Hey there everyone, I am going to individual expansion tanks for my cannons. Is there any science to the recommended volume of each tank? 1 cubic inch, 2 cubic inch? I intend to run a one way valve to each one too, I'm under the impression that isn't overkill. I had been using a 4 cubic inch tank to cover all the guns in the past. Thank you all, Harry
Whoa, hold up there. First of all, what ruleset are you building for? Big Gun? Fast Gun? The designs, specifications, and recommendations are very different between the two. That said, here's the answer if you're building Big Gun: The recommended size for an accumulator is 1.5 to 2 cubic inches per barrel. choose the smaller end of the spectrum for small calibers, bigger size for larger calibers. And remember, this is per barrel. So for a triple turret, you'd want three times the volume you'd use for a single-barrel cannon on check valves: this one applies to both Big Gun and Fast Gun, so pay attention. Check valves can be very risky to use, as they do not permit the accumulator to drain when you disconnect the air. A pressurized accumulator, especially when your gas is turned off and you think it's safe, is an accident waiting to happen. It is possible to use check valves safely, but the complexity of a system that uses check valves and still bleeds the accumulators when you depressurize the system is immensely greater than a system without any check valves at all, and much more prone to leaks and failures. I personally avoid them like a plague. Basically, stay away from check valves unless you REALLY know what you're doing.
That nails it... Fast gun is just the smaller caliber. If 4 did it before, than going a bit bigger won't hurt. It becomes a weight and room inside the ship thing.
Sorry, forgot to mention... fast gun, USS California. I was wondering about venting the system after use with the check valves. I guess with approx 2ci per gun, there shouldn't be too much loss in any of the cannons (Im not THAT fast..). I'm running a Clippard solenoid system. HH
Frankly, I have yet to hear a good reason why anyone needs check valves in their air systems. I've heard a few Big Gunners claim that when they fire front and rear guns in rapid succession, the second shot is weaker than the first, but I have yet to see such a problem and I've seen a lot of battleships in my day. I cannot conceive of what a Fast Gun ship would be doing with them. IIRC, to use check valves safely, I believe you need a 5-way switch immediately after your regulator. The trick was to run one set of check valves on the way in to the accumulators, and a second set on dedicated drainage lines, that led to either the fourth or fifth port on the 5-way switch. In the ON position, gas could go from the regulator to the rest of the boat, while the dedicated drainage lines from the accumulators were blocked off. In the OFF position, gas from the regulator to the rest of the boat was shut off, and the dedicated drainage lines would be opened, venting all the air in them. Several years ago, when improper use of check valves became an issue in the WWCC, I sketched out a plumbing diagram and listed all the parts you need for safely using check valves, but all I can recall now was that it used a huge pile of parts and had a heckuva lotta failure points for leaks, lines blowing off barbs, component failures, etc.
What you have heard from the big-gunners is basically correct. Since the accumulators are fed from a common system, firing the front then the rear guns in rapid succession can cause the rear guns to fire below optimum. It appears that the rear accumulators backflow when the front accumulators empty. The check valve prevents this. Not a problem I've had myself, since Rodneys guns fire all at once.
