custom cannons

I'm confused now. Is the Mogador built for big gun, or fast gun? Post some photos so we can see what you've got so far.

I would never put a check valve on an accumulator, it defeats the purpose of a safety valve by keeping the gas pressure needed to fire still in position to be fired (it is also illegal in the WWCC: safety valve must bleed gas from the accumulators).

 

Mogador is big gun. Monk's Balto is fast gun. I was recommending a fast gun setup for the balto.

I don't see why Mogador would need separate expansion tanks, I'd think one would be good enough, but that's just me. It's just something to equalize pressure between all the guns.

 

Tug again I’m lost go figure by accumulator is that like an Expansion Tanks?? I'm still on paintball lingo I guess the whole cannon thing Don will have to teach me once mine come in [8D]

 

I set up the Roma with no accumulators. All the guns fire hard and evenly. Tested them over the weekend shooting into a target box with a spool of heavy grade paper and the cannons shredded them. Tried the cannons individualy and no loss of pressure from each one. Did have what appeared to be loss of pressure but was found to be a kinked hose at the valve stem of the cap where the piston resides. Unkinked it returned to normal.
My Yamato uses a 3 inch accumulator for the tripples and 2 inch accumulators dedicated for each pair of dual sidemounts. They all fire hard and well. Bismarck uses no accumulators and all guns fire hard and well.
There was a Bama in our club that had the clippard accumulators 3 bundled one per cannon for the tripples. It fired consistently but not very hard.I always wondered if the size of the tank or the Volume avaible somehow affects how the accumulators work. He was using a 70z bottle. I think that maybe there was not enough volume to keep adequate supply of co2 in the accumulators, or maybe only 1 accumulator was needed. I don't know, just some observations.
When I build Prince of Wales I plan to have 1 large accumulator for the stern Quads or maybe an accumulator of each pair of cannons in the stern turret, or then again maybe one accumulator tank per cannon but smaller say 1 in long for a total of 4. Hmmm need to think about this.

 

That clears things up a bit for me, Mike. Talking about a big gun and a fast gun destroyer in the same thread is just a bit confusing.

Tugolas, it makes perfect sense for fast gun cannons. Big gun cannons contain all their energy in the accumulators, which are usually home-made. The WWCC is just a bit leery of letting people keep pressure in a home-made accumulator when it comes off the water. An accumulator explosion on the water is much less of a problem than one in the pit.

Monk, accumulators are not like expansion tanks (if I understand the paintball term correctly). Accumulators are a volume chamber meant to store gas so that it may be used by the cannons at a faster rate than the gas line would. My brother made a thread about big gun cannons that should explain a bit better, though it got sidetracked by page 2.
http://www.rcnavalcombat.com/rcnavalcombat/forum/topic.asp?TOPIC_ID=181

 

OK Knight4hire, here's the answer to your question (as best I understand). You asked if it is possible to have four .177" bb cannons fire using a single accumulator. The basic answer is YES. However I think you'll be more interested in the more advanced answer:

*The advanced answer*
When you say "four bb guns", I am assuming you mean "four bb-caliber barrels, in two twin turrets". I am further assuming that these two twin turrets are on the same side of the boat (either bow or stern). The basic Big Gun cannon design consists of a pressure-storing volume chamber (called an accumulator), a high-flow poppet valve (called a buna-ball valve or ball valve), and a breech/magazine assembly and barrels. In order to meet your design requirement of four bb-caliber barrels from a single accumulator, you would need to design a cannon with a breech/magazine assembly that fires four barrels. That is not a great challenge, and in fact I have seen it done before and tested one in combat.

Based on my experience with four-barrel two-turret bb cannons, I don't think that such an armament is the wisest choice available. If you asked me what armament to choose, I would suggest to only arm two barrels in a single turret, or torpedoes. Arming all four barrels brings up several less-known obstacles. The first is that, due to some strange quirk of fluid dynamics, one pair of barrels will always fire significantly harder than the other pair of barrels. While the strong pair of barrels will blow through the foam penetration test at 100 PSI, the weaker pair would potentially be bouncing off the foam at the same pressure. My experience was not quite so extreme, but it was close. The second obstacle is that, unless you are precise in your manufacture to a few thousandths of an inch, you run the risk of the ball valve getting jammed open and draining your co2 cartridge in short order. Again, this is due to the peculiarities of a four-barrel, two-turret cannon.

If, on the other hand, you choose to build a two-barrel bb cannon, you will avoid both of the aforementioned problems, as well as increasing gas efficiency, saving internal space, and increasing your ship's stability. And, as I have found out through personal experience, it is far better to have a two-barrel cannon that fires every time you pull the trigger than a four-barrel cannon that fires every other time you pull the trigger. While you won't deal quite as much damage with every shot, you will spend much more time in the water shooting at other ships than you will on the bench wondering why your cannon isn't working right.

My personal preference for destroyer armament, however, is torpedoes. And the Mogador is a wonderful ship to arm with torpedoes. A torpedo cannon is similar in design to a regular cannon, except that it is the largest caliber available and fixed directly off the side of the boat. The biggest single advantage to torpedoes is that they possess the knockout punch to damage and potentially sink a capital ship. Let's face it, bbs make small holes, and they don't let in very much water even if you do make bb-sized holes below the waterline. Torpedoes, on the other hand, make nice big 1/4" holes that let in lots of water, and they are aimed specifically to hit below the waterline where they will let in lots of water indeed. Here's a photo tour of a very successful torpedo-armed Le Fantasque, the Mogador's little sister:
http://robwood.net/Warships/Destroyers/planviews.html

Is that enough information? If you have any more questions, please don't hesitate to ask.

 

yeah guys im going to build a Z class destroyer from BC and it looks kinda small to fit stuff in

 

Yeah it's way too small for a first ship.

 

Thanks Kotori87.
The advance answer is what I needed.
And you are correct, two double .177 turrets is what I am atempting to arm.
I have done a lot of thinking on arming the torps.
The trouble is, I am with a big gun group and torps are a single shot weapon!
I am doing R&D on a spring fired torp.
If I can get the bb turrets to work and still have some draft to play with, I fully intend to arm the torps as well.
I see this ship as a convoy killer. I have no intention to go toe to toe with the big capital ships. So I rather have multiple shots with bb's than a single shot with torps, then have to sail around for 30 minutes unarmed!

 

Knight4hire, that's exactly how I'd love to arm my Z-25, albeit with two 0.177 guns in front and one in back with the two banks of single-shot torpedos to either side.

Where my Mogador is concerned, however, I might try arming two in front, two in back ( both fore and aft batteries with rotation), and the torpedos.

 

Lets see if I did this correctly.
Here is a link to see where she is in the water.
That is right there are no turrets on her at this point in time.
Everything is in the hull.

 

She's already awfully close to the waterline. What's the total weight of her so far? Also, did you add the extra 3/8" hull depth? I may need to cut all the ribs on my Mogador and add that to stand any chance of carrying my intended armament.

 

Wookie, Knight, how does your club handle rearming of ships? The WWCC allows single-shot torpedo ships to come back to home port at any time to reload, while other ships must reload in between our short sorties. The NTXBG allows all ships to return to reload after five minutes.

I can assure you both from personal experience that torpedoes in a large destroyer or light cruiser can be a far more dangerous weapon than the same boat armed with bb guns. Two years of chaos, carnage, and more sinks than any other two years in the entire 22 year history of the WWCC should attest to that pretty well. The most important element of these ships is their speed, which is often in excess of 40kts and allows them to get around the pond easily and engage targets at will. The speed also makes it a blast to drive, and I heard one skipper say it's like going from a Ford Model T to a Ferrari. The second element is the large, 1/4" torpedoes, which are usually in double, triple, or larger mounts (wwcc limits ships to triple mounts). The balls have the mass needed to provide superior underwater penetration compared to a bb, and can often take out a chunk of balsa instead of leaving clean holes. Also, the single shot nature of the gun (or 30 second reload time) forces the skipper to use hit and run tactics that are difficult at best for battleships to deal with. The third element is the simple gas system that torpedoes permit. A reloading torpedo system, powered from a 16-gram CO2 cartridge, can expect to get about 10-12 shots off on a good day. A bb gun setup will use the same gas per shot, so if you want any reasonable number of shots you'll need a 3.5oz or 4oz CO2 bottle, which is not easy in a destroyer. Furthermore, a NON-reloading torpedo system can use a shore-based air compressor instead of a CO2 system, which not only saves mass and space inside your tightly packed ship but also frees you from any sort of CO2 limitations whatsoever. If someone forgets to fill up the club tank before a battle, you'll still be able to fight. The fourth element is their small size, which not only helps their turning (in addition to the speed) but also makes it very difficult to hit them at 6' and nearly impossible to hit at 10'. This also means that they can't stand up to much punishment. If you want to get down and dirty and mix it up as hard as you can, expect to go swimming on occasion. Take it easy, and you may have battles where you don't need to patch. "By these elements combined, I am CAPTAIN TORPEDO CRUISER!"

Some of the elements I described apply to all light cruisers and destroyers. The speed and small size mean that you will have fun no matter what. However, I've never seen a bb gun boat sink another ship, while my brother's torpedo cruiser put 15 enemy ships on the bottom in a year and a half and earned him the Most Feared Captain twice in a row. Ok, I think that about wraps up my advertisement for torp cruisers. After this, no more campaigning my personal views, I'll try to help you do whatever you want to do (convert your Mogador to carry torpedoes, right? )

 

Yes, she has the extra 3/8.
I have never put her on a scale, so I have no idea of her weight.
I have been installing gear into her hull, then floating her in the bath tub so see how deep she settles.
I have been reducing the size of the battery to be able to add the armorment.

 

aaaa skip that im going with the prinz eugen

 

Never have a check valve on an accumulator only way to disarm is to fire.You need to be able to flick one toggle and vent all high pressure ,including accumulators,this was a standard saftey requirment in MBG

 

I think the reason your torpedoes were so deadly was the length of a rod as compared to the ball we used in MBG.My guess is the rods tear a much bigger hole than a ball and will travel farther underwater

 

The WWCC doesn't use rod for most torpedoes. Up until last year, we used two 1/4" balls per barrel for non-reloading torpedoes, and 1 ball per barrel for reloading torpedoes. Now we just changed the rules to use one ball per barrel because that may reduce the incidence of chunking, but I think chunking is also related to multiple barrels hitting right next to each other. We allow the use of short rods for submarines, but I was told by a submarine skipper that they often have an unfortunate tendency to plug up the hole they made. The Queens Own and Battlestations allow rod for torpedoes. Battlestations hasn't yet had a ship armed with them, and the QO limits them to PT boats and such. There is a photo on the old QO website that shows a destroyer that was hit by one of these torpedoes, which apparently tumbled and caved in a section.