Lockheed EC-121T Warning Star
One of the lessons learned in World War II was the value of radar in intercepting aircraft: Chain Home radar used during the Battle of Britain proved invaluable to the Royal Air Force in getting its fighters in the air to fend off Luftwaffe attacks. Ground radar, however, was generally limited to line-of-sight, thus the curvature of the Earth prevented long-range detection.
To put large ground radars aloft required a bigger aircraft, and in June 1949, the US Navy acquired two Lockheed L-749 Constellation airliners, adding an APS-45 height-finder radar above the fuselage and an APS-20 search radar below it. Despite the ungainly appearance of the aircraft, flight performance was not overly handicapped and the experiment was deemed a success. Initially designated PO-1W, the Navy changed the designation to WV-2 in 1952, as production aircraft were based on the larger, longer-ranged L-1049 Super Constellation; though it was officially named Warning Star by Lockheed, its crews used the phonetic alphabet to coin a more long-lasting nickname: Willy Victor. The usefulness of an airborne early warning aircraft was apparent to the USAF as well, and in 1953, it acquired WV-2s diverted from Navy production, designated EC-121D.
The initial purpose of both the WV-2s and EC-121s was to operate the “ocean barrier,” along the coasts of the United States, providing early warning of any Soviet attack from the sea or against Alaska or Hawaii. Typically up to five aircraft from either or both services would be on station at any given time, and EC-121s were forward deployed to Japan and Iceland as well. These aircraft were used extensively during the Cuban Missile Crisis of 1962, tracking Soviet ships approaching the blockade line, as well as monitoring Cuban air activity over the island itself. As satellites began to take over the early warning role, the barrier patrols were discontinued in 1965.
It would be in Vietnam that the AEW concept first proved itself. At the beginning of Operation Rolling Thunder in 1965, there were significant gaps in American radar coverage of North Vietnam, and 7th Air Force requested a detachment of EC-121Ds be deployed to Southeast Asia under Operation Big Eye. Orbiting over Laos, the EC-121s did provide some assistance to USAF strike crews, while US Navy WV-2s did the same over Tonkin Gulf; the first successful EC-121 controlled intercept took place in July 1965 and resulted in the downing of two MiG-17s.
However, as the EC-121 had been designed to detect targets over water, the mountains of North Vietnam provided plenty of hiding places for North Vietnamese MiG fighters, communications between fighters and controllers was poor, and the APS-70 height finder did not have the range from Laos to reach the vital “Pak Six” area over Hanoi, which limited Big Eye EC-121s primarily to raid warning. Moreover, the air conditioning system on the EC-121 had never been designed for a tropical environment, and eight-hour missions in a sweltering hot fuselage were distinctly uncomfortable.
Beginning in April 1967, USAF strike forces began noticing a distinct improvement in the EC-121s’ raid warning and interception coordination, as their callsign shifted to College Eye. Unbeknownst to most of the USAF, the EC-121s had been secretly fitted with QRC-248 sensors that homed in on the Identification Friend/Foe (IFF) signals sent out by North Vietnamese MiGs. College Eye EC-121s still could not give altitude, but they could instantly warn the force when MiGs were taking off and their general direction of attack.
During the pause between Rolling Thunder and Operation Linebacker in 1972, the USAF modified its EC-121Ds to EC-121T standard. Besides making the QRC-248 standard, it also fitted the Warning Stars with equipment codenamed Rivet Top and Rivet Gym: the former allowed the EC-121s to detect radar transponders used by MiGs even when their IFF was turned off, while the latter allowed Vietnamese-speaking personnel to listen in on radio traffic between the MiGs and their ground controllers.
Most of this equipment was highly secret: even more so was the EC-121s’ integration into Teaball, a coordinated ground-air detection system. Now with the callsign Disco, EC-121Ts could, in theory, provide instant detection, warning, and coordination for American fighters; Disco was, however, limited by its radar setup, the need to route information through the ground-based Teaball system, and the secretive nature of its equipment. Rarely was Disco able to give real-time warning. When the system worked, however, it was very effective. 25 MiG kills were done with College Eye/Disco assistance, while rescue coordination by EC-121s led to the recovery of 80 downed Americans. Despite 98,000 combat hours, no EC-121s were lost during the Vietnam War.
The limitations of the EC-121 and its increasing age (there were no losses over Vietnam, but accidents elsewhere cost both services no less than 31 aircraft) meant that, following the end of American involvement in Vietnam, a more advanced replacement was required: the US Navy had already begun with the introduction of the E-2 Hawkeye, while the USAF began experimenting with the EC-137D, which became the E-3 Sentry. The EC-121 was gradually withdrawn, with the last EC-121T of the USAF leaving Air Force Reserve units in 1979. 232 aircraft were built and 12 survive in museums, with two aircraft being restored to flyable condition.
This EC-121T is an aircraft of the 552nd Airborne Early Warning and Control Wing, based at McClellan AFB, California, and detached to the 553rd Reconnaissance Wing at Korat Royal Thai AFB, Thailand. It is painted in standard EC-121 colors of overall light gray, with both Tactical Air Command and Air Defense Command patches on the tail.
Lockheed EC-121T Warning Star
One of the lessons learned in World War II was the value of radar in intercepting aircraft: Chain Home radar used during the Battle of Britain proved invaluable to the Royal Air Force in getting its fighters in the air to fend off Luftwaffe attacks. Ground radar, however, was generally limited to line-of-sight, thus the curvature of the Earth prevented long-range detection.
To put large ground radars aloft required a bigger aircraft, and in June 1949, the US Navy acquired two Lockheed L-749 Constellation airliners, adding an APS-45 height-finder radar above the fuselage and an APS-20 search radar below it. Despite the ungainly appearance of the aircraft, flight performance was not overly handicapped and the experiment was deemed a success. Initially designated PO-1W, the Navy changed the designation to WV-2 in 1952, as production aircraft were based on the larger, longer-ranged L-1049 Super Constellation; though it was officially named Warning Star by Lockheed, its crews used the phonetic alphabet to coin a more long-lasting nickname: Willy Victor. The usefulness of an airborne early warning aircraft was apparent to the USAF as well, and in 1953, it acquired WV-2s diverted from Navy production, designated EC-121D.
The initial purpose of both the WV-2s and EC-121s was to operate the “ocean barrier,” along the coasts of the United States, providing early warning of any Soviet attack from the sea or against Alaska or Hawaii. Typically up to five aircraft from either or both services would be on station at any given time, and EC-121s were forward deployed to Japan and Iceland as well. These aircraft were used extensively during the Cuban Missile Crisis of 1962, tracking Soviet ships approaching the blockade line, as well as monitoring Cuban air activity over the island itself. As satellites began to take over the early warning role, the barrier patrols were discontinued in 1965.
It would be in Vietnam that the AEW concept first proved itself. At the beginning of Operation Rolling Thunder in 1965, there were significant gaps in American radar coverage of North Vietnam, and 7th Air Force requested a detachment of EC-121Ds be deployed to Southeast Asia under Operation Big Eye. Orbiting over Laos, the EC-121s did provide some assistance to USAF strike crews, while US Navy WV-2s did the same over Tonkin Gulf; the first successful EC-121 controlled intercept took place in July 1965 and resulted in the downing of two MiG-17s.
However, as the EC-121 had been designed to detect targets over water, the mountains of North Vietnam provided plenty of hiding places for North Vietnamese MiG fighters, communications between fighters and controllers was poor, and the APS-70 height finder did not have the range from Laos to reach the vital “Pak Six” area over Hanoi, which limited Big Eye EC-121s primarily to raid warning. Moreover, the air conditioning system on the EC-121 had never been designed for a tropical environment, and eight-hour missions in a sweltering hot fuselage were distinctly uncomfortable.
Beginning in April 1967, USAF strike forces began noticing a distinct improvement in the EC-121s’ raid warning and interception coordination, as their callsign shifted to College Eye. Unbeknownst to most of the USAF, the EC-121s had been secretly fitted with QRC-248 sensors that homed in on the Identification Friend/Foe (IFF) signals sent out by North Vietnamese MiGs. College Eye EC-121s still could not give altitude, but they could instantly warn the force when MiGs were taking off and their general direction of attack.
During the pause between Rolling Thunder and Operation Linebacker in 1972, the USAF modified its EC-121Ds to EC-121T standard. Besides making the QRC-248 standard, it also fitted the Warning Stars with equipment codenamed Rivet Top and Rivet Gym: the former allowed the EC-121s to detect radar transponders used by MiGs even when their IFF was turned off, while the latter allowed Vietnamese-speaking personnel to listen in on radio traffic between the MiGs and their ground controllers.
Most of this equipment was highly secret: even more so was the EC-121s’ integration into Teaball, a coordinated ground-air detection system. Now with the callsign Disco, EC-121Ts could, in theory, provide instant detection, warning, and coordination for American fighters; Disco was, however, limited by its radar setup, the need to route information through the ground-based Teaball system, and the secretive nature of its equipment. Rarely was Disco able to give real-time warning. When the system worked, however, it was very effective. 25 MiG kills were done with College Eye/Disco assistance, while rescue coordination by EC-121s led to the recovery of 80 downed Americans. Despite 98,000 combat hours, no EC-121s were lost during the Vietnam War.
The limitations of the EC-121 and its increasing age (there were no losses over Vietnam, but accidents elsewhere cost both services no less than 31 aircraft) meant that, following the end of American involvement in Vietnam, a more advanced replacement was required: the US Navy had already begun with the introduction of the E-2 Hawkeye, while the USAF began experimenting with the EC-137D, which became the E-3 Sentry. The EC-121 was gradually withdrawn, with the last EC-121T of the USAF leaving Air Force Reserve units in 1979. 232 aircraft were built and 12 survive in museums, with two aircraft being restored to flyable condition.
This EC-121T is an aircraft of the 552nd Airborne Early Warning and Control Wing, based at McClellan AFB, California, and detached to the 553rd Reconnaissance Wing at Korat Royal Thai AFB, Thailand. It is painted in standard EC-121 colors of overall light gray, with both Tactical Air Command and Air Defense Command patches on the tail.