No changes to the receiver itself. You need a "Y-connector" that plugs into the receiver and into two servos, one for each turret. Both turrets will rotate at the same time.
Consider the USS South Dakota as an example. It has two turrets forward (A and B), and one aft (C). The simplest setup has all three cannons linked to the same rotation motor, in such a way that they will all rotate to the same side for a broadside, and will stop around 90* of the centerline. In this case, the rotatin motor can either have velocity control, via a speed controler, or position control like a servo. The speed control is by far the most common setup. It is run of the horizontal axis of one of the sticks on the controller, and right converges the guns to starboard while left sends them the opposite way. Another setup that is a bit more complex involves a separate rotation motor for the forward two turrets and the after turret. A and B turret will still be linked, but C turret is separate. The cannons are allowed to rotate much farther than 90* pas the centerline, often to 135* or more. The rotation motors usually have positional control, and are run off both the horizontal and vertical axes of one of the sticks on a controller, one axis for each turret. I have heard that this takes a lot of practice to get used to, but allows for better control of the guns. Nobody runs this setup in my club, so I have not seen this system in action. This is likely due to the expense of servos with the necessary large range of motion. Depression requires one servo per turret, and are always run off a Y-connector, so they are all on the same channel. Most often, it is assigned to a dial to provide full proportional control of the range. One skipper I know has assigned depression to a switch that sends the cannons to a couple fixed positions. He says it is easier to remember where the guns are hitting at each setting, then adjust the range by how he sails. In some cases, it is difficult to fit the depression servos in, so not all cannons have depression servos. On South Dakota, B turret would usually have a servo while A and C turrets might not. Y connectors should be available at any hobby shop that carries a decent selection of RC equipment. There are also several online hobby shops that are usually cheaper, but take more time to deliver. www.towerhobbies.com www.hobbico.com www.hobby-lobby.com
Are there any exaples of a rotating and elevating cannon to get an idea of what this really looks like?
I wrote this up yesterday, then forgot to post it! This shows various methods of rotation and depression used in the WWCC. A cannon and micro servo mounted on top of the magazine: for depression http://www.westernwarshipcombat.com/chartroom/album32/Pocket_Bow_Gun.jpg The mount and rotation motor for the cannon: http://www.westernwarshipcombat.com/chartroom/album32/Pocket_Bow_Gun_Mount.jpg note that the servo has been hacked for continuous rotation, so it will act like a motor and gearbox, rather than a servo. There will be a rubber belt connecting the servo to the cannon, to allow for slippage. A cannon from a different ship showing the rotation system: http://www.westernwarshipcombat.com/gallery/album35/9_midship_turret_and_switches You can see the rotation servo (another hacked servo) and the rubber belt, as well as the rubber belt linking this cannon to another one that will rotate with it. There is no depression servo on this cannon. A tandem cannon from Prinz Eugen: http://www.westernwarshipcombat.com/gallery/Prinz-Eugen/Rear_cannons The two magazines are linked with rubber belt, but the hacked rotation servo is pressed up against one of the magazines, rather than using a belt. A common battleship setup: http://www.westernwarshipcombat.com/gallery/album37/00009_G Tirpitz has only a single hacked rotation servo that is connected to all four turrets. However, two of the turrets will rotate in the opposite direction of the other pair, so they go to the broadside position. A cannon from the Dutch Battle Cruiser http://www.westernwarshipcombat.com/gallery/dseibel/DSCN0477 This uses a motor and 90* gear box rather than a hacked servo for rotation, but the result is the same. No depression servo. A cannon from the Vainamoinen: http://www.westernwarshipcombat.com/gallery/Vainamoinen/van5 Again, this uses a motor with a 90* gear box and belt for rotation. The ship is too small to fit a depression servo. There is a threaded rod and spring are used to hold the barrels in place. A tandem cannon from Baden: http://www.westernwarshipcombat.com/gallery/album03/P1300002 A 20lb test fishing line is used to link the two magazines, and the depression system is clearly visible with a micro servo on one magazine and a standard servo on the other. The rotation mechanism from Baden: http://www.westernwarshipcombat.com/gallery/album03/P1300010 A sail winch servo is used to drive the cable. A sail winch servo can rotate more than the standard 90*, and is often used to provide proportional control over the cannons. The downside is that they are much more expensive than hacking a standard servo. Now before you try building your own ship and duplicating any of the cannons I have pointed out, I should warn you that many of the cannons shown are not sterling examples of quality workmanship. The top two pictures show a BDE cannon and a high-quality mount for it, the rest are home made and occasionally fail in combat.
The Baden Looks like a fun ship indeed... now i see how they elevate too. A servo drags the barrels down and pushes them up with a small metal arm... But what is the flexible material that lets the cannons move up and down... ( the brownish stuff on the badden that connects the barrles to the magazine on the same picture that shows the servos under that barrles )
Any sort of flexible tubing can be used, and there is some commonly available at hardware stores. The name of the material is slipping my mind right now, but its really easy to get, and is often clear rather than brown (actually pink in poor lighting). I do not think very highly of Baden as a combat ship. It is very small for a battleship and difficult to fit in all four turrets along with running gear and enough CO2 to last a sortie. The builder of this model was able to make it an effective model, but he has a lot of experience building combat models.
