I suspect the people that told you not to use rudder during takeoff probably stayed heavy on the rudder after takeoff & large amounts of rudder combined with yanking the plane off the ground with alot of elevator equals a snap roll. If you need a large amount of rudder to keep your plane going straight down the runway, dont yank it into the air! Let the model build up airspeed and gradully apply your elevator. Once airborn you can get off the rudder. Most trainers are not sensative to snapping with Rudder & Elevator, so I am guessing you are not talking about a trainer type? Im not sure if a trainer will even snap roll, (mine wont). Learn to use the rudder....Gene