RE: Tiger Stick 40 Rolling Too Slow
Dennis and Dick,
Sorry guys, you are both wrong. It doesn't matter how you get there. If you have a 30* servo rotation make a 15* surface deflection, that's going to be the same torque on the servo no matter if you use a long servo arm and long horn, or a short arm and a short horn. Since you are basically talking torque on both ends anyway.
Where it does matter is in the pushrod flex and control slop.
If your pushrod has to move a long distance, then that means it doesn't have to exert much force. Or, to put it another way, if you look at the torque required to move the surface, you find that as you get more "inches" of control arm, you get less "oz" of force. So to reduce pushrod flex, go out on the servo arm and out on the control horn.
If you have slop in your fittings, like clevis pins in over-sized holes, going out on the arm and out on the control surface makes for less slop, or rather, the slop is a smaller % of the pushrod travel, so has less effect in the air.
On the downside, long servo arms and control arms can sometimes flex and they are harder to fit in some small places. You can also get binding because of the larger sideways motion.
And a final "btw", one thing you shouldn't do is set up a servo with a long arm and a short control arm on the surface, then use ATV to restrict the servo to a small portion of travel. (my personal limit is 80%. If I find I'm using less than 80% travel, it's time to change something physical). The reason is that the RX only has so many "steps" or positions it can send to the servo, and you want all you can get for the best servo resolution. When you cut down ATV, you loose steps. In the extreme, you can have trouble getting the surface to center consistantly.