Peacemaker had been under development by Consolidated, and work on it was shifted from its San Diego, California plant to its government-leased plant in Fort Worth. By 1947 the initial production version B-36A was ready and in June 1948 the first Convair B-36A Peacekeeper was delivered. The first B-36A was designated the "City of Fort Worth" (AF Serial No. 44-92015), and was assigned to the 492d Bomb Squadron. B-36s continued to roll out from the production plant throughout 1948 and being assigned to the 7th. The group's last B-29 being transferred on 6 December to the 97th Bomb Group at Biggs AFB. For 10 years, the "Peacemaker" cast a large shadow on the Iron Curtain and served as the nation's major deterrent weapons system. In January 1951, the 7th took part in a special training mission to the United Kingdom. The purpose of the mission was to evaluate the B-36D under simulated war plan conditions. Also, to evaluate further the equivalent airspeed and compression tactics for heavy bombardment aircraft. The aircraft, staging through Limestone AFB, Maine, would land at RAF Lakenheath, the United Kingdom, following a night radar bombing attack on Heligoland, West Germany. From there the bombers would conduct a simulated bomb run on the Heston Bomb Plot, London, finally landing at RAF Lakenheath. This was the first deployment of wing and SAC B-36 aircraft to England and Europe. For the next four days, the flight flew sorties out of England. The aircraft redeployed to the states on 20 January arriving at Carswell on 21 January. On 16 February 1951 the 7th became a paper organization. With all assigned flying squadrons reassigned directly to the 7th Bombardment Wing as part of the Tri-Deputate organization plan adopted by the wing. The group inactivated on 16 June 1952. 11th Bombardment Group On 1 December 1948, the 11th Bombardment Group was reactivated by SAC at Carswell AFB and was equipped with B-36s. 7th Bomb Group personnel began training the new 11th group people in the new aircraft and the 11th soon began receiving them. Cold War In 1947, shortly after the United States Air Force was established as a separate branch of the United States military, the Hobson Wing-Base Organization Plan was implemented. The 7th was selected as one of the "Test Wings" to evaluate the new organization T/O and on 17 November 1947 the 7th Bombardment Wing was established. The test