The Lockheed EC-121 Warning Star was a United States Navy and United States Air Force airborne early warning and control radar surveillance aircraft, a military version of the Lockheed L-1049 Super Constellation designed to supplement the Distant Early Warning Line with two large radomes, a vertical dome above and a horizontal one below the fuselage. EC-121s were also used for intelligence gathering, and the type was introduced in 1954 and retired from service in 1978, although a single specially modified EW aircraft remained in service with the U.S. Navy until 1982. Navy versions initially procured were designated WV-1 (PO-1W), WV-2, and WV-3. Warning Stars of the U.S. Air Force served during the Vietnam War as both electronic sensor monitors and a forerunner to the Boeing E-3 Sentry AWACS. U.S. Air Force aircrews used the civil nickname "Connie," while naval aircrews used the term "Willie Victor," based on a slang version of the NATO phonetic alphabet and the Navy's pre-1962 "WV-" designations for the aircraft type. Its specifications were a span of 126 ft. 2 in., a length of 116 ft. 2 in., a height of 27 ft., a maximum weight of 145,000 lbs., no armament, four Wright R-3350 engines of 3,400 hp. each, a cost of $2,031,000, serial number 141297, a maximum speed of 290 mph., a cruising speed of 240 mph., a range of 4,000 miles, and a service ceiling of 18,000 ft.