I flew a new plane today (a CL Slow Combat plane converted to RC) and got full down un-commanded inputs about three times in a 1 minute flight, the last two as I was trying to get on the ground. 'Survived, but wasted some heartbeats.

Belatedly . . . I did a range check and at about 50 feet, with the antenna down, I was getting chattering and un-commanded down elevator.

The receiver came out of another plane where it was working fine.

Where should I start on my efforts to correct this?