Standard servos are fine, OS 46 FX (or AX), or the 50 SX if you can afford any of them. A 46 with ball bearings is more than enough power for almost any 40 size plane, unless you're planning on flying 3D, in which case the 50 might be better. (But why fly 3D with a plane, just fly the heli. )

IF you get to flying 3D down the road, then consider digital servos, but they're useless in a trainer.

I'm sure the club you joined will have instructors, and it really is the most sensible way to get into planes.
Dennis-