Would like to know what size and torque servo you guys are using for steering on your sport 40 s??? </p>

Hi-tec HS 645MG or higher.

Thanx Ron How much torque and does metal gears make a difference??????

I couldn't tell you off-hand what the numbers are. I've used the 645 in everything from .21 mono's up to my gas boats including the Sport 40 that I had.
You can check the spec's of all Hi-tec servos at www.hitecrcd.com .
Metal gears are less prone to breakage. Pull the cover off any servo, especially one with plastic gears and see how fine the teeth are and why you'd want metal ones in there.

the HS-645MG have 133oz/in at 6volts (5cell pack).

Dan.

thnx guys Now I know the servo I was planning to use does not have enough torque. Planning to use a jr z590 it has metal gears but only has 82 oz of torque.