Originally by Frank Granelli for Sport Aviator
Three versus four-channel operation can be a difficult choice. There are strong opinions about this and many factual misunderstandings. Both the 3-channel Hobbico Superstar-EP and the 4-channel Hobby Lobby’s Bonnie 40 are great electric-powered trainers and can teach anyone to fly RC. The Superstar-EP flies a bit more slowly since it is lighter than the Bonnie. It is also far less expensive and much easier to assemble.
But the three-channel control arrangement does impose a few limits. Rolls are more difficult since rudder affect reverses when the aircraft is inverted. The only way to complete a roll is to either release or never apply down elevator during the inverted part of the roll. As the nose drops, the airplane can complete the roll. Many other maneuvers such as loops, inverted flight and snap rolls are possible however, using just three channels.
Aerobatic ability is not a real criterion when evaluating trainers. But three-channel aircraft have one performance characteristic that does affect training. In order to keep the aircraft in a banked turn, the pilot must continue to hold the rudder control (positioned on the right, or aileron, stick) throughout the turn. If this is not done, most three-channel aircraft will roll out of the turn. This is exactly what the pilot must not do with an aileron-equipped aircraft. Continuing to apply ailerons after the aircraft has reached the desired bank angle causes the aircraft to continue the roll and then fall off into a steep, descending spiral.
When transitioning to an aileron-equipped aircraft, the new pilot will have to re-learn how to make proper turns. This is not a major problem but one you should be aware of before selecting a trainer.
Read more about selecting a trainer model: