The first AWACS aircraft in the United States were created during the Second World War. The urgent need for such machines appeared after the Japanese attack on Pearl Harbor. American admirals wanted to receive information about the approaching enemy aircraft with enough time to lift fighters into the air. In addition, the aircraft of the radar patrol could control the actions of their own aviation at a distance from the aircraft carrier.
The first American "flying radar" TBM-3W with APS-20 radar was built on the basis of the torpedo bomber "Avenger". The HTVM-3W prototype took off for the first time in August 1944, and the US Navy, faced with kamikaze attacks in the battles for Okinawa, ordered the immediate conversion of 40 TVM-3 and TVM-3E aircraft into the TVM-3W radar patrol aircraft. However, these vehicles did not have time for the war, the first operational unit with combat-ready TVM-3Ws, appeared in the fleet only at the beginning of 1946.
The operation of the TVM-3W on the decks of aircraft carriers and coastal airfields has made it possible to accumulate the necessary experience and formulate the requirements for the next generation “flying radars”. The American military realized that, along with a compact carrier-based aircraft, a coastal-based vehicle with a greater range and time in the air was also needed. In addition, the use of a more spacious four-engine platform made it possible to improve working conditions, increase the number of crew members and the power of the radar.
In 1945, 24 B-17G bombers, after installing the APS-20 radar, were operated by the US Air Force under the designation PB-1W. These machines did not have time to take part in the war, just like the TVM-3W, but they continued to serve until 1955, when they were replaced by the WV-2 radar patrol aircraft.
In 1951, three B-29 bombers were converted into WB-29 AWACS aircraft for the Air Force, and the improved APS-20A radar was installed on these machines. Unlike Avenger, long-range bombers had significantly longer patrol times. But the capabilities of the already obsolete radar with a detection range of 50 miles no longer suited the military.
When creating the next aircraft for the radar patrol, American experts drew attention to the Lockheed C-69 Constellation ("Constellation"). This four-engine military transport vehicle has been used by the American military for long-distance transport since 1944. In general, the aircraft proved to be quite good, during the war they managed to build 22 units, but after the end of hostilities, large-scale orders from the military department, on which the management of the Lockheed company were counting, did not follow.
Lockheed c-69 constellation
In the post-war period, the L-049 passenger airliner was created on the basis of the military transport C-69, but it was difficult for it to compete with the Douglas DC-6. The airlines bought the Douglas aircraft much more willingly, in addition, there was an excess of aircraft in the civilian transport and passenger segment in the United States immediately after the war, as there were many demobilized inexpensive aircraft in very good condition on the market. In this regard, in general, a very good airliner L-049 was in little demand.
Several airlines purchased the Constellation for long-haul flights, for example, Pan American World Airways (Pan Am) from February 5, 1946 used an upgraded Lockheed L-749 Constellation with increased fuel capacity and a reinforced landing gear for transatlantic flights. In 1948, the military transport S-121A appeared, featuring a reinforced floor and a large aft cargo door. In 1947, the United States Air Force (USAF) signed a contract with Lockheed for ten transport aircraft. In 1950, six C-121A were converted to carry VIPs and renamed VC-121A, of which three were used for overseas official visits by President Dwight D. Eisenhower.
Dwight D. Eisenhower's VC-121A
It was on the basis of the C-121A that the US Navy (USN) decided to build coast-based AWACS aircraft under the designation PO-1W (later WV-1). The first RO-1W flight took place on June 9, 1949. Radar fairings on this aircraft were located in the lower and upper fuselage.
PO-1W at Barbers Point Airfield in 1952
The first PO-1W radar surveillance and surveillance aircraft were, in fact, flying laboratories, and few were built. On two PO-1Ws, equipment was tested and the technique of airborne watch was worked out. It soon became clear that the composition of the radar equipment and its placement were not optimal. After renaming to WV-1, the aircraft were transferred to the United States Federal Aviation Administration (FAA), where they were used until 1959.
In the late 1940s, Lockheed specialists attempted to increase the airliner's carrying capacity and fuel efficiency by lengthening the fuselage. But at that moment there were no suitable engines for them. In 1953, the Lockheed L-1049 Super Constellation lengthened by 18 feet (5.5 m) took off. The new modification used Wright R-3350 stage turbocharged piston engines. Engines of the Wright R-3350 Duplex-Cyclone family were among the most powerful production piston engines, being an air-cooled, turbocharged, twin 18-cylinder star. Initially, these engines were used on the B-29 bombers.
Serial military transport aircraft were equipped with four Wright R-3350-75 engines with a capacity of 2500 hp. each. The Super Constellation passenger aircraft served as the basis for the C-121C military-technical cooperation, and on the basis of this version in 1953, the PO-2W AWACS aircraft was created. The initial order was for the construction of 10 vehicles.
The third instance of PO-2W built during a test flight
Unlike the PO-1W, the elongated PO-2Ws with new engines were already fully-fledged airspace control aircraft. When designing them, the shortcomings of the previous model were taken into account. The PO-2W was equipped with the improved APS-20E radar and the APS-45 radar.
The advanced radar APS-20E with a peak power of up to 2 MW operated at a frequency of 2880 MHz, it detected large surface targets at a distance of up to 300 km. The detection range of the B-29 bomber flying at an altitude of 7000 meters near the APS-20E station was 150 km, and the F-86 fighter - 115 km. The detection range of the APS-45 station operating at a frequency of 9375 MHz in the lower hemisphere was 200 km. The PO-2W crew initially consisted of 18 people, of which six officers (two pilots, two navigators, two senior shift officers) and 12 enlisted men (two flight engineers, one radio operator, two shift commanders of operators, five radar operators, two radar technique). In the later versions with an expanded composition of equipment, the staffing of the crew was 26 people.
APS-45 radar operator's workplace
In 1954, the PO-2W was renamed WV-2. The aircraft entered the order of the Navy and from 1956 to 1965. used in the "Barrier Forces". By the beginning of the massive arrival of radar patrol aircraft in the US Navy, the views of admirals regarding their use had changed. Instead of providing cover for aircraft carrier groups, the main task was to provide air defense for the continental United States. AWACS aircraft became part of the so-called "Atlantic Barrier" created in 1956, and 1958 into the "Pacific Barrier". However, WV-2s were not the only means of monitoring the air situation along the western and eastern coasts of the United States. Coastal radars, radar patrol ships (converted Liberty-class transport ships and destroyers), as well as ZPG-2W and ZPG-3W balloons were linked into a single warning network. The main purpose of the "Barrier Force", located on the Atlantic and Pacific coasts of the United States, was to monitor the airspace for the purpose of early warning of approaching Soviet bombers. The Barrier Force was a complement to the DEW line radars located in Alaska, Canada and Greenland.
The first AWACS aircraft entered two squadrons in Patuxent River, one more squadron was deployed in Canada in the area of Newfoundland and Barbers Point. After the US Navy tested the WV-2 for six months and eliminated "childhood sores", an order was placed for another 132 AWACS aircraft. The following options received a more advanced avionics. Designed during the Second World War, the morally and physically obsolete APS-20 radar was replaced by a modern AN / APS-95 station operating in the 406-450 MHz frequency range. The AN / APS-95 station could see surface and air targets at a distance of up to 400 km.
Even at the design stage, the designers paid great attention to the convenience and habitability of the crew and operators of electronic systems, as well as ensuring the protection of personnel from microwave radiation. The patrol time was usually 12 hours at an altitude of 4000 to 7000 meters, but sometimes the duration of the flight reached 20 hours. Due to the fact that the duration of the flight often exceeded 12 hours, there was a refrigerator with a stock of food, a kitchen and places to rest on board.
For the Navy, Lockheed offered the XW2V-1 long-range radar patrol aircraft with Allison T56 turboprop engines based on the Lockheed L-1249 Super Constellation airliner. It was supposed to have a higher flight speed and carry a new generation of radars, in addition, the aircraft was supposed to be armed with air-to-air missiles. That is, in addition to the AWACS functions, the new machine could be used as a loitering interceptor. However, this project did not interest the military, and not a single prototype was ever built.
"Flying radars" patrolling the Atlantic coast flew to the Azores, also in their area of responsibility included Greenland, Iceland and the British Isles. The aircraft made a stopover at Keflavik airbase in Iceland. In the Pacific Ocean, taking off from Barbers Point, WV-2s sometimes flew to Hawaii and made a stopover at Midway airfield. For full radar coverage, five radar patrol aircraft had to be on the patrol route. At the same time, they worked closely with the ships of the US Navy. To ensure round-the-clock watch in the air, taking into account possible technical problems, nine vehicles were required.
In 1962, the WV-2 received the designation EC-121C Warning Star, and in 1965 the operations of the Barrier Force were terminated. First of all, this was due to the fact that the main threat to the territory of the United States began to be presented not by Soviet long-range bombers, but by ICBMs, which the AWACS aircraft could not detect in time. Approximately half of the ES-121C aircraft of the first series. owned by the Navy, was sent to the storage base "Davis Montan" or they were converted for other purposes. 13 naval AWACS WV-2 aircraft were converted into WV-2Q radio reconnaissance aircraft. They were used in the RTR VQ-1 (Pacific Fleet) and VQ-2 (Atlantic) squadrons.
Several aircraft changed their specialization as a result of the replacement of electronic filling. Eight WV-3 (WC-121N) were used for weather reconnaissance and typhoon tracking. For this, the standard radars of the AWACS aircraft were modernized, which made it possible to stay outside the storm wind zone and monitor the vortex from a safe distance. However, the hurricane catcher service was quite dangerous. On August 1, 1964, Hurricane Clio severely battered board # 137891. The plane's fuselage was deformed by the elements, the end fuel tanks were torn off, and most of the onboard electronics were disabled. Nevertheless, the crew managed to safely land the vehicle, which could not be restored.
The vehicles that remained in service underwent refurbishment and modernization and were used to monitor the airspace of Cuba, the USSR, the PRC and the DPRK. The aircraft were based at Atsugi airbases in Japan, Rota in Spain, Jacksonville in Florida, Roosevelt Roads in Puerto Rico and Agana in Guam.
NC-121C
The aircraft, designated NC-121C, received a set of equipment for jamming. This machine was mainly used as a "training desk" in the training of specialists in the field of electronic warfare. In addition, during the exercises, the NC-121C often imitated Soviet electronic warfare aircraft, it was used to interfere with American ground, sea and airborne radars. The aircraft numbered 141292 served in the 33rd tactical squadron of the Navy (VAQ-33) stationed at Key West airbase until 1982, after which it was sent to the "bone graveyard" in Davis Montan.
WV-2E
In 1957, the WV-2E flying laboratory was built with the AN / APS-82 radar, which had a rotating antenna in a disc-shaped fairing. Thanks to this solution, the ability to detect air targets against the background of the earth has increased. But the Warning Star aircraft with a rotating antenna was built in a single copy. An advanced radar station with a circular view capable of detecting targets against the background of the earth, showed low reliability and required fine-tuning. In addition, a serious drawback of an aircraft with relatively low-power piston engines was a small practical ceiling (the higher the radar is located, the greater the range it can cover).
A little later than in the navy, the EU-121 was adopted by the US Air Force. At the same time, the features of operation and disadvantages of early models were taken into account. The first in the Air Force were 10 RC-121Cs, originally intended for the Navy. On these machines, the obsolete APS-20 radar was immediately replaced by the AN / APS-95 station. In the Air Force, the EU-121C was brought together into specially formed 551st and 552nd AWACS and control wings deployed at Otis airbases (Massachusetts) and McKillan (California). But the age of the EC-121C in the Air Force was short-lived, after the appearance of more advanced modifications of the Warning Starov, they all rushed to withdraw to the reserve and re-equip them into TS-121S training aircraft intended for training AWACS aircraft operators.
EC-121D
Soon the EC-121D became the main one for the Air Force; this model differed from earlier modifications by improved equipment of the operator's cabin and an increased fuel reserve. In total, the Air Force received 72 new RC-121Ds in 1952-1954. Another 73rd copy of this modification was obtained by re-equipping one of the military transport C-121S.
LTH EC-121D
The introduction of the SAGE automatic fighter-interceptor guidance system in the United States and Canada required an upgrade of the EC-121D aircraft equipment to enable them to interact with the system. In 1962, additional equipment of AWACS aircraft began with automatic data transmission equipment to ground control points of the air defense system. The repeater antenna was mounted in a small fairing at the top of the fuselage. A total of 42 aircraft received such transmitters. Vehicles with automated radar information repeaters were designated EC-121H and EC-121J. These aircraft differed among themselves in the composition of the avionics of the operator's workplaces. The nominal number of crew members on the later modifications of the EC-121 reached 26 people.
The introduction of the SAGE automatic fighter-interceptor guidance system in the United States and Canada required an upgrade of the EC-121D aircraft equipment to enable them to interact with the system. In 1962, additional equipment of AWACS aircraft began with automatic data transmission equipment to ground control points of the air defense system. The repeater antenna was mounted in a small fairing at the top of the fuselage. A total of 42 aircraft received such transmitters. Vehicles with automated radar information repeaters were designated EC-121H and EC-121J. These aircraft differed among themselves in the composition of the avionics of the operator's workplaces. The nominal number of crew members on the later modifications of the EC-121 reached 26 people.
The most advanced, but not numerous, modification of the Warning Star in the Air Force was the EC-121Q. On this aircraft, the AN / APS-45 radars were replaced by the AN / APS-103 radars. The new radar made it possible to steadily see targets against the background of the earth's surface. Four EC-121Q aircraft became part of the 966th AWACS Air Wing and Controls at McCoy Air Base (Florida). At the very end of the 60s, seven EC-121Ns and 15 EC-121Ds received new "friend or foe" equipment and improved means of displaying radar information. This variant was designated EC-121T. In 1973, part of the ES-121T was equipped with AN / ALQ-124 electronic reconnaissance and jamming stations.
In the 60s and 70s, the now largely forgotten EC-121 Warning Star was one of the symbols of the Cold War, along with the B-52 Stratofortress bombers, the P-3 Orion base patrol aircraft or the F-4 Phantom II fighters. Cuba became the first "hot spot" for the EU-121. The southern tip of Florida was what is called “one step” from the Cuban coast. A fighter flying at the speed of sound could cover a distance of 100 km in about 5 minutes. After the modern jet combat aircraft supplied from the USSR appeared in Cuba, American "flying radars" began to control the airspace of the "Freedom Island". In addition to tracking the ES-121 aircraft taking off from Cuban airfields, they escorted and provided information support to U-2 high-altitude reconnaissance aircraft that regularly flew over the island. Particularly close attention to Cuba became with the beginning of the "Cuban missile crisis". After the parties agreed, and the missiles were withdrawn from the island, tensions in this region significantly decreased, however, patrol flights of the EU-121 around Cuba continued until the decommissioning of these aircraft.
Just like many other American aircraft, the combat debut of the EU-121 was the war in Southeast Asia. In 1965, the Committee of the Chiefs of Staff of the US Armed Forces decided to send three EC-121Ds from the 552nd Air Wing into the combat zone. However, the planes did not go to South Vietnam, but to Taiwan, at the beginning of 1967 the Ubon in Thailand became the base airfield. In 1965, the activity of the DRV aviation was small, the main task of the Warning Star crews was air traffic control in the airspace of South Vietnam, as well as navigation support for the aircraft participating in the raids on the DRV. However, already in 1967, AWACS aircraft began to coordinate the actions of American aviation in the conduct of air battles with North Vietnamese MiGs.
In the middle of 1970, due to problems with ensuring flight safety and the destructive influence of the tropical climate on avionics, EC-121D aircraft were withdrawn from Thailand. But the commanders of the air units directly participating in the hostilities, left without the support of the air patrols, insistently demanded their return. By that time, the MiG-21s of the DRV Air Force were already posing a serious threat to American aviation. The AWACS aircraft were returned to the Korat airbase in Thailand in November 1970. These were seven modernized ES-121T 552 airborne AWACS and electronic warfare. "Warning Stary" carried out combat missions until August 15, 1973, operating, including from the Thai airbase "Ubon". Thanks to the information received from the AWACS in a timely manner, it was possible to thwart several attacks of the Serovian MiGs. In addition, the ES-121T radars have repeatedly recorded the launches of the S-75 air defense system against American bombers in the airspace of the DRV. This made it possible to carry out an evasive maneuver in a timely manner, apply countermeasures and determine the location of the air defense missile system's positions.
The ES-121 in Southeast Asia flew 98699 hours in 13921 sorties without incurring combat losses, although there were several attempts to break through to them by fighters of the DRV Air Force. Usually, while on duty, the ES-121 was covered by the Phantom unit. With the informational support of Warning Star, a dozen and a half MiGs were shot down in air battles, about 135,000 sorties of strike aircraft were carried out and more than 80 search and rescue and special operations were carried out.
Talking about AWACS aircraft, it is worth mentioning other machines from the "Constellation" family. Five EC-121Cs were redesigned EC-121R Batcat, these reconnaissance aircraft flying over South Vietnam received information over the radio channel from a network of reconnaissance acoustic and seismic sensors scattered from the air. Analyzing the information received from the ES-121R reconnaissance aircraft, the American command decided to strike at certain parts of the jungle, thus trying to prevent the covert movement of the partisans. The value of ground reconnaissance units was especially great at night, when it was difficult to conduct visual aerial reconnaissance.
EC-121R Batcat
The EC-121R Batcat aircraft were camouflaged, making them difficult to spot against the ground. Two such aircraft were lost in Vietnam. One crashed while landing on September 6, 1969. Another was lost on April 25, 1969, and is believed to have crashed during a thunderstorm.
The electronic reconnaissance aircraft received the designation EC-121M. Several of these vehicles also operated from air bases located in Thailand. In addition to determining the coordinates of the radar and the characteristics of high-frequency radiation, electronic reconnaissance officers were able to intercept messages transmitted from VHF radio stations and over radio relay lines. From July 1970 to January 1971, five EC-121S electronic warfare aircraft from the 193rd electronic warfare squadron operated in Southeast Asia. In addition to jamming, the electronic equipment of these aircraft made it possible to record the operation of onboard radio sources of Soviet-made fighters.
The service of AWACS, electronic warfare and electronic reconnaissance aircraft of the Sozvezdiye family continued in the United States for almost 30 years. The EC-121 was serially built from 1953 to 1958. In the late 1950s, the new RC-121D cost the US treasury more than $ 2 million. According to American data, 232 aircraft were transferred to the Air Force and Navy during this time, but, apparently, this number includes not only radar patrol aircraft, but also other special modifications. At the same time, most of the aircraft built have been repeatedly re-equipped and modernized, mainly related to the "electronic filling". Automated systems controlled by computers were introduced into its structure. The transition from electric vacuum devices to solid-state electronics made it possible to reduce the weight of equipment and its energy consumption.
Aircraft EC-121 of all modifications were actively used at the forefront of the Cold War. In the 60s and 70s, these machines often made provocative flights, keeping the Soviet air defense system in suspense. Often, fighters had to be lifted into the air to drive them out of Soviet airspace. In total, over the years of service, the US Navy lost 20 EU-121s in flight accidents, while 113 crew members died. The Air Force, in turn, lost 5 aircraft, 50 people died in accidents.
But not all "Warning Stars" were lost for "natural reasons", it is reliably known about one downed plane, although there could have been more. On April 15, 1969, an EC-121M reconnaissance aircraft with tactical number "PR-21" from the US Navy's VQ-1 aerial electronic reconnaissance squadron took off from Atsugi airbase in Japan at 07:00 local time. The plane headed for the north-west of the Sea of Japan, the crew intended to fly along the air border with the Soviet Union and the DPRK. After completing the mission, the EC-121M was to land at Osan Air Base in South Korea. In the past, this and other similar aircraft have already performed about 200 reconnaissance flights along this route. The flight was carried out in the interests of the intelligence services of the Seventh Fleet, the Unified Asia-Pacific Command and the US National Security Agency. There were 31 people on board. In addition to pilots, navigators, flight engineers, control officers, radar operators and technicians serving electronic equipment, the crew included linguists who spoke Russian and Korean. The crew commander was instructed not to approach closer than 50 nautical miles (90 km) to the coast of North Korea.
After takeoff, the aircraft maintained communications and radar contact with the Hakata and Yokota airbases in Japan. At the same time, American radio intercept stations in Japan and South Korea controlled the radio networks of the Soviet and North Korean air defense forces. At 10.15am, signals from the DPRK were intercepted indicating that an American reconnaissance aircraft had been detected, but since the ES-121M was sailing outside North Korean airspace, this activity was considered not dangerous. Radars in South Korea recorded several MiG-17s and MiG-21s taking off in the Wonsan area, but soon lost sight of them. At about 14:00 local time, communication with the ES-121M was lost. After 10 minutes, two F-106 Delta Dart interceptors took off from an airfield in South Korea for control, but they were unable to locate the Warning Star, which had disappeared from the radar screens.
A few hours later, a search and rescue operation began, a search HC-130 Hercules and a KC-135A Stratotanker tanker were sent to the alleged crash site about 90 nautical miles (167 km) from the North Korean port of Thengdinbu. Two American destroyers left the Japanese port of Sasebo in search of them.
The first results were received the next day, at about 09:30 am. The American P-3B Orion anti-submarine aircraft detected in the area two Soviet destroyers, pr. 56 and pr. 61, and established radio communication with them. From the Soviet ships reported the discovery of aircraft wreckage. The American destroyer "Henry W. Tucker", which arrived at the crash site, received the wreckage from the destroyer "Inspirational", after which the Pacific Fleet ships left the search area. The Americans managed to find the bodies of two crew members of the missing ES-121M among the wreckage. Soon, by the nature of the damage to some fragments of the discovered wreckage, the Americans came to the conclusion that their reconnaissance aircraft had been shot down by a K-13 missile. Apparently, the ES-121M was attacked by the North Korean MiG-21.
Soon, DPRK officials announced that the American "spy plane" was shot down after it invaded DPRK airspace. The fact that the attack on the Warning Star took place on April 15, 1969, on the day of the celebration of Kim Il Sung's 57th birthday, makes this incident especially piquant. It may also be recalled that shortly before that, on January 23, 1968, there was an incident with the American reconnaissance ship "Pueblo". The DPRK warships, after the shelling, escorted the Pueblo to the North Korean port of Wonsan. The United States had to publicly apologize and admit the invasion of the territorial waters of North Korea in exchange for a promise from the DPRK authorities to release the captured American sailors. After the whole world learned that the American plane was shot down by a North Korean fighter jet, there were no serious consequences for the DPRK. Having received information about the destruction of the EU-121M, the US leadership initially gave the order to send a squadron of ships to the shores of North Korea. The largest ships in the squadron would be the nuclear-powered aircraft carrier Enterprise, the aircraft carriers Ticonderoga, Ranger, Hornet, and the battleship New Jersey. Hundreds of bomber and tactical squadron aircraft were additionally deployed to South Korea. But in the end, the Nixon administration chose not to exacerbate the situation against the background of the extremely belligerent rhetoric of the DPRK leadership.
EC-121D at the National Museum of the United States Air Force
In the late 70s, the EC-121 began to be replaced in the radar patrol squadrons by E-3A AWACS aircraft based on the passenger Boeing 707-300B. After being withdrawn into stock, the EC-121 aircraft were located at the Davis Montan aircraft storage base in Arizona until the end of the 1980s, after which they were cut into metal. Currently, 11 surviving EC-121 of various modifications are exhibited in American museums.
