I'm using Hitec 225 with plastic gears on each elevator in a World Models 40 Ultimate Bipe. Working fine.

Also using HS-81 on each aileron of the same plane. The reaosn why they are working is because they are overkill for each surface.

67oz on each elevator in this plane. 45oz on each aileron in this plane. Total overkill.

It's not a 3D plane, but I bang it around without a shred of mercy. Servos are holding up fine, but thats becaue they aren't marginal for the plane. They are overkill.

Any plane with marginal servos is going to suffer from wear and slop quickly. Put a Hitec HS-81 on the ailerons of your slowest flying 40 size trainer--they won't last 3 flights. Too much aileron and too much mass involved. But put 1 on each aileron--like my little bipe--and they work fine.

I'm a nut job about hanger rash. Takes me 15 minutes to carry a plane up from the basement and put it in the truck. Thats because I'm not banging it into doorways and throwing it in the truck. Hanger rash has crashed more planes than anything else. Guys break the gears or severely weaken the gears by banging the plane into doors and such. Take it to the field and wiggle the sticks. Everything checks out untill you put flight loads on that weak gear. SPLAT!! Dead plane because of a stripped gear.

Just be sensible about the loads that your exposing the servo too. Is the rudder huge on your 3D plane? 225 probably ain't gonna do it. With a large cord on the rudder, and extreme throws--the gears just can't handle it. But, for this little bipe with a 2" cord on the rudder--a 225 is fine. 67oz on a rudder thats 8" tall and a 2" cord--totally fine.

Put a 225 on the rudder of a 40 size Powerline Edge 540 and it'll strip on the first knif-edge. That rudder is HUGE. Cord is probably 8" or 9" and it's 12" tall. Lot more surface area there.