What brand of electric retracts are they?

Electric retracts have their own actuator. No servos involved.

Mechanical retracts are driven by servos and setting up the linkages is a nightmare the first couple of times. My Hangar9 Hellcat originally took H9 mechanicals driven by one centrally located retract servo. They worked, but with the model balanced as recommended, it nosed over constantly. The H9 P40s weren't much better. I swapped those mechanicals for EFlite 60-120 size 95degree electricals. They have no slop, lock at both ends of the rotation, and have worked since day one.

If you've got one servo in your wing, what model is it?