No. | Cause | Fix | Comment |
1 | Undercarriage spring stiffness too low. | Stiffen undercarriage. | On landing the undercarriage comes under pressure loading it like a spring. When the loading releases, the model is launched off the ground. |
2 | Descent velocity too high. | Reduce sink rate in final approach. | Sink rate can be reduced by starting the approach from a lower altitude. |
3 | Landing speed too high. | Reduce landing speed. | Landing speed can be reduced in many ways, e.g. flaps, air brakes, side slipping and starting the approach at a lower altitude. |
4 | Undercarriage too far forward. | Optimise undercarriage position. | If the undercarriage is too far forward, then at wheels down, the torque rotating the aircraft tail down is strong. This increases the main plane's angle of attack, which helps to get the aircraft airborne again. |