Yes, there is a danger from wake turbulence. The way heavies usually avoid it is a careful joinup that resembles an upside down ILS approach. At about 1 NM
from the tanker the receiver will start a gentle climb (about 300 FPM) while he's overtaking the tanker. If he does it right he normally won't hit turbies. It's not unusual to still get some this way but if you do it's usually just some transients. Fighters use a different style for their joinup; F4wso should be able to help out with the fighter puke perspective.
EMBQA is right on the money with his words. Heavies like the FRED, Barney, and the E-4 have a very noticeable bow wave. Autopilot-on isn't too rough. But AP
-off really sucks. Not much the tanker crews can do except hope for accurate distance calls from the boomer (helps with the pilots trim rythym) and a smooth receiver. With either one missing the tanker, and by default the receiver, will start to PIO (pilot induced oscillation). Not much fun there, especially from the back. Breakaways are pretty common from this.