Hey CGR

Usually you'll be using the rudder to hold the tail UP in a turn. Here's why:

When we use ailerons, we increase lift on the wing that will be on the outside of the turn, and decrease (spoil) lift on the inside wing. Making lift makes drag, so the upgoing wing, the outside wing, is draggier than the downgoing, inside wing. This yaws the aircraft to the outside, upgoing, draggy wing. This is adverse yaw. The rudder yaws the aircraft back to the intended line of the turn.

Many people correct adverse yaw by adding aileron differential. Basically, the ailerons will move much further up than down. That helps prevent the adverse yaw by limiting the extra lift that the outbound wing generates, and instead spoiling lift on the inside. Many modern airliners do not have ailerons, just spoilers. Only the spoiler on the inside wing lifts, the other wing stays clean. The spoiler on the inside wing all at once adds drag, yawing the plane in the correct direction for the turn, and spoils lift, rolling the plane in the intended direction!

Cool, eh?

J