RadioControl I has the same problem for the first 12 or so landings. I hate slowing a plane down too much on landing because of the snap factor and I was landing too fast.

I finally managed to land my R4 without bouncing by doing long flat approaches on long runway and holding it a few inches above the ground to determine how slow it would fly. I was amazed how slow the plane flew in ground effect without stalling. Using flaps helps a steeper the approach, but do most of the landings without them.

Good luck.