Iuse the Spektrum AR6030 and AR6020in all of my 4 jets (Carf hawk/Flash, Graupner Inspiration,PST ReVision)

The AR6030 is an excellent servo as others have said 20kg,digital,coreless and with a very strong titanium output gear.

On the smaller Jets (Flash and Inspiration) I use the AR6020 on rudder and steering.(10kg digital metal gears)which retail forless than £30.00each in UK

These Spektrum servos are made by Savox for Spektrum but with a JR output spline.

No problems at all they just work fine with very good centering and will take and are designed to take 6 volts input.

Personally I cant see why JR servos although excellent cost twice the price. Their pricing on some of their smaller digital servos is outrageous.

The servo market is hopping up with manufacturers like Savox, MK, Hyperion all producing high quality digital servos at reasonable prices.

Phil.