Yu-4 torpedo
Encyclopedia
Yu-4 torpedo is the Chinese development of the Russian SAET-50 ASuW
passive acoustic homing torpedo, and it is the Russian SAET-50 torpedo incorporating active acoustic homing guidance. Yu-4 torpedo is often erroneously claimed by many sources as the Chinese version of the SAET-60 acoustic homing torpedo, but Soviets had not completed the development of SAET-60 and only fielded the weapon in 1961, by then the relationship between former-Soviet Union
and China
had already worsened and China had not received any technical assistance on SAET-60 torpedo. The background of the development of Yu-4 torpedo is identical to that of Yu-1 torpedo
and Yu-2 torpedo
.
Zhang Aiping
and the deputy commander-in-chief of PLAN
Luo Shunchu (罗舜初) led a military delegation to visit former-Soviet Union
signed a deal with Soviets to produce three types of Soviet torpedoes in China. In comparison with other military programs each with dozens or even hundreds of Soviet advisors, however, the former-Soviet Union
did not put too much emphasis on torpedo capability: the total number of Soviet advisors initially sent to China for all of its torpedo programs was only five. The Soviet Union
quickly delivered the samples and technical information of the three types of torpedoes to China with the five advisors to China as promised. Two Soviet advisors were assigned to assist China to produce the RAT-52 rocket-powered torpedo at No. 123 Factory, while others were assigned to teach China about compressed oxygen powered torpedo and SAET-50 acoustic homing torpedoes. In July 1960, the first two samples of Chinese-built rocket propelled torpedoes were completed. Type 920 electrical propulsion system and electronics of the electrically powered passive acoustic homing torpedo had also been completed, while the basic technologies of compressed oxygen torpedoes were also mastered by China.
Everything appeared to be great but the subsequent Sino-Soviet split
ended the promising future: from July 28 to September 1, 1960, former-Soviet Union
had quickly withdrawn all of its advisors from China. Compounding the problem, other domestic political turmoil such as Great Leap Forward
further hindered the Chinese development of torpedoes. The 7th Academy consequently ordered the 705th Research Institute to lead a team consisted of No. 724 Factory, Pinyang Machinery Factory (平阳机械厂, also known as Factory 874) in Houma, Shanxi
, and East Wind Instrumentation Factory (东风仪表厂, also known as Factory 872) in Xi'an
to indigenously manufacture Soviet compressed oxygen powered torpedo. In 1962, Field Marshal
Nie Rongzhen
ordered all resources to be concentrated on achieving the goal of fielding “two boats and a torpedo” (Two boats: torpedo boat
and submarine
, torpedo: heavy torpedo of 533 mm diameter). In July, 1962, researchers at 705th Institute concluded that despite having samples and design drawings, compressed oxygen powered torpedoes was unsafe and after numerous accidental explosions, they were rarely used by the Soviet Navy, and Chinese navy was not happy with oxygen powered torpedo either. Chinese researchers recommended steam powered torpedo instead, and in the following year, PLAN
issued an order to first develop steam powered torpedo, and then the electrically powered acoustic homing torpedo. The electrically powered Yu-4 torpedo program was put on hold despite the earlier successful development of components.
had encouraged the Chinese to resume the development of the Yu-4 torpedo after several years of dormancy which begun in early 1960s. At the end of 1971, 5 samples were produced based on the experience gained in the development of the Yu-3 torpedo. However, the speed was low and other results were not satisfactory either. The Chinese researchers decided to take a prudent approach by developing two different versions, one with passive acoustic homing guidance and the other with combined passive / active acoustic homing guidance. The one with passive acoustic homing begun its development in the mid-1960s and was named as Yu-4 Jia (鱼-4甲), or sometimes as Yu-4A, while the combined active / passive acoustic homing version begun its development in the late-1960’s and named as Yu-4 Yi (鱼-4乙) or sometimes as Yu-4B. Yu-4A was designed by the East Wind Instrumentation Factory (东风仪表厂) in Xi'an
, while Y-4B was designed jointly by Northwestern Polytechnical University
(primary contractor) and Pinyang Machinery Factory (平阳机械厂) in Houma, Shanxi
. Pinyang Machinery Factory (平阳机械厂) was tasked with manufacturing both Yu-4A and Y-4B.
In March 1977, Yu-4A went through first oceanic tests and was considered meeting most of the requirements. Further tests in September, 1979 indicated that the last two problems still existed: the high level of noise generated by the motor and the accidental arming of the fuse. After efforts were spent to attack the problems, the sample Yu-4A torpedoes were once again tested in June, 1980, proving that the problems appeared to be solved. However, after 78 sample torpedoes had be test fired in July, 1981, it was revealed that the problem of the fuse still existed despite drastic reduction of the occurrence, and more worked was needed. Finally, in December 1982, all problems had been solved and Yu-4A went to series production, and the export version was designated as ET31. Yu-4B, on the other hand, experienced more difficulties and new measures had to be developed, including replacing the original mechanically scanned equipment with electronically scanned equipment to improve the accuracy of depth setting and a new electro-magnetic fuse. In March 1987, after the final test of 63 torpedoes, Yu-4B was accepted into service and went into series production.
range was considered rather short for modern naval warfare by the Chinese navy, which led to one of the major upgrade resulted in increased range (up to 15 km), and in comparison to Yu-1 torpedo, there were not as many Yu-4 torpedoes entering service like Yu-1 torpedo. Like Yu-1 torpedo, Yu-4 torpedoes in Chinese inventory have been continuously modified, such as incorporating ASW
capability, updated electronics and propulsion system, and being converted as part of CAPTOR mine
type mine systems.
ASUW
ASUW may refer to:*Associated Students of the University of Washington*Associated Students of the University of Wyoming*Anti-Surface Warfare...
passive acoustic homing torpedo, and it is the Russian SAET-50 torpedo incorporating active acoustic homing guidance. Yu-4 torpedo is often erroneously claimed by many sources as the Chinese version of the SAET-60 acoustic homing torpedo, but Soviets had not completed the development of SAET-60 and only fielded the weapon in 1961, by then the relationship between former-Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
and China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
had already worsened and China had not received any technical assistance on SAET-60 torpedo. The background of the development of Yu-4 torpedo is identical to that of Yu-1 torpedo
Yu-1 torpedo
Yu-1 torpedo was the first Chinese built steam powered torpedo, it was a development of the unguided straight-running Soviet ASuW Type 53 torpedo. It was type classified in September 1971. The Yu-1 was actually the second domestically produced torpedo to enter Chinese service, the first was the...
and Yu-2 torpedo
Yu-2 torpedo
Yu-2 torpedo was a Chinese development of the unguided straight-running Soviet ASuW RAT-52 torpedo with passive acoustic homing capability added. The historical background of Yu–2 is identical to that of Yu-1 torpedo and Yu-4 torpedo...
.
Background
In August, 1958, the deputy chief-of-staff of PLAPeople's Liberation Army
The People's Liberation Army is the unified military organization of all land, sea, strategic missile and air forces of the People's Republic of China. The PLA was established on August 1, 1927 — celebrated annually as "PLA Day" — as the military arm of the Communist Party of China...
Zhang Aiping
Zhang Aiping
Zhang Aiping was a Chinese communist military leader.-Biography:...
and the deputy commander-in-chief of PLAN
People's Liberation Army Navy
The People's Liberation Army Navy is the naval branch of the People's Liberation Army , the military of the People's Republic of China. Until the early 1990s, the navy performed a subordinate role to the PLA Land Forces. Since then, it has undergone rapid modernisation...
Luo Shunchu (罗舜初) led a military delegation to visit former-Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
signed a deal with Soviets to produce three types of Soviet torpedoes in China. In comparison with other military programs each with dozens or even hundreds of Soviet advisors, however, the former-Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
did not put too much emphasis on torpedo capability: the total number of Soviet advisors initially sent to China for all of its torpedo programs was only five. The Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
quickly delivered the samples and technical information of the three types of torpedoes to China with the five advisors to China as promised. Two Soviet advisors were assigned to assist China to produce the RAT-52 rocket-powered torpedo at No. 123 Factory, while others were assigned to teach China about compressed oxygen powered torpedo and SAET-50 acoustic homing torpedoes. In July 1960, the first two samples of Chinese-built rocket propelled torpedoes were completed. Type 920 electrical propulsion system and electronics of the electrically powered passive acoustic homing torpedo had also been completed, while the basic technologies of compressed oxygen torpedoes were also mastered by China.
Everything appeared to be great but the subsequent Sino-Soviet split
Sino-Soviet split
In political science, the term Sino–Soviet split denotes the worsening of political and ideologic relations between the People's Republic of China and the Union of Soviet Socialist Republics during the Cold War...
ended the promising future: from July 28 to September 1, 1960, former-Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
had quickly withdrawn all of its advisors from China. Compounding the problem, other domestic political turmoil such as Great Leap Forward
Great Leap Forward
The Great Leap Forward of the People's Republic of China was an economic and social campaign of the Communist Party of China , reflected in planning decisions from 1958 to 1961, which aimed to use China's vast population to rapidly transform the country from an agrarian economy into a modern...
further hindered the Chinese development of torpedoes. The 7th Academy consequently ordered the 705th Research Institute to lead a team consisted of No. 724 Factory, Pinyang Machinery Factory (平阳机械厂, also known as Factory 874) in Houma, Shanxi
Houma, Shanxi
Houma is a city in the Shanxi province on the People's Republic of China, on the Fen River south of Linfen. It is 274 km large and has a population of 102,400....
, and East Wind Instrumentation Factory (东风仪表厂, also known as Factory 872) in Xi'an
Xi'an
Xi'an is the capital of the Shaanxi province, and a sub-provincial city in the People's Republic of China. One of the oldest cities in China, with more than 3,100 years of history, the city was known as Chang'an before the Ming Dynasty...
to indigenously manufacture Soviet compressed oxygen powered torpedo. In 1962, Field Marshal
Yuan Shuai
Yuan Shuai was a Chinese military rank that corresponds to a marshal in other nations. It is given to distinguished generals during China's dynastic and republican periods. A higher level rank of Da Yuan Shuai , which corresponds to a Generalissimo, also existed.-People's Republic of China:The...
Nie Rongzhen
Nie Rongzhen
Nie Rongzhen was a prominent Chinese Communist military leader, and one of ten Marshals in the People's Liberation Army of China. He was the last surviving PLA officer with the rank of Marshal.-Biography:...
ordered all resources to be concentrated on achieving the goal of fielding “two boats and a torpedo” (Two boats: torpedo boat
Torpedo boat
A torpedo boat is a relatively small and fast naval vessel designed to carry torpedoes into battle. The first designs rammed enemy ships with explosive spar torpedoes, and later designs launched self-propelled Whitehead torpedoes. They were created to counter battleships and other large, slow and...
and submarine
Submarine
A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...
, torpedo: heavy torpedo of 533 mm diameter). In July, 1962, researchers at 705th Institute concluded that despite having samples and design drawings, compressed oxygen powered torpedoes was unsafe and after numerous accidental explosions, they were rarely used by the Soviet Navy, and Chinese navy was not happy with oxygen powered torpedo either. Chinese researchers recommended steam powered torpedo instead, and in the following year, PLAN
People's Liberation Army Navy
The People's Liberation Army Navy is the naval branch of the People's Liberation Army , the military of the People's Republic of China. Until the early 1990s, the navy performed a subordinate role to the PLA Land Forces. Since then, it has undergone rapid modernisation...
issued an order to first develop steam powered torpedo, and then the electrically powered acoustic homing torpedo. The electrically powered Yu-4 torpedo program was put on hold despite the earlier successful development of components.
Development
The progress made in the development of the Yu-3 torpedoYu-3 torpedo
The Yu-3 is a Chinese acoustic homing torpedo designed to be fired from submarines against surface targets. It entered service with the Chinese Navy in 1984. Several sources state that it may be a copy of the Soviet SET-65E, although this seems unlikely as development began in 1965 after the...
had encouraged the Chinese to resume the development of the Yu-4 torpedo after several years of dormancy which begun in early 1960s. At the end of 1971, 5 samples were produced based on the experience gained in the development of the Yu-3 torpedo. However, the speed was low and other results were not satisfactory either. The Chinese researchers decided to take a prudent approach by developing two different versions, one with passive acoustic homing guidance and the other with combined passive / active acoustic homing guidance. The one with passive acoustic homing begun its development in the mid-1960s and was named as Yu-4 Jia (鱼-4甲), or sometimes as Yu-4A, while the combined active / passive acoustic homing version begun its development in the late-1960’s and named as Yu-4 Yi (鱼-4乙) or sometimes as Yu-4B. Yu-4A was designed by the East Wind Instrumentation Factory (东风仪表厂) in Xi'an
Xi'an
Xi'an is the capital of the Shaanxi province, and a sub-provincial city in the People's Republic of China. One of the oldest cities in China, with more than 3,100 years of history, the city was known as Chang'an before the Ming Dynasty...
, while Y-4B was designed jointly by Northwestern Polytechnical University
Northwestern Polytechnical University
Northwestern Polytechnical University is a University located in 127#, Youyi West Road, Xi'an, Shaanxi, People's Republic of China.-History:...
(primary contractor) and Pinyang Machinery Factory (平阳机械厂) in Houma, Shanxi
Houma, Shanxi
Houma is a city in the Shanxi province on the People's Republic of China, on the Fen River south of Linfen. It is 274 km large and has a population of 102,400....
. Pinyang Machinery Factory (平阳机械厂) was tasked with manufacturing both Yu-4A and Y-4B.
In March 1977, Yu-4A went through first oceanic tests and was considered meeting most of the requirements. Further tests in September, 1979 indicated that the last two problems still existed: the high level of noise generated by the motor and the accidental arming of the fuse. After efforts were spent to attack the problems, the sample Yu-4A torpedoes were once again tested in June, 1980, proving that the problems appeared to be solved. However, after 78 sample torpedoes had be test fired in July, 1981, it was revealed that the problem of the fuse still existed despite drastic reduction of the occurrence, and more worked was needed. Finally, in December 1982, all problems had been solved and Yu-4A went to series production, and the export version was designated as ET31. Yu-4B, on the other hand, experienced more difficulties and new measures had to be developed, including replacing the original mechanically scanned equipment with electronically scanned equipment to improve the accuracy of depth setting and a new electro-magnetic fuse. In March 1987, after the final test of 63 torpedoes, Yu-4B was accepted into service and went into series production.
Specification
- Diameter: 533 mm
- Length: 7.75 m
- Weight: 1,775 kg (1,628 kg for the training version)
- Warhead: 309 kg
- Guidance: acoustic homing: Yu-4A: passive, Yu-4B: active/passive
- Propulsion: electrical, silver-zinc batterySilver-oxide batteryA silver oxide battery , not to be confused with a similar but different silver–zinc battery, which is a secondary cell, is a primary cell with relatively very high energy/weight ratio. They are costly due to the high price of silver...
- Range: 6 km (original) @ 30 knots (58.8 km/h), 15 km (upgraded) @ 40 knots (78.4 km/h)
- Speed: 30 kt (56 km/h) or 40 kt (75 km) upgraded
- Depth: NA, ASuWASUWASUW may refer to:*Associated Students of the University of Washington*Associated Students of the University of Wyoming*Anti-Surface Warfare...
torpedo
Modification
Due to the adoption of newer technologies such as the silver-zinc battery, the performance of Yu-4 torpedo has exceeded the Russian SAET-50 torpedo it is based on, and reached that of SAET-50M: the speed of the Yu-4 torpedo is increased more than 25% to 30 knots (58.8 km/h), even 1 knots (2 km/h) faster than the SAET-50M, and the range is increased 50% to 6 km, equal to that of SAET-50M. For these reasons, the Yu-4 torpedo is considered at least equal or better than Russian SAET-50M torpedo, the successor of SAET-50 torpedo, and even comparable to Russian SAET-60 torpedo in some aspects. However, the 6 kmKM
KM, Km, or km may stand for:*Kilometre *Kernel methods*Kettle Moraine High School*Khmer language *Kuomintang , a centre-right political party in the Republic of China on Taiwan...
range was considered rather short for modern naval warfare by the Chinese navy, which led to one of the major upgrade resulted in increased range (up to 15 km), and in comparison to Yu-1 torpedo, there were not as many Yu-4 torpedoes entering service like Yu-1 torpedo. Like Yu-1 torpedo, Yu-4 torpedoes in Chinese inventory have been continuously modified, such as incorporating ASW
Anti-submarine warfare
Anti-submarine warfare is a branch of naval warfare that uses surface warships, aircraft, or other submarines to find, track and deter, damage or destroy enemy submarines....
capability, updated electronics and propulsion system, and being converted as part of CAPTOR mine
CAPTOR mine
The CAPTOR is the United States Navy's primary anti-submarine naval mine. This deep-water mine is laid by ship, aircraft or submarine, and is anchored to the ocean floor. When its sonar detects a hostile submarine, the CAPTOR launches a Mark 46 torpedo.The name CAPTOR is short for enCAPsulated...
type mine systems.