ORIGINAL: AndyAndrews
400 flights why bother? Why add extra weight to your jet if it doesn't really make any noticable difference, especially if the factories don't even recommend it in most cases?
Because the servo is always buzzing against the weight, which means that it is drawing unnecessary current, and must be buzzing back and forth a tiny amount on the pot which will add to its wear on one spot. As it happens that model would benefit from a slight rearward shift in the balance so a spot of weight at the tail would be good. otoh there is the question of just how much weight has to be put into the stab to balance it, because the servo has to accelerate that mass. With a highly swept stab it could be a lot of weight. The large increase in inertia when trying to move the stab rapidly might neutralise or even outweigh any advantage from balancing it. It's one of those aspects that full-size do lots of calculations on to determine the best compromise, we just judge each for ourselves which system we feel most comfy with!
There's a huge difference between a factory not making any recommendation, and making a recommendation not to. I suspect most brands are simply not mentioning it? My AD F-100 instructions do mention it, it says to drill into the l/e of the stabs and put in lead to balance them both.
H.