More than you might think!

In flight, I've noticed a small amount of rudder blow-back when using Hitec HS5925 servos on the tail which are rated at 128oz/in on 6V.

It's not the linkages (metal arms, 4/40 clevises and carbon pushrods), it's the servo.

I've got Futaba 3010s on the ailerons and they're *awful*. There's now a good 3/8"-1/2" of slop (measured at the aileron trailing edge) due to slop in the output shaft on these servos. They are the *worst*.