The thing I remember about a KC-135A takeoff was 1) the very distinct and loud whine of the J57's when the plane was flying towards you, 2) the load roar as the plane passed overhead and flying away from you, and 3) the long smoke trail when water injection was turned on. Small wonder why when the USAF had to chance to modify a bunch of KC-135A's with JT3D turbofan engines salvaged from scrapped Boeing 707 airliners they did it really quickly.
A snap crackle and pop when they got past you on while on water. It was particularly noticeable on a cold day.
I can remember days at Altus AFB when the 135's were louder than the B-52's on takeoff.