The reason I am saying not to use the ailerons is that turning with the ailerons will cause the wings to bank. The banked wings are losing lift due to the angle. That drains the airspeed really quick. In addition, many people automatically add in up elevator to keep the nose up which causes further drag and loss of airspeed. By making the turn with just the rudder, you are minimizing airspeed loss since the main wing remains level still providing lift and the elevator is not raised to cause additional drag and possibly raise the nose.

When you have a "Dead Stick", you have suddenly become a glider pilot, and it is a VERY HEAVY GLIDER.

If you have a sim, try it out and you will see exactly what I am saying.