I just got into R/C airplanes and was wondering what alirons did to the
plane as it flew and controled them???? Are they important to have???
Can the plane still turn in the air with out them????
 

If you have a trainer type airplane (high wing) and it has a good bit of
dihedral (upward slant of the wings so the tips are higher than the center
of the wing), rudder is sufficient for turning. Usually, a little up
elevator is added to keep the nose from dropping and to hold altitude in the
turn. Your smaller trainers sometimes use rudder - elevator - motor, and
sometimes as in 1/2-A (i.e., Cox .049) don't have motor control.

Ailerons allow the plane to roll (one wing higher than the other). If you
don't have rudder, turn is accomplished by adding a little up elevator.
With rudder, you "coordinate both" by adding a little of each, to get it to
turn. Some 1/2-A types such as the House of Balsa Sport Stealth have fewer
controls and get by with elevator - aileron. Full aileron will allow axial
rolls (plane flies straight, goes upside down then right side up.)

If you are just starting, you'll want a trainer type plane. They have more
inherit stability, and are easier to fly (and fun.)

 
 
 Ailerons will roll the plane, so you can control it in curves.
A plane with Dutch roll (roll coupled to yaw) will also be flyable as many
trainer models prove. These planes have much dihedral, so when you apply
rudder, it will roll (sort of).
 
 

Ailerons make the plane roll. Aerodynamics make the banked wings generate
different amounts of drag and lift, which causes the plane to turn. A plane
can also be turned with the rudder. Many models have only rudder control, and
some have only aileron control, since the functions overlap in turns. You can
fly with either, but it's nice to have both for smoother response and more
aerobatic potential.
 

Some of the old timers can give you a better understanding but what
the ailerons will cause one wing to gain lift and the other to lose
lift causing the plane to roll around its long axis.

What I have found is that initially you only need two controls to fly.
Aileron and Elevator. You roll the plane on its side and then use the
elevator to force the plane to turn around. You then roll the plane
back to level flight.

I have seen where a guy forgot to hook up the Ailerons and flew the
plane with elevator and rudder. I have also seen park flyers fly with
two channel systems of elevators and rudder.