Constructed as YB-36, all updated features were added to this one while on the production line; retained by Convair. 4 Dec '47: First flight. 15 Dec '47: Third flight, reached 40,000+ ft. 1948: Redesignated YB-36A after several modifications. 31 May '49: TOS USAF; assigned to 72nd Bombardment Wing (Heavy) (SAC), Ramey AFB, PR 10/50: Converted to RB-36E with added four J-47 jet engines to the wings and returned to 72nd BW. 18 Feb 1957: Flown from Ramey AFB to Patterson Field, Wright-Patterson AFB, OH, for display at the Air Force Museum. 1971: Scrapped. Parts to Walter Soplata of Newbury, OH.

Second prototype B-36 converted to RB-36E status. Sold by USAFM when it moved to its new site and large sections of the aircraft are believed to survive in the private Soplata Collection.