a ys 140 would be ok, but it would be way overkill. something like a ys 110, saito 1.20, or os 1.20 would suffice. i have no experiance with those servos, but for something with such alrge control surfaces, digitals really shine. they are not necessary however. while the plane is obviouysly physically capable of flight without metal gears, they are highly reccomended.