ORLANDO, Fla.--The Air Force designated the Long Range Strike Bomber (LRSB) B-21 while an artist's rendering released Friday shows similarities to the B-2 and another experimental aircraft platform from the early days of aviation.Air Force Secretary Deborah James told reporters Friday here at the Air Force Association's (AFA) winter Air Warfare Symposium she chose B-21 after conferring with Air Force Chief of Staff Gen. Mark Welsh and others. James said the B-21 designation represents a bomber for the 21st century. Welsh…