did it have any variants?
Yes, the B-52 went through several design changes and variants over its 10 years of production, such as the B-52B
Boeing B-52 Stratofortress
The B-52 went through several design changes and variants over its 10 years of production.

The B-52B was the first version to enter service with the USAF on 29 June 1955 with the 93rd Bombardment Wing at Castle AFB, California. 
what is the 1994 fairchild air force base b-52 crash about? On Friday, 24 June 1994, a United States Air Force (USAF) Boeing B-52 Stratofortress crashed at Fairchild Air Force Base, Washington, United States who designed boeing b-52? Boeing engineers George S. Schairer, Art Carlsen and Vaughn Blumenthal when did it get upgraded? July 2013 was it a part of any war? Yes,  Cold War, Vietnam War, Gulf War when did the second war take place? UNANSWERABLE
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Boeing B-52 Stratofortress [SEP] Variants
The B-52 went through several design changes and variants over its 10 years of production. The B-52B was the first version to enter service with the USAF on 29 June 1955 with the 93rd Bombardment Wing at Castle AFB, California. This version included minor changes to engines and avionics, enabling an extra 12,000 pounds of thrust using water injection. Temporary grounding of the aircraft after a crash in February 1956 and again the following July caused training delays, and at mid-year there were still no combat-ready B-52 crews.