Geoharry,

What I mean buy the engine working harder in the suburban is the load on that engine would be greater than that of the one in the corvette, due to the weight of the suburban and the larger force required to accelerate a greater mass!

So if you put a standard servo on a 12 pound 3d plane elevator, it would be working alot harder than the same servo in a 5 pound trainer.

So servo chose really comes down to what you want to get out of the plane (eg. 3d , IMAC, Sport), and the size of the surface(s) you wish to move.