Topic: Which Hitech Servo

Hello chaps. Recently bought a Phoenix Extra 330  90 size, 1620mm / 64" Phoenix model
to which  I am fitting a Zenoah 20. I don't think I need digitals but I cold be wromg. Is the choice then between the 625MG and 645MG. Are they overkill on a model this size. 2 on ailerons, 2on ssplit elevator, 1 on rudder. Any thoughts?
Cheers, Rob.

i have the cm-pro extra 300 90 size it runs fine for me with hitec 422 servos i have a better one on the tail but cant remember what one
Ron

added
i dont/cant do 3D so no idea if they would stand up to it
Ron

I was under the impression that you needed to use metal gear servo in conjunction with a petrol engine  due to the higher levels of vibration.

Hi Rob

I used pretty basic 422's on a 68in span CAP 232 with a Zenoah 23, and no problem with vibration in over 6 years of flying.  Used a 645 on the rudder for the extra torque needed here.  Digital not required, unless you want the extra speed/precision.  I have just put together a 70 in SU26 for the same motor - used non digi 5kg JR servos on all surfaces except the rudder, where I banged in a non digi 10kg servo - this one is the only metal geared servo.

With hindsight, I would not put the 422's in if you can stretch to the extra for slightly better servos.  Go for the best you can afford!

not checked but haven't the 422 servos got carbonite gears   
i haven't bought any for around a year as i have gone petrol 26cc size and use the tower pro digi's
all my smaller models 90 size down evan 50 size helis have 325 or 422 hitec servos in what must be 8-10 years no problems so far
but as said no 3D just basic sport flying
Ron