HEY GUYS..............
I WAS WONDERING IF A DIGITAL SERVO SPEKTRUM DS821 IS OVERKILL FOR A THROTTLE SERVO.
WILL IT DRAW MY BATTERY (MUCH) FASTER THAN A GOOD QUALITY STANDERD SERVO? [sm=confused.gif]

I don't know anything about the DS821 but a digital servo would be fine. I use Hitec HS 5625's on my throttle for my 90 se's and my 100cc and 50cc planks just because they are fast. Some giant scale plane guys don't like digital on the throttle, they say engine vibration and the direct link to the servo causes the servo to wear out, I've never had a problem.

It will be fine. Its probably the only place I'd use on of those on a heli.

I use micros on my throttles. Good speed and very lite. Speed is what is important on the throttle IMO

To a point. These 100 dollar tail servos, even on a high frame rate governor and working that throttle arm back and forth faster than an internal combustion engine can respond to throttle changes. Also keep in mind, even with identical speed servos on the pitch and throttle, the throttle will always be faster because it doesnt have nearly as far to move (usually 50 to 100 percent, back and forth in that area) while the collective is moving end to end. Also throw in the fact that the collective servo has a constant load on it wheras the throttle barrel presents no appreciable load, there comes a point where servo speed on the throttle becomes moot.

In practice, anything at or near .2sec / 60 degrees is fine, anything over that and no matter how fast you are moving that arm back and forth you arent going to get any benefit to in flight.