the assigned tasks were successfully fulfilled. Since 1980 they have been exclusively used in nuclear test sampling.
Changkong 1 Low Altitude Drone (CK-IB)
In order to evaluate and certificate a low altitude antiaircraft missile by target shooting the NAI was requested to develop the Changkong 1 low altitude drone in February 1980. It was an improvement of CKI, the medium-high altitude drone. To meet the need of low altitude flight were incorporated some major modifications, e.g.the use of low thrust " low altitude cruise condition" which was an equivalent of 40 per cent of WP6 rated static thrust, one 160 liters auxiliary fuel tank under each wing for extended range and the adjustment of flight control system.
Successful first flight of the low altitude drone was made on May 18, 1982. It flew for 48 minutes and landed safely. The design was certificated and was approved for small scale production in February 1983. Afterwards, the production drones were successively supplied to meet the need of target practice for domestic low altitude missiles.
Changkong 1 High Manoeuvrable Drone (CK-IC)
To strengthen the national defence a number of high performance Missiles had to be tested and certificated and, therefore, a high manoeuvrable drone which could fly a sharp level turning at low and medium altitudes and at high speed was in urgent need. At that time this kind of drone was not available in China although they were available in a few other countries.
The task assigned to NAI in early 1983 was to develop and produce a high performance and high manoeuvrable drone in one year and a half. The task was tough, required technology complicated and time strictly limited. This meant that no fault was allowed in general design concept and in prototype production and that every pieces of the work had to be carried out in fast speed and high quality and in a systematic fashion. After acceptance of the task the NAI decided to go all out to fulfil the urgent task. A leading group headed by president of NAI, the chief designer system and the administration system were set up. The system engineering management was applied and the contractual system was also applied on trial basis. The development of the drone was thus fully under way in NAI.
Lu Qingfeng, chief designer, and Luo Feng, vice chief designer, directed conceptual definition study and determined that the Changkong 1 low altitude drone would be used as the basis of the new drone. The design team was faced with a key technical problem, the improvements to the power plant, structure, flight control system, fuel supply, electromagnetic compatibility, electrical network and flight trajectory. Among them the most challenging and most critical ones were the improvements of flight control system and fuel supply system.
New flight control system was required to control engine thrust and movements of three control surfaces according to control laws so that sharp turning could be flown in a more constant speed and altitude. This requirement was fulfilled by redesigning autopilot components, and by carrying out of ground centrifugal test and hybrid computer simulation of whole system. To realize coordinated controls for high manoeuvrable turn a high precision load factor transducer was used in an American pilotless aircraft to adjust bank but to keep load factor. But this transducer was not available at that time in China, therefore the designers creatively used other kind of domestic equipment to realize coordinated turn at constant altitude and at load factor of high manoeuvrability. To ensure normal fuel supply in high manuverability flight a unique fuel supply system was designd which used bleed air from engine compressor to pressurize fuel supply system.
More than 10 key technical problems were tackled by the technical people in the development of the high manoeuvrable drone. Among these technical people was Yao Kaidi, a veteran lecturer in his fifties, who was in charge of the technology of the fuel supply system. He contracted abdominal malignant tumour and had had 'two operations on his abdominal muscle so that he could not stand for a long time. But during the fuel line system test he came to the laboratory every time and very often worked ten hours and more a day. Although the kerosene smell made him feel dizzy and nauseating, he insisted on staying and working there. He tried hard to contribute to our cause of pilotless aircraft.
The construction of two flight test prototype aircraft was completed in July 1984. The flight test made at a test range in September was a complete success. The load factor of level turn reached 4g. Another eight high manoeuvrable drones were built at NAI by the end of 1984. In the certification test of a high performance missile carried out from February to March in 1985 only four drones were used as targets for five effective missile launches.
The Changkong 1 high manuverable drone has excellent performance as a target to meet a variety of missiles training requirements and it is the one of most advanced drones in the world. To commend the NAI upon its great contribution to the development of the pilotless aircraft the MAI awarded it a collective merit and Lu Qingfeng and Luo Feng first class merit. Except five failures in flight test of the medium-high altitude drone the later three derivatives of the Changkong 1 series all succeeded in their first flight test. So far a great number of drones in various versions have been operated and no accident has ever been recorded.
Changkong-1 Ultra Low Altitude Drone
An improvement of the Changkon-1 Maneuverable Drone, the ultra-low altitude variant, was developed by Nanjing Aeronautical Institute. Like the former, the drone was designed for missile testing, in this case for low-altitude air-to-ground missiles. To make the drone capable of such mission requirements, the drone's wingspan was shortened, the structure stiffer, and the flight control system was upgraded. The drone's design was approved in March 1989.
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