Ballooning is applying the flaps and having the model rise signifigantly. Dropping flaps increases a wing's lift, and you can program in down elevator to counteract this with a computer mix. The flatter the bottom of the airfoil the more noticable this is. Trainers tend to float on forever when landing and using spoilers instead of flaps can help with landings. Trainers also have very bouncy landing gear, and too steep of an approach will make for very bouncy landings. Start with small changes and don't assume all models will react the same way. And, don't confuse flaps with airbrakes. If you apply the flaps "at speed" it will shoot the plane up, and your natural response is down elevator and to cut the throttle. But, with the plane slowing from the additional drag of the flaps and the sudden loss of thrust, it drops faster than planned. Do a lot of slow practice approaches at twice the landing altitude and then apply flaps so you can observe how they effect your model.

The best airbrake for a model is a big prop and a low idle.

CROW (also called "Butterfly") is the dropping of inner-wing flaps at the same time the outer ailerons are raised as spoilers - usually on a sailplane model. This allows a very precise landing when needed.

The "Pre-Super" is the 9C transmitter as it was first introduced. The later version is the 9C Super and has a little more flexibility in user-assigning the switches. IMHO it's not worth buying a new radio, but it can make a difference when someone tells you how they set-up their controls.

Charlie
Thank you for your advice to me. Can you explain more for me?
1. What is difference between Ballooning and Tip stall durling landing?
2. Do you mean that usually do not use CROW in airplane? If I want to use CROW,how can I setup my control?
3. Can you tell me about your setting on your control for pmix#1-#7 including which event do you use them?
If possible,I would like you to suggest others to me. Thank you very much.
vuth