5645's on the elevators of my ViperJet---No issues and rock solid in trim--This was the largest servo that I could install on the surface. No way I was going to install the Hitec 5125's or JR DS 168's that the plane called for as these were burning out due to not being able to handle the load...(47 inch ounce servos called for on an elevator---C'mon!!!) Hitec had issues with the early versions of the 5625/5645 servos---These issues have been worked out to the best of my knowledge...

Kevin