The China People's Liberation Army established the Army Air Force in the mid-1980s. At that time, there was a shortage of helicopters in the People's Liberation Army, and the domestic Zhi -5 had poor performance. The developed Zhi -6 and Zhi -7 were successively dismounted. After the establishment of the army aviation, all the helicopters of the general were quickly concentrated. Among these helicopters, 1984 S-70 Black Hawk imported from the United States is particularly eye-catching, not only because of its special background, but also because of its excellent aircraft. In the early 1980s, Sino-US relations ushered in an unprecedented honeymoon period, and the two sides carried out a lot of cooperation in the military field. China government not only invited Grumman to improve the J-8 fighter, but also began to purchase American-made equipment. 1in July, 1984, the government of China signed a contract with Sikorsky Company of the United States to purchase 24 S-70 civil Black Hawk helicopters, each at a cost of 7 million US dollars (the current price of the newer UH-60L is 8.6 million US dollars, while that of MH-60G is/kloc-0.02 million US dollars), although this is equivalent to that of China, which has just started the reform and opening up. 1984165438+10 The first batch of four Black Hawks arrived in Tianjin, China, and the last one was delivered in198565438+February. This plane is all made by Sikorsky Company of the United States. It is one of the few American-made equipment known to the public in the PLA sequence, and it is also the general helicopter with the best plateau performance owned by the PLA so far.
The Black Hawk purchased by China is the civil model S-70C in Sikorsky S-70 series, and the number allocated by Sikorsky Company to the Black Hawk in China is S-70C-2. This machine originally used two CT7-2C engines of General Electric Company, with output power of 1.625 shaft horsepower, or it can be a CT7-2D turboshaft engine with output power of 1.723 shaft horsepower. The output power of gearbox is 3 130 shaft horsepower, and the internal oil tank is 1370 liter. The rotor brake has been greatly improved. The upper main deceleration shell of SH-60 Seahawk is used, and LTN3 100 VLF navigation system is used to replace the standard Doppler navigation system of the US military. The maximum takeoff weight is 9 185 kg, the transition range is over 500 km, and the external cargo hook can lift 3630 kg of goods. The plane is equipped with two pilots. Under normal circumstances, the cargo hold can carry passengers 12, and in case of emergency, it can carry passengers 19.
Before the introduction of Black Hawk, our army didn't have any helicopters used above 3000 meters above sea level. In the snowy plateau with an average altitude of more than 3000 meters, the oxygen content is less than half of the sea level, and the power of any engine will be reduced by about 40%. Moreover, the climate on the Qinghai-Tibet Plateau is so bad that ordinary helicopters can't fly. There are even rumors that a domestic helicopter once flew to Medog to perform a special task, only to find that the fuselage was stretched by one foot after landing and the plane was scrapped. Even after the introduction, the PLA still spent a lot of manpower and material resources to complete the theoretical study of flight routes, take-off weight and load at various altitudes in the Qinghai-Tibet Plateau, and solved a series of theoretical problems such as starting power, and then conducted field flight test demonstration. Theoretical calculation and experiment alone took three months. The test flight started from the airport at an altitude of 1700 meters and gradually advanced to the plateau. Above 3000 meters above sea level, the engine power drops sharply, resulting in insufficient lift of the aircraft. After another three months, my researchers finally overcame the technical difficulties and solved the lift problem. Finally, the Black Hawk flew over the Tanggula Mountain at an altitude of more than 5,200 meters and landed in the Ali area. Our technician Wen Qingcheng's paper "The Use and Maintenance of Helicopters on the Plateau" made the world know the characteristics and great difficulties of helicopter flight on the Qinghai-Tibet Plateau for the first time. All aspects of the United States also regard this as an important achievement and experience, and Sikorsky Company has obtained a huge advertising effect.
According to foreign periodicals, these black hawks were mainly deployed in Beijing Military Region and Chengdu Military Region, and entered Tibet and Xinjiang Plateau after 1985. The military appreciates its plateau performance very much. In fact, the S-70 is also the only helicopter that can successfully fight in the plateau area. Its engine performance is excellent, and the perfect deicing system on board can reduce the risk of its use in plateau areas. S-70 has participated in the rescue of disaster areas in Tibet and the recovery of recoverable satellites for many times, and its use intensity is high. Before 1989, the total flight time exceeded 1 1000 hours. High attendance will naturally increase the number of accidents. Black Hawk is mainly used in Qinghai-Tibet Plateau, and its climatic conditions can be considered as the worst in the world. There are too many accidents in which people are killed by airplanes. But most of them are caused by climatic reasons or human errors, and only a few are caused by mechanical failures. According to reports, 1987, 10 On June 8, a Black Hawk helicopter of a certain regiment of the PLA Air Force flew in Qinghai Province, its tail rotor suddenly failed and fell to the ground. After landing, it broke into three pieces, causing three deaths and fifteen injuries. The Air Force Flight Accident and Fault Analysis Center immediately sent personnel to the scene to investigate, and Sikorsky Company also sent three groups of experts to the crash site to inspect the wreckage. The two sides are deadlocked over the cause of the accident. Later, our expert group found an imperceptible metal knife mark on the helicopter tail rotor. Through electron microscope and spectral analysis, it is confirmed that this undiscovered knife mark caused the fatigue and fracture of metal, which led to the death of the plane. The United States compensated China for $3 million. This is the first time that China has successfully claimed compensation from foreign businessmen since it imported military aircraft. Of course, the most serious accident when Black Hawk was used in China was that in June 199 16, a Black Hawk crashed in Tibet, and 12 all PLA personnel were killed, including several senior generals of Chengdu Military Region.
Both Lu Hang and Sikorsky have high hopes for the Black Hawk. Sikorsky had expected to sell 65,438+000 Black Hawks to China. However, due to well-known reasons, these ideas failed after 1989. China tried to imitate Black Hawk Surveying and Mapping, hoping to achieve localization like Zhi -8 and Zhi -9 in the end, but this beautiful idea was not realized because of the weak industrial base at that time. If our country can successfully imitate surveying and mapping, the transportation capacity of our army's land aviation will have a qualitative leap. After 1989, although Sino-US relations were once again deadlocked, the supply of spare parts for the maintenance of Black Hawk helicopters was never interrupted. It is said that because China's Black Hawk is often used in humanitarian relief operations in Tibet and Xinjiang, all walks of life in the United States have not opposed the sale of the above spare parts, and China has also been able to buy the necessary spare parts from Sikorsky Company (of course, some of them are also made in China), occupying a considerable part of the US trade with the China Continental Army.
Unable to obtain more S-70 Black Hawks, Luhang quickly turned to buy Russian Mi-17 helicopters. A large number of meters-17 eased the urgent demand of land aviation. But on the whole, the advanced nature of S-70 is beyond doubt. For example, the T700 engine on the S-70 has only two fuses, and the fuses have been improved or even cancelled. Mi -8 engine needs fuses in many places, with more than 20 adjustment points and as many as 45 random tools. In our army, the maintenance of S-70 is much easier than Mi -8 and Mi-17. S-70 has an overwhelming advantage in plateau performance and corrosion protection.