Yes. You do need to learn to use rudder.
Most club instructors tend to make sure you use it in co-ordinated turns. However, if you have learnt so far without its use try some steep climbs and add the rudder slowly. At first just waggle it and see the results. Turns on most scale aircraft have to be flown with co-ordinated rudder. Aerobatic planes do also.
If you are a club member get one of the experinced members to help you through. You will wonder how you flew without it once you have learnt.
Hope this helps.