Ken_NJ:
One thing I was thinking after my post was that I don't want the turrets to rotate as I turn the control on the transmitter. More like this, move the transmitter to a certain position, than have the turret slowly rotate as though it is being turned by a motor and stop once it reaches that point. Not looking for one to one control from transmitter to turret and they would only need to turn maybe 270 degrees, never full rotation. So far I'm using Nimh so no problem with power there.
Still have to order the Uno board so I am a long way off from starting this. I will check out your blog, thanks.
As you know, servos can turn quite fast, and while it would be rather funny to watch the turrets turning madly - it's obviously not what you want.
:)
What you would need to do is set the Arduino up to control the turrets - you know this much already. But you have another problem (if I am understanding you correctly): You need to have the Arduino take your commands from the RC receiver, and interpret those to do what you intend. The problem is you can have only so many servos on a standard Arduino (12, IIRC, on the Uno - not sure how many on the Mega), but you'll need to use some of the pins for the channels from the receiver.
Will you have one channel per turret (that doesn't seem very feasible - but then again, maybe it is)? Will you have a channel for a "set button" or something? However it is set up, you'll need to use that many pins on the Arduino, which may cut into the budget on the number of servos you can have (unless you go fancy and have two Arduinos being used one for interpretation of the RC commands, the other to control the servos - communicating thru some kind of serial connection or similar).
So - you'll have some code that interprets the RC commands (there's examples and tutorials out there on doing this; I suggest you compile what you can find right now, with the aim to understand it later), then applies the commands to move a servo to the desired position. At it simplest, these interfaces read the PPM channel from the receiver and turn the result into a number that corresponds to the signal; from what I've seen, you can apply this number (sometimes via the map() function) directly to the Servo library to output PPM to the servos. In essence, the Arduino is a "pass-thru" device. You might want to get this to work, first, because it will be essential to understand what you need to do next.
What you'll want to do is then, rather than "passing thru" the value to the servo, is instead increment the servo slowly from the current servo's PPM setting in the Servo library to the "next" setting. There are examples of how to do this as well out there. Unfortunately, what you want to do goes into potentially (not sure, never researched it) territory where you will probably want to set the position of a servo, hit "set", then move to the "next" servo, position, then "set", and so on - so that the turrets are all moving, slowly from one position to the next; in a sort of multi-servo slow-positioning "ballet".
Getting servos to do this is possible, and I know I have seen something akin to this discussed in these forums and elsewhere (but perhaps relating to other projects - one area you might look into is hexapod and biped walking robots). Do some searching around, I am sure others have had this same issue.
Another possibility, though, which may be ultimately simpler - is to look into servo animation controllers. These are devices which can generally be communicated with using a microcontroller (I am sure some of them might even allow you to communicate using an R/C receiver) and programmed in such a way as to command a myriad of servos all at the same time; the more complex ones allow for things like "easing", "slow-mo", and "tweening" functionalities.
Check out vendors like Pololu, CrustCrawler, and LynxMotion; you might also check out Servo City as well. Another area to look into for such ideas is the Halloween "Dark Ride"/"Haunted House" enthusiast sites; they generally are interested in and come up with interesting and unique animatronic control solutions using multiple servos, and may have some ideas/postings for multiple-servo control that may be applicable.
Good luck with your project!