Don't put the Futaba S-3003 or S-3004 (or Tower TS-53 which is a S-3003) on for your .30 size heli's tailrotor. The constant motion and vibration of the heli combine to wear the things out prematurely.

It turns out that Futaba's servo info on thier website recommends against using the 3004 on a heli at all. The difference between the 3003 and 3004 is a ball bearing. (which means the 3004 should handle it better...)

It is not fun to have the tailrotor suddenly go to full throw.

It is not worth having a 3003 on helis at all, leave alone rudder as they are designed for cars. for .30sized begginer the best low cost would be 3001 or s148. on aileron, elevator, collective, throttle, and a better on on the rudder. 9202 if you want to be spending some extra money would probably be a better idea.
http://www.futabarc.com/servos/servo-application.html will give you an idea.

Too bad no one said to check the chart to me BEFORE I had 2 servos go out... ("Sure... use the 3003's they'll work" [:'(] )

Penny wise... thought I was going to get eaten by a heli.[X(]

I have a 3004 on my throttle and so far so good

The probelm is... you MIGHT get away with it for a long time... it could decide to jump over to full throw with no warning at any time. (thats how they both failed)

Out of control high head speed sound like a good idea?

I understand there is a difference in the design of the 3003, 3004 that makes them more affected by vibration (something to do with the direct link to the potentiometer). The 3001 and 148 are different and should be fine.

This is a quote from the Futaba website

Both the S3003 and S3004 use a direct drive potentiometer. What that means is the output gear is connected directly to the potentiometer. Since the output gear is connected directly to the pot it is very possible that vibration will damage the pot. This is why we do not recommend these servos to be used in helis. Helis generate a very high frequency vibration due to the high rpm of the engine and the close proximity of the engine to the servos.

As an aside I had two JR 591 failures caused by vibration on my heli. It turns out that the web on mounting lugs was touching the frame. This was enough to pass the vibration to the servo motor and destroy it. Make sure that your servos are mounted on vibration mounts and that no part of the servo case touches the frame. The results of not doing this are not funny!

NOW... knowing this difference in the servos... I'm changing my plans from moving to all 3004's for everything I own... to using the 3001's. (with a higher power one here or there... and of course the micros for the little electric stuff...)

So what if the servo costs twice as much? I'm going to get a more reliable servo and have safer aircraft.

Good thing I have some 148's to use for a while to break up the costs.