Misplaced Pages

#714285

79-739: During the Korean War, the dam was bombed by the United Nations Command three separate times in order to disrupt power generation for the North Koreans. At the time of its completion, the dam was the largest in Asia, and power station was third-largest (after Hoover Dam and Wilson Dam ) hydroelectric power station in the world. It is still the largest hydroelectric power station on the Yalu (Korean: Amnok) River. Power produced at

158-669: A bombing force of 25 B-29s of the 19th and 307th Bomb Groups using SHORAN navigation aids to locate the target. After the take off from Kadena Air Base , Okinawa , at 19:00 on September 12, the bomber force suffered its first setback when an unexpected cold front over Korea caused icing in the upper surfaces of wings and fuselage of some B-29s. A 19th Bomb Group bomber stalled and crashed 21 miles (34 km) southwest of Kangnung , killing all but one of its crew. The flak suppression forces were able to locate and attack only eight searchlights, and flak shot down an F4U of VF-193. The B-29 force arrived at Sui-ho at 23:55, but in spite of

237-428: A consequential loss of accuracy. The Soviet after-action report stated: Up to 500 bombs weighting 250/450/1000 kgs were dropped on the target. Three bombs hit the upper part of the dam, one hit the part of the turbine room which had been already destroyed, and up to 50 hit the previously destroyed transformer facility. The remaining bombs missed the target by 1–2 km to the southeast. In addition to high-explosive bombs,

316-939: A joint command of the People's Liberation Army Air Force and Korean People's Army Air Force , were also combat operational in Northeast China with 275 MiG-15s. A third fighter division of the 64th IAK was based in the rear areas at Mukden and Anshan with four additional regiments. It was still in training and was not fully combat operational until July 12. The 37-mm guns of the PVO 87th ZAD (Antiaircraft Artillery Division) were responsible to provide local anti-aircraft artillery defense to Sui-ho, Choshin, Fusen and Kyosen. Source: The United States Air Force in Korea , p. 487 Source: Carrier and Air Group Action Reports Task Force 77 had four aircraft carriers available for

395-813: A significant increase in AAA defenses. On July 23, the thermo-electric plant at Wonsan was attacked for the first time, by aircraft from Bon Homme Richard , which reported it completely destroyed. On the nights of July 19–20, and July 21–22, 44 B-29 sorties were flown against Choshin No. 2. Air Group Seven attacked Puryŏng-ŭp No. 3 on July 26, the Kojǒ No. 3 transformer yard on July 31, Choshin No. 1 on August 1, Kyosen No. 2 on August 3, and Kyosen No. 1 on September 21. A newly activated air group, Air Task Group Two (ATG-2), aboard USS  Essex , also attacked Kyosen No. 2 on August 3, then struck Choshin No. 1 and Kyosen No. 1 on August 5. In

474-408: A surface area of 274 km (106 sq mi). The original power station at the base of the dam contains six 105 MW Francis turbine -generators which are afforded an average hydraulic head of 77 m (253 ft). The additional power station on China's side contains two 67.5 MW Francis turbine generators. The total installed capacity of the dam's power stations is 765 MW. Attack on

553-533: A tentative date of June 23 or June 24, which would allow Briscoe to use four aircraft carriers in the operation. The operations plan was finalized when Clark proposed to Weyland that naval aircraft, originally slated only for the eastern complexes, be added to the attack on Sui-ho. The following air combat units were assigned to the attacks on the North Korean hydroelectric plants: The defending Soviet Air Forces (VVS) were represented on June 23, 1952, by

632-464: A third raid on the dam on 15 February which left the power station inoperable once again. Throughout the dam's history, it underwent several renovations and repairs. Flooding in 1946 damaged the stilling basin at the toe of the dam and destroyed its spillway , requiring repairs the next year. Between September 1949 and April 1950, in a second repair, the spillway and plunge pool were renovated. Between 1955 and 1958, permanent post-war repairs were made to

711-692: A vote in the House of Commons to censure the Churchill government, based on the British government's "failure to secure effective consultation" from the U.S. beforehand (The Minister of Defence , Lord Harold Alexander , had been in Korea when Clark first approved the FEAF plan, but had left Korea before the JCS input). The government barely survived the vote after U.S. Secretary of State Dean Acheson publicly took

790-498: A wheels-up landing, and another from VA-75 was severely damaged when it was struck by debris from a bomb explosion but recovered aboard Bon Homme Richard . The only other battle damage reported by the attacking units was by Carrier Air Group 11 off Philippine Sea : a Corsair hit in an accessory compartment over Kyosen No. 3, and a Skyraider at Sui-ho struck by small arms fire. Although interpretation of reconnaissance photos and assessments by returning pilots indicated heavy damage to

869-436: A wide range of heads and flows. This versatility, along with their high efficiency, has made them the most widely used turbine in the world. Francis type units cover a head range from 40 to 600 m (130 to 2,000 ft), and their connected generator output power varies from just a few kilowatts up to 1000 MW. Large Francis turbines are individually designed for each site to operate with the given water flow and water head at

SECTION 10

#1732791778715

948-404: Is a type of reaction turbine, a category of turbine in which the working fluid comes to the turbine under immense pressure and the energy is extracted by the turbine blades from the working fluid. A part of the energy is given up by the fluid because of pressure changes occurring on the blades of the turbine, quantified by the expression of degree of reaction , while the remaining part of the energy

1027-476: Is equal to that at the inlet to the draft tube. Using the Euler turbine equation, E / m = e = V w1 U 1 , where e is the energy transfer to the rotor per unit mass of the fluid. From the inlet velocity triangle, and Therefore The loss of kinetic energy per unit mass at the outlet is V f2 /2 . Therefore, neglecting friction, the blade efficiency becomes i.e. Degree of reaction can be defined as

1106-445: Is extracted by the volute casing of the turbine. At the exit, water acts on the spinning cup-shaped runner features, leaving at low velocity and low swirl with very little kinetic or potential energy left. The turbine's exit tube is shaped to help decelerate the water flow and recover the pressure. Usually the flow velocity (velocity perpendicular to the tangential direction) remains constant throughout, i.e. V f1 = V f2 and

1185-455: Is necessary, as these are major parameters affecting power production. Draft tube : The draft tube is a conduit that connects the runner exit to the tail race where the water is discharged from the turbine. Its primary function is to reduce the velocity of discharged water to minimize the loss of kinetic energy at the outlet. This permits the turbine to be set above the tail water without appreciable drop of available head. The Francis turbine

1264-581: The 64th Fighter Aviation Corps employing two of its three Soviet Air Defence Forces fighter aviation divisions ( USAF wing-equivalent ) on forward air bases of the Antung airfield complex in Northeast China , totaling six regiments with 246 MiG-15/MiG-15bis , of which 210 were rated combat-ready. In addition, six full-strength fighter aviation divisions of the Unified Air Army (UAA),

1343-708: The Kyosen ( P'ungsan ) system, was on the Namdae Ch'on with its terminus at Tanch'on. The Fusen ( Pujǒn ) system was due north of Hungnam on the Songch'on-gang, with its four plants close together but in mountain gorges . The Choshin ( Changjin ) ran south and then east in the mountain canyons from the Chosin Reservoir and connected with the Songch'on-gang south of Fusen Plant No. 4. North Korea had six hydroelectric systems and six small thermoelectric plants at

1422-541: The Port Arthur and Dairen regions of northeast China. Three of the five other hydroelectric systems were located near each other in South Hamgyong Province north of Hungnam . Each consisted of four plants 8–16 km (5.0–9.9 mi) apart along a 50 km (31 mi) stretch of river, numbered by planners as 1 through 4, with plant 1 closest to its respective reservoir. The northernmost,

1501-677: The Pusan Perimeter and well before the UN landing at Inchon , planners of the USAF FEAF ( Far East Air Forces ) had asked if the hydroelectric system should be attacked; no decision had yet been made as to whether North Korea was to be occupied. On September 21, 1950, FEAF attacked a plant of the Fusen system near Hungnam, completely destroying its transformers, and recommended that all the plants be destroyed. General Douglas MacArthur directed

1580-739: The United States Air Force , US Navy , US Marine Corps , and South African Air Force , the first time in 21 months that the separate air arms had worked together on a massive scale. The attack on the facilities was followed seventeen days later by another series of large-scale joint attacks on the capital city of Pyongyang . The attacks destroyed 90% of the facilities targeted and completely knocked out power in North Korea for two weeks, as well as reducing available power to northeast China by 23%. North Korea built new facilities but did not restore its previous capacity until after

1659-412: The electric generators generally ranges from just a few kilowatts up to 1000 MW, though mini-hydro installations may be lower. The best performance is seen when the head height is between 100–300 metres (330–980 ft). Penstock diameters are between 1 and 10 m (3.3 and 32.8 ft). The speeds of different turbine units range from 70 to 1000  rpm . A wicket gate around the outside of

SECTION 20

#1732791778715

1738-592: The turbine's rotating runner controls the rate of water flow through the turbine for different power production rates. Francis turbines are usually mounted with a vertical shaft, to isolate water from the generator. This also facilitates installation and maintenance. Water wheels of different types have been used for more than 1,000 years to power mills of all types, but they were relatively inefficient. Nineteenth-century efficiency improvements of water turbines allowed them to replace nearly all water wheel applications and compete with steam engines wherever water power

1817-513: The Dairen region failed to meet production quotas . For two weeks North Korea endured a total power blackout. Both China and the Soviet Union immediately sent technicians into North Korea to repair or re-build lost generators. For much of the summer of 1952 only approximately 10% of former energy production was restored, primarily by its thermoelectric plants. Any effect the attacks had on

1896-426: The JCS. Secretary of Defense Robert A. Lovett , to whom the inquiries were made, cited seven factors, but some were long obsolete by the time of the attacks and others clearly badly estimated. Despite the lack of political effect on the truce talks, and the widely publicized negative reactions on both sides, the campaign against the hydroelectric system became an acceptable tactic of UN forces. Within ten days of

1975-482: The Korean coast at Mayang-do northeast of Hungnam and flew low over the mountains at 5,000 feet (1,500 m) to mask their radar signature . The propeller and jet divisions rendezvoused approximately 50 miles (80 km) east of Suiho shortly before 16:00 and climbed to the attack altitude of 10,000 feet (3,000 m) for a high-speed run-in. Eighty-four F-86 Sabres of the 4th and 51st Fighter-Interceptor Groups were

2054-652: The Korean peninsula and southern Manchuria ( Manchukuo at the time). After World War II, in 1947, the Soviet Union occupied the area, and dismantled and carried three of the seven generators to the Irtysh River dam in Kazakhstan . They were later re-installed during the 1950s. The dam's power station and transformer yard were targeted by the United Nations Command three times during the Korean War in order to disrupt power supply. Between 23 and 24 June 1952,

2133-456: The Kyosen complex were bombed by 102 Corsairs, 18 Skyraiders and 18 Panthers off the carriers. In all on June 23, Task Force 77 flew 208 strike sorties and FEAF 202. At 19:00, two RF-80 photo-recon aircraft of the 67th Reconnaissance Group , escorted by six flights of F-86s, returned to Sui-ho, while Marine F2H-2P Banshee photo-recon planes of VMJ-1 and Navy F9F-2P Panthers of VC-61 overflew

2212-476: The North Korean infrastructure by attacking the smaller power-generating plants of the North Korean power grid during the summer of 1952 to prevent them from filling the void in power generation. The Sui-ho Dam (now Supung Dam or sometimes Shuifeng Dam) on the Yalu River ( 40°28′N 124°58′E  /  40.467°N 124.967°E  / 40.467; 124.967 ), at the time the fourth largest in

2291-567: The Sui-ho Dam [REDACTED]   United Nations Multiple MiGs shot down/destroyed Unknown number of AA guns destroyed/damaged The attack on the Sui-ho Dam was the collective name for a series of mass air attacks during the Korean War on thirteen hydroelectric generating facilities by United Nations Command air forces as part of the North Korean bombing campaign on June 23–24 and June 26–27, 1952. Primarily targeting

2370-617: The Sui-ho generating plant with 79 sorties by F-84 Thunderjets of the 49th and 136th Fighter-Bomber Groups and 45 by F-80 Shooting Stars of the 8th Fighter-Bomber Group (8th Fighter-Bomber Wing). At almost the same time, 52 F-51 Mustangs of the 18th Fighter-Bomber Group and the South African 2 Squadron struck Fusen plants 3 and 4, west of Hungnam, while 40 Marine Skyraiders and F4U Corsairs of MAG-12 bombed Choshin No. 4, and 38 Panthers of MAG-33 hit Choshin No. 3. The lower Fusen plants and

2449-462: The Sui-ho, Choshin, Fusen and Kyosen No. 1 and 2 plants, most of the targets were re-struck the next day, June 24, in both morning and afternoon missions. In the morning missions, Air Force F-84s and Navy Skyraiders attacked Sui-ho, judging it totally destroyed, with one Skyraider suffering minor damage. Princeton aircraft bombed Fusen, Mustangs of the 18th FBG hit the unscathed Choshin plants 1 and 2, and planes off Boxer and Philippine Sea struck

Sup'ung Dam - Misplaced Pages Continue

2528-724: The UN staff, and Churchill's designate was appointed as a deputy chief of staff on July 31, 1952. The other factor crippling the political effect of the strikes occurred in the United States and was the opposite of that in Britain. Critics of the Truman administration in Congress quickly seized on the military success of the strikes to question why the attacks had taken almost two years to be approved. General Clark, who agreed, so advised

2607-493: The added force needed, arriving early on June 23. The mission was to be launched at 08:00 June 23 (all times local time zone), with strikes beginning at 09:30 at all targets. However, weather reconnaissance aircraft reported unbroken clouds over the Yalu River, and Weyland postponed the attack at 07:40. As the morning passed, however, the weather system moved south, and Weyland immediately reversed himself and at 13:00 ordered

2686-523: The armistice in 1953. Politically, the attacks failed to sway the truce talks, as highly publicized repercussions in both the UK and the United States Congress undermined their impact. Four attacks on a much more limited scale occurred between September 12, 1952, and June 7, 1953, causing only minor damage and little impact on the outcome of the truce talks. UN forces also exerted pressure on

2765-449: The attacks to proceed, but before that happened the JCS authorized MacArthur to enter North Korea and advised that targets of "long-term importance" including the hydroelectric plants should not be destroyed. A ban on bombing the Sui-ho (Sup'ung) Dam was put in place on November 6, 1950, at the direction of the U.S. State Department , to avoid providing a provocation for entry in the war by China . Even after China's massive intervention in

2844-487: The attacks to proceed, using the heavy clouds as concealment for the attackers en route to their targets, with a new attack time of 16:00. Aircraft from all four U.N. services were a mixture of propeller -driven and jet aircraft , and in general the propeller aircraft launched up to an hour earlier than the jets to coordinate their arrival over the target together. The carriers launched their propeller aircraft at 14:00 and their jets at 15:00. Air Force fighter-bombers, having

2923-407: The attacks. USS  Philippine Sea was already on the line during the planning process, joined by USS  Princeton on June 2 and USS  Boxer on June 9. Rear Adm. Apollo Soucek was aboard Boxer and took operational command of Task Force 77. When Weyland approved Navy participation in the Sui-ho strike, USS  Bon Homme Richard sailed from Yokosuka , Japan, on June 21 to provide

3002-418: The battleline—were excluded. The plans, submitted to Clark on June 11, included both FEAF and Task Force 77 units, and Clark approved the lesser plan on June 17, naming Weyland as "coordinating agent". However, in reviewing the plans, the JCS recommended to Truman that the Sui-ho Dam also be attacked and he approved. The JCS authorized the attack on June 19, and the alternate plan was put into effect with

3081-471: The blame, stating the U.S. was at fault for not consulting the British "as a courtesy", although the price for this stance was undercutting Clark and the Panmunjom negotiators. Naval historian James Field commented that cooperation between the services was much smoother than between the allies. While conferring with Alexander, Clark had already agreed in principle to British requests for a representative of

3160-546: The communist hierarchy's representatives at the truce talks was immediately negated by reaction of the Labour Party leaders Clement Attlee and Aneurin Bevan who criticized the operation as risking World War III , even though there were no allegations of territorial violations or objections that the plants were non-military targets. The Labour Party saw an opportunity to cripple the ruling Conservatives and called for

3239-431: The complex was still in limited operation, indicated by the flow of tailrace water from two turbines. Reconnaissance photographs of tailrace activity continued to indicate that two generators of the Sui-ho hydroelectric complex remained in operation. A low-level attack by 24 F-84s of the 49th FBG on February 15, 1953, carrying two 1000-pound bombs each and escorted by 82 F-86s, struck the complex without loss. However,

Sup'ung Dam - Misplaced Pages Continue

3318-483: The dam and power station. The generators removed by the Soviets were replaced and the installed capacity of the power station upgraded to 630 MW. In 1983, China began constructing an additional power station just downstream of the dam on their side of the river with two 67.5 MW generators. The first was commissioned in 1987 and the second in 1988. The most recent renovation occurred between 2009 and 2011 in order to improve

3397-420: The dam consists of 16 sluice gates and has a maximum discharge capacity of 17,046 m/s (601,974 cu ft/s). The dam's reservoir has a capacity of 14,600,000,000 m (11,836,413  acre⋅ft ) of which 7,900,000,000 m (6,404,634  acre⋅ft ) is active (or "useful") for power generation. The dam sits at the head of a 52,912 km (20,429 sq mi) catchment area and its reservoir has

3476-491: The dam was attacked by 250 bombers and fighters, dropping 90 tons of munitions on the power station, transformer yard and auxiliary facilities. The power station was destroyed but the dam left intact. After intelligence indicated it may have been partially operational again, the power station was again targeted and disabled on 12 September 1952 by B-29 bombers. By 1 February 1953, it was believed that two generators had been repaired and were operational once again. This resulted in

3555-550: The dam's main 630 MW power station is evenly shared between China and North Korea. The dam is featured on the national emblem of North Korea . In 1937, during Japan's colonization of Korea , the Yalu Hydroelectric Company was established and in the same year construction began on the dam, with the Pyeongbuk Railway opening a rail line in 1939 to assist with the construction. In 1941, the dam

3634-477: The day, but 25 bombers already prepared for the mission were re-targeted to radar-directed close support sorties along the front lines. After a pause on June 25, Choshin and Fusen were re-attacked by smaller numbers of Air Force fighters on June 26–27 to complete the hydroelectric attacks. Total bombing sorties during the four-day effort were 730 by land-based fighter-bombers and 546 by carrier aircraft. F-86 Sabres flew an additional 238 counter-air sorties to protect

3713-406: The design of high-efficiency turbines to precisely match a site's water flow and pressure ( water head ). A Francis turbine consists of the following main parts: Spiral casing : The spiral casing around the runner of the turbine is known as the volute casing or scroll case. Throughout its length, it has numerous openings at regular intervals to allow the working fluid to impinge on the blades of

3792-549: The eastern systems to assess damage. Two F-80s of the 8th FBW were battle-damaged by flak over Sui-ho, and written off after crash landings at Taegu . An F4U flown by the squadron commander of VF-63 (from Boxer ) was heavily damaged over Kyosen No. 4 and made a water-landing in which the pilot was rescued, the only naval plane lost. A VA-115 Skyraider (from Philippine Sea ) had its hydraulic system damaged by flak over Sui-ho and diverted to K-14 airfield in South Korea, for

3871-512: The enemy used incendiary and napalm bombs. The dam, the working turbines, the generators and the transformers were not damaged. The shock waves destroyed a high-voltage overhead cable and six peasant huts. The warehouse storing the POW’s food burned down. One local man was killed and two were wounded. Despite initial USAF estimates claiming five hits on the main powerhouse and three on the transformer yards, photo reconnaissance on October 12 reported that

3950-475: The escorts were attacked by 30 MiG-15s, and in the ensuing combat the Soviet 913th IAP (32nd IAD) claimed two F-86s shot down, for the loss of one MiG. Escorting F-86s, however, claimed four MiGs shot down and reported no losses. Francis turbine The Francis turbine is a type of water turbine . It is an inward-flow reaction turbine that combines radial and axial flow concepts. Francis turbines are

4029-418: The event of complete stalemate, and he repeated his recommendation to bomb the hydroelectric plants. Ridgway objected to the JCS on May 1, stating that no attack should be made except on his recommendation, to which the JCS agreed. The next day the communists totally rejected the UN proposal, and while the talks continued, the UN took the stance that their position was irrevocable. Clark took command on May 12,

SECTION 50

#1732791778715

4108-626: The fifteen attacks by the Navy, no carrier aircraft were lost. Further B-29 sorties were directed against Choshin No.1, sixteen on the night of August 29, and fifty on the night of September 1. The United Nations again attacked the Sui-ho hydroelectric complex on the night of September 12–13, 1952, employing a strike force consisting of flak/searchlight suppression flights of B-26 Invaders and naval aircraft of USS Princeton , an electronic counter-measures flight of four specially modified B-29 Superfortresses to jam Soviet AAA radars and communications, and

4187-532: The first of a series of key changes in the military command in Korea. On May 19 Vice Admiral Joseph J. Clark became commander of the Seventh Fleet , on May 30 Lieutenant general Glenn O. Barcus took over the Fifth Air Force , and on June 4 Vice Admiral Robert P. Briscoe became commander of Naval Forces Far East. All brought a new aggressiveness to their commands and were desirous of attacking

4266-450: The first to arrive in the Sui-ho target area, tasked to provide cover against MiG attack and, according to one participant, to prevent MiGs from taking off by overflying their bases at low altitude, even though officially UN aircraft were not allowed to cross the Yalu except in hot pursuit . According to US sources, 160 MiGs took off before the arrival of the covering force but flew deeper into China, possibly fearing that their airfields were

4345-537: The following month the ban was never rescinded, and it was reiterated by the UN Command when the truce talks began in July 1951. On March 3, 1952, when the peace talks appeared to be near stalemate, FEAF commander, General Otto P. Weyland , recommended to UN commander General Matthew Ridgway that the hydroelectric plants be attacked to "create psychological and political effects to our advantage." Ridgway rejected

4424-562: The force from MiGs. UN losses were five aircraft: two Navy Corsairs crashed at sea and three Air Force jets written off at their home bases. All of the pilots were rescued. Approximately 90% of North Korea's power-production capacity was destroyed in the attacks, with 11 of the 13 generating plants put totally out of operation and the remaining two doubtful of operating. China suffered an estimated loss of 23% of its electric requirements for northeast China, and other intelligence estimates stated that industrial output in 60% of its key industries in

4503-467: The function of the dam's spillways. The US$ 24.5 million renovation was funded by State Grid Corporation of China . The Supung is a 106 m (348 ft) tall and 899.5 m (2,951 ft) long concrete gravity dam with a crest elevation of 126.4 m (415 ft). The dam's spillway consists of 26 sluice gates with a maximum discharge capacity of 37,650 m/s (1,329,597 cu ft/s). An auxiliary spillway 1.7 km (1 mi) north of

4582-436: The guide and stay vanes is to convert the pressure energy of the fluid into kinetic energy. It also serves to direct the flow at design angles to the runner blades. Runner blades : Runner blades are the heart of any turbine. These are the centers where the fluid strikes and the tangential force of the impact produces torque causing the shaft of the turbine to rotate. Close attention to design of blade angles at inlet and outlet

4661-515: The highest possible efficiency, typically over 90% (to 99% ). In contrast to the Pelton turbine , the Francis turbine operates at its best completely filled with water at all times. The turbine and the outlet channel may be placed lower than the lake or sea level outside, reducing the tendency for cavitation . In addition to electrical production , they may also be used for pumped storage , where

4740-549: The hydroelectric complex associated with the Sui-ho Dam in North Korea , the attacks were intended to apply political pressure at the stalled truce negotiations at Panmunjeom . Heavily defended by Soviet , Chinese and North Korean Air Forces , as well as major anti-aircraft guns, the hydroelectric targets were subjected to attacks totaling 1,514 sorties. These were conducted jointly by fighters and fighter-bombers of

4819-535: The hydroelectric plants. Briscoe made the recommendation to Clark on June 6, followed by Weyland the next day. At Clark's direction, FEAF prepared two attack plans on the system, one of which included bombing the Sui-ho Dam while the other did not. The three systems in South Hamgyong were targeted, while two smaller systems—one near the border with the Soviet Union and the other immediately behind

SECTION 60

#1732791778715

4898-453: The jamming by the ECM aircraft encountered a dense flak barrage. A B-29 of the 307th BG was shot down, either by a MiG-15 as claimed by the Soviets or by AAA as reported by a surviving crew member, and another of the 19th BG was damaged. Two others were hit by flak, making emergency landings at Taegu AB, South Korea. The intensity of AAA fire and MiG attacks dispersed the bomber formation with

4977-525: The longest distance to fly, took off at 14:30. Because the Sui-ho Dam was located less than forty miles (64 km) from the MiG-15 fighter base complex at Antung/Tai Ton Chao/Phen Chen in China, where 150 MiGs had been counted by the weather reconnaissance, a coordinated simultaneous arrival over the targets was crucial to limiting the effectiveness of any defensive reaction. The carrier aircraft of TF77 crossed

5056-677: The mission had been cancelled because of fog in the target area. Bon Homme Richard' s Air Group Seven further damaged Kyosen No.1, but smoke obscured Kyosen No.2, and it was restruck on July 8, destroying its powerhouse and penstocks (piping that delivers water to the turbines). USAF F-84s of the 49th FBW attacked the Choshin plants on July 8, striking the generators, transformer yards, and penstocks in 41 sorties. On July 19, Air Group Seven's aircraft bombed Choshin No. 3, scoring five hits on its transformer yard, while Air Group Nineteen aboard Princeton bombed Choshin No. 1, and again on July 20, noting

5135-425: The most common water turbine in use today, and can achieve over 95% efficiency. The process of arriving at the modern Francis runner design took from 1848 to approximately 1920. It became known as the Francis turbine around 1920, being named after British-American engineer James B. Francis who in 1848 created a new turbine design. Francis turbines are primarily used for producing electricity. The power output of

5214-622: The outbreak of the war, and all were on the list of strategically important targets compiled by the Joint Chiefs of Staff (JCS). B-29 Superfortresses of the United States Air Force had begun bombing industrial targets in North Korea soon after the invasion of the South in the summer of 1950 but had not attacked any part of the power transmission grid. As early as August 23, 1950, while UN forces were still struggling to hold

5293-400: The plan and also informed the JCS that he was unwilling to use force except as the last resort. On April 28, President Harry Truman announced that Ridgway was being replaced as commander in Korea by General Mark Clark , and UN negotiators at Panmunjom made a compromise proposal on the stalemated issues. The next day the JCS asked Weyland to provide target information and recommendations in

5372-477: The power grid at Chungdae-ri, Naemǒkpang, and Man'gyo-ri, in the vicinity of Kojǒ ( Kangwon Province ), and at Yuchǒn, Haeju, Chaeryong, Kaishu, and Chang-yôn in North Hwanghae Province . Attacks by B-29 Superfortresses scheduled against Choshin No. 1 and 2 for the night of June 24–25, on the second anniversary of the start of the war, were cancelled after the targets were struck by F-51s during

5451-433: The ratio of pressure energy change in the blades to total energy change of the fluid. This means that it is a ratio indicating the fraction of total change in fluid pressure energy occurring in the blades of the turbine. The rest of the changes occur in the stator blades of the turbines and the volute casing as it has a varying cross-sectional area. For example, if the degree of reaction is given as 50%, that means that half of

5530-434: The remainder of the Kyosen plants. In the afternoon Princeton completed the destruction of Kyosen No. 3, but incurred the loss of a Corsair of VF-192 in the process, although the pilot was rescued at sea by a helicopter from USS  Helena . An F-86E of the 335th FIS was written off after its return to K-14, the result of damage by a MiG attack. Aircraft from the other three carriers struck transformer stations along

5609-400: The runner. These openings convert the pressure energy of the fluid into kinetic energy just before the fluid impinges on the blades. This maintains a constant velocity despite the fact that numerous openings have been provided for the fluid to enter the blades, as the cross-sectional area of this casing decreases uniformly along the circumference. Guide and stay vanes : The primary function of

5688-606: The same principles. S. B. Howd obtained a US patent in 1838 for a similar design. In 1848 James B. Francis , while working as head engineer of the Locks and Canals company in the water wheel-powered textile factory city of Lowell, Massachusetts , improved on these designs to create more efficient turbines. He applied scientific principles and testing methods to produce a very efficient turbine design. More importantly, his mathematical and graphical calculation methods improved turbine design and engineering. His analytical methods allowed

5767-529: The strike, to avoid pointless losses during takeoffs. At 16:00, 35 Navy F9F Panthers began runs to suppress the anti-aircraft fire from 44 heavy caliber gun and 37 automatic weapons emplacements reported around the dam. Twelve AD Skyraiders of VA-65 off Boxer then began their dive-bombing runs on the Sui-ho generating stations, followed by 23 Skyraiders off Princeton and Philippine Sea , releasing 81 tons of bombs in little more than two minutes. Between 16:10 and 17:00, USAF jets added 145 tons of bombs on

5846-467: The strikes, UN air forces resumed attacks to keep the power grid out of service, although the Sui-ho Dam and its environs were not among the targets. Task Force 77 renewed its strikes on July 3 with attacks by Navy aircraft from the carriers Philippine Sea , Bon Homme Richard , and Boxer . Both Kyosen power plants were targeted, as were three power plants at Puryŏng-ŭp (Funei). The latter, previously unstruck, had been scheduled to be bombed on June 29 but

5925-759: The targets, and none attempted to intercept the strike force. Incursions into Manchuria by pilots of the 51st FIG to surprise MiGs over their own airfields had resulted in heavy losses for the 64th IAK during the previous months, with at least half of the MiGs destroyed in April and May 1952 shot down during take-offs or landings. The Soviets developed a counter-tactic to cover takeoffs from Antung with combat air patrols launched from Mukden and Anshan, but on June 23, despite good weather over Antung, inclement conditions at Mukden prevented covering MiGs from taking off. In turn, this kept Soviet fighters based at Antung from countering

6004-883: The total energy change of the fluid is taking place in the rotor blades and the other half is occurring in the stator blades. If the degree of reaction is zero it means that the energy changes due to the rotor blades is zero, leading to a different turbine design called the Pelton Turbine . The second equality above holds, since discharge is radial in a Francis turbine. Now, putting in the value of 'e' from above and using V 1 2 − V f 2 2 = V f 1 2 cot ⁡ α 2 {\displaystyle V_{1}^{2}-V_{f2}^{2}=V_{f1}^{2}\cot \alpha _{2}} (as V f 2 = V f 1 {\displaystyle V_{f2}=V_{f1}} ) Francis turbines may be designed for

6083-537: The world, had been constructed in 1941 by Japan . The concrete dam was 853 m (2,799 ft) long, 97 m (318 ft) thick at the base, 18 m (59 ft) wide at the crest, and 160 m (520 ft) high. Its reservoir storage capacity was more than 20 billion cubic meters, and the Japanese had built six turbine generators each with a capacity of 100,000 kilowatts . The dam's generating facilities provided power for much of western North Korea and for

6162-520: Was available. After electric generators were developed in the late 1800s, turbines were a natural source of generator power where potential hydropower sources existed. In 1826 the French engineer Benoit Fourneyron developed a high-efficiency (80%) outward-flow water turbine. Water was directed tangentially through the turbine runner, causing it to spin. Another French engineer, Jean-Victor Poncelet , designed an inward-flow turbine in about 1820 that used

6241-404: Was complete with two 100 MW generators operational, and the emperor of Manchukuo , Puyi , visited the dam. Four more generators were later operational in 1943. The seventh generator was German-made and not delivered due to shipping difficulties during World War II . At the time of its completion, the dam was the largest in Asia and third largest in the world. Power from the dam was used throughout

#714285