Yes he uses 1 on each aileron.myself i would use 2 605s.He was unhappy about it coming out heavier than they said it would but it flys nicely on a OS160.The 645 mg is a perfect replacement for the 615 and costs the same and has over 130" of push on a 6 volt pack and would have no trouble pushing that big(huge)rudder around.Check out SERVO CITY on line for all the specs and they have great prices also.