Monday, April 28, 2008

Lavochkin La-17 / CAF Chang Kong 1

The Lavochkin La-17 began flight tests in the 1950s and was one of the first Soviet UAVs to enter service. It was a small radio-controlled target drone used for training surface-to-air missile battery crews and interceptor aircraft pilots. The La-17 had a pretty simple configuration with a slim fuselage straight wings and tail surfaces and a ramjet under the fuselage. The drone was air launched and landed belly first. The ramjet was considered expendable.

The La-17 was rather crude however and also expensive to operate because of the need for a carrier aircraft and was soon supplemented by the ground launched La-17M which was turbojet powered and launched from a trolley using rocket assistance. Later improvements added an autopilot, the ability to operate at low-level and a landing skid to avoid damage to the engine when it landed.

The Soviet Union explored using the La-17 as a reconnaissance drone, the La-17R appeared in the early 1960s with a longer nose able to carry a variety of reconnaissance sensors including cameras, TV cameras and radiation monitoring equipment. The last version of the drone was the La-17K which had a different engine based on the engine used in the MiG-21. Some may still be in Russian Air Force use today.

The Chang Kong 1

China received a number of La-17s in the late 1950s but when relations between the USSR and China cooled and stocks of the drone ran low the Chinese reverse-engineered the drone and started to produce their own. The Shenyang B-5 or Chang Kong 1 is their version of the La-17 and continues in production to this day at the Changzhou Aircraft Factory (CK-1G).

The Chinese have continued to improve the CK-1 as it is known with the high manoeuvrability CK-1C appearing in the mid-1980s able to make bank turns of up to 77 degrees and the CK-1E for extra low level missions. A radiation sampling version, CK-1A, was also built for sampling air in the aftermath of Chinese nuclear tests.

Technical details

The CK-1 autopilot stabilises the drone in response to radio commands from the control station though the first 85 seconds of flight are pre-programmed. Up to 24 different command signals can be sent to the autopilot and in return there is a 52 channel telemetry downlink allowing the controller to keep tabs on altitude, speed, engine rpm et cetera. An onboard radar transponder allows the drone to be identified and tracked.

For aerial target use the CK-1 has a miss-distance indicator, infra-red augmentation pods, radar reflectors and smoke generators to aid visual tracking. The CK-1E has flares instead of smoke. The CK-1s these days are powered by WP6 turbojets taken from retired J-6 fighters. The CK-1 has a speed of around 900km/h with a flight endurance between 45 and 60 minutes.

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