can any1 reccomend servos for a big gun battle ship maryland (4 turrets w/elevation +depression, hobby king radio set 6ch)
For turret rotation, IF you are going with proportional rotation - you might want to look into the sail-Winch servos now carried by Strike Models . Or the Hitec Sail Winch servo (much larger, fewer turns). For depression (Elevation is not allowed), Strike has several to chose from, including some really tiny microservos and the Traxxas is also nice. If you are going with non-proportional turrets, the advice is different.
For the most part, you'll want analog servos. Digital has a lot of advantages, but in a combat ship, most of those benefits are overkill. Digital servos provide better torque and response time than analog servos, tend to have better guts than equivalent analog servos, and can be programmed for range of motion, deadband, speed, etc. with a digital servo programmer. On the other hand, digital servos also are much more expensive than analog servos, and in most cases, a cheap $10 standard analog servo will do the trick. To answer your original question, about what servos to use in your Big Gun Maryland: I use hitec servos, so that's the product numbers I recommend. You can use the equivalents in whatever brand of servos you prefer. Rudder: HS-311 standard servo: dirt cheap, and good enough. Circuitboard can be skotchkoted and case drilled to drain water, in case of sink. Firing: HS-311 standard servo: again, this servo is plenty good enough to push firing buttons. Rotation: if you're using the Morgret Command and Control system (coming soon!) or other positional turret control, then the Strike Models standard-sized sail winch servos will work. If you're NOT using positional turret control, then you can either use a pair of HS-1425CR continuous-rotation servos, or gut a pair of HS-311's and drive them with a VEX motor-controller circuitboard. The first option requires a Y-splitter and a servo reverser, while the other option requires a soldering iron and some skill with wiring. I have personally seen both systems used in combat ships, and can assure you that they work far better than old hacked-servo rotation systems. Depression: if you can fit HS-311 standard servos, I highly recommend that you do. The HS-311 is sturdier and more powerful than the micro servo many people use for rotation, and for less than half the cost. If you cannot fit an HS-311, though, the HS-82MG is the most popular choice for depression servos. You should also consider starting out without servo-controlled depression. Even guns without servo-controlled depression can be adjusted via one or more screws, so you can still dial your depression in to the correct level. Plus, without depression to worry about, you have less cables to tangle, less electronics to spend money on, and less controls for your brain to worry about. Depression may be useful to have, but there's a very good reason why many ships go without. Keep in mind that, while I have used Hitec servo numbers to describe my recommendations, nearly all servo companies make equivalents. For example, Futaba's standard servo is the S-3003, and Strike Models carries another fine standard servo, the VS-2. Any one of those will work fine for rudder or firing. Getting the right type of servo is far more important than getting the exact same brand as me. If you find a deal on a radio with servos, or a friend offers you some servos, do not hesitate to use those instead. Lastly, try to pick one servo spline type and stick with it. I have seen a number of skippers driven crazy trying to replace a glitchy rudder servo because the spare servo had the wrong type of spline. There's a lot to be said for standardization.
As far as how many servos, depends upon if you are using solonoids or mechanical means to shoot. If electrical, one servo with two micro switches will fire both forward and rear guns. Another thing about digital servos is that the take power all of the time unlike analog which only take power when moving. As for rotation, that was covered rather well in Kotori's post. Marty "Fast gun"
It is very common for a ship with only main guns armed to have a single firing servo, whether it's got 2 turrets, 3 turrets, or 4 turrets. Because Big Gun cannons all require a small firing valve to supply pressure to their main firing actuators, you can simply use a "T" fitting to branch off the gas from one of your firing valves to operate multiple turrets. For example, in the Maryland you would have two firing valves and two "T" fittings to operate your four turrets. When you press the button to fire the forward guns, the forward small firing valve (either an SMAV-3 or a MAV-3) sends air pressure to the T fitting. The T fitting branches that air pressure off to the main actuators of both forward guns, triggering both at the same time. One button press, and both turrets fire. Same thing in the back. If you want to include systems like secondary guns or torpedoes, you will need additional firing servos, however. I believe there is a diagram in the NTXBG knowledge base website that shows how to plumb multiple guns to operate from a single firing valve. For rotation, the number of servos depends on whether you want to rotate the aft turrets or not. If you want to rotate all your turrets, you will need two sail-winch servos, continuous rotation servos, or modified standard servos. You can easily link both forward turrets to operate from one servo, and do the same for the aft turrets, but it is much harder (and in some cases impossible) to link the aft turrets to the forward turrets. You may be interested in not rotating the aft turrets, however. Like cannon depression, turret rotation implies extra cost, maintenance, and effort to use in battle. You would be surprised at how many skippers use non-rotating aft turrets with great results. While non-rotating aft turrets weakens your broadside fire, it frees up your brain from worrying about where two sets of turrets are pointing. This allows you to focus on aiming your forward turrets well. My own battleship, the Viribus Unitis, has neither depression nor aft rotation, and I love the simplicity. I have been known, on occasion, to engage one ship with my fixed aft guns while fighting another with my rotating forward guns. That sort of fighting is only possible with non-rotating aft guns.
